Solid State Structure, and Optical and Magnetic Properties, of Free

Jan 10, 2018 - The composition of the crystals, which was determined by X-ray diffraction on a single crystal, was {cryptand[2.2.2.]( ..... The magnet...
0 downloads 7 Views 1MB Size
Download PDF
Article pubs.acs.org/joc

Cite This: J. Org. Chem. 2018, 83, 1861−1866

Solid State Structure, and Optical and Magnetic Properties, of Free Base Tetra(4-pyridyl)porphyrin {H2T(4-Py)P}•− Radical Anions Dmitri V. Konarev,*,† Aleksey V. Kuzmin,‡ Salavat S. Khasanov,‡ Alexander F. Shestakov,† Evgeniya I. Yudanova,† Akihiro Otsuka,§,∥ Hideki Yamochi,§,∥ Hiroshi Kitagawa,∥ and Rimma N. Lyubovskaya† †

Institute of Problems of Chemical Physics RAS, Chernogolovka, Moscow Region, 142432 Russia Institute of Solid State Physics RAS, Chernogolovka, Moscow Region, 142432 Russia § Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan ∥ Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan ‡

S Supporting Information *

ABSTRACT: A crystalline {cryptand[2.2.2.](K+)}{H2T(4-Py)P•−}·C6H4Cl2 (1) salt with tetra(4-pyridyl)porphyrin radical anions was obtained, enabling the effect of reduction on a metal-free porphyrin macrocycle to be studied. In contrast to pristine H2T(4-Py)P, the H2T(4-Py)P•− radical anions have altered C−C(meso) bonds due to partial loss of aromaticity from the porphyrin macrocycle. Short and long bonds have average lengths of 1.396(3) and 1.426(3) Å, which thus differ by 0.03 Å. Reduction affects the positions of the Soret and Q-bands of porphyrin observed in the spectrum of 1 at 439 and 512, 583, and 614 nm, and new bands of the radical anion appear at 684, 755, and 900 nm. The H2T(4-Py)P•− radical anions have a spin state of S = 1/2 and a magnetic moment of 1.64 μB at 300 K. Salt 1 shows a narrow asymmetric EPR signal fitted with two Lorentzian lines, with g⊥ = 2.0031 and a line width (ΔH) of 0.186 mT, and g∥ = 2.0019 (ΔH = 0.284 mT) at 295 K, and this signal splits into three components below 39 K. Salt 1 shows antiferromagnetic spin coupling with a Weiss temperature of −2 K.

■

INTRODUCTION Heterocyclic macrocycles are a large group of organic compounds that includes porphyrins, phthalocyanines, corroles, and others that can bind metals to form complexes.1,2 These macrocycles and their metal complexes are very important with respect to their biological activity3 and have various applications as materials.4,5 To achieve magnetic interactions or high conductivity, macrocycles must have unpaired spins that appear when they are oxidized or reduced. The oxidation chemistry of macrocycles has a long history and has provided many compounds with promising magnetic and conducting properties, including not only porphyrins but also phthalocyanines and other macrocycles.6,7 The reduction chemistry of these macrocycles has been studied to a lesser degree. Free base phthalocyanine (H2Pc) has a first reduction potential of −0.66 V vs SCE in DMF,8 and radical anions of phthalocyanines are formed when relatively strong reductants are used. Several salts of H2Pc were obtained and structurally characterized in order to study the effect of reduction on the structure and properties of H2Pc.9−11 Recently, radical dianions of free base corrole (H2TPCor•2−) were obtained by reduction and deprotonation of 5, 10, 15-triphenylcorrole (H3TPCor) in the presence of a strong donor, decamethylchromocene (Cp*2Cr).12 Substituted corroles (H3TRCor, where R can be different aryl substituents) have more negative first reduction potentials of −0.98 to −1.36 © 2018 American Chemical Society

