Tricarbonyl Mono- and Dinuclear Rhenium(I) Complexes with Redox

Article pubs.acs.org/Organometallics

Tricarbonyl Mono- and Dinuclear Rhenium(I) Complexes with RedoxActive Bis(pyrazole)−Tetrathiafulvalene Ligands: Syntheses, Crystal Structures, and Properties Jing Xiong,† Wei Liu,‡ Yong Wang,‡ Long Cui,† Yi-Zhi Li,† and Jing-Lin Zuo*,† †

State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, People’s Republic of China ‡ College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215006, People’s Republic of China S Supporting Information *

ABSTRACT: Two new bis(3,5-dimethylpyrazole)-substituted tetrathiafulvalene ligands, 2,6(7)-bis(methylthio)-3,7(6)-bis(3sulfanyl-3,5-dimethylpyrazole)tetrathiafulvalene (L1) and 2,3-bis(methylthio)-6,7-bis(3-sulfanyl-3,5-dimethylpyrazole)tetrathiafulvalene (L2), have been prepared and characterized. On the basis of the two ligands, three interesting rhenium(I) tricarbonyl mono- or dinuclear complexes, ClRe(CO)3(cis-L1) (1), [ClRe(CO)3(trans-L1)]2 (2), and [ClRe(CO)3(L2)]2 (3), have been prepared and structurally characterized. Electrochemical studies show sequential oxidation processes of the compounds to the corresponding radical cation and dication states, suggesting that redox events are essentially dependent on the structures of the rhenium(I) complexes. The results have evidenced electronic interactions between the TTF cores in complexes 1 and 2. Geometric and electronic structures as well as the spectroscopic properties for complexes 1−3 have been investigated by using DFT and TDDFT calculations.

■

INTRODUCTION Since its first synthesis in 1970,1 tetrathiafulvalene (TTF) and its derivatives have long been known as essential building blocks for the preparation of organic conductors and superconductors.2,3 By either chemical or electrochemical oxidation at easily accessible potential windows, the TTF moiety can be reversibly oxidized to a cation radical (TTF•+) and a dication (TTF2+). Many attempts have focused on developing TTF as a donor unit in charge-transfer systems with potential applications as molecular electronic devices, nonlinear optics, organic metals, and chromophores for dyes.4 A prominent class of redox-active ligands based on designed mono- and multidentate coordinating functional groups attached to TTF moieties has been extensively studied.5−7 In particular, transition-metal ions have also been incorporated in these functional ligands to prepare electroactive metal complexes.8 First, through metal−ligand interactions, the metal ions may serve as a bridge in order to assemble two or more TTF units. Interplay could possibly occur between the © 2012 American Chemical Society

electron-donating properties of the electroactive ligand and the electron density on the metallic center, especially when functional groups are directly bonded to the TTF framework. Second, the functional redox ligands may be further activated and assembled by chemical or electrochemical oxidation. It is expected that such interactions between the inorganic and organic substructures will modify and improve the electronic properties. In the skeleton of TTF, the central CC double bond linking the two five-membered rings can show a cis or trans configuration in the appropriate bis-, tris-, and tetrakissubstituted derivatives. Transformation of the cis or trans configuration of TTF can be controlled by chemical, electrochemical, or photochemical mean,9 offering the possibility of generating molecular-sized switches.10 Received: February 26, 2012 Published: May 7, 2012 3938

dx.doi.org/10.1021/om300159r | Organometallics 2012, 31, 3938−3946

Organometallics

Article

Scheme 1. Synthetic Routes to Complexes 1−3

prepared, and their chelating ability was proved by the formation of some mononuclear rhenium(I) complexes.17 With two or more pyrazole substituents introduced to the TTF center at different sites, we may expect the formation of

On the other hand, due to their unique photophysical and photochemical properties,11 air-stable tricarbonylrhenium(I) complexes have been widely studied.12−16 In our previous work, a series of monosubstituted pyrazole TTF ligands have been 3939


Organometallics

Article

Table 1. Crystallographic Data for Complexes 1−3 empirical formula Mr cryst syst space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z ρc (g cm−3) F(000) T/K μ(Mo Kα)/mm−1 index ranges

