Preparation, X-ray Structures, Spectroscopic, and Redox Properties of

Article pubs.acs.org/IC

Preparation, X‑ray Structures, Spectroscopic, and Redox Properties of Di- and Trinuclear Iron−Zirconium and Iron−Hafnium Porphyrinoclathrochelates Semyon V. Dudkin,†,‡,§ Nathan R. Erickson,§ Anna V. Vologzhanina,‡ Valentin V. Novikov,‡ Hannah M. Rhoda,§ Cole D. Holstrom,§ Yuriy V. Zatsikha,§,¶ Mekhman S. Yusubov,† Yan Z. Voloshin,*,‡ and Victor N. Nemykin*,§,¶ §

Department of Chemistry & Biochemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, United States Department of Technology of Organic Substances & Polymer Materials, Tomsk Polytechnic University, 634050 Tomsk, Russia ‡ Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russia ¶ Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada †

S Supporting Information *

ABSTRACT: The first hybrid di- and trinuclear iron(II)−zirconium(IV) and iron(II)−hafnium(IV) macrobicyclic complexes with one or two apical 5,10,15,20tetraphenylporphyrin fragments were obtained using transmetalation reaction between n-butylboron-triethylantimony-capped or bis(triethylantimony)-capped iron(II) clathrochelate precursors and dichlorozirconium(IV)- or dichlorohafnium(IV)-5,10,15,20-tetraphenylporphyrins under mild conditions. New di- and trinuclear porphyrinoclathrochelates of general formula FeNx3((Bn-Bu)(MTPP)) and FeNx3(MTPP)2 [M = Zr, Hf; TPP = 5,10,15,20tetraporphyrinato(2-); Nx = nioximo(2-)] were characterized by one-dimensional (1H and 13C{1H}) and two-dimensional (COSY and HSQC) NMR, highresolution electrospray ionization mass spectrometry, UV−visible, and magnetic circular dichroism spectra, single-crystal X-ray diffraction experiments, as well as elemental analyses. Redox properties of all complexes were probed using electrochemical and spectroelectrochemical approaches. Electrochemical and spectroelectrochemical data suggestive of a very weak, if any, long-range electronic coupling between two porphyrin π-systems in FeNx3(MTPP)2 complexes. Density functional theory and time-dependent density functional theory calculations were used to correlate spectroscopic signatures and redox properties of new compounds with their electronic structures.

■

catalysts for hydrogen evolution reaction.14 The studies of the tetrapyrrole macrocycles such as porphyrins and phthalocyanines and their metal complexes underwent tremendous growth in several recent decades15 because of their use in catalysis,16 photodynamic therapy of cancer,17 photodynamic inactivation of microbial pathogens,18 bioimaging,19 chemical sensors,20 semiconductors,21 functional polymers and liquid crystals,22 light-harvesting modules for dye-sensitized solar cells and organic photovoltaics,23,24 nanotechnology,25 and nonlinear optics.26 Because of these potential applications, optical, redox, and structural properties of several hybrid polytopic cage complexes such as zirconium-, hafnium(IV)-, and lutetium(III)-capped iron(II) phthalocyaninoclathrochelates (Chart 1) have been investigated by our group during the past decade.27 In all of these complexes, however, 1:1 ratio between clathrochelate and phthalocyanine ligands was always observed, while no 1:2

INTRODUCTION Inorganic and organometallic transition-metal arrays have been intensively studied during the past several decades because of their potential application as active components and suitable molecular scaffolds for molecular electronic devices,1 molecular logic systems,2 molecular machines,3 and supramolecular systems.4 A typical design of such nanoscale materials consists of several specifically tailored functional molecules interconnected by the axial or equatorial linking groups.5 In the majority of cases, such linking groups are chosen from a variety of simple organic redox-inert π-chromophores,6 although several systems with redox-active linking groups have also been reported.7 Macrobicyclic cage complexes with encapsulated metal ions (clathrochelates) are representatives of a class of coordination compounds with unusual chemical and spectroscopic properties.8 Their cage frameworks have been widely used as molecular scaffolds for the design and preparation of polyfunctional and polytopic molecular and supramolecular systems,9,10 single molecular magnets,11 topological drugs,12 electrochromic materials,13 and the precursors of clathrochelate-based electro© 2016 American Chemical Society

Received: August 10, 2016 Published: November 1, 2016 11867

DOI: 10.1021/acs.inorgchem.6b01936 Inorg. Chem. 2016, 55, 11867−11882

Article

Inorganic Chemistry Chart 1. Structures of the Previously Reported Hybrid Iron(II) Phthalocyaninoclathrochelates

Scheme 1. Preparation of the Hybrid Di- and Tritopic Iron(II) Porphyrinoclathrochelates

(clathrochelate/aromatic macrocycle) complexes were reported up to date. Such 1:2 assemblies represent a new class of macrocyclic arrays, in which aromatic porphyrinoid ligands might be electronically coupled to each other. Thus, herein, we report synthesis of the first diporphyrinoclathrochelates as well as their monoporphyrinclathrochelate analogues as a new type of hybrid polytopic multinuclear molecular systems (Scheme

1). All new complexes were characterized using variety of spectroscopic methods, X-ray crystallography, electrochemical, and spectroelectrochemical approaches, while their electronic structures and excited-state properties were probed by the density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. 11868


Article

Inorganic Chemistry

■

142.2, 148.0, 150.1. HR ESI MS: calcd for C106H80FeN14O6Zr2, 1882.3861; found, 1882.3831 [M]+. UV−vis (CH2Cl2): λ/nm (ε × 10−3, mol−1 L cm−1) 419 (723), 544 (44). Synthesis of FeNx3(HfTPP)2. This complex was obtained similar to FeNx3(HfTPP)2 compound, except that TPPHfCl2 precursor (0.100 g, 0.116 mmol) was used instead of TPPZrCl2. Yield 0.027 g (23%). Rf 0.52 (SiO2, CH2Cl2). Anal. Calcd for C106H80N14O6FeHf2: C, 61.81; H, 3.89; N, 9.52. Found: C, 61.99; H, 3.97; N, 9.43%. 1H NMR (C6D6) δ 1H NMR (CD2Cl2) δ 0.46 (br, 6H, α-CH2), 0.61 (br, 6H, α′-CH2), 0.60 (br, 6H, β −CH2), 1.01 (br, 6H, β′-CH2), 7.42 (t, 4H, m4-Ph, J = 8.4 Hz), 7.44 (t, 4H, p-Ph, J = 7.2 Hz), 7.50 (t, 4H, m2-Ph, J = 7.8 Hz), 7.86 (d, 4H, o5-Ph, J = 7.2), 8.37 (d, 4H, o1-Ph, J = 7.2 Hz), 9.06 (AB-system, 8H, β-pyr, J = 4.6 Hz). 13C NMR (CD2Cl2) δ 20.53 (s, α-CH2), 24.56 (s, β-CH2), 124.23 (s, C-meso), 126.57 (s, CH, m2Ph), 126.70 (s, CH, m4-Ph), 127.19 (s, CH, p-Ph), 131.50 (s, CH, βpyr), 134.67 (s, CH, o1-Ph), 134.98 (s, CH, o5-Ph), 142.94 (s, C, ipsoPh), 148.57 (s, C, -CN, Nx), 150.42 (s, C, α-pyr). HR ESI MS: calcd for C 106 H 80 FeN 14 O 6 Hf2 , 2057.4579; found, 2057.4535 [M]+.UV−vis (CH2Cl2): λ/nm (ε × 10−3, mol−1 L cm−1) 419 (712), 544 (38). Instrumentation. 1H and 13C NMR spectra were recorded in CD2Cl2 solutions using Bruker Avance 600 spectrometer. All UV−vis data were obtained on a JASCO-720 spectrophotometer at room temperature. Magnetic circular dichroism (MCD) data were recorded using OLIS DCM 17 CD spectropolarimeter using 1.4 T DeSa magnet at room temperature in parallel and antiparallel directions with respect to the magnetic field. Electrochemical measurements were conducted at room temperature using a CHI-620C electrochemical analyzer utilizing the three-electrode scheme. Platinum working and auxiliary electrodes along with the Ag/AgCl pseudoreference electrode were used in 0.05 M solution of TFAB in CH2Cl2 with redox potentials corrected using internal standard (decamethylferrocene). Estimated accuracy for measured potentials were ±5 mV in all cases. Spectroelectrochemical data were collected using a custom-made 1 mm cell equipped with a platinum mesh working electrode in 0.15 M solution of TFAB in CH2Cl2. HR ESI MS were recorded using a Bruker MicrOTOF-III system for freshly prepared samples dissolved in CH2Cl2 under an ambient atmosphere. Elemental analyses were obtained with a Carlo Erba model 1106 microanalyzer (INEOS RAS). Computational Details. All computations were performed using Gaussian 09 software running under Windows or UNIX OS.29 Molecular orbital contributions were compiled from single-point calculations using the QMForge program.30 Hybrid TPSSh31 exchange correlation functional was used in all calculations. Effective core potential LANL2DZ basis set for all atoms32 was employed to provide a reasonable computational cost for TDDFT calculations. Solvent effects were modeled using PCM approach and CH2Cl2 as a solvent.33 In TDDFT calculations, the lowest-energy 100 or 150 excited states were considered for FeNx3((Bn-C4H9)(MTPP)) and FeNx3(MTPP)2 complexes, respectively, to cover experimentally observed transitions in the UV−vis region. X-ray Crystallography. Single crystals of FeNx3((Bn-C4H9)(ZrTPP))·0.5C 6H 14, FeNx 3 (ZrTPP) 2 ·C 8 H18 ·0.25C 6 H5 CH3 , and FeNx3(HfTPP)2·0.33C8H18 were grown at room temperature from CH2Cl2−hexane or toluene-isooctane mixtures. The X-ray diffraction experiment for the FeNx3((Bn-C4H9) (ZrTPP))·0.5C6H14 was conducted using Rigaku RAPID-II diffractometer equipped with graphite monochromated and Mo−Kα radiation (λ = 0.710 73 Å). X-ray data for the FeNx 3 (ZrTPP) 2 ·C 8 H18 ·0.25C 6 H5 CH3 and FeNx3(HfTPP)2·0.33C8H18 were collected using Bruker Apex II CCD diffractometer equipped with multilayer optics and Cu−Kα radiation (λ = 1.541 78 Å). The structures were solved by the direct method and refined by full-matrix least-squares against F2. Nonhydrogen atoms were refined in anisotropic approximation except those for the disordered fragments. One cyclohexane ribbed fragment and two phenyl substituents in the FeNx 3 (ZrTPP) 2 ·C 8 H 18 · 0.25C6H5CH3 structure and the cyclohexane fragment in the FeNx3(HfTPP)2·0.33C8H18 structure are equally disordered over two sites, and carbon atoms of these fragments were refined isotropically. For the FeNx3(ZrTPP)2·C8H18·0.25C6H5CH3 and FeNx3(HfTPP)2·