V vs SCE in benzonitrile, and reduction is accompanied by deprotonation.13 Reduction of the porphyrin macrocycle is realized at very negative reduction potentials; these are −1.23 V for H2TPP (TPP is tetraphenylporphyrin),14 −1.255 V for H2T(4-Py)P,15 and −1.46 V for H2OEP (OEP is octaethylporphyrin)14 (all potentials were measured vs SCE in CH2Cl2). Until now, only two compounds containing a macrocyclic deprotonated porphyrin trianion radical bound to aluminum or silicon atoms have been obtained in the solid state as {AlIII(THF)2(TPP•3−)} and {SiIV(THF)2(TPP4−)}.16,17 Radical anions of free base porphyrins (H2P•−) have still not been obtained in the solid state, and their structure, and optical and magnetic properties, are unknown. This information is essential for understanding the properties of reduced porphyrin macrocycles and developing functional compounds based on them. In this work, the salt {cryptand[2.2.2.](K+)}{H2T(4Py)P}•−·C6H4Cl2 (1) was obtained, which contained radical anions of free base tetra(4-pyridyl)porphyrin. This allowed the effect of reduction on the geometry of the porphyrin macrocycle, as well as its optical and magnetic properties, to be studied for the first time. Comparing the obtained results Received: November 4, 2017 Published: January 10, 2018 1861

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866

Article

The Journal of Organic Chemistry

Figure 1. Length of the C−N and C−C bonds in the porphyrin macrocycle of pristine H2T(4-Py)P according to ref 18 (a) and of the H2T(4-Py)P•− radical anion in salt 1 (b). Carbon is shown in brown and nitrogen in blue. The molecular structure of the H2T(4-Py)P•− radical anion according to the DFT calculations (c). Labels s and l indicate shortened and elongated bonds, respectively, compared with those in (a).

(0.003 Å). Alteration of the C−C bonds is also clearly observed in the pyrrole rings, since four of these bonds in opposing pyrrole rings (in accordance with the crystallographic symmetry) are short, while four bonds belonging to two other opposing pyrrole rings are long (Figure 1b). The difference between the average lengths of the short and long bonds in this case is 0.036 Å. The C−C(meso) bonds and the C−C bonds in the pyrrole rings also show some alteration in neutral H2T(4-Py)P (Figure 1a), indicating that other effects (for example, the presence of hydrogen atoms at only two of the four nitrogen atoms) can also weakly distort the geometry of the macrocycle. However, differences in the average lengths of the short and long bonds of 0.006 and 0.016 Å, respectively, are smaller (by 2.5−5 times) than those for H2T(4-Py)P•−. Therefore, the distortion of H2T(4-Py)P•− cannot be explained only by the factors that cause weak distortion of neutral H2T(4Py)P. The planes of pyridine substituents are more coplanar with the 24 atom porphyrin plane in H2T(4-Py)P•− than in pristine H2T(4-Py)P,18 since the dihedral angles between these planes are in the ranges 59.14−70.87° and 67.70−86.01°, respectively. Previously, the Jahn−Teller deformation of the TPP•3− macrocycle in vanadyl porphyrin radical anions {VIVO(TPP•3−)} was predicted using DFT calculations.19 These show that rectangular or rhombic distortions can occur in porphyrin radical trianions. All of these distortions decrease the symmetry of the macrocycle from C4v to C2v but are characterized by different bond structures.19 Rectangular deformation of TPP•3− radical trianions19 was confirmed experimentally for {AlIII(THF)2(TPP•3−)}.16 The alteration of the bonds, which is characteristic of rectangular deformations,19 corresponds well to that of the bonds observed in our case for H2T(4-Py)P•−. DFT calculations were performed to determine the geometry of the macrocycles in neutral H2T(4-Py)P (Figure S1) and in H2T(4-Py)P•− radical anions (Figures S2 and 1c). The geometry of the H2TPP, H2TPP•−, and {AlIII(TPP•3−)} species containing H2TPP•− and TPP•3− macrocycles (Figure S3) as well as H2P and H2P•− (Figure S4) was also calculated for comparison. The calculated lengths of the C−C and C−N bonds regularly exceed the experimental values18,20,16 by an average of 0.01 Å in all the computed structures. However, the difference between nonequivalent bonds is reproduced with an accuracy of a thousandth of an angstrom. The geometry of the H2T(4-Py)P•− radical anion in the isolated molecule and in the complex with the countercation

with those obtained for reduced free base phthalocyanine, and reduced and deprotonated free base triphenylcorrole, enabled understanding the general tendencies of changes in the structure, and optical and magnetic properties, of these macrocycles resulting from reduction.