GOF (F2) R1,a wR2b (I > 2σ(I)) R1,a wR2b (all data) a

1

2·3CHCl3·1.5H2O

3·2C4H8O

C21H18ClN4O3ReS8 852.52 triclinic P1̅ 9.792(1) 11.979 (1) 14.821(1) 111.514(2) 95.467(3) 109.355(2) 1478.7(3) 2 1.915 832 291(2) 4.796 −12 ≤ h ≤11 −14 ≤ k ≤ 14 −17 ≤ l ≤ 18 1.005 0.0429, 0.0967 0.0499, 0.0983

C45H42Cl11N8O7.5Re2S16 2090.18 triclinic P1̅ 11.219(1) 11.773(1) 32.702(1) 85.256(2) 88.350(3) 67.472(2) 3976.0(7) 2 1.746 2042 291(2) 3.879 −13 ≤ h ≤ 13 −14 ≤ k ≤ 14 −32 ≤ l ≤ 40 1.164 0.0487, 0.1135 0.0673, 0.1231

C50H56Cl2N8O8Re2S16 1853.29 monoclinic P21/c 10.382(2) 27.918(2) 13.283(1) 90 113.004(3) 90 3543.6(9) 2 1.737 1832 291(2) 4.013 −12 ≤ h ≤ 9 −34 ≤ h ≤ 26 −16 ≤ h ≤ 16 1.051 0.0477, 0.1140 0.0715, 0.1250

R1 = ∑||Fo| − |Fc||/∑|Fo|. bwR2 = [∑w(Fo2 − Fc2)2/w(Fo2)2]1/2.

ability of our newly synthesized tetrathiafulvalene−pyrazole ligands. Crystal Structures. The solid structures of 1−3 were determined by single-crystal X-ray diffraction. The crystallographic and data collection parameters are given in Table 1; selected bond lengths and angles are given in Tables 2−4.

new multinuclear or even polymeric metal complexes. In this paper, the bis-chelating pyrazole-substituted TTF ligands L1 and L2 have been successfully synthesized (Scheme 1). L1 is obtained as cis and trans isomers that are difficult to separate by flash chromatography. Reactions of L1 and L2 with Re(CO)5Cl afford interesting rhenium(I) tricarbonyl mono- and dinuclear complexes: ClRe(CO)3(cis-L1) (1), [ClRe(CO)3(trans-L1)]2 (2), and [ClRe(CO)3(L2)]2 (3), respectively. Herein, the syntheses, structures, and properties of these new compounds are described.

Table 2. Selected Bond Distances (Å) and Angles (deg) for 1 Re(1)−N(1) Re(1)−C(1) Re(1)−C(3) N(1)−N(2) C(9)−C(10) C(16)−S(1) C(12)−C(13) N(3)−Re(1)−N(1) C(2)−Re(1)−N(1)

■

RESULTS AND DISCUSSION Synthesis and Characterization. As shown in Scheme 1, treatment with a mixture of cis-/trans- tetrathiafulvalenesubstituted thiapropanenitrile precursor (P1) isomers in the presence of 3-chloro-2,4-pentanedione affords a tetrathiafulvalenyl−acetylacetonate precursor (P2) isomers. Further reactions of these tetrathiafulvalene-fused acetylacetonate precursors (P2 and P3) with hydrazine hydrate (N2H4·H2O) afford the new bis(3,5-dimethylpyrazole)-substituted tetrathiafulvalene ligands cis-/trans-L1 and L2. Rhenium(I) complexes 1−3 are synthesized by refluxing Re(CO)5Cl with 1 equiv of the corresponding ligand. In particular, complexes 1 and 2 can be separated successfully by flash chromatography on a silica gel column and they show good solubility in CH2Cl2 and CHCl3. The characterization of 1 and 2 has been accomplished by IR, mass spectrometry, 1H NMR, and UV−vis spectra. However, it is difficult to characterize complex 3 by these spectroscopic methods in solution due to its poor solubility. Three typical bands in the CO stretching region are observed in IR spectra for complexes 1−3, which indicate the facial arrangement of the three coordinated CO ligands. In the 1H NMR spectra for 1 and 2, the presence of a single set (ca. 12.18 and 11.91 ppm) of pyrazole signals indicates the equivalence of the two ligands in each complex. The results show the versatile coordination

2.231(6) 1.892(6) 1.875(7) 1.324(8) 1.330(10) 1.760(7) 1.337(10) 86.7(1) 174.9(3)