EXPERIMENTAL SECTION

Materials. All commercial reagents were ACS grade and were used without further purification; silica gel (60 Å) for flash chromatography was purchased from Dynamic Adsorbents, Inc. All synthetic procedures were performed under dry argon with flame-dried glassware. Tetrabutylammonium tetrakis(pentafluorophenyl)borate (TFAB; (C4H9)4N[B(C6F5)4]),28a zirconium(IV) and hafnium(IV) 5,10,15,20-tetraphenylporphyrins (TPPZrCl2 and TPPHfCl2),28b mono- and bis(triethylantimony)capped clathrochelate precursors FeNx3((Sb(C2H5)3)(Bn-C4H9)) and FeNx3(Sb(C2H5)3)228c were prepared according to literature procedures. Synthetic Work. Synthesis of FeNx 3 ((Bn-C4 H 9 ) (ZrTPP)). TPPZrCl2 complex (0.090 g, 0.116 mmol) and a clathrochelate precursor FeNx3((Sb(C2H5)3)(Bn-C4H9)) (0.088g, 0.116 mmol) were dissolved in DCM (5 mL), and the reaction mixture was stirred for 8 h at room temperature and then was filtered off. The precipitate was washed with methanol and dried in air. Crude product was purified by flash chromatography on silica gel (50 mm layer; eluent: dichloromethane (DCM)). Yield 0.090 g (59%). Rf 0.56 (SiO2, CH2Cl2). Anal. Calcd for C66H61N10O6BFeZr (%): C, 63.51; H, 4.89; N, 11.22. Found (%): C, 63.39; H, 4.75; N, 11.04. 1H NMR (CD2Cl2) δ 0.06 (m, 2H, BCH2), 0.71 (t, 3H, CH3, J = 7.2 Hz), 1.00 (m, 2H, BCH2CH2(Bu)), 1.09 (m, 2H, CH3CH2(Bu)), 1.27 (t, 6H, α′-CH2, J = 6.2 Hz), 1.32 (m, 12H, β-CH2 + β′-CH2), 2.17 (t, 6H, α-CH2, J = 6.1 Hz), 7.76 (t, 4H, m4-Ph, J = 7.6 Hz), 7.84 (t, 4H, p-Ph, J = 7.6 Hz), 7.89 (t, 4H, m2Ph, J = 7.6 Hz), 7.99 (d, 4H, o5-Ph, J = 7.4), 8.55 (d, 4H, o1-Ph, J = 7.4 Hz), 9.03 (s, 8H, β-pyr). 13C NMR (CD2Cl2) δ 14.06 (s, CH3), 17.68 (br. s, BCH2), 21.12 (s, β-CH2 + β′-CH2), 25.01 (s, α-CH2), 25.12 (s, α′-CH2), 26.12 (s, CH3CH2), 26.41(s, BCH2CH2), 124.50 (s, Cmeso), 126.80 (s, CH, m2-Ph), 126.91 (s, CH, m4-Ph), 127.74 (s, CH, p-Ph), 131.77 (s, CH, β-pyr), 134.22 (s, CH, o1-Ph), 135.13 (s, CH, o5-Ph), 142.39 (s, C, ipso-Ph), 149.80 (s, C, α′-CN, Nx), 150.14 (s, C, α-pyr), 151.12(s, C, α-CN, Nx). High-resolution (HR) electrospray ionization (ESI) mass spectrometry (MS): calcd for C66H61BFeN10O6Zr, 1247.3353; found, 1247.3325 [M]+. UV−vis (CH2Cl2): λ/nm (ε × 10−3, mol−1 L cm−1) 421 (449), 547 (28). Synthesis of FeNx3((Bn-C4H9)(HfTPP)). This complex was obtained similar to FeNx3((Bn-C4H9) (ZrTPP)) compound except that TPPHfCl2 precursor (0.100 g, 0.116 mmol) was used instead of TPPZrCl2. Yield 0.093 g (61%). Rf 0.52 (SiO2, CH2Cl2). Anal. Calcd for C66H61N10O6BFeHf: C, 59.32; H, 4.56; N, 10.48. Found: C, 59.39; H, 4.65; N, 10.38%. 1H NMR (CD2Cl2) δ 0.05 (m, 2H, BCH2), 0.71 (t, 3H, CH3, J = 7.2 Hz), 0.99 (m, 2H, BCH2CH2(Bu)), 1.09 (m, 2H, CH3CH2(Bu)), 1.32 (m, 18H, α′-CH2 + β-CH2 + β′-CH2), 2.16 (t, 6H, α-CH2, J = 6.22 Hz), 7.76 (t, 4H, m4-Ph, J = 7.6 Hz), 7.84 (td, 4H, p-Ph, J = 7.6 Hz, 4J = 1.3 Hz), 7.89 (t, 4H, m2-Ph, J = 7.6 Hz), 7.98 (d, 4H, o5-Ph, J = 7.5), 8.56 (d, 4H, o1-Ph, J = 7.4 Hz), 9.06 (s, 8H, β-pyr). 13 C NMR (CD2Cl2) δ 14.06 (s, CH3), 17.68 (br. s, BCH2), 21.12 (s, β-CH2 + β′-CH2), 25.01 (s, α-CH2), 25.12 (s, α′-CH2), 26.12 (s, CH3CH2), 26.41(s, BCH2CH2), 124.50 (s, C-meso), 126.80 (s, CH, m2-Ph), 126.91 (s, CH, m4-Ph), 127.74 (s, CH, p-Ph), 131.77 (s, CH, β-pyr), 134.22 (s, CH, o1-Ph), 135.13 (s, CH, o5-Ph), 142.39 (s, C, ipso-Ph), 149.80 (s, C, α′-CN, Nx), 150.14 (s, C, α-pyr), 151.12(s, C, α-CN, Nx). HR ESI MS: calcd for C66H61BFeN10O6Hf, 1336.3697; found, 1336.3756 [M]+. UV−vis (CH2Cl2): λ/nm (ε × 10−3, mol−1 L cm−1) 422 (469), 544 (31). Synthesis of FeNx3(ZrTPP)2. TPPZrCl2 complex (0.090 g, 0.116 mmol) and a FeNx3(Sb(C2H5)3)2 clathrochelate precursor (0.052g, 0.058 mmol) were dissolved in DCM (5 mL), and the reaction mixture was stirred for 8 h at room temperature and then was filtered off. The precipitate was washed with methanol and dried in air. Crude product was further purified using flash chromatography on silica gel (50 mm layer; eluent: DCM). Yield 0.032 g (27%). Rf 0.52 (SiO2, CH2Cl2). Anal. Calcd for C106H80N14O6FeZr2: C, 67.57; H, 4.25; N, 10.41. Found: C, 67.39; H, 4.35; N, 10.28%. 1H NMR (CDCl3) δ 0.21 (br.s, 6H, α-CH2), 0.71 (br.s, 6H, β-CH2), 0.85 (br.s, 6H, β′-CH2), 0.91 (br.s, 6H, α′-CH2),7.50−7.75 (m, 32H, m4-Ph, p-Ph, m2-Ph, o5Ph), 8.20 (br.d, 8H, o1-Ph), 9.03 (AB-system, 16H, β-pyr). 13C NMR (CDCl3) δ 24.1, 29.5, 123.9, 126.1, 126.3, 126.9, 131.8, 134.0, 134.9, 11869


Article

Inorganic Chemistry 0.33C8H18 structures, the DFIX instruction was applied to fix the C−C distances in their solvates molecule at idealized values; positions of hydrogen atoms were calculated. The unit cells of FeNx3((ZrTPP)2) and FeNx3((HfTPP)2) contain highly disordered solvent molecules, which have been treated as a diffuse contribution to the overal scattering without specific atom positions by SQUEEZE/PLATON.34a The H(C) atoms were included in the refinement by the riding model with Uiso(H) = nUeq(C), where n = 1.5 for methyl groups and 1.2 for the other atoms. All calculations were made using the SHELXTL34b and OLEX234c program packages. Complete crystallographic information is provided in the Supporting Information.

under mild reaction conditions (Scheme 1). In addition, the first heterotrinuclear FeNx3(ZrTPP)2 and FeNx3(HfTPP)2 complexes with two apical porphyrin fragments were prepared under mild conditions using the same synthetic approach by transmetalation reaction between the bis-triethylantimonycapped tris-nioximate iron(II) FeNx3(Sb(C2H5)3)2 clathrochelate as a macrobicyclic precursor with two reactive apical groups (Scheme 1). The formation of di- and tritopic clathrochelate complexes were confirmed by elemental analysis, one-dimensional (1H and 13 C{1H}) and two-dimensional (COSY and HSQC) NMR spectra (Supporting Information Figures S1−S9), HR ESI MS (Supporting Information Figures S10−S13), UV−vis and MCD spectra, as well as the single-crystal X-ray diffraction experiments. HR ESI MS of all hybrid di- and tritopic porphyrinoclathrochelate complexes confirm their elemental compositions. (Supporting Information Figures S10−S13). Indepth analysis of the isotope distribution at the molecular ion mass region for the ditopic FeNx3((Bn-C4H9)(MTPP)) and tritopic FeNx3(ZrTPP)2 complexes is indicative of the presence of both [M]+ and [M+1]+ ions, which was observed earlier for similar systems.35 NMR spectra of new hybrid porphyrinclathrochelates are significantly different from NMR spectra of the corresponding clathrochelate and porphyrin precursors. For instance, the 1H NMR signals associated with the nioxime protons27a are considerably shifted upfield by well-known porphyrin ring current effect36 with the largest shielding (Δδ = −1.5 ppm) observed for the α′-methylene group that is the closest to porphyrin macrocycle. Because of the bulky clathrochelate ligand located above the porphyrin plane, the protons of the phenyl substituents in TPP ligand are diastereotopic (Supporting Information Figures S7 and S8),37 and similar behavior was observed in the case of the other Zr(IV) and Hf(IV) porphyrins with bulky axial substituents.38 The effect of slow rotational dynamics is also observed for the ribbed nioximate protons of the tritopic FeNx3(ZrTPP)2 and FeNx3(HfTPP)2 complexes. Indeed, at room temperature, the protons of both the α- and βCH2 groups are nonequivalent (Supporting Information Figures S7 and S9). The UV−vis and MCD spectra of the iron(II) porphyrinoclathrochelates and their precursors are shown in Figure 1 and Supporting Information Figures S14 and S15. The UV−vis and MCD spectra of all iron(II) porphyrinoclathrochelates are a superposition of the absorption spectra of respective pophyrin and clathrochelate chromophores. Indeed, UV−vis spectra of all compounds are dominated by the very intense Soret band observed between 412 and 422 nm, which is assigned to the porphyrin-centered π−π* transitions and associated with a very strong MCD Faraday A-term. The presence of such Faraday Aterm is indicative of the effective degeneracy of the excited states associated with the Soret band, and a similar situation was observed for discussed earlier hybrid phthalocyaninoclathrochelate complexes.27a Position of the Soret band is not very sensitive to nature of the central metal located in the porphyrin cavity and type of the axial ligand, which is not surprising, as it is expected that the axial clathrochelate ligand would have only minor influence on the orthogonal porphyrin π-system. The low-energy part of the UV−vis and MCD spectra of new porphyrinoclathrochelates is more difficult to interpret. The UV−vis spectra of the starting TPPMCl2 in Q-band region are dominated by a single band ∼540 nm with a low-intensity shoulders at ∼500 and 570 nm and very similar spectra were

■

RESULTS AND DISCUSSION Synthesis, Spectroscopy, and X-ray Crystallography. We used a method reported earlier for preparation of the

Figure 1. UV−vis (top) and MCD (bottom) spectra of TPPZrCl2 (a), FeNx3((Bn-C4H9)(ZrTPP)) (b), and FeNx3(ZrTPP)2 (c) in DCM.

ditopic tris-nioximate phthalocyaninoclathrochelate systems (Chart 1)27c for synthesis of di- and triheterometallic porphypinoclathrochelates. In particular, ditopic monoporphyrinoclathrochelates FeNx 3 ((Bn-C 4 H 9 )(ZrTPP)) and FeNx3((Bn-C4H9)(HfTPP)) were prepared in moderate yields using transmetalation reaction between the boron−antimonycapped tris-nioximate iron(II) FeNx3((Sb(C2H5)3)(Bn-C4H9)) clathrochelate as a macrobicyclic precursor and zirconium(IV) or hafnium(IV) 5,10,15,20-tetraphenylporphyrins as Lewis acid 11870


Article

Inorganic Chemistry

Figure 2. Side (a) and top (b) views of the FeNx3((Bn-C4H9)(ZrTPP)) complex; truncated trigonal pyramidal FeN6-coordination polyhedron of an encapsulated iron(II) ion is also shown (c). All hydrogen atoms are omitted for clarity.

Figure 3. Side (a) and top (b) views of the FeNx3(ZrTPP)2 complex; truncated trigonal pyramidal FeN6-coordination polyhedron of an encapsulated iron(II) ion is also shown (c). All hydrogen atoms are omitted for clarity.

Figure 4. Side (a) and top (b) views of the FeNx3(HfTPP)2 complex. All hydrogen atoms are omitted for clarity.

hybrids (Figure 1b,c and S14b,c). The most intense porphyrincentered Q-band at ∼540 nm in UV−vis spectra of all complexes is associated with a strong Faraday MCD A-term,

reported for TPPMX2 (M = Zr or Hf) and TPPScX complexes.38,39 Low-energy shoulder at ∼570−580 nm can also be clearly seen in the case of all porphyrin−clathrochelate 11871


Article

Inorganic Chemistry

Figure 5. Formation of the dimeric structure in the FeNx3((Bn-C4H9)(ZrTPP))·0.5C6H14 crystal (a); the intermolecular pseudocolumnar stacking and C−H···N interactions in the FeNx3(ZrTPP)2·C8H18·0.25C7H8 crystal (b). Hydrogen atoms, which do not form the C−H···N interactions, are omitted for clarity.