■

RESULTS AND DISCUSSION Synthesis. A diffusion technique was used to prepare 1. H2T(4-Py)P was reduced in o-C6H4Cl2 by excess KC8 in the presence of 1 equiv of cryptand[2.2.2.]. Initially, the red solution of H2T(4-Py)P changed to dark green (yellow-green for thin layer). The solution was filtered into a diffusion tube, and n-hexane was layered over the solution. Crystals were obtained on the walls of the tube. These were isolated and washed with n-hexane to yield black trapezoid crystals. The composition of the crystals, which was determined by X-ray diffraction on a single crystal, was {cryptand[2.2.2.](K+)}{H2T(4-Py)P•−}·C6H4Cl2 (1). Crystal Structure and DFT Calculations. The crystal structure of 1 was studied at 100 K (Figure S6). It consists of one independent cryptand[2.2.2.](K+) cation, a C6H4Cl2 molecule, and two halves of independent H2T(4-Py)P•− radical anions. One of these radical anions contains ordered hydrogen atoms in the center of the macrocycle; however, these are statistically disordered between two positions in another radical anion. Therefore, the geometry of H2T(4-Py)P•− is only considered with ordered hydrogen atoms. The H2T(4-Py)P•− macrocycles and cryptand[2.2.2.](K+) cations form chains in which they alternate along the c axis (Figure S7). The macrocycles are positioned in the chains in a zigzag manner with an angle of 69.61° between the porphyrin planes. Figure 1 shows the bond lengths in pristine H2T(4-Py)P18 and H2T(4-Py)P•−. The macrocycle is almost planar in both porphyrins with slight deviation of the pyrrole nitrogen and carbon atoms from the 24 atom porphyrin plane by 0.003− 0.129 and 0.072−0.149 Å, respectively. The macrocycle contains eight C−C(meso) and C−N(pyrrole) bonds. The latter are not altered and are centered at 1.369(3) and 1.380(3) Å in the neutral and the radical anion porphyrin, respectively (Figure 1a,b). The C−C(meso) bonds are altered in H2T(4Py)P•−, since four of the bonds to two opposing pyrrole subunits (in accordance with the crystallographic symmetry) are short, and four other bonds to two other opposing pyrrole subunits are long (Figure 1b). The difference of 0.030 Å between the average lengths of the short and long bonds essentially exceeds the error in determining these bond lengths 1862