Re(1)−N(3) Re(1)−C(2) Re(1)−Cl(1) N(3)−N(4) C(15)−C(16) C(19)−S(1) C(18)−N(3) C(1)−Re(1)−N(1) C(3)−Re(1)−Cl(1)

2.209(5) 1.915(8) 2.505(1) 1.342(8) 1.307(9) 1.755(6) 1.357(8) 90.4(2) 175.1(2)

Figure 1 gives an ORTEP view of 1 with atomic numbering. The asymmetric unit is composed of a ReI metal center and a cis-bis(3,5-dimethylpyrazole)tetrathiafulvalene. The ReI ions adopt a distorted-octahedral geometry and are coordinated by three carbonyl ligands in a fac arrangement, a halogen atom, and two nitrogen atoms from the ligand. The average Re−C and Re−N distances of 1.89 and 2.22 Å, respectively, are similar to corresponding distances reported for analogous complexes.18 The TTF core is not planar and adopts a boatlike configuration. Distortion from planarity of the TTF subunit is observed, and the dihedral angle between the planes of the five-membered rings (including the atoms S(3), S(4), C(13), C(15), and C(16), and the atoms S(5), S(6), C(12), C(9) and C(10)) is 51.2°.19 The whole molecule looks like a crab (Figure 2): the TTF skeleton forms the body of the crab, and the two 3,5dimethylpyrazole groups form a pair of pinchers that clamp the ReI ion. 3940


Organometallics

Article

Table 3. Selected Bond Distances (Å) and Angles (deg) for 2 Re(1)−N(1) Re(2)−N(4) Re(1)−C(1) Re(1)−C(3) Re(2)−C(22) Re(2)−C(24) N(7)−Re(1)−N(1) C(2)−Re(1)−N(7) N(4)−Re(2)−N(5) C(23)−Re(2)−N(5)

2.180(5) 2.185(5) 1.885(8) 1.780(7) 1.884(7) 1.847(7) 82.5(2) 175.3(3) 84.7(2) 176.5(3)

Re(1)−N(7) Re(2)−N(5) Re(1)−C(2) Re(1)−Cl(1) Re(2)−C(23) Re(2)−Cl(2) C(3)−Re(1)−N(1) C(1)−Re(1)−Cl(1) C(24)−Re(2)−N(4) C(22)−Re(2)−Cl(2)

intermolecular S···S contacts (3.75 Å) are observed in the structure through stacking of molecules, while these contacts are much longer (4.21 and 4.16 Å) in the case of intermolecular interactions (Figure S1, Supporting Information). In comparison with the crystal structures of 17-membered and 19membered complexes in the literature,20 complex 2 appears to be less strained, with a 30-membered rectangular metallamacrocycle. The structure of 2 is somewhat similar to that in other multinuclear Re complexes,21 and the cavity of the metallamacrocycle could be achieved with rough dimensions of 15.3 × 4.3 Å for complex 2. In complex 3, the two TTF cores are nearly planar and parallel with each other (Figure 4). In comparison with complex 2, the Re−N(pz) bond distances in 3 are 0.05 Å longer (on average). The N(1)−Re(1)−N(3) angle is also slightly larger (about 4°) than that in complex 2, which may result from intermolecular steric repulsions. Two 3,5dimethylpyrazole groups are within the same side of TTF moiety, and they are the bonding sites to the central ReI ion, forming a metallamacrocycle with 22 atoms, less than the number in complex 2. Electrochemical and Spectroscopic Properties. The electrochemical behaviors of cis-/trans-L1, 1, and 2 were investigated in CH2Cl2 using (n-NBu4)ClO4 as supporting electrolyte by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). As expected, ligand L1 exhibits two reversible one-electron redox couples, the first at 0.37 V and the second at 0.67 V (vs Ag/Ag+), which correspond to the formation of its radical cation and dication species, respectively (Figure 5). For comparison with the monopyrazole-substituted TTF ligand 4a,17 cyclic voltammetry vs Fc/Fc+ has been performed for cis-/trans-L1 and L2 and the data are given in Table S1 (Supporting Information). In comparison with 4a, bis(pyrazole)-substituted ligands L1 and L2 are slightly difficult to oxidize to the radical cation state, which is due to the relatively electron-withdrawing inductive effect of the pyrazole group. Among these ligands, further oxidation to the dication state is the least favorable for L2. Complex 1 shows three oxidation processes (E1ox = 0.68 V, 2 E ox = 0.77 V, E3ox = 1.24 V vs Ag/Ag+; Figure 5). Since the first two redox waves were not fully separated, differential pulse voltammetry (DPV) was performed (Figure 6). According to differential pulse votammetry, it is obvious that there are two peaks. In comparison with L1, it is noteworthy that the first redox couple is significantly anodically shifted. The reason is perhaps that the boatlike configuration of the TTF core makes oxidation unfavorable.9c,20,22 The structural feature is of crucial importance: when the TTF backbone is bent significantly, its well-defined reversible electrochemical properties and therefore