Table 1. Selected Geometric Parameters of the Iron(II) Porphyrinoclathrochelates and their Analogues parameter

FeNx3(Bn-C4H9)242

capping atom(s) Fe−N(1,3,5) (Å) Fe−N(2,4,6) (Å) M−O(1,3,5) (Å) M−O(2,4,6) (Å) M−N (Å) B−O (Å) N−O (Å) CN (Å) C−C (Å) average N···N (1,3,5) (Å) average N···N (2,4,6) (Å) average O···O (1,3,5) (Å) average O···O (2,4,6) (Å) φ (deg) α (deg) h (Å)

FeNx3((BnC4H9)(ZrTPP))

FeNx3((Bn-C4H9) (ZrPc))27a

FeNx3((Bn-C4H9) (HfPc))27c

FeNx3(ZrTPP)2

FeNx3(HfTPP)2

B

B, Zr

B, Zr

B, Hf

Zr

Hf

1.895(3)−1.915(3) 1.898(4)−1.917(3)

1.897(3)−1.906(4) 1.909(4)−1.922(5)

1.896(3)−1.905(3) 1.913(3)−1.927(3)

1.894(2)−1.907(2) 1.914(2)−1.926(2)

2.092(3)−2.115(3) 2.257(4)−2.266(4) 1.507(5)−1.513(5) 1.347(4)−1.390(4) 1.294(5)−1.306(5) 1.439(6)−1.441(6) 2.597

2.077(2)−2.106(2) 2.237(2)−2.246(2) 1.501(4)−1.512(4) 1.351(3)−1.376(3) 1.298(3)−1.307(3) 1.440(3)−1.447(3) 2.593

1.897(9)−1.904(9) 1.902(6)−1.937(7) 2.092(7)−2.115(5) 2.089(7)−2.121(7) 2.262(6)−2.290(5)

1.486(3)−1.532(4) 1.365(3)−1.392(4) 1.296(4)−1.325(4) 1.429(4)−1.445(3) 2.610

2.106(3)−2.130(6) 2.273(3)−2.296(4) 1.498(7)−1.510(7) 1.354(4)−1.388(4) 1.299(6)−1.317(6) 1.430(7)−1.436(6) 2.596

1.904(4)−1.920(5) 1.898(5)−1.923(4) 2.104(5)−2.132(4) 2.102(4)−2.132(4) 2.286(5)−2.305(4) 1.356(8)−1.375(8) 1.298(6)−1.311(9) 1.428(9)−1.451(9) 2.654

1.358(6)−1.373(7) 1.29(1)−1.33(2) 1.42(1)−1.43(1) 2.653

2.609

2.678

2.693

2.685

2.659

2.644

2.455

2.464

2.468

2.459

2.782

2.770

2.460

2.778

2.801

2.790

2.784

2.775

21.2 39.3 2.36

29.4 39.5 2.30

30.2 39.5 2.30

30.0 39.5 2.30

34.0 39.9 2.28

32.6 39.7 2.28

which can be clearly indentified around 540−550 nm. This Aterm is also has expected for tetraarylporphyrins with an effective fourfold symmetry negative-to-positive amplitude in ascending energy. MCD spectra of all porphyrin compounds studied in this paper reveal an additional derivative-shaped MCD A-term centered at ∼580 nm. This A-term has reverse sign sequence (i.e., positive to negative in ascending energy)

and is associated with the low-energy shoulder observed in corresponding UV−vis spectra. Since intensity of this A-term is easily detectable in MCD spectra of all complexes discussed in this paper including precursor porphyrins, and since its position is almost independent from the axial ligand, this signal cannot be associated with any charge-transfer transitions involving axial fragments. Next, taking into consideration d0 nature of the 11872


Article

Inorganic Chemistry

Figure 6. CVs (blue) and DPVs (red) of the FeNx3((Bn-C4H9)(ZrTPP)) (a) and FeNx3(ZrTPP)2 (b) complexes in DCM/0.05 M TFAB system.

unoccupied porphyrin-centered orbitals with ML ± 5), which is not achievable in the “standard” metal tetraphenylporphyrins with fourfold effective symmetry. Such relationship, however, is very characteristic for chlorins (i.e., reduced porphyrins), which usually have a Soret band observed at the normal for porphyrins region and Q-band of slightly lower energy compared to the corresponding parent porphyrins.41 Thus, we might speculate that the reversed low-energy MCD Faraday A-term is associated with a minor chlorin impurity, which is typical for commercially available metal-free porphyrins. Taking into consideration small amount of such an impurity, it will be difficult to detect it both in NMR and mass spectra (both zirconium and hafnium have a rich isotope pattern). Alternatively, the reverse-sign MCD A-term can be seen as a sum of several overlapping regular-sign MCD signals. For instance, negative and positive signals at 573 and 563 nm, respectively, in TPPZrCl2 complex (Figure 1a) can form MCD A-term centered at 567 nm, while very weak negative signal at ∼600 nm and positive signal at 582 nm can form MCD A-term centered at 590 nm. In this case, the Q-band region might be described in terms of three overlapping regular-sign MCD Aterms, which does not contradict symmetry considerations and DFT calculations presented below. Moreover, a very similar low-intensity low-energy band in TPPScCl was assigned as a Q0−0 band by Gouterman and co-workers.39a Our spectroelec-

Table 2. Redox Properties (V) of the Hybrid Porphyrinoclathrochelatesa complex FeNx3((Bn-C4H9) (ZrTPP)) FeNx3((Bn-C4H9) (HfTPP)) FeNx3(ZrTPP)2 FeNx3(HfTPP)2 a

Ox3

Ox2

Ox1

R1

R2

0.84 0.81

0.86 0.81 0.73 0.72

0.18 0.18 −0.18 −0.18

−1.96 −1.79 −1.96 −1.84

−2.02 −1.89

All potentials (±5 mV) are referenced to the FcH/FcH+ couple.

Zr(IV) and Hf(IV) ions, any low-energy metal-to-ligand charge-transfer (MLCT) transitions can also be excluded. Similarly, on the basis of the electrochemical, UV−vis, and MCD data, lowest unoccupied molecular orbital (LUMO) and LUMO+1 in all precursor porphyrins and hybrid systems discussed in this paper are porphyrin-centered, which excludes any possibility of the low-energy ligand-to-metal charge-transfer (LMCT) transitions. One of the possible explanations for the low-energy reverse-sign MCD Faraday A-term is the macrocycle-centered π−π* transition. According to perimeter model applied to porphyrins and their analogues,40 the reverse sign sequence would require ΔHOMO < ΔLUMO relationship (ΔHOMO is the energy difference between two highest-energy occupied porphyrin-centered orbitals with ML ± 4, and ΔLUMO is the energy difference between two lowest-energy 11873


Article

Inorganic Chemistry

Figure 9. DFT-predicted MO energy diagram for FeNx3((BnC4H9)(ZrTPP)) (1), FeNx3(ZrTPP)2 (2), FeNx3(HfTPP)2 (3), and FeNx3((Bn-C4H9) (HfTPP)) (4).

suggest against the presence of chlorin impurity in solution. To resolve this ambiguity, we are planning to investigate a number of Zr(IV) and Sc(III) porphyrin complexes with different axial ligands in the future. The spectra of FeNx3(MTPP)2 complexes with equivalent cross-linking groups (so their molecules contain a symmetry plane passing through the centers of chelate α-dioximate C−C bonds and an encapsulated iron(II) ion) in the visible region also contain two less intensive bands with λmax at ∼510 and 600 nm (ε ≈ 1 × 104 mol−1·L·cm−1) assigned to chlathrochelatecentered MLCT Fe(d)→L(π*) transitions.27 Such assignment is further supported by the low-intensity MCD signals associated with these bands, and a similar behavior was observed in reported earlier phthalocyaninoclathrochelate systems.27a The FeNx3((Bn-C4H9)(MTPP)) complexes do not have the aforementioned symmetry plane. As a result, their UV−vis spectra (Figure 1b and Supporting Information Figure S14b) are more complicated and contain several overlapping bands in the visible region. Two of them with λmax approximately at 500 and 600 nm were tentatively assigned to the MTPP(π)→L(π*) transitions. In addition, two bands observed at 450 and 470 nm in FeNx3((Bn-C4H9)(MTPP)) complexes were tentatively assigned to chlathrochelatecentered MLCT Fe(d)→L(π*) transitions bands, as their energies are close to MLCT transitions at 440 and 460 nm in FeNx3(Bn-C4H9)2 complex (Figure S15). Finally, the UV−vis spectra of all hybrid porphyrinclathrochelate complexes in the UV region contain superimposed bands of π−π* transitions associated with clathrochelate and porphyrin fragments. The single-crystal X-ray structures of hybrid porphyrinoclathrochelates FeNx3((Bn-C4H9)(ZrTPP)), FeNx3(ZrTPP)2, and FeNx3(HfTPP)2 are shown in Figures 2−5, while their main geometrical parameters as well as those for the boron-capped and phthalocyaninoclathrochelate analogues are listed in Table 1 and Supporting Information Table S1. The FeN6 polyhedra of these macrobicyclic complexes with equivalent capping groups possess a geometry intermediate between a trigonal prism (TP; the distortion angle φ = 0°) and a trigonal antiprism (TAP; φ = 60°). The φ values for the complexes of interest increase from the n-butylboron-capped clathrochelate FeNx3(Bn-C4H9)2 (φ = 21.2°) to its diporphyrinoclathrochelate analogues FeNx3(MTPP)2 (φ = 33−34°). Such TP distortion of the rigid diboron-capped polyazomethine cage framework can be explained by the steric restrictions due to smaller physical ionic (Shannon) radius of its capping tetrahedral boron atom (ri = 0.25 Å) as compared with those for heptacoordinate zirconium and hafnium ions (ri = 0.92 and 0.90 Å, respectively) with simultaneous increase in the height h

Figure 7. Transformation of the UV−vis−NIR spectra of FeNx3((BnC4H9)(HfTPP)) complex during first (top) and second (bottom) oxidations under spectroelectrochemical conditions in DCM/0.15 M TFAB system.

Figure 8. Transformation of the UV−vis−NIR spectra of FeNx3(ZrTPP)2 complex during first (top) and second/third (bottom) oxidations under spectroelectrochemical conditions in DCM/0.15 M TFAB system.

trochemical data presented below indicate that the lowintensity low-energy shoulder in the Q-band region remains intact during oxidation of the axial clathrochelate ligand. Moreover, chemical treatment of the starting TPPMCl2 complexes with DDQ (Supporting Information Figure S17) also does not affect the shape of Q-band region, which might 11874


Article

Inorganic Chemistry

Figure 10. DFT-predicted compositions for the frontier orbitals. Color coding: light blue−BMe fragment; orange−iron ion; blue−clathrochelate ligand; red−capping metal ion; green−porphyrin fragment.

dioximate fragments and four nitrogen atoms of the corresponding porphyrin macrocycle. The observed M−N and M−O bond lengths in the molecules of these zirconiumand hafnium-capped iron(II) porphyrinoclathrochelates are very close to each other and to those for their phthalocyaninoclathrochelate analogues.27 Four nitrogen atoms in the porphyrin macrocycles are almost coplanar, whereas the central metal ions are located ∼1.1 Å above this plane. In all cases, the TPP ligands adapt slightly domed conformation to reduce steric interactions between the clathrochelate and porphyrin fragments. Despite such nonplanarity and the presence of four bulky phenyl substituents in each porphyrin ligand, the FeNx3((Bn-C4H9)(ZrTPP))·0.5C6H14 structure consists of individual porphyrinoclathrochelate dimers formed by the C− H···N and π−π interactions (Figure 5a). The infinite pseudocolumnar arrangements are also observed in the crystal structures of FeNx 3 (ZrTPP) 2 ·C 8 H 18 ·0.25C 6 H 5 CH 3 and FeNx3(HfTPP)2·0.33C8H18 (Figure 5b). Such intermolecular interactions create voids accessible for the solvent molecules. Redox Properties. The redox properties of the iron(II) porphyrinoclathrochelates were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) approaches in the DCM/TFAB system (Figure 6, Table 2, and Supporting Information Figure S9). In the case of 1:1 clathrochelate-to-porphyrin hybrids, three redox processes were clearly identified in electrochemical experiments. The two reversible oxidation waves were attributed to Fe2+/Fe3+ (Ox1) and TPP2−/TPP1− (Ox2) processes localized at the clathrochelate and porphyrin fragments, respectively, while the reduction wave (R1) was assigned to the TPP2−/TPP3− process. In the case of the FeNx3(MTPP)2 hybrids, the clathrochelate-centered

of its TP−TAP FeN6 polyhedron from 2.28 to 2.36 Å. The Fe− N distances for their zirconium- and hafnium-capped tripodal ligand’s fragments are greater than those for the boron-crosslinked groups (the average values are 1.92 and 1.90 Å, respectively). So, the encapsulated iron(II) ion in the boron− zirconium-capped macrobicyclic molecule FeNx3(Bn-C4H9)(ZrTPP) as well as that in its phthalocyaninoclathrochelate analogues27a,c is slightly shifted from the center of FeN6polyhedron in the direction of apical boron atom along the corresponding molecular M···Fe···B axis. In general, the coordination polyhedra of the boron−zirconium(hafnium)capped hybrid FeNx3((Bn-C4H9)(ZrTPP)), FeNx3((Bn-C4H9)(HfPc)), and FeNx3((Bn-C4H9)(ZrPc)) complexes possess a geometry intermediate between a TP and a TAP with the distortion angles φ of ∼30° and the h values of ∼2.30 Å; these values are intermediate between those for their TP−TAP diboron- and dizirconium(dihafnium)-capped analogues vide supra. The average bite chelate angles α (half of the N−Fe−N angle) and the C = N, O−N, and C−C bond lengths in their clathrochelate frameworks are similar for all the listed in Table 1 cage compounds, whereas the N···N and O···O distances in their bases strongly depend on the nature of cross-linking capping atoms: for boron-capped tripodal groups, the average N···N and O···O distances are equal to ∼2.60 and ∼2.45 Å, respectively, while those for the zirconium(hafnium)-capped fragments vary from ∼2.65 to ∼2.69 Å and from ∼2.77 to ∼2.80 Å, respectively. The heptacoordinate cross-linking zirconium and hafnium(IV) ions in the FeNx3((Bn-C4H9)(ZrTPP)), FeNx3(ZrTPP)2, and FeNx3(HfTPP)2 complexes bind oxygen atoms of three donor oxime fragments of their three ribbed chelate α11875