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866

Article

The Journal of Organic Chemistry was calculated, taking into account the Coulomb field of the surrounding ions (Figures S2 and 1c). It was found that this led to better agreement with the experiment, especially with respect to the alteration of the C−C bond lengths. This calculation indicates increased alteration of the bonds during the transition from H2T(4-Py)P to H2T(4-Py)P•−, since the difference between short and long C−C(meso) bonds in the macrocycle changes from 0.0065−0.007 {0.006(3)} to 0.017−0.020 {0.030(3)} Å, respectively (the experimental values are given in braces).18 The C−C bonds in the pyrrole rings exhibit a similar tendency. In this case, the differences are 0.025 {0.016(3)} and 0.041−0.042 {0.036(3)} Å, respectively. Thus, the DFT calculations effectively predict the distortion of the porphyrin macrocycle during reduction. The substitution of pyridyl substituents of H2T(4-Py)P by phenyl substituents in H2TTP results in similar geometry of the porphyrin macrocycle in the neutral and radical anion states. In this case, similar distortion of the macrocycle occurs, and the difference in bond length is similar to that in H2T(4-Py)P. This is 0.006 {0.001(3)} and 0.025 {0.025(3)} Å for neutral H2TPP and 0.016 and 0.044 Å for the calculated structure of the H2TPP•− radical anion (the experimental values for pristine H2TPP are given in braces).20a Previously, the TPP•3− radical trianion structures were studied in the neutral {AlIII(THF)2(TPP•3−)} radical.16 The macrocycle shows a small distortion in the radical trianion state with differences in the corresponding C−C bond lengths of 0.025(3) and 0.027(3) Å, respectively. The C−C bond differences of 0.026 and 0.021 Å in the calculated structure of the TPP•3− radical trianion in {AlIII(THF)2(TPP•3−)} show excellent agreement with the experimental values. Comparing the geometry of H2P and H2TPP in the neutral and radical anion states (Figures S4 and S3, respectively) indicates that systematic elongation of the C− C(meso) bonds by an average of 0.010−0.012 Å is caused by the phenyl substituents. The calculated structures for the H2P•− and H2TPP•− radical anions show very similar distortion of the macrocycle, since, in H2P•−, the differences in the C−C(meso) and C−C bond lengths in the pyrrole rings are 0.019 and 0.044 Å (Figure S4b). This behavior differs from that of the corrole (Cor) macrocycle, which shows increased alteration of the C− C bonds of H2Cor•2− in comparison with those of H2TPCor•2− (0.010 Å). This was explained by the distribution of the additional negative charge in H2TPCor•2− among the phenyl substituents.12 However, this situation does not occur in the reduced H2T(4-Py)P•− and H2TPP•− macrocycles. Alteration of C−N(imine) bonds was previously observed in H2Pc•− radical anions in several salts.21 In this case, bonds are positioned so that four short and four long bonds belong to two opposing isoindole subunits, and the average difference between them is approximately 0.04 Å (Figure 2a). Recently, the first deprotonated and reduced triphenylcorrole radical dianions (H2TPCor•2−) were prepared in the solid state. They also show alteration of the C−C(meso) bonds, and the difference between the lengths of the short and long bonds is 0.02 Å. Calculations showed that one excess electron in H2TPCor•2− is largely delocalized over phenyl substituents, which decreases the effect of reduction on the π-system of corrole.12 The positions of short and long bonds in H2TPCor•2− are similar to those in H2T(4-Py)P•−, except that one short C− C(meso) bond is absent in H2TPCor•2− (Figure 2b). It should be noted that, in free base macrocycles, distortion is related to the position of hydrogen atoms in the center of the macrocycle.

Figure 2. (a) Alteration of the C−N(imine) bonds in the H2Pc•− radical anion according to ref 21; (b) alteration of the C−C(meso) bonds in the H2TPCor•2− radical dianion according to ref 12; (c) alteration of the C−C(meso) bonds in the H2T(4-Py)P•− radical anion in 1. The lengths of short (type 1) and long (type 2) bonds are also shown. Δ is the difference between the average lengths of the short and long bonds.

Long C−N(imine) and C−C(meso) bonds are always positioned so that they belong to the isoindole or pyrrole subunits containing N−H bonds (Figure 2). The observed alteration of the bonds in the macrocycles can be attributed to Jahn−Teller distortion16,17,19,22 and partial disruption of their aromaticity9−12 resulting from the formation of a less stable 19 π-electron system in comparison with the stable aromatic 18 πelectron systems of pristine macrocycles. Similar alteration of the C−N(imine) and C−C(meso) bonds was found experimentally for deprotonated phthalocyanine and porphyrin radical trianions.10,11,21,16 Optical Properties. UV−visible−NIR spectra of H2T(4Py)P and salt 1 are shown in Figure 3. The pristine macrocycle

Figure 3. UV−visible−NIR spectra of pristine H2T(4-Py)P (a) and salt 1 (b). Both spectra were measured as KBr pellets. The pellet for 1 was prepared under anaerobic conditions. The inset shows spectra of H2T(4-Py)P (a) and salt 1 (b) in the 500−780 nm range. The positions of the bands are marked with red bars.

shows Soret and Q-bands in the visible range at 434 and 521, 592, and 645 nm, respectively (Figure 3, curve a). The Soret band is significantly narrowed in the spectrum of 1 but retains its position at 439 nm (Figure 3, curve b). Three Q-bands are weakly blue-shifted compared with those in the spectrum of H2T(4-Py)P and appear at 512, 584, and 614 nm (Figure 3, curve b). Since the LUMO orbital of H2T(4-Py)P is populated in the radical anion state to form a single occupied molecular orbital (SOMO), new low-energy bands appear in the spectrum of 1 at 684, 755, and 900 nm due to the appearance of new transitions from the SOMO to the upper orbitals. The appearance of low-energy bands is characteristic of the radical anion state, since, for reduced macrocycles, new low-energy 1863