Table 4. Selected Bond Distances (Å) and Angles (deg) for 3 Re(1)−N(1) Re(1)−C(1) Re(1)−C(3) N(1)−Re(1)−N(3) C(1)−Re(1)−N(3)

2.222(5) 1.929(7) 1.865(7) 87.6(2) 175.5(2)

Re(1)−N(3) Re(1)−C(2) Re(1)−Cl(1) C(2)−Re(1)−N(1) C(3)−Re(1)−Cl(1)

2.156(6) 2.212(6) 1.885(7) 2.483(1) 1.885(7) 2.469(1) 173.3(3) 178.1(2) 177.7(3) 176.0(2)

2.237(6) 1.886(8) 2.480(2) 178.2(3) 175.1(2)

Figure 1. ORTEP view of complex 1 with the atom-numbering scheme. Ellipsoids are drawn at the 30% probability level. Hydrogen atoms are omitted for clarity.

Figure 2. Crab-shaped complex 1.

The asymmetric unit of complex 2 consists of two ReI metal centers linked by two trans-bis(3,5-dimethylpyrazole)tetrathiafulvalene molecules (trans-L1). The coordination environment of the ReI ion is similar to that of complex 1, except for two nitrogen atoms from different ligands (Figure 3). The TTF core is nearly planar, with a small dihedral angle of 5.6°. It is almost perpendicular to the plane formed by the appended pyrazole group, with a dihedral angle of 80.9°. Weak 3941


Organometallics

Article

Figure 3. Crystal structure of complex 2. Solvated molecules are omitted for clarity.

Figure 6. Differential pulse voltammogram for compounds 1 and 2 (5 × 10−4 M), measured in CH2Cl2 (vs Ag/Ag+), at a scan rate of 100 mV/s.

Figure 4. Crystal structure of complex 3. Hydrogen atoms and solvated molecules are omitted for clarity.

applicability to redox-responsive ligands will be seriously affected. The first two well-defined peaks (E1ox = 0.43 V, E2ox = 0.70 V) indicate two sequential oxidation steps for complex 2. The first peak at 0.43 V is a one-electron-oxidation step, while the

second peak at higher potential is a three-electron process. This result is reminiscent of what was previously observed for other complexes such as Re(CO)3Cl[TTF-Pz]2.17 In Re(CO)3Cl[TTF-Pz]2 type complexes, two TTF moieties are linked by a Re(SPz)2 bridge. Oxidation of two TTF moieties undergoes three steps: two one-electron-oxidation steps and a twoelectron process. The splitting of the two redox systems may result from bond interactions. Similar interactions between the donor cores are electrochemically evidenced in compounds involving two TTF moieties described previously.23 For complex 2, two TTF moieties are linked by two Re(SPz)2 bridges: i.e., there are two bonding pathways through the Re(SPz)2 bridges for TTFs. The intramolecular interactions between TTF cores are much stronger than that in Re(CO)3Cl[TTF-Pz]2. Additionally, weak intra- and intermolecular S···S contacts are also observed in the structure (Figure S1, Supporting Information). Therefore, we may deduce that after oxidation of one TTF skeleton into the species 2•+, the other TTF skeleton may bend due to strong intra- and intermolecular interactions and would be difficult to oxidize. Then, the next redox couple is shifted anodically and merges with the following two-electron process, forming a threeelectron-oxidation process.