Article

Inorganic Chemistry

with the clathrochelate fragment, reduced in intensity (Figure 7a). The most intense Soret band at ∼420 nm reduces in intensity and undergoes a small high-energy shift. Significant reduction of the clathrochelate-associated charge-transfer bands with minimal changes of the porphyrin-centered π−π* transitions is indicative of oxidation of an encapsulated iron(II) ion to iron(III) state. This assignment also correlates well with electrochemical results, which indicate that the first oxidation process in FeNx3((Bn-C4H9)(MTPP)) complexes is clathrochelate-centered. During the second oxidation process, Soret band reduces in intensity, and several prominent bands between 450 and 800 nm appear in the UV−vis spectra of the [FeNx3(Bn-C4H9)(MTPP)]2+ complexes (Figure 7b). In addition, formation of a very characteristic, low-intensity band at ∼1000 nm was observed in the NIR region. These changes are very characteristic and indicative of a formation of porphyrin-centered cation radical.44 Thus, the second reversible oxidation process in FeNx3((Bn-C4H9)(MTPP)) complexes can be comfortably assigned to the oxidation of the porphyrin macrocycle. In the case of FeNx3(MTPP)2 complexes, during the first oxidation, porpyrin Q- and Soret bands undergo only minor energy and intensity shifts, while charge-transfer transitions between 450 and 520 nm associated with the clathrochelate fragment disappear (Figure 8a). Again, these spectroscopic changes are indicative of the iron(II) to iron(III) oxidation and associated with the clathrochelate fragment. Interestingly, during further electrolysis, only one spectroscopic change in the UV−vis−NIR spectra of FeNx3(ZrTPP)2 complexes was observed (Figure 8b). During this transformation, intensities of both Q- and Soret bands diminished, while a set of new bands between 450 and 800 nm as well as low-intensity band at ∼1000 nm appear in the spectra. During repetitive spectroelectrochemical experiments, on FeNx3(MTPP)2 complexes we were not be able to detect any intense intervalence charge transfer band formation in the NIR region, which can be viewed as the lack of electronic communication between two porphyrin ligands. Thus, spectroelectrochemical data on the FeNx3(MTPP)2 complexes are rather suggestive that the observed in electrochemical experiments small splitting between the porphyrin-centered second and third oxidation waves could be attributed to the electrostatic effects. DFT and TDDFT Calculations. The electronic structure and nature of the excited states in FeNx3((Bn-C4H9)(MTPP)) and FeNx3(MTPP)2 complexes were studied by DFT and TDDFT approaches. DFT-predicted molecular energy diagram, molecular orbital compositions, and representative images of frontier orbitals are shown in Figures 9−11. When compared in pairs (FeNx3((Bn-C4H9)(HfTPP)) vs FeNx3((Bn-C4H9)(ZrTPP)) and FeNx3(HfTPP)2 vs FeNx3(ZrTPP)2), an influence of the capping zirconium and hafnium centers on the orbital energies and compositions is negligibly small. In all cases studied, the HOMO is dominated by the contribution from the clathrochelate fragment, which agrees well with the experimental electrochemical data indicative of oxidation of the clathrochelate unit. The HOMO in FeNx3(MTPP)2 complexes is almost pure chlathrochelate-centered, while the HOMO in FeNx3((Bn-C4H9)(MTPP)) complexes has a substantial (>40%) contribution from the porphyrin ligand and thus has highly delocalized nature. DFT-predicted energy of the HOMO in FeNx3(MTPP)2 complexes is higher compared to the FeNx3((Bn-C4H9)(MTPP)) compounds, which also correlate well with the 360 mV lower first oxidation potential in

Figure 11. Representative examples of the DFT-predicted frontier orbitals of FeNx3((Bn-C4H9)(MTPP)) and FeNx3(MTPP)2 complexes. Only zirconium-capped hybrids are shown for a sake of simplicity.

Fe2+/Fe3+ (Ox1) couple is shifted by 360 mV to lower potential reflecting more electron-donating properties of porphyrin ligand compared to the capping boron atom. In addition, porphyrin-centered oxidation was observed in a form of two closely spaced (90−110 mV) but clearly recognized waves (Ox2 and Ox3). Similarly, porphyrin-centered reduction was detected in a form of two closely spaced (50−60 mV) electrochemical processes (R1 and R2). Although separation between the porphyrin-centered oxidation and reduction waves can be clearly detected in electrochemical experiments, one must be careful about degree of electronic coupling between the porphyrin chromophores in the FeNx3(MTPP)2 systems, as a separation between electrochemical events can be affected by the variety of factors including polarity of the solvent and ionpairing ability of electrolyte.43 To evaluate a possible electronic coupling between two porphyrin fragments in FeNx 3(MTPP)2 complexes, we investigated UV−vis−NIR spectra of the redox-active species in mono- and bisporphyrin-containing systems under spectroelectrochemical oxidation conditions (Figures 7 and 8). For all four compounds studied, spectroelectrochemical data revealed a very similar trend. Indeed, during the first oxidation of the 1:1 clathrochelate-to-porphyrin hybrids, the most prominent band in Q-band region undergoes a small highenergy shift with slight increase in intensity, while chargetransfer bands between 450 and 520 nm, which are associated 11876


Article

Inorganic Chemistry

Figure 12. Experimental and TDDFT-predicted UV−vis spectra of the FeNx3((Bn-C4H9)(MTPP)) and FeNx3(MTPP)2 complexes.

diporphyrin systems. The porphyin-centered π-orbitals were predicted to have slightly lower energies than predominantly clathrochelate-centered orbitals (Figure 9). Thus, in the case of FeNx3(MTPP)2 complexes, HOMO−4 to HOMO−6 molecular orbitals (MOs) are predominantly centered at the porphyrin ligand, while in the case of FeNx3((Bn-C4H9)(MTPP)) compounds HOMO−5 and HOMO−9 are the highenergy porphypin-centered occupied orbitals. The nearly degenerate LUMO and LUMO+1 in all cases were predicted to be porphyrin-centered, which again correlate well with electrochemical results. The presence of two porphyrin ligands in FeNx3(MTPP)2 complexes results in the presence of additional porphyrin-centered LUMO to LUMO+3 MOs. The highly delocalized nature of the HOMO in the FeNx3((Bn-C4H9)(MTPP)) complexes makes it quite challenging to assign TDDFT-predicted single-electron excitation contributions with the experimentally observed transitions in the UV−vis region. Indeed, TDDFT predicts that the most intense bands in Q-band region of the FeNx3((Bn-C4H9)(MTPP)) systems should be associated with the excited states 7 and 8, which have large contributions from the porphyrincentered HOMO−4→LUMO, LUMO+1 single-electron π−π* transitions (Figure 12). In addition, relatively intense excited states 1 and 2, which were predicted at ∼580 nm, are dominated by the HOMO→LUMO, LUMO+1 single-electron transitions, which have substantial π−π* character. TDDFT predicts that the Soret band region of the FeNx3((Bn-

C4H9)(MTPP)) complexes should be dominated by the excites states 19 and 21, which have the largest contribution from the porphyrin-centered HOMO−4→LUMO, LUMO+1 singleelectron π−π* transitions. In the case of FeNx3(MTPP)2 complexes, DFT predicts that the HOMO to HOMO−2 are almost pure clathrochelatecentered MOs with only small contribution from the porphyrin ligand. Not surprisingly, TDDFT predicts that the first 12 excited states will be dominated by the low-intensity chlathrochelate-to-porphyrin charge-transfer transitions. TDDFT also predicts that the most intense transitions in the Q-band region of the FeNx3(MTPP)2 complexes (excited states 13, 15, and 16) should have porphyrin-centered π−π* character and be dominated by HOMO−3−HOMO−6→LUMO− LUMO+3 single-electron excitations. The same single-electron excitations provide the major contribution into extremely intense Soret-type transitions (excited states 47 and 48) of the FeNx3(MTPP)2 complexes. Overall, DFT and TDDFT calculations support complex electronic structure of the clathrochelate−porphyrin hybrids and predict a presence of the large number of porphyrincentered π−π*, intramolecular chlathrochelate-centered, and chlathrochelate-to-porphyrin centered transitions. As expected, porphyrin-centered π−π* transitions give the most intense excited states, while intensities of the intramolecular clathrochelate-centered and chlathrochelate-to-porphyrin centered transitions are significantly smaller. 11877


Inorganic Chemistry

■

■

CONCLUSIONS In this work, we developed a synthetic procedure for preparation of the first hybrid di- and trinuclear iron(II)− zirconium(IV) and iron(II)−hafnium(IV) macrobicyclic complexes with one or two apical 5,10,15,20-tetraphenylporphyrin fragments, which utilizes a transmetalation reaction between nbutylboron−triethylantimony-capped or bis(triethylantimony)capped iron(II) clathrochelate precursors and dichlorozirconium(IV)- or dichlorohafnium(IV)-5,10,15,20-tetraphenylporphyrins. New di- and trinuclear porphyrinoclathrochelates of general formula FeNx3((Bn-C4H9)(MTPP)) and FeNx3(MTPP)2 [M = Zr, Hf] were characterized by onedimensional (1H and 13C{1H}) and two-dimensional (COSY and HSQC) NMR, high-resolution ESI MS, UV−vis, and MCD spectra, and single-crystal X-ray diffraction experiments as well as elemental analyses. UV−vis and MCD spectra of the new hybrids are indicative of the lack of electronic communication between clathrochelate and porphyrin fragments. Redox properties of all complexes were probed using electrochemical and spectroelectrochemical experiments. Electrochemical data confirm a very weak, if any, long-range electronic coupling between two porphyrin π-systems in FeNx3(MTPP)2 complexes. DFT and TDDFT calculations were used to correlate spectroscopic signatures and redox properties of new compounds with their electronic structures.