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866

Article

The Journal of Organic Chemistry

atures. As shown in Figure 4b, the g-factors are significantly shifted to larger and smaller values, and all the components are noticeably broadened below 39 K. The H 2 T(4-Py)P •− spectrum of 1 at 6.5 K is shown in Figure S10. The ESR signal of H2T(4-Py)P•− generated by KC8 in the presence of cryptand[2.2.2.] in o-dichlorobenzene solution at 77 K (Figure S11) contained a single line of nearly Lorentzian shape with g = 2.0024 and ΔH = 0.75 mT. This is characteristic of magnetically diluted radicals in solution with average anisotropy. The g-factor for H2T(4-Py)P•− is close to that of free electrons, indicating a weak spin−orbital interaction of spin S = 1/2 with the orbital moments of the H2T(4-Py)P atoms. Thus, the EPR spectra of the reduced macrocycles, H2T(4Py)P•−, H2Pc•−,9−11 and H2TPCor•2−,12 have some similarities. The signals contain two components at room temperature, and the number of components increases to three for H2T(4Py)P•− when the temperature decreases below 39 K. The gfactors of the EPR signals from the reduced macrocycles are generally above 2.0000 for H2T(4-Py)P•− and H2Pc•−9−11 and slightly below 2.0000 for H2TPCor•2− (g1 = 1.9971 and g2 = 1.9790).12 All the salts containing reduced macrocycles manifest antiferromagnetic spin coupling. This results in additional asymmetry of the EPR signals, since the g-factors of the components shift to larger and smaller values and are broadened as the temperature decreases. It is interesting that the EPR lines are narrow (0.2−0.7 mT) for H2T(4-Py)P•− and H2Pc•−9−11 but wider (1−2 mT) for H2TPCor•2−.12 None of the signals from the reduced macrocycles show hyperfine splitting due to the interaction of the spin with nitrogen atoms. It is probably necessary to measure strongly diluted samples to observe such splitting in the solid state.

bands are observed in the solid state spectra at about 750 nm for H2TPCor•2−,12 900 nm for H2T(4-Py)P•−, and 1028−1033 nm for H2Pc•−.9−11 It can be concluded that extension of the πsystem of the macrocycle induces a red shift of the lowestenergy bands. IR spectra of H2T(4-Py)P and salt 1 are shown in Figure S5, and related data are listed in Table S1. Nearly all the absorption bands of H2T(4-Py)P are reproduced in the spectrum of 1, although some bands shifted by up to 10 cm−1. Magnetic Properties. The magnetic properties of 1 were studied by superconducting quantum interference device (SQUID) and electron paramagnetic resonance (EPR) techniques. The effective magnetic moment of 1 is 1.65 μB at 300 K (Figure S8), which indicates a contribution from one noninteracting S = 1/2 spin per H2T(4-Py)P•− radical anion (the calculated value is 1.73 μB). It was previously shown that one S = 1/2 spin is present in the H2TPCor•2− and H2Pc•− macrocycles. The Weiss temperature is only −2 K (Figure S9), indicating weak antiferromagnetic spin coupling in 1. This may be due to the absence of direct overlap between porphyrin macrocycles. The EPR spectra of 1 contains an intense signal which is good simulated with two Lorentzian components at 295 K due to the axial symmetry of the H2T(4-Py)P•− radical anions with g⊥ = 2.0031, line width ΔH⊥ = 0.186 mT, and g∥ = 2.0019 (ΔH∥ = 0.284 mT) (Figure 4a shows the spectrum of 1 at 230