Figure 5. Cyclic voltammogram for compounds L1, 1, and 2 (5 × 10−4 M), measured in CH2Cl2 (vs Ag/Ag+), at a scan rate of 100 mV/s. 3942


Organometallics

Article

Rationalizations of UV−vis spectra have been performed for complexes 1−3 using time-dependent DFT (TDDFT), possibly providing some insight into the spectroscopic properties. As shown in Figure 8, Figures S3 and S4 (Supporting Information), and Table 6, the calculated absorptions are similar for complexes 1−3; detailed discussions are presented for complex 1 only. The calculated electronic absorption spectrum of complex 1 and the dominantly involved orbitals are depicted in Figure 8. The experimental intense absorption around 338 nm corresponds to the calculated band at 320 nm, which may originate from a mixed transition of HOMO → LUMO+4 and HOMO-2 → LUMO/LUMO+1 with significant oscillator strength. Such a transition can be ascribed to a combination of intramolecular charge transfer (ICT), π → π*, and ligand to metal charge transfer (LMCT), due to the orbital characters of the corresponding starting and ending states.

The last oxidation peak in the range of 1.24−1.35 V is observed for ReI/ReII in cyclic voltammograms of 1 and 2. It is noteworthy that the waves are not of equal in intensity to the TTF oxidation peak, possibly due to adsorption phenomena or instability of the fully oxidized units. UV−vis spectra of L1, 1, and 2 in CH2Cl2 are shown in Figure 7. Intense absorption bands around ca. 245−400 nm for

■

CONCLUSION In summary, two new 3,5-dimethylpyrazole-substituted tetrathiafulvalene ligands gave been successfully prepared and their coordination ability has been confirmed by the formation of interesting rhenium(I) tricarbonyl mono- and dinuclear complexes. The highly electron conjugated structures and interesting redox-active properties for compounds 1 and 2 have been evidenced by electrochemical studies. DFT and TDDFT calculations have been used to interpret the electronic and vibrational properties of complexes 1−3. The results show that there are electronic interactions between TTFs in complexes 1 and 2. Further investigations in this work will focus on binding of TTF-pyrazole type ligands to other transition-metal ions and exploring new functional materials.

Figure 7. UV−vis absorption spectra of L1, 1, and 2 (5 × 10−5 M) measured in CH2Cl2.

L1, 1, and 2 can be assigned to intraligand (IL) transitions, since similar absorptions are observed for free ligands. However, no obvious absorption band with metal-to-ligand charge transfer (MLCT) character are observed for complexes 1 and 2. Since complex 3 has poor solubility in common solvents, UV−vis spectra for all complexes have also been measured in the solid state (Figure S2, Supporting Information). In comparison to the related ligands, an additional broad absorption is observed around 857 nm for complexes 1−3. Computational Studies. Theoretical calculations were carried out by using density functional theory (DFT) for complexes 1−3 in the neutral state. The optimized geometries are in good agreement with the experimental structures, reproducing the boatlike conformation of the TTF moiety in the neutral molecules. The carbonyl group (CO) stretching vibrations of complexes 1−3 are calculated (scaled by 0.961424 and compared with experimental results, Table 5). For complex 2, the experimental

■

General Procedures. Schlenk techniques were used in carrying out manipulations under a N2 atmosphere. The IR spectra were taken on a Vector22 Bruker spectrophotometer (400−4000 cm−1) with KBr pellets. Mass spectra were recorded on a Bruker Autoflex II instrument for MALDI-TOF-MS or on a Varian MAT 311A instrument for ESIMS. Elemental analyses for C, H, and N were performed on a PerkinElmer 240C analyzer. Absorption spectra were measured on a Shimadzu UV-3100 spectrophotometer. Cyclic voltammetry was performed on an IM6ex electrochemical workstation, with platinum as the working and counter electrodes, Ag/Ag+ as the reference electrode, and 0.1 M n-Bu4NClO4 as the supporting electrolyte. NMR spectra were measured on a Bruker AM 500 spectrometer. 2,6(7)Bis[(2-cyanoethyl)thio]-3,7(6)-bis(methylthio)tetrathiafulvalene (cis-/ trans-P 1 ) and 2,3-bis(methylthio)-6,7-bis(3-sulfanyl-2,4pentanedione)tetrathiafulvalene (P3) were synthesized in high yields according to literature methods.25 2,6(7)-Bis(methylthio)-3,7(6)-bis(3-sulfanyl-2,4pentanedione)tetrathiafulvalene (cis-/trans-P2). Under a nitrogen atmosphere, a solution of CsOH·H2O (369 mg, 2.2 mmol) in 6 mL of CH3OH was added dropwise to a solution of cis-/trans-P1 (932 mg, 2 mmol) in 25 mL of THF at room temperature. The mixture was stirred for 30 min, and 3-chloro-2,4-pentanedione (0.27 mL, 3 mmol) was added. The reaction mixture was stirred overnight. Then the solvent was evaporated and the orange residue was extracted with CH2Cl2 and washed with water. The organic extract was purified by column chromatography (CH2Cl2/petroleum ether) on silica gel. After evaporation of solvent, a pure orange-red oil was collected. Yield: 912 mg, 82%. IR (KBr, cm−1): 3448, 1563, 1407, 1385, 1263, 1018, 892, 770. 1H NMR (500 MHz, CDCl3, ppm): δ 2.44 (s, 6H), 2.51 (s, 12H), 17.25 (s, 2H). MS (MALDI-TOF): m/z 556.0 [M+]. Anal. Calcd for C18H20O4S8: C, 38.82; H, 3.62. Found: C, 38.73; H, 3.56.