■

REFERENCES

(1) (a) Zhang, H.; Zou, R.; Zhao, Y. Macrocycle-Based MetalOrganic Frameworks. Coord. Chem. Rev. 2015, 292, 74−90. (b) Jurow, M.; Schuckman, A. E.; Batteas, J. D.; Drain, C. M. Porphyrins as Molecular Electronic Components of Functional Devices. Coord. Chem. Rev. 2010, 254, 2297−2310. (2) (a) Bill, N. L.; Trukhina, O.; Sessler, J. L.; Torres, T. Supramolecular Electron Transfer-Based Switching Involving Pyrrolic Macrocycles. A New Approach to Sensor Development? Chem. Commun. 2015, 51, 7781−7794. (b) Andreasson, J.; Pischel, U. Molecules with a Sence of Logic: a Progress Report. Chem. Soc. Rev. 2015, 44, 1053−1069. (c) Wilson, A.; Gasparini, G.; Matile, S. Functional Systems with Orthogonal Dynamic Covalent Bonds. Chem. Soc. Rev. 2014, 43, 1948−1962. (3) (a) Liljeroth, P. Molecular Electronics: Flipping a Single Proton Switch. Nat. Nanotechnol. 2011, 7, 5−6. (b) Kinbara, K.; Muraoka, T.; Aida, T. Chiral Ferrocenes as Novel Rotary Modules for Molecular Machines. Org. Biomol. Chem. 2008, 6, 1871−1876. (c) Muraoka, T.; Kinbara, K.; Aida, T. Mechanical Twisting of a Guest by a Photoresponsive Host. Nature 2006, 440, 512−515. (4) Zhang, L.; Lin, Y.-J.; Li, Z.-H.; Jin, G.-X. Rational Design of Polynuclear Organometallic Assemblies from a Simple Heteromultifunctional Ligand. J. Am. Chem. Soc. 2015, 137, 13670−13678. (5) (a) KC, C. B.; D’Souza, F. Design and Photochemical Study of Supramolecular Donor-Acceptor Systems Assembled via Metal-Ligand Axial Coordination. Coord. Chem. Rev. 2016, 322, 104−141. (b) Yoon, Z. S.; Yang, J.; Yoo, H.; Cho, S.; Kim, D. Photophysical Properties of Various Directly Linked Porphyrin Arrays. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd.: Singapore, 2010; Vol. 1, pp 439−505. (c) Vecchi, A.; Galloni, P.; Floris, B.; Dudkin, S. V.; Nemykin, V. N. Metallocenes Meet Porphyrinoids: Consequence of a “Fusion. Coord. Chem. Rev. 2015, 291, 95−171. (d) Vecchi, A.; Galloni, P.; Floris, B.; Nemykin, V. N. New Developments in Chemistry of Organometallic Porphyrins and their Analogs. J. Porphyrins Phthalocyanines 2013, 17, 165−196. (6) (a) Garno, J. C.; Xu, C.; Bazzan, G.; Batteas, J. D.; Drain, C. M. Designing Supramolecular Porphyrin Arrays for Surface Assembly and Patterning of Optoelectronic Materials. ACS Symp. Ser. 2006, 928, 168−183. (b) Langford, S. J.; Lau, V.-L.; Lee, M. A. P.; Lygris, E. Porphyrin-Based Supermolecules and Supramolecular Arrays. J. Porphyrins Phthalocyanines 2002, 6, 748−756. (c) Drain, C. M.; Batteas, J. D.; Flynn, G. W.; Milic, T.; Chi, N.; Yablon, D. G.; Sommers, H. Designing Supramolecular Porphyrin Arrays that SelfOrganize into Nanoscale Optical and Magnetic Materials. Proc. Natl. Acad. Sci. U. S. A. 2002, 99, 6498−6502. (d) Huh, S.; Kim, S.-J.; Kim, Y. Porphyrinic Metal-Organic Frameworks from Custom-Designed Porphyrins. CrystEngComm 2016, 18, 345−368. (e) Ishida, Y. Manipulation of Supramolecular 2D Assembly of Functional Dyes Toward Artificial Light-Harvesting Systems. Pure Appl. Chem. 2015, 87, 3−14. (f) Iengo, E.; Cavigli, P.; Milano, D.; Tecilla, P. Metal Mediated Self-Assembled Porphyrin Metallacycles: Synthesis and Multipurpose Applications. Inorg. Chim. Acta 2014, 417, 59−78. (g) Fukuzumi, S.; Ohkubo, K. Long-Lived Photoinduced Charge Separation for Solar Cell Applications in Supramolecular Complexes of Multi-Metalloporphyrins and Fullerenes. Dalton Trans. 2013, 42, 15846−15858. (h) de la Torre, G.; Bottari, G.; Sekita, M.; Hausmann, A.; Guldi, D. M.; Torres, T. A Voyage into the Synthesis and Photophysics of Homo- and Heterobinuclear Ensembles of Phthalocyanines and Porphyrins. Chem. Soc. Rev. 2013, 42, 8049− 8105. (7) (a) Wang, S.-P.; Shen, Y.-F.; Zhu, B.-Y.; Wu, J.; Li, S. Recent Advances in the Template-Directed Synthesis of Porphyrin Nanorings. Chem. Commun. 2016, 52, 10205−10216. (b) Ogoshi, T.; Yamagishi, T.; Nakamoto, Y. Pillar-Shaped Macrocyclic Hosts Pillar[n]arenes: New Key Players for Supramolecular Chemistry. Chem. Rev. 2016, 116, 7937−8002. (c) Hasobe, T. Supramolecular Assemblies of Porphyrin and Phthalocyanine Derivatives for Solar Energy Conversion and Molecular Electronics. In Handbook of Porphyrin Science; Kadish, K.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.6b01936. Additional spectroscopic, crystallographic, and electrochemical data for target compounds (PDF) X-ray crystallographic data (CIF)

■

Article

AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. (V.N.N.) *E-mail: [email protected]. (Y.Z.V.) Notes

The authors declare no competing financial interest. CCDC Nos. 1489185 (FeNx3((Bn-C4H9) (ZrTPP))·0.5 C6H14), 1489186 (FeNx3(ZrTPP)2·C8H18·0.25 C6H5CH3), and 1489187 (FeNx3(HfTPP)2·0.33 C8H18) contain the supplementary crystallographic data for these compounds. These data can be obtained free of charge via www.ccdc.cam.ac. uk/conts/retrieving.html (or from Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, U.K.; fax: (+44) 1223−336−033 or [email protected]).

■

ACKNOWLEDGMENTS This work was supported by research Grants from the National Science Foundation (CHE-1401375, CHE-1464711, NSF MRI-1420373, and MRI-0922366) grants, Minnesota Supercomputing Institute, and University of Manitoba to VNN. The NMR measurements were performed with the support of the Russian Science Foundation (project 14-13-00724). We are also thankful to the Ministry of Education and Science of Russian Federation (project “Science” No. 4.2569.2014/K) and Russian Foundation for Basic Research (projects 15-29-01112 and 16-03-00368). 11878


Article

Inorganic Chemistry M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd.: Singapore, 2014; Vol. 34, pp 147−194. (d) Nemykin, V. N.; Dudkin, S. V.; Fathi-Rasekh, M.; Spaeth, A. D.; Rhoda, H. M.; Belosludov, R. V.; Barybin, M. V. Probing Electronic Communications in Heterotrinuclear Fe−Ru−Fe Molecular Wires Formed by Ruthenium(II) Tetraphenylporphyrin and Isocyanoferrocene or 1,1′Diisocyanoferrocene Ligands. Inorg. Chem. 2015, 54, 10711−10724. (e) Nemykin, V. N.; Purchel, A. A.; Spaeth, A. D.; Barybin, M. V. Probing the Electronic Properties of a Trinuclear Molecular Wire Involving Isocyanoferrocene and Iron(II) Phthalocyanine Motifs. Inorg. Chem. 2013, 52, 11004−11012. (8) (a) Voloshin, Ya.; Belaya, I.; Krämer, R. The Encapsulation Phenomenon: Synthesis, Reactivity and Applications of Caged Ions and Molecules; Springer International Publishing: Switzerland, 2016; 638pp. (b) Clathrochelates: Synthesis, Structure and Properties; Voloshin, Ya. Z., Kostromina, N. A., Krämer, R., Eds.; Elsevier Science B. V.: Amsterdam, 2002; 419 pp. (c) Ingham, A.; Rodopoulos, M.; Coulter, K.; Rodopouls, T.; Subramanian, S.; McAuley, A. Synthesis, Characterization and Reactivity of Some Macrobicyclic and Macrotricyclic Hetero-Clathrochelate Complexes. Coord. Chem. Rev. 2002, 233−234, 255−271. (9) (a) Voloshin, Ya. Z.; Varzatskii, O. A.; Belov, A. S.; Starikova, Z. A.; Dolganov, A. V.; Magdesieva, T. V. New Antimony-Capped Iron(II) and Cobalt(III) Clathrochelate Precursors of the Polytopic Hybrid Cage Complexes: Synthesis, X-ray Structures and Electrochemistry. Polyhedron 2008, 27, 325−334. (b) Voloshin, Ya. Z.; Varzatskii, O. A.; Belov, A. S.; Lebedev, A.; Makarov, I. S.; Gurskii, M. E.; Antipin, M.; Starikova, Z. A.; Bubnov, Yu. N. Cage Iron(II) Complexes with Apical and Ribbed Adamantyl Substituents: The Creation of Second (Hydrophobic) Shell of an Encapsulated Metal Ion. Inorg. Chim. Acta 2007, 360, 1543−1554. (c) Voloshin, Y. Z.; Varzatskii, O. A.; Palchik, A. V.; Starikova, Z. A.; Antipin, M. Y.; Lebed, E. G.; Bubnov, Y. N. Mono- and Trichloride Clathrochelate Iron(II) Chloroglyoximates and their Functionalization: the Effect of the Substituents in the Clathrochelate Framework on the Reactivity of the Chlorine-Containing Fragments in Nucleophilic Substitution Reactions. Inorg. Chim. Acta 2006, 359, 553−569. (d) Voloshin, Y. Z.; Varzatskii, O. A.; Kron, T. E.; Belsky, V. K.; Zavodnik, V. E.; Palchik, A. V.; et al. Triribbed-Functionalized Clathrochelate Iron(II) Dioximates as a New and Promising Tool to Obtain Polynucleating and Polynuclear Compounds with Improved Properties. Inorg. Chem. 2000, 39, 1907−1918. (e) Voloshin, Y. Z.; Varzatskii, O. A.; Palchik, A. V.; Stash, A. I.; Belsky, V. K. The Synthesis and Structure of a Macrobicyclic Hexahalogenide Trisdioximate as a Promising Precursor of Functionalized Clathrochelates. New J. Chem. 1999, 23, 355−358. (10) (a) Jansze, S. M.; Cecot, G.; Wise, M. D.; Zhurov, K. O.; Ronson, T. K.; Castilla, A. M.; Finelli, A.; Pattison, P.; Solari, E.; Scopelliti, R.; Zelinskii, G. E.; Vologzhanina, A. V.; Voloshin, Ya. Z.; Nitschke, J. R.; Severin, K. Ligand Aspect Ratio as a Decisive Factor for the Self-Assembly of Coordination Cages. J. Am. Chem. Soc. 2016, 138, 2046−2054. (b) Varzatskii, O. A.; Denisenko, I. N.; Belov, A. S.; Vologzhanina, A. V.; Bubnov, Yu. N.; Volkov, S. V.; Voloshin, Ya. Z. Metal-Catalyzed Cross-Coupling Reactions of Iron(II) Cage Complexes: New Furyl-Containing Macrobicyclic Scaffold, a Reactive Halogenoclathrochelate Precursor and its Ribbed-Functionalized Derivatives. Inorg. Chem. Commun. 2014, 44, 134−138. (c) Varzatskii, O. A.; Denisenko, I. N.; Volkov, S. V.; Belov, A. S.; Dolganov, A. V.; Vologzhanina, A. V.; Novikov, V. V.; Bubnov, Yu. N.; Voloshin, Ya. Z. Perfluoroarylation of Iron(II) Di- and Hexaiodoclathrochelates − Synthesis, X-ray Structure, and Properties of the First Cage Complexes with Inherent Pentafluorophenyl Substituent(s). Eur. J. Inorg. Chem. 2013, 2013, 3178−3184. (d) Varzatskii, O. A.; Kats Menkach, S. V.; Penkova, L. V.; Volkov, S. V.; Dolganov, A. V.; Vologzhanina, A. V.; Bubnov, Yu. N.; Voloshin, Ya. Z. Cage Metal Complexes: Synthesis, Xray Structure, and Spectral and Redox Behavior of the First Hybrid Iron(II) Clathrochelatoscorpionate and Its Pyrazoloxime-Armed Macrocyclic Intermediate. Eur. J. Inorg. Chem. 2013, 2013, 1987−1992. (11) (a) Novikov, V. V.; Pavlov, A. A.; Nelyubina, Yu. V.; Boulon, M.-E.; Varzatskii, O. A.; Voloshin, Ya. Z.; Winpenny, R. E. P. A