■

CONCLUSIONS In conclusion, we obtained a salt with radical anions of tetra(4pyridyl)porphyrin that allowed us to study for the first time the effect of reduction on the molecular structure, and the optical and magnetic properties, of the free base porphyrin macrocycle. Reduction results in alteration of the C−C(meso) and C−C bonds in the pyrrole rings of H2T(4-Py)P•− accompanied by the appearance of short and long bonds belonging to two opposing pyrrole subunits. The H2T(4-Py)P•− radical anions show new low-energy bands with the most intense band appearing at 900 nm in the solid state spectrum. The position of this band is intermediate between those for H2TPCor•2− and H2Pc•−. Porphyrin radical anions are paramagnetic and have spin state S = 1/2. Thus, they manifest an intense EPR signal consisting of two narrow components at room temperature. The asymmetry of the signal increases at lower temperatures. This work shows that radical anions of porphyrins and metalloporphyrins can be synthesized, which allows the development of magnetic and conducting assemblies based on reduced porphyrin macrocycles. Since H2T(4-Py)P is a known ligand in the construction of supramolecular assemblies with metals and metal complexes,23 paramagnetic H2T(4Py)P•− radical anions can be used to design magnetic assemblies with essential magnetic interactions. This work is currently in progress.

Figure 4. EPR signal for polycrystalline 1 at 230 (a) and 39 K (b). Signal fitting to two or three Lorentzian components is shown below. Temperature dependences of the g-factor (c) and line width (d) for the components.

K). When temperature decreases below 39 K, the ESR line shape changes and is better simulated by three components; this may be associated with transition from axial to orthorhombic symmetry of the radical anion. The component parameters are gx = 2.0034 and ΔHx = 0.176 mT, gy = 2.0025 and ΔHy = 0.212 mT, and gz = 2.0008 and ΔHz = 0.263 mT at 39 K (Figure 4b). These changes can be associated with the appearance of static Jahn−Teller distortion manifested at low temperatures as discussed in the section on crystal structure. Additionally, antiferromagnetic intermolecular exchange between the spins of H2T(4-Py)P•− makes an additional contribution to the asymmetry of the signal at low temper-

■

EXPERIMENTAL SECTION

Materials. Free base 5,10,15,20-tetra(4-pyridyl)porphyrin (H2T(4Py)P, >97%) was purchased from Sigma-Aldrich. Potassium graphite (KC8) was purchased from Strem. Cryptand[2.2.2.] was purchased from TCI Reagents. The solvent o-dichlorobenzene (C6H4Cl2, Acros) 1864