Table 5. Calculated and Experimental IR Spectroscopic Data (cm−1) of the Carbonyl Group (CO) Stretching Vibrations for 1−3 symmetric vibrations

anti-symmetric vibrations

complex

calcd

exptl

calcd

exptl

calcd

exptl

1 2 3

2038 2035 2033

2027 2029 2027

1966 1963 1960

1926 1921 1921

1926 1926 1924

1895 1890 1900

EXPERIMENTAL SECTION

symmetric vibration (2029 cm−1) matches the calculated value very well (2035 cm−1). The two anti-symmetric vibrations are calculated at 1963 and 1926 cm−1, slightly higher than experimental data by 42 and 36 cm−1. Similar data are observed for complexes 1 and 3. Thus, experimental geometries and vibration frequencies are reproduced sufficiently by the calculations. 3943


Organometallics

Article

Figure 8. Simulated spectrum of 1 and relevant molecular orbitals involved in the most intense transition (320 nm, f = 0.1565) (contour value 0.02 au). 895, 767. 1H NMR (500 MHz, d6-DMSO, ppm): δ 2.26−2.50 (m, 18H). MS (MALDI-TOF): m/z 548.1 [M+]. Anal. Calcd for C18H20N4S8: C, 39.39; H, 3.67; N, 10.21. Found: C, 39.45; H, 3.72; N, 10.12. ClRe(CO)3(cis-L1) (1) and [ClRe(CO)3(trans-L1)]2 (2). Under a nitrogen atmosphere, a mixture of Re(CO)5Cl (72 mg, 0.2 mmol) and cis-/trans-L1 (110 mg, 0.2 mmol) was refluxed in 10 mL of toluene for 1 h. The solvent was removed to give the orange crude product. Purification was achieved by flash chromatography on a silica gel column using CH2Cl2 as eluent. Data for 1 are as follows. Yield: 63 mg (37%). IR (KBr, cm−1): 2027, 1926, 1895 (νC≡O). 1H NMR (500 MHz, CDCl3, ppm): δ 2.37−2.42 (m, 12H), δ 2.51 (s, 6H), 12.18 (s, 2H). MS (ESI): m/z 853.3 [M+]. Anal. Calcd for C21H18ClN4O3ReS8: C, 29.58; H, 2.13; N, 6.57. Found: C, 29.65; H, 2.17; N, 6.49. Data for 2 are as follows. Yield: 85 mg (50%). IR (KBr, cm−1): 2029, 1921, 1890 (νCO). 1H NMR (500 MHz, CDCl3, ppm): δ 2.42−2.44 (m, 24 H), 2.57 (s, 12H), 11.91 (s, 4H). MS (ESI): m/z 1707.7 [M+]. Anal. Calcd for C42H36Cl2N8O6Re2S16: C, 29.58; H, 2.13; N, 6.57. Found: C, 29.53; H, 2.19; N, 6.56. [ClRe(CO)3L2]2 (3). Under a nitrogen atmosphere, a mixture of Re(CO)5Cl (72 mg, 0.2 mmol) and L2 (110 mg, 0.2 mmol) was refluxed in 10 mL of toluene for 40 min. The solvent was removed to give the brown crude product. Purification was achieved by flash chromatography on a silica gel column (CH2Cl2/THF 20/1). Yield: 17 mg (10%). IR (KBr, cm−1): 2027, 1921, 1900 (νCO). Anal. Calcd for C42H36Cl2N8O6Re2S16: C, 29.58; H, 2.13; N, 6.57. Found: C, 29.61; H, 2.10; N, 6.54. Crystal Structure Determination. The data were collected on a Bruker Smart Apex CCD diffractometer equipped with graphitemonochromated Mo Kα (λ = 0.710 73 Å) radiation using a ω−2θ scan mode at 293 K. The highly redundant data sets were reduced using SAINT and corrected for Lorentz and polarization effects. Absorption corrections were applied using SADABS supplied by Bruker. The structure was solved by direct methods and refined by full-matrix leastsquares methods on F2 using SHELXTL-97. All non-hydrogen atoms were found in alternating difference Fourier syntheses and leastsquares refinement cycles and, during the final cycles, were refined anisotropically. Hydrogen atoms were placed in calculated positions and refined as riding atoms with a uniform value of Uiso. Computational Details. All calculations were carried out with Gaussian03 programs.26 Density functional theory (DFT) and timedependent DFT (TDDFT) with the three-parameter hybrid functional (B3LYP) were employed.27 The calculations were carried out using a 6-31G* basis set for C, H, N, O, S, and Cl atoms and effective core