Trigonal Prismatic Mononuclear Cobalt(II) Complex Showing SingleMolecule Magnet Behavior. J. Am. Chem. Soc. 2015, 137, 9792−9795. (b) Novikov, V. V.; Pavlov, A. A.; Belov, A. S.; Vologzhanina, A. V.; Savitsky, A.; Voloshin, Ya. Z. Transition Ion Strikes Back: Large Magnetic Susceptibility Anisotropy in Cobalt(II) Clathrochelates. J. Phys. Chem. Lett. 2014, 5, 3799−3803. (12) (a) Blechinger, J.; Varzackii, O. A.; Kovalska, V.; Zelinskii, G. E.; Voloshin, Ya. Z.; Kinski, E.; Mokhir, A. Cytotoxicity of Electrophilic Iron(II)-Clathrochelates in Human Promyelocytic Leukemia Cell Line. Bioorg. Med. Chem. Lett. 2016, 26, 626−629. (b) Zelinskii, G. E.; Belov, A. S.; Vologzhanina, A. V.; Pavlov, A. A.; Novikov, V. V.; Varzatskii, O. A.; Voloshin, Ya.Z. Synthesis, Structure and ADMET Properties of the Monoribbed-Functionalized Iron(II) Clathrochelates with Terminal DNA-Relevant Groups. Inorg. Chim. Acta 2016, 448, 7− 15. (c) Voloshin, Ya.Z.; Novikov, V. V.; Nelyubina, Yu.V. Recent Advances in Biological Applications of Cage Metal Complexes. RSC Adv. 2015, 5, 72621−72637. (13) Burdukov, A. B.; Vershinin, M. A.; Pervukhina, N. V.; Boguslvaskii, E. G.; Eltsov, I. V.; Shundrin, L. A.; Selector, S. L.; Shokurov, A. V.; Voloshin, Ya. Z. Towards the clathrochelate-based electrochromic materials: The case study of the first iron(II) cage complex with an annelated quinoxaline fragment. Inorg. Chem. Commun. 2014, 44, 183−187. (14) (a) Pantani, O.; Naskar, S.; Guillot, R.; Millet, P.; AnxolabéhèreMallart, E.; Aukauloo, A. Cobalt Clathrochelate Complexes as Hydrogen-Producing Catalysts. Angew. Chem., Int. Ed. 2008, 47, 9948−9950. (b) Dinh Nguyen, M. T.; Charlot, M.-F.; Aukauloo, A. Structural, Electronic, and Theoretical Description of a Series of Cobalt Clathrochelate Complexes in the Co(III), Co(II) and Co(I) Oxidation States. J. Phys. Chem. A 2011, 115, 911−922. (c) Voloshin, Y. Z.; Dolganov, A. V.; Varzatskii, O. A.; Bubnov, Y. N. Efficient Electrocatalytic Hydrogen Production from H+ Ions Using Specially Designed Boron-Capped Cobalt Clathrochelates. Chem. Commun. 2011, 47, 7737−7739. (d) Voloshin, Ya. Z.; Belov, A. S.; Vologzhanina, A. V.; Aleksandrov, G. G.; Dolganov, A. V.; Novikov, V. V.; Varzatskii, O. A.; Bubnov, Yu. N. Synthesis, Structure, Properties and Immobilization on a Gold Surface of the Monoribbed-Functionalized Tris-Dioximate Cobalt(II) Clathrochelates and an Electrocatalytic Hydrogen Production from H+ ions. Dalton Trans. 2012, 41, 6078−6093. (e) Anxolabéhère-Mallart, E.; Costentin, C.; Fournier, M.; Nowak, S.; Robert, M.; Savéant, J.-M. Boron-Capped Tris(glyoximato) Cobalt Clathrochelate as a Precursor for the Electrodeposition of Nanoparticles Catalyzing H2 Evolution in Water. J. Am. Chem. Soc. 2012, 134, 6104−6107. (f) Dolganov, A. V.; Belov, A. S.; Novikov, V. V.; Vologzhanina, A. V.; Mokhir, A.; Bubnov, Yu. N.; Voloshin, Ya. Z. Iron vs. Cobalt Clathrochelate Electrocatalysts of HER: the First Example on a Cage Iron Complex. Dalton Trans. 2013, 42, 4373− 4376. (g) Belaya, I. G.; Svidlov, S. V.; Dolganov, A. V.; Zelinskii, G. E.; Potapova, T. V.; Vologzhanina, A. V.; Varzatskii, O. A.; Bubnov, Yu. N.; Voloshin, Ya. Z. Apically Linked Iron(II) α-Dioximate and αOximehydrazonate bis-Clathrochelates: Synthesis, Structure and Electrocatalytic Properties. Dalton Trans. 2013, 42, 13667−13678. (h) El Ghachtouli, S.; Fournier, M.; Cherdo, S.; Guillot, R.; Charlot, M.-F.; Anxolabéhère-Mallart, E.; Robert, M.; Aukauloo, A. Monometallic Cobalt-Trisglyoximato Complexes as Precatalysts for Catalytic H2 Evolution in Water. J. Phys. Chem. C 2013, 117, 17073−17077. (i) Dolganov, A. V.; Belov, A. S.; Novikov, V. V.; Vologzhanina, A. V.; Romanenko, G. V.; Budnikova, Yu. G.; Zelinskii, G. E.; Voloshin, Ya. Z.; et al. First iron and cobalt(II) hexabromoclathrochelates: structural, magnetic, redox, and electrocatalytic behavior. Dalton Trans. 2015, 44, 2476−2487. (15) (a) Pushkarev, V. E.; Tomilova, L. G.; Nemykin, V. N. Historic Overview and New Developments in Synthetic Methods for Preparation of the Rare-Earth Tetrapyrrolic Complexes. Coord. Chem. Rev. 2016, 319, 110−179. (b) Lu, H.; Kobayashi, N. Optically Active Porphyrin and Phthalocyanine Systems. Chem. Rev. 2016, 116, 6184−6261. (c) Dudkin, S. V.; Makarova, E. A.; Lukyanets, E. A. Synthesis of Chlorins, Bacteriochlorins and their Tetraaza Analogues. Russ. Chem. Rev. 2016, 85, 700−730. (d) Nemykin, V. N.; Dudkin, S. 11879


Article

Inorganic Chemistry

Microorganisms: Antimicrobial Photodynamic Treatment. Mini-Rev. Med. Chem. 2009, 9, 974−983. (h) Maisch, T. Revitalized Strategies Against Multi-Resistant Bacteria: Antimicrobial Photodynamic Therapy and Bacteriophage Therapy. Anti-Infect. Agents Med. Chem. 2007, 6, 145−150. (19) (a) Waghorn, P. A. J. Labelled Compd. Radiopharm. 2014, 57, 304. (b) Calvete, M. J. E.; Simoes, A. V. C.; Henriques, C. A.; Pinto, S. M. A.; Pereira, M. M. Tetrapyrrolic Macrocycles: Potentialities in Medical Imaging Technologies. Curr. Org. Synth. 2014, 11, 127−140. (c) Josefsen, L. B.; Boyle, R. W. Unique Diagnostic and Therapeutic Roles of Porphyrins and Phthalocyanines in Photodynamic Therapy, Imaging and Theranostics. Theranostics 2012, 2, 916−966. (d) Sekkat, N.; van den Bergh, H.; Nyokong, T.; Lange, N. Like a Bolt from the Blue: Phthalocyanines in Biomedical Optics. Molecules 2012, 17, 98− 144. (e) Ethirajan, M.; Chen, Y.; Joshi, P.; Pandey, R. K. The Role of Porphyrin Chemistry in Tumor Imaging and Photodynamic Therapy. Chem. Soc. Rev. 2011, 40, 340−362. (f) Costa, S. M. B.; Andrade, S. M.; Togashi, D. M.; Paulo, P. M. R.; Laia, C. A. T.; Isabel Viseu, M.; Goncalves da Silva, A. M. Optical Sectroscopy and Photochemistry of Porphyrins and Phthalocyanines. J. Porphyrins Phthalocyanines 2009, 13, 509−517. (20) (a) Wang, L.; Li, H.; Deng, J.; Cao, D. Tetrapyrrolic Macrocycles: Potentialities in Medical Imaging Technologies. Curr. Org. Chem. 2013, 17, 3078−3091. (b) Giancane, G.; Valli, L. Adv. Colloid Interface Sci. 2012, 171−172, 17. (c) Ö ztürk, Z. Z.; Kılınç, N.; Atilla, D.; Gürek, A. G.; Ahsen, V. Recent Studies Chemical Sensors Based on Phthalocyanines. J. Porphyrins Phthalocyanines 2009, 13, 1179−1187. (d) Valli, L. Phthalocyanine-Based Langmuir−Blodgett Films as Chemical Sensors. Adv. Colloid Interface Sci. 2005, 116, 13− 44. (e) Bouvet, M. Phthalocyanine-Based Field-Effect Transistors as Gas Sensors. Anal. Bioanal. Chem. 2005, 384, 366−373. (f) Winnischofer, H.; Toma, H. E.; Araki, K. Polymetallated porphyrin ultrathin films as transducing elements for molecular devices and logic gates. J. Nanosci. Nanotechnol. 2006, 6, 1701−1709. (g) Zhou, R.; Josse, F.; Göpel, W.; Ö ztürk, Z. Z.; Bekaroğlu, O. Phthalocyanines as Sensitive Materials for Chemical Sensors. Appl. Organomet. Chem. 1996, 10, 557−577. (21) (a) Zenkevich, E. I.; von Borczyskowski, C. Self-Organization principles in the Formation of Multiporphyrin Complexes and ″Semiconductor Quantum Dot-Porphyrin″ Nanoassemblies. J. Porphyrins Phthalocyanines 2014, 18, 1−19. (b) Lindsey, J. S.; Bocian, D. F. Molecules for Charge-Based Information Storage. Acc. Chem. Res. 2011, 44, 638−650. (c) Duclairoir, F.; Marchon, J.-C. Anchoring of Porphyrins and Phthalocyanines on Conductors and Semiconductors for Use in Hybrid Electronics. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2010; Vol. 10, pp 245−312. (d) Li, L.; Tang, Q.; Li, H.; Hu, W.; Yang, X.; Shuai, Z.; Liu, Y.; Zhu, D. Organic Thin-Film Transistors of Phthalocyanines. Pure Appl. Chem. 2008, 80, 2231−2240. (e) Takagi, S.; Eguchi, M.; Tryk, D. A.; Inoue, H. Porphyrin Photochemistry in Inorganic/Organic Hybrid Materials: Clays, Layered Semiconductors, Nanotubes, and Mesoporous Materials. J. Photochem. Photobiol. C 2006, 7, 104−126. (f) de la Torre, G.; Nicolau, M.; Torres, T. Phthalocyanines: Synthesis, Supramolecular Organization, and Physical Properties. In Supramolecular photosensitive and electroactive materials; Nalwa, H. S., Ed.; Academic Press: San Diego, CA, 2001; pp 1−111. (22) Ohta, K.; Nguyen-Tran, H.-D.; Tauchi, L.; Kanai, Y.; Megumi, T.; Takagi, Y. Liquid Crystals of Phthalocyanines, Porphyrins and Related Compounds. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2011; Vol. 12, pp 1−120. (23) (a) Higashino, T.; Imahori, H. Porphyrins as Excellent Dyes for Dye-Sensitized Solar Cells: Recent Developments and Insights. Dalton Trans. 2015, 44, 448−463. (b) Urbani, M.; Grätzel, M.; Nazeeruddin, M. K.; Torres, T. meso-Substituted Porphyrins for Dye-Sensitized Solar Cells. Chem. Rev. 2014, 114, 12330−12396. (c) Imahori, H.; Kurotobi, K.; Walter, M. G.; Rudine, A. B.; Wamser, C. C. Porphyrinand Phthalocyanine-Based Solar Cells. In Handbook of Porphyrin