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866

Article

The Journal of Organic Chemistry was distilled over CaH2 under reduced pressure, while n-hexane was distilled over Na/benzophenone. Solvents were degassed and stored in an MBraun 150B-G glovebox. Salt 1 was synthesized and stored in the glovebox in a controlled atmosphere containing less than 1 ppm water and oxygen. KBr pellets used for IR and UV−visible−NIR spectroscopy were prepared in the glovebox. Magnetic measurements were performed on a polycrystalline sample of 1 sealed in a 2 mm quartz tube under ambient pressure and anaerobic conditions. General. UV−visible−NIR spectra were measured as KBr pellets on a PerkinElmer Lambda 1050 spectrometer in the range 250−2500 nm. FT-IR spectra were obtained in KBr pellets with a PerkinElmer Spectrum 400 spectrometer (400−7800 cm−1). EPR spectra were recorded for a polycrystalline sample of 1 from room temperature (RT) to liquid helium temperature with a JEOL JES-TE 200 X-band ESR spectrometer equipped with a JEOL ES-CT470 cryostat. A Quantum Design MPMS-XL SQUID magnetometer was used to measure the static magnetic susceptibility of 1 in a magnetic field of 100 mT in the range 300−1.9 K. The contribution of the sample holder and core temperature independent diamagnetic susceptibility (χd) were subtracted from the experimental values. The χd values were estimated by extrapolating the data to the high-temperature range and fitting it using the following expression: χM = C/(T − Θ) + χd, where C is the Curie constant and Θ is the Weiss temperature. The effective magnetic moment (μeff) was calculated using the following formula: μeff = (8·χM·T)1/2 (Figure S8). Synthesis. Crystals of {cryptand[2.2.2.](K+)}{H2T(4-Py)P•−}· C6H4Cl2 (1) were obtained by reducing H2T(4-Py)P (25.8 mg, 0.042 mmol) with an excess of KC8 (20 mg, 0.148 mmol) in the presence of 1 equiv of cryptand[2,2,2] (16 mg, 0.042 mmol) in 16 mL of o-dichlorobenzene; the mixture was stirred at 80 °C for 24 h. The color of the solution changed from red to deep green and H2T(4-Py)P completely dissolved. The obtained solution was cooled to RT and filtered into a 50 mL glass tube with a ground glass plug and a 1.8 cm diameter; 30 mL of n-hexane was then layered over the solution. Crystals precipitated after slow mixing of the solutions over 1 month. The solvent was then decanted from the crystals, which were washed with n-hexane. Black trapezoids of 1 were obtained in 72% yield (35.7 mg). The composition of the obtained compound was determined by X-ray diffraction on a single crystal. Several crystals from a single synthesis were found to consist of a single crystalline phase. The composition of 1 could not be confirmed by elemental analysis due to extreme air sensitivity. X-ray Crystal Structure Determination. Crystal data of 1 at 100(1) K: C64H66Cl2KN10O6; Mr = 1181.26 g mol−1; black trapezoid; triclinic; P1̅; a = 13.2276(5) Å; b = 13.6630(5) Å; c = 19.1637(7) Å; α = 104.170(3)°; β = 98.467(3)°; γ = 113.339(4)°; V = 2965.0(2) Å3; Z = 2; dcalc = 1.323 g·cm−3; μ = 0.241 mm−1; F(000) = 1242; 2θmax = 58.678°; reflections measured, 38 510; unique reflections, 14 795; reflections with I > 2σ(I) = 10 407; parameters refined, 748; R1 = 0.0619; wR2 = 0.1526; G.O.F. = 1.024; CCDC 1572272. X-ray diffraction data for 1 at 100(1) K were collected on a Bruker Smart Apex II CCD diffractometer with graphite monochromated Mo Kα radiation using a DX-CS190LD cooling system (Japan Thermal Engineering Co.). Raw data reduction to F2 was carried out using a Bruker SAINT instrument.24 The structures were solved by direct methods and refined by the full-matrix least-squares method against F2 using SHELX 2016/6 and Olex2 1.2.25 Non-hydrogen atoms were refined in the anisotropic approximation. There are two halves of independent H2T(4-Py)P units in 1. The positions of hydrogen atoms connected to pyrrole nitrogen atoms of H2T(4-Py)P were found in a difference electron density map. The H atom is ordered in one independent half of H2T(4-Py)P and is statistically disordered over two sites in the other independent half of H2T(4-Py)P. Other hydrogen atoms were positioned geometrically.

■

■

Details of theoretical calculations, IR spectra of starting compounds and 1, crystal structure of 1, SQUID data for 1, EPR spectrum for 1 at 6.5 K (PDF) Crystallographic data for 1 (CIF)

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Dmitri V. Konarev: 0000-0002-7326-8118 Hiroshi Kitagawa: 0000-0001-6955-3015 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS The work was supported by the Russian Science Foundation (project No. 17-13-01215) and by JSPS KAKENHI Grant Number 26288035, and the JST (ACCEL) 27 (100150500010) project.