Table 6. Main Calculated and Experimental Optical Transitions for 1−3 orbital excitationa 1

2

3

179 (H) → 184 (L+4) 177 (H-2) → 180 (L) 177 (H-2) → 181 (L+1) 357 (H-1) → 361 (L+2) 357 (H-1) → 362 (L+3) 357 (H-1) → 363 (L+4) 357(H-1) → 361(L+2) 357 (H-1) → 362 (L+3) 358 (H) → 361 (L+2) 358 (H) → 362 (L+3)

character π → π* ICT LMCT

composition 0.581 26

exptl value/ nm

calcd value/ nm

f

320

0.1565

338

375

0.0495

336

369

0.0905

b

0.254 60 0.190 67 π → π* ICT LMCT

0.186 68

0.639 03 0.157 05 ICT π → π*

−0.358 87 −0.225 26 −0.290 23 0.434 45

a

The molecular orbital number involved in each transition. bOscillator strength.

2,6(7)-Bis(methylthio)-3,7(6)-bis(3-sulfanyl-3,5dimethylpyrazole)tetrathiafulvalene (cis-/trans-L1). To a suspension of cis-/trans-P2 (556 mg, 1 mmol) in 25 mL of ethanol was added hydrazine hydrate (0.15 mL, 3 mmol) at room temperature with stirring. The reaction mixture was refluxed for 5 h and cooled to room temperature. The orange crystalline solids of L1 were filtered, washed with Et2O, and dried under vacuum. Yield: 356 mg (65%). IR (KBr, cm−1): 3404, 3147, 3078, 2918, 1566, 1425, 1305, 1028, 892, 769. 1H NMR (500 MHz, d6-DMSO, ppm): δ 2.18−2.42 (m, 18H). MS (MALDI-TOF): m/z 547.9 [M+]. Anal. Calcd for C18H20N4S8: C, 39.39; H, 3.67; N, 10.21. Found: C, 39.41; H, 3.61; N, 10.15. 2,3-Bis(methylthio)-6,7-bis(3-sulfanyl-3,5dimethylpyrazole)tetrathiafulvalene (L2). L2 was obtained according to the method described above for L1. Yield: 390 mg (67%). IR (KBr, cm−1): 3410, 3069, 2920, 1561, 1423, 1308, 1030, 3944