V.; Dumoulin, F.; Hirel, C.; Gurek, A. G.; Ahsen, V. Synthetic Approaches to Asymmetric Phthalocyanines and their Analogues. Arkivoc 2014, 46, 142−204. (e) Vicente, M. G. H.; Smith, K. M. Syntheses and Functionalizations of Porphyrin Macrocycles. Curr. Org. Synth. 2014, 11, 3−28. (f) Gorbunova, Yu. G.; Martynov, A. G.; Tsivadze, A. Yu. Crown-Substituted Phthalocyanines: From Synthesis Towards Materials. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd.: Singapore, 2012; Vol. 24, pp 271−388. (g) Lindsey, J. S. Synthetic Routes to meso-Patterned Porphyrins. Acc. Chem. Res. 2010, 43, 300−311. (h) Nemykin, V. N.; Lukyanets, E. A. The Key Role of Peripheral Substituents in the Chemistry of Phthalocyanines. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2010; Vol. 3, pp 1−323. (i) Mack, J.; Kobayashi, N. Low Symmetry Phthalocyanines and Their Analogues. Chem. Rev. 2011, 111, 281− 321. (j) Rio, Y.; Rodriguez-Morgade, M. S.; Torres, T. Modulating the Electronic Properties of Porphyrinoids: a Voyage from the Violet to the Infrared Regions of the Electromagnetic Spectrum. Org. Biomol. Chem. 2008, 6, 1877−1894. (k) Lindsey, J. S. Synthesis of mesoSubstituted Porphyrins. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, CA, 2000; Vol. 1, pp 45−118. (16) (a) Zhao, M.; Ou, S.; Wu, C.-D. Porous Metal-Organic Frameworks for Heterogeneous Biomimetic Catalysis. Acc. Chem. Res. 2014, 47, 1199−1207. (b) Sorokin, A. Phthalocyanine Metal Complexes in Catalysis. Chem. Rev. 2013, 113, 8152−8192. (c) Calvete, M. J. F.; Silva, M.; Pereira, M. M.; Burrows, H. D. Inorganic Helping Organic: Recent Advances in Catalytic Heterogeneous Oxidations by Immobilised Tetrapyrrolic Macrocycles in Micro and Mesoporous Supports. RSC Adv. 2013, 3, 22774−22789. (17) (a) Abrahamse, H.; Hamblin, M. R. New Photosensitizers for Photodynamic Therapy. Biochem. J. 2016, 473, 347−364. (b) Dąbrowski, J. M.; Arnaut, L. G. Photodynamic Therapy (PDT) of Cancer: from Local to Systemic Treatment. Photochem. Photobiol. Sci. 2015, 14, 1765−1780. (c) St. Denis, T. G.; Huang, Y.-Y.; Hamblin, M. R. Cyclic Tetrapyrroles in Photodynamic Therapy: The Chemistry of Porphyrins and Related Compounds in Medicine. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2013; Vol. 27, pp 255− 301. (d) Ali, H.; van Lier, J. E. Porphyrins and Phthalocyanines as Photosensitizers and Radiosensitizers. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2010; Vol. 4, pp 1−119. (e) Bonnett, R. Photosensitizers of the Porphyrin and Phthalocyanine Series for Photodynamic Therapy. Chem. Soc. Rev. 1995, 24, 19−33. (18) (a) Souza, E.; Medeiros, A. C.; Gurgel, B. C.; Sarmento, C. Antimicrobial Photodynamic Therapy in the Treatment of Aggressive Periodontitis: a Systematic Review and Meta-Analysis. Lasers Med. Sci. 2016, 31, 187−196. (b) Maisch, T. Strategies to optimize photosensitizers for photodynamic inactivation of bacteria. J. Photochem. Photobiol., B 2015, 150, 2−10. (c) Yin, R.; Agrawal, T.; Khan, U.; Gupta, G. K.; Rai, V.; Huang, Y.-Y.; Hamblin, M. R. Antimicrobial photodynamic inactivation in nanomedicine: small light strides against bad bugs. Nanomedicine 2015, 10, 2379−2404. (d) Rocha, D. M. G. C.; Venkatramaiah, N.; Gomes, M. C.; Almeida, A.; Faustino, M. A F.; Almeida Paz, F. A.; Cunha, A.; Tomé, J. P.C. Photodynamic Inactivation of Escherichia coli with Cationic Ammonium Zn(II) Phthalocyanines. Photochem. Photobiol. Sci. 2015, 14, 1872−1879. (e) Lourenço, L. M. O.; Sousa, A.; Gomes, M. C.; Faustino, M. A. F.; Almeida, A.; Silva, A. M. S.; Neves, M. G. P. M. S.; Cavaleiro, J. A. S.; Cunha, A.; Tomé, J. P. C. Inverted methoxypyridinium phthalocyanines for PDI of pathogenic bacteria. Photochem. Photobiol. Sci. 2015, 14, 1853−1863. (f) Almeida, A.; Cunha, A.; Faustino, M. A. F.; Tome, A. C.; Neves, M. G. P. M. S. Porphyrins as Antimicrobial Photosensitizing Agents. In Photodynamic Inactivation of Microbial Pathogens: Medical and Environmental Applications; Hamblin, M. R., Jori, G., Eds.; RSC Publishing: Cambridge, 2011; pp 83−160. (g) Maisch, T. A New Strategy to Destroy Antibiotic Resistant 11880


Article

Inorganic Chemistry Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2012; Vol. 18, pp 57−121. (d) Schlettwein, D.; Nyokong, T. Phthalocyanines as Sensitizers in Dye-Sensitized Solar Cells. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2012; Vol. 24, pp 389−420. (e) Martinez-Diaz, V. M.; Torres, T. On the Significance of Phthalocyanines in Solar Cells. In Handbook of Porphyrin Science; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; World Scientific Publishing Co. Pte. Ltd: Singapore, 2010; Vol. 10, pp 141−182. (24) (a) Low, P. J. Metal Complexes in Molecular Electronics: Progress and Possibilities. Dalton Trans. 2005, 2821−2824. (b) Koepf, M.; Trabolsi, A.; Elhabiri, M.; Wytko, J. A.; Paul, D.; Albrecht-Gary, A. M.; Weiss, J. Building Blocks for Self-Assembled Porphyrinic Photonic Wires. Org. Lett. 2005, 7, 1279−1282. (c) Cheng, P.-N.; Chiang, P.-T.; Chiu, S.-H. A switchable macrocycle−clip complex that functions as a NOR logic gate. Chem. Commun. 2005, 1285−1287. (d) Leigh, D. A.; Morales, M. A. F.; Perez, E. M.; Wong, J. K. Y.; Saiz, C. G.; Slawin, A. M. Z.; Carmichael, A. J.; Haddleton, D. M.; Brouwer, A. M.; Buma, W. J.; Wurpel, G. W. H.; Leon, S.; Zerbetto, F. Patterning through Controlled Submolecular Motion: Rotaxane-Based Switches and Logic Gates that Function in Solution and Polymer Films. Angew. Chem., Int. Ed. 2005, 44, 3062−3067. (e) Steuerman, D. W.; Tseng, H.-R.; Peters, A. J.; Flood, A. H.; Jeppesen, J. O.; Nielsen, K. A.; Stoddart, J. F.; Heath, J. R. Molecular-Mechanical Switch-Based Solid-State Electrochromic Devices. Angew. Chem., Int. Ed. 2004, 43, 6486−6491. (f) Lent, C. S.; Isaksen, B.; Lieberman, M. Molecular Quantum-Dot Cellular Automata. J. Am. Chem. Soc. 2003, 125, 1056−1063. (25) (a) Bottari, j.; de la Torre, G.; Torres, T. PhthalocyanineNanocarbon Ensembles: From Discrete Molecular and Supramolecular Systems to Hybrid Nanomaterials. Acc. Chem. Res. 2015, 48, 900−910. (b) Mondal, D.; Bera, S. Porphyrins and Phthalocyanines: Promising Molecules for Light-Triggered Antibacterial Nanoparticles. Adv. Nat. Sci.: Nanosci. Nanotechnol. 2014, 5, 33002. (c) D’Souza, F.; Ito, O. Photosensitized electron transfer processes of nanocarbons applicable to solar cells. Chem. Soc. Rev. 2012, 41, 86− 96. (d) Bottari, G.; de la Torre, G.; Guldi, D. M.; Torres, T. Covalent and Noncovalent Phthalocyanine-Carbon Nanostructure Systems: Synthesis, Photoinduced Electron Transfer, and Application to Molecular Photovoltaics. Chem. Rev. 2010, 110, 6768−6816. (e) Zhang, L.; Wang, L. Recent Research Progress on Optical Limiting Property of Materials Based on Phthalocyanine, its Derivatives, and Carbon Nanotubes. J. Mater. Sci. 2008, 43, 5692− 5701. (f) de la Torre, G.; Claessens, C. G.; Torres, T. Phthalocyanines: Old Dyes, New Materials. Putting Color in Nanotechnology. Chem. Commun. 2007, 2000−2015. (g) Elemans, J. A. A. W.; van Hameren, R.; Nolte, R. J. M.; Rowan, A. E. Molecular Materials by Self-Assembly of Porphyrins, Phthalocyanines, and Perylenes. Adv. Mater. 2006, 18, 1251−1266. (26) (a) Ayhan, M. M.; Singh, A.; Hirel, C.; Gürek, A. G.; Ahsen, V.; Jeanneau, E.; Ledoux-Rak, I.; Zyss, J.; Andraud, C.; Bretonnière, Y. ABAB Homoleptic Bis(phthalocyaninato)lutetium(III) Complex: Toward the Real Octupolar Cube and Giant Quadratic Hyperpolarizability. J. Am. Chem. Soc. 2012, 134, 3655−3658. (b) de la Torre, G.; Vazquez, P.; Agullo-Lopez, F.; Torres, T. Role of Structural Factors in the Nonlinear Optical Properties of Phthalocyanines and Related Compounds. Chem. Rev. 2004, 104, 3723−3750. (c) Flom, S. R. Nonlinear Optical Properties of Phthalocyanines. In Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, CA, 2003; Vol. 19, pp 179−190. (d) Hanack, M.; Dini, D.; Barthel, M.; Vagin, S. Conjugated Macrocycles as Active Materials in Nonlinear Optical Processes: Optical Limiting Effect with Phthalocyanines and Related Compounds. Chem. Rec. 2002, 2, 129− 148. (e) Hanack, M.; Schneider, T.; Barthel, M.; Shirk, J. S.; Flom, S. R.; Pong, R. G. S. Indium phthalocyanines anf naphthalocyanines for optical limiting. Coord. Chem. Rev. 2001, 219−221, 235−258. (f) Schultz, H.; Lehmann, H.; Rein, M.; Hanack, M. Phthalocyaninatometal and related complexes with special electrical and optical properties. In Structure and Bonding; Buchler, J. W., Ed.; Springer-

Verlag: Berlin, Germany, 1991; Vol. 74, pp 41−146. (g) Nalwa, H. S.; Shirk, J. A. Nonlinear Optical Properties of Metallophthalocyanines. In Phthalocyanines: properties and applications; Leznoff, C. C., Lever, A. B. P., Eds.; VCH: New York, 1996; Vol. 4, pp 79−182. (27) (a) Sabin, J. R.; Varzatskii, O. A.; Voloshin, Y. Z.; Starikova, Z. A.; Novikov, V. V.; Nemykin, V. N. Insight into the Electronic Structure, Optical Properties, and Redox Behavior of the Hybrid Phthalocyaninoclathrochelates from Experimental and Density Functional Theory Approaches. Inorg. Chem. 2012, 51, 8362−8372. (b) Voloshin, Y. Z.; Varzatskii, O. A.; Tomilova, L. G.; Breusova, M. O.; Magdesieva, T. V.; Bubnov, Yu. N.; Krämer, R. First Hybrid Oximehydrazonate Phthalocyaninoclathrochelates: The Synthesis and Properties of Lutetium Phthalocyanine-Capped Cage Iron(II) Complexes. Polyhedron 2007, 26, 2733−2740. (c) Voloshin, Y. Z.; Varzatskii, O. A.; Korobko, S. V.; Chernii, V. Y.; Volkov, S. V.; Tomachynski, L. A.; Pehn’o, V. I.; Antipin, M.; Starikova, Z. A. Ditopic Macropolycyclic Complexes: Synthesis of Hybrid Phthalocyaninoclathrochelates. Inorg. Chem. 2005, 44, 822−824. (28) (a) LeSuer, R. L.; Buttolph, C.; Geiger, W. Comparison of the Conductivity Properties of the Tetrabutylammonium Salt of Tetrakis(pentafluorophenyl)borate Anion with Those of Traditional Supporting Electrolyte Anions in Nonaqueous Solvents. Anal. Chem. 2004, 76, 6395−6401. (b) Huhmann, J. L.; Corey, J. Y.; Rath, N. P.; Campana, C. F. Reaction of (POR)M(OAc)2(M = Zr, Hf) with nBuLi and Soild State Structure of [(TPP)Zr(μ-OH)2]2. J. Organomet. Chem. 1996, 513, 17−26. (c) Voloshin, Y. Z.; Varzatskii, O. A.; Korobko, S. V.; Antipin, M.; Vorontsov, I. I.; Lyssenko, K. A.; Kochubey, D. I.; Nikitenko, S. G.; Strizhakova, N. G. Pathways of Directed Synthesis of Iron(II) Clathrochelates and Polyclathrochelates with Non-Equivalent Capping Groups Starting from Antimony- and Germanium-Containing Precursors. Inorg. Chim. Acta 2004, 357, 3187−3204. (29) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A., Jr.; Vreven, T.; et al. Gaussian 09, revision A.01; Gaussian, Inc: Wallingford, CT, 2009. See the Supporting Information for full citation. (30) Tenderholt, A. L. QMForge, version 2.1; Stanford University: Stanford, CA, 2011. (31) Tao, J.; Perdew, J. P.; Staroverov, V. N.; Scuseria, G. E. Climbing the Density Functional Ladder: Nonempirical Meta-Generalized Gradient Approximation Designed for Molecules and Solids. Phys. Rev. Lett. 2003, 91, 146401. (32) Hay, P. J.; Wadt, W. R. Ab Initio Effective Core Potentials for Molecular Calculations. Potentials for the Transition Metal Atoms Sc to Hg. J. Chem. Phys. 1985, 82, 270−283. (33) Tomasi, J.; Mennucci, B.; Cammi, R. Quantum Mechanical Continuum Solvation Models. Chem. Rev. 2005, 105, 2999−3094. (34) (a) Spek, A. L. PLATON SQUEEZE: A Tool for the Calculation of the Disordered Solvent Contribution to the Calculated Structure Factors. Acta Crystallogr., Sect. C: Struct. Chem. 2015, C71, 9−18. (b) Sheldrick, G. M. A Short History of SHELX. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, A64, 112−122. (c) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. OLEX2: a Complete Structure Solution, Refinement and Analysis Program. J. Appl. Crystallogr. 2009, 42, 339−341. (35) (a) Gorbunova, Y. G.; Enakieva, Y. Y.; Sakharov, S. G.; Tsivadze, A. Yu. Synthesis and Spectral Properties of Ruthenium(II) Complexes with Tetra-15-Crown-5-Phthalocyanine and N-Donor Ligands. J. Porphyrins Phthalocyanines 2003, 7, 795−800. (b) Lapkina, L. A.; Gorbunova, Y. G.; Gil, D. O.; Ivanov, V. K.; Konstantinov, N. Y.; Tsivadze, A. Yu. Synthesis, Spectral Properties, Cation-Induced Dimerization and Photochemical Stability of Tetra-(15-crown-5)Phthalocyaninato Indium(III). J. Porphyrins Phthalocyanines 2013, 17, 564−572. (c) Martynov, A. G.; Gorbunova, Y. G. Heteroleptic P h t ha l o cy a n i n a t o -[T e t r a ( 1 5 - Cr o wn -5 ) P ht ha l oc y an i n a t o] Lanthanides(III) Double-Deckers: Synthesis and Cation-Induced Supramolecular Dimerization. Inorg. Chim. Acta 2007, 360, 122−130. (36) (a) Medforth, C. J.; Muzzi, C. M.; Shea, K. M.; Smith, K. M.; Abraham, R. J.; Jia, S.; Shelnutt, J. A. NMR studies of nonplanar 11881