■

REFERENCES

(1) The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press, Inc.: London, 2000; Vols. 1 and 2, Chapters 10−13; Vol. 3, Chapter 25. (2) Milgrom, L. R. The Colors of Life: An Introduction to the Chemistry of Porphyrins and Related Compounds; Oxford University Press: Oxford, U.K., 1997; p 249. (3) Mashiko, T.; Dolphin, D. Porphyrins, Hydroporphyrins, Azaporphyrins, Phthalocyanines, Corroles, Corrins and Related Macrocycles. In Comprehensive Coordination Chemistry; Wilkinson, G., Guilard, R., McCleverty, S. A., Eds.; Pergamon Press: Oxford, U.K., 1987; Vol. 2, pp 813−898. (4) Claessens, C. G.; Blau, W. J.; Cook, M.; Hanack, M.; Nolte, R. J. M.; Torres, T.; Wöhrle, D. Monatsh. Chem. 2001, 132, 3−11. (5) Drain, C. M.; Varotto, A.; Radivojevic, I. Chem. Rev. 2009, 109, 1630−1658. (6) Inabe, T.; Tajima, H. Chem. Rev. 2004, 104, 5503−5534. (7) Miller, J. S. Inorg. Chem. 2000, 39, 4392−4408. (8) Clack, D. W.; Hush, N. S.; Woolsey, I. S. Inorg. Chim. Acta 1976, 19, 129−132. (9) Konarev, D. V.; Zorina, L. V.; Khasanov, S. S.; Litvinov, A. L.; Otsuka, A.; Yamochi, H.; Saito, G.; Lyubovskaya, R. N. Dalton Trans. 2013, 42, 6810−6816. (10) Konarev, D. V.; Kuzmin, A. V.; Faraonov, M. A.; Ishikawa, M.; Nakano, Y.; Khasanov, S. S.; Otsuka, A.; Yamochi, H.; Saito, G.; Lyubovskaya, R. N. Chem. - Eur. J. 2015, 21, 1014−1028. (11) Konarev, D. V.; Khasanov, S. S.; Ishikawa, M.; Otsuka, A.; Yamochi, H.; Saito, G.; Lyubovskaya, R. N. Dalton Trans. 2017, 46, 3492−3499. (12) Konarev, D. V.; Karimov, D. R.; Khasanov, S. S.; Otsuka, A.; Yamochi, H.; Kitagawa, H.; Lyubovskaya, R. N.; Shestakov, A. E. Dalton. Trans. 2017, 46, 13994−14001. (13) Shen, J.; Shao, J.; Ou, Z.; E, W.; Gryko, D. T.; Kadish, K. M.; Koszarna, B. Inorg. Chem. 2006, 45, 2251−2265. (14) Kadish, K. M.; Royal, G.; van Caemelbecke, E.; Gueletti, L. In The Porphyrin Handbook; Kadish, K. M., Smith, K. M., Guilard, R., Eds.; Academic Press: San Diego, CA, 2000; Vol. 9, pp 1−219. (15) Kon, H.; Tsuge, K.; Imamura, T.; Sasaki, Y.; Ishizaka, S.; Kitamura, N. Inorg. Chem. 2006, 45, 6875−6883. (16) Cissell, J. A.; Vaid, T. P.; Rheingold, A. L. Inorg. Chem. 2006, 45, 2367−2369. (17) Cissell, J. A.; Vaid, T. P.; Rheingold, A. L. J. Am. Chem. Soc. 2005, 127, 12212−12213. (18) Yoon, S. M.; Hwang, I.-C.; Kim, K. S.; Choi, H. C. Angew. Chem., Int. Ed. 2009, 48, 2506−2509.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.joc.7b02791. 1865

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866

Article

The Journal of Organic Chemistry (19) Gao, H.-L.; Chen, F.; Yao, G.-H.; Chen, D.-M. Chin. J. Chem. Phys. 2013, 26, 504−511. (20) (a) Li, Z.; Hu, Y.; Li, T. Mol. Cryst. Liq. Cryst. 2014, 605, 135− 145. (b) Chen, B. M. L.; Tulinsky, A. J. Am. Chem. Soc. 1972, 94, 4144−4151. (21) Konarev, D. V.; Khasanov, S. S.; Lyubovskaya, R. N. Asian J. Org. Chem. 2017, 6, 1028−1033. (22) Cissell, J. A.; Vaid, T. P.; DiPasquale, A. G.; Rheingold, A. L. Inorg. Chem. 2007, 46, 7713−7715. (23) (a) Sun, D.; Tham, F. S.; Reed, C. A.; Boyd, P. D. W. Proc. Natl. Acad. Sci. U. S. A. 2002, 99, 5088−5092. (b) Lipstman, S.; Goldberg, I. Cryst. Growth Des. 2010, 10, 1823−1832. (24) Bruker SAINT; Bruker Analytical X-ray Systems: Madison, WI, 1999. (25) (a) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. J. Appl. Crystallogr. 2009, 42, 339−341. (b) Sheldrick, G. M. Acta Crystallogr., Sect. C: Struct. Chem. 2015, 71, 3−8.

1866

DOI: 10.1021/acs.joc.7b02791 J. Org. Chem. 2018, 83, 1861−1866