Article

Inorganic Chemistry

Circular Dichroism Spectroscopy of meso-TetraphenylporphyrinDerived Hydroporphyrins and Pyrrole-Modified Porphyrins. J. Phys. Chem. A 2016, 120, 5805−5815. (42) (a) Kubow, S. A.; Takeuchi, K. J.; Grzybowski, J. J.; Jircitano, A. J.; Goedken, V. L. Distortions from Trigonal Prismatic Geometry for Several Structurally Characterized Clathrochelate complexes: Significance of π-Backbonding on Clathrochelate Coordination Geometry. Inorg. Chim. Acta 1996, 241, 21−30. (b) Voloshin, Y. Z.; Varzatskii, O. A.; Belov, A. S.; Starikova, Z. A.; Strizhakova, N. G.; Dolganov, A. V.; Kochubey, D. I.; Bubnov, Yu. N. Synthesis, X-ray Structure and Redox Properties of the Macrobicyclic Iron(II) N2- and S2-containing vicdioximates. Inorg. Chim. Acta 2010, 363, 134−146. (43) (a) Geiger, W. E.; Connelly, N. G. The Electron-Transfer Reactions of Polynuclear Organotransition Metal Complexes. Adv. Organomet. Chem. 1985, 24, 87−130. (b) Solntsev, P. V.; Dudkin, S. V.; Sabin, J. R.; Nemykin, V. N. Electronic Communications in (Z)Bis(ferrocenyl)ethylenes with Electron-Withdrawing Substituents. Organometallics 2011, 30, 3037−3046. (c) Hildebrandt, A.; Lehrich, S. W.; Schaarschmidt, D.; Jaeschke, R.; Schreiter, K.; Spange, S.; Lang, H. Ferrocenyl Maleimides − Synthesis, (Spectro-)Electrochemistry, and Solvatochromism. Eur. J. Inorg. Chem. 2012, 1114−1121. (d) Hildebrandt, A.; Schaarschmidt, D.; Claus, R.; Lang, H. Influence of Electron Delocalization in Heterocyclic Core Systems on the Electrochemical Communication in 2,5-Di- and 2,3,4,5-Tetraferrocenyl Thiophenes, Furans, and Pyrroles. Inorg. Chem. 2011, 50, 10623− 10632. (e) Hildebrandt, A.; Schaarschmidt, D.; Lang, H. Electronically Intercommunicating Iron Centers in Di- and Tetraferrocenyl Pyrroles. Organometallics 2011, 30, 556−563. (f) D’Alessandro, D. M.; Keene, F. R. A Cautionary Warning on the Use of Electrochemical Measurements to Calculate Comproportionation Constants for Mixed-Valence Compounds. Dalton Trans. 2004, 3950−3954. (g) D’Alessandro, D.; Keene, R. Current Trends and Future Challenges in the Experimental, Theoretical and Computational Analysis of Intervalence Charge Transfer (IVCT) Transitions. Chem. Soc. Rev. 2006, 35, 424−440. (h) Winter, R. F. Half-Wave Potential Splittings ΔE1/2 as a Measure of Electronic Coupling in Mixed-Valent Systems: Triumphs and Defeats. Organometallics 2014, 33, 4517− 4536. (44) (a) Tran, T. T. H.; Chang, Y.-R.; Hoang, T. K. A.; Kuo, M.-Y.; Su, Y. O. Electrochemical Behavior of meso-Substituted Porphyrins: The Role of Cation Radicals to the Half-Wave Oxidation Potential Splitting. J. Phys. Chem. A 2016, 120, 5504−5511. (b) Ye, L.; Ou, Z.; Fang, Y.; Xue, S.; Song, Y.; Wang, L.; Wang, M.; Kadish, K. M. Electrochemistry of nonplanar copper(II) tetrabutano- and tetrabenzotetraarylporphyrins in nonaqueous media. RSC Adv. 2015, 5, 77088−77096. (c) Kadish, K. M.; Lin, M.; Van Caemelbecke, E.; De Stefano, G.; Medforth, C. J.; Nurco, D. J.; Nelson, N. Y.; Krattinger, B.; Muzzi, C. M.; Jaquinod, L.; et al. Influence of Electronic and Structural Effects on the Oxidative Behavior of Nickel Porphyrins. Inorg. Chem. 2002, 41, 6673−6687. (d) D’Souza, F.; Zandler, M. E.; Tagliatesta, P.; Ou, Z.; Shao, J.; Van Caemelbecke, E.; Kadish, K. M. Electronic, Spectral, and Electrochemical Properties of (TPPBrx)Zn where TPPBrx is the Dianion of β-Brominated-Pyrrole Tetraphenylporphyrin and x Varies from 0 to 8. Inorg. Chem. 1998, 37, 4567−4572.

porphyrins. Part 2. Effect of nonplanarconformational distortions on the porphyrin ring current. J. Chem. Soc., Perkin Trans. 2 1997, 839− 844. (b) Abraham, R. J.; Smith, K. M.; Goff, D. A.; Lai, J.-J. NMR Spectra of Porphyrins. 18. A Ring-Current Model for Chlorophyll Derivatives. J. Am. Chem. Soc. 1982, 104, 4332−4337. (c) Janson, T. R.; Katz, J. J. Nuclear Magnetic Resonance Spectroscopy of Diamagnetic Porphyrins. In The Porphyrins; Dolphin, D., Ed.; Academic Press: New York, 1979; Vol. 4, pp 1−59. (d) Riche, C.; Gouedard, M.; Gaudemer, A. Structural Studies on Metalloporphyrins. 4. Determination of the Conformation of Amines and Amino-Esters Complexed with Cobalt(III) porphyrins. J. Chem. Res. 1978, S, 36−37. (e) Caughey, W.; Koski, W. S. Nuclear Magnetic Resonance Spectra of Porphyrins. Biochemistry 1962, 1, 923−931. (f) Nemykin, V. N.; Polshina, A. E.; Chernii, V. Y.; Polshin, E. V.; Kobayashi, N. Synthesis, Properties and Mössbauer Spectra of Bisaxially Co-Ordinated Iron(II) Phthalocyanine Low-Spin Complexes: the First Semi-Quantitative Explanation of the Influence of the Character of Axial Ligands on the Spectral Parameters. J. Chem. Soc., Dalton Trans. 2000, 1019−1025. (37) Eaton, S. S.; Eaton, G. R. Rotation of Phenyl Rings in Metal Complexes of Substituted Tetraphenylporphyrins. J. Am. Chem. Soc. 1975, 97, 3660−3666. (38) (a) Falber, A.; Burton-Pye, B. P.; Radivojevic, I.; Todaro, L.; Saleh, R.; Francesconi, L. C.; Drain, C. M. Ternary Porphyrinato HfIV and ZrIV Polyoxometalate Complexes. Eur. J. Inorg. Chem. 2009, 2459−2466. (b) Falber, A.; Todaro, L.; Goldberg, I.; Favilla, M. V.; Drain, C. M. Routes for New Hafnium(IV) Tetraaryl Porphyrins and Crystal Structures of Unusual Phosphate-, Sulfate-, and PeroxideBridged Dimers. Inorg. Chem. 2008, 47, 454−467. (39) (a) Gouterman, M.; Hanson, L. K.; Khalil, G.-E.; Buchler, J. W.; Rohbock, K.; Dolphin, D. Porphyrins. XXXI. Chemical Properties and Electronic Spectra of d0 Transition-Metal Complexes. J. Am. Chem. Soc. 1975, 97, 3142−3149. (b) Knör, G.; Strasser, A. Enhanced photoreactivity of zirconium(IV) and hafnium(IV) porphyrin complexes promoted by water molecules. Inorg. Chem. Commun. 2005, 8, 471−473. (40) (a) Waluk, J.; Michl, J. Perimeter Model and Magnetic Circular Dichroism of Porphyrin Analogs. J. Org. Chem. 1991, 56, 2729−2735. (b) Michl, J. Magnetic Circular Dichroism of Aromatic Molecules. Tetrahedron 1984, 40, 3845−3934. (c) Michl, J. Electronic Structure of Aromatic π-Electron Systems as Reflected in their MCD Spectra. Pure Appl. Chem. 1980, 52, 1549−1563. (d) Michl, J. Magnetic Circular Dichroism of Cyclic π-Electron Systems. 3. Classification of Cyclic π Chromophores with a (4N + 2)-Electron [n]annulene Perimeter and General Rules for Substituent Effects on the MCD Spectra of Soft Chromophores. J. Am. Chem. Soc. 1978, 100, 6819−6824. (e) Michl, J. Magnetic Circular Dichroism of Cyclic π-Electron Systems. 2. Algebraic Solution of the Perimeter Model for the B Terms of Systems with a (4N + 2)-Electron [n]annulene perimeter. J. Am. Chem. Soc. 1978, 100, 6812−6818. (f) Michl, J. Magnetic Circular Dichroism of Cyclic π-Electron Systems. 1. Algebraic solution of the Perimeter Model for the A and B Terms of High-Symmetry Systems with a (4N + 2)-Electron [n]annulene Perimeter. J. Am. Chem. Soc. 1978, 100, 6801−6811. (41) (a) Keegan, J. D.; Stolzenberg, A. M.; Lu, Y. C.; Linder, R. E.; Barth, G.; Moscowitz, A.; Bunnenberg, E.; Djerassi, C. Magnetic Circular Dichroism Studies. 61. Substituent-Induced Sign Variation in the Magnetic Circular Dichroism Spectra of Reduced Porphyrins. 2. Perturbed Molecular Orbital Analysis. J. Am. Chem. Soc. 1982, 104, 4317−4329. (b) Keegan, J. D.; Stolzenberg, A. M.; Lu, Y. C.; Linder, R. E.; Barth, G.; Moscowitz, A.; Bunnenberg, E.; Djerassi, C. Magnetic Circular Dichroism Studies. 60. Substituent-Induced Sign Variation in the Magnetic Circular Dichroism Spectra of Reduced Porphyrins. 1. Spectra and Band Assignments. J. Am. Chem. Soc. 1982, 104, 4305− 4317. (c) Keegan, J. D.; Stolzenberg, A. M.; Lu, Y.-C.; Linder, R. E.; Barth, G.; Bunnenberg, E.; Djerassi, C.; Moscowitz, A. Magnetic Circular Dichroism Studies. 59. Substituent-Induced Sign Variation in the Magnetic Circular Dichroism Spectra of Chlorins. J. Am. Chem. Soc. 1981, 103, 3201−3203. (d) Rhoda, H. M.; Akhigbe, J.; Ogikubo, J.; Sabin, J. R.; Ziegler, C. J.; Brückner, C.; Nemykin, V. N. Magnetic 11882


Preparation, X-ray Structures, Spectroscopic, and Redox Properties of

Recommend Documents