Organometallics

Article

Gal, Y.; Golhen, S.; Cador, O.; Ouahab, L. Inorg. Chem. 2009, 48, 7421. (c) Pointillart, F.; Cauchy, T.; Le Gal, Y.; Golhen, S.; Cador, O.; Ouahab, L. Inorg. Chem. 2010, 49, 1947. (d) Pointillart, F.; Klementieva, S.; Kuropatov, V.; Le Gal, Y.; Golhen, S.; Cador, O.; Cherkasov, V.; Ouahab, L. Chem. Commun. 2012, 48, 714. (e) Cosquer, G.; Pointillart, F.; Le Gal, Y.; Golhen, S.; Cador, O.; Ouahab, L. Chem.Eur. J. 2011, 17, 12502. (9) (a) Souizi, A.; Robert, A. J. Org. Chem. 1987, 52, 1610. (b) Ballardini, R.; Balzani, V.; Becher, J.; Di Fabio, A.; Gandolfi, M. T.; Mattersteig, G.; Nielsen, B. M.; Raymo, M. F.; Rowan, J. S.; Stoddart, J. F.; White, J. P. A.; Williams, J. D. J. Org. Chem. 2000, 65, 4120. (10) (a) Kaifer, A. E. Acc. Chem. Res. 1999, 32, 62. (b) Fabbrizzi, L.; Licchelli, M.; Pallavicini, P. Acc. Chem. Res. 1999, 32, 846. (11) (a) Wrighton, M.; Morse, D. L. J. Am. Chem. Soc. 1974, 96, 998. (b) Lucia, L. A.; Abboud, K.; Schanze, K. S. Inorg. Chem. 1997, 36, 6224. (12) (a) Lo, K. K. W.; Tsang, K. H. K.; Zhu, N. Organometallics 2006, 25, 3220. (b) Busby, M.; Matousek, P.; Towrie, M.; Clark, I. P.; Motevalli, M.; Hartl, F.; Vlček, A., Jr. Inorg. Chem. 2004, 43, 4523. (c) Wei, L.; Babich, J.; Ouellette, W. W.; Zubieta, J. Inorg. Chem. 2006, 45, 3057. (d) Wang, K. Z.; Huang, L.; Gao, L. H.; Jin, L. P.; Huang, C. H. Inorg. Chem. 2002, 41, 3353. (e) Yam, V. W. W.; Ko, C. C.; Zhu, N. J. Am. Chem. Soc. 2004, 126, 12734. (13) (a) Koike, K.; Okoshi, N.; Hori, H.; Takeuchi, K.; Ishitani, O.; Tsubaki, H.; Clark, I. P.; George, M. W.; Johnson, F. P. A.; Turner, J. J. J. Am. Chem. Soc. 2002, 124, 11448. (b) Tsubaki, H.; Sekine, A.; Ohashi, Y.; Koike, K.; Takeda, H.; Ishitani, O. J. Am. Chem. Soc. 2005, 127, 15544. (c) Marti, N.; Spingler, B.; Breher, F.; Schibli, R. Inorg. Chem. 2005, 44, 6082. (d) de Silva, A. P.; Gunaratne, N.; Gunnlaugsson, T.; Huxley, A. J. M.; McCoy, C. P.; Rademacher, J. T.; Rice, T. E. Chem. Rev. 1997, 97, 1515. (e) Stufkens, D. J.; Vlček, A., Jr. Coord. Chem. Rev. 1998, 117, 127. (14) (a) Pomestchenko, I. E.; Polyansky, D. E.; Castellano, F. N. Inorg. Chem. 2005, 44, 3412. (b) Lam, S. C. F.; Yam, V. W. W.; Wong, K. M. C.; Cheng, E. C. C.; Zhu, N. Organometallics 2005, 24, 4298. (c) Gabrielsson, A.; Hartl, F.; Zhang, H.; Lindsay Smith, J. R.; Towrie, M.; Vlĕk, A., Jr.; Perutz, R. N. J. Am. Chem. Soc. 2006, 128, 4253. (d) Coe, B. J.; Curati, N. R. M.; Fitzgerald, E. C.; Coles, S. J.; Horton, P. N.; Light, M. E.; Hursthouse, M. B. Organometallics 2007, 26, 2318. (e) Blanco-Rodríguez, A. M.; Towrie, M.; Collin, J. P.; Záliš, S.; Vlček, A., Jr. Dalton Trans. 2009, 3941. (15) (a) Reger, D. L.; Watson, R. P.; Smith, M. D.; Pellechia, P. J. Organometallics 2005, 24, 1544. (b) Wei, Q. H.; Yin, G. Q.; Zhang, L. Y.; Chen, Z. N. Inorg. Chem. 2006, 45, 10371. (c) Cattaneo, M.; Fagalde, F.; Katz, N. E. Inorg. Chem. 2006, 45, 6884. (d) de Wolf, P.; Waywell, P.; Hanson, M.; Heath, S. L.; Meijer, A. J. H. M.; Teat, S. J.; Thomas, J. A. Chem. Eur. J. 2006, 12, 2188. (16) (a) Wong, K. M. C.; Lam, S. C. F.; Ko, C. C.; Zhu, N.; Yam, V. W. W.; Roué, S.; Lapinte, C.; Fathallah, S.; Costuas, K.; Kahlal, S.; Halet, J. F. Inorg. Chem. 2003, 42, 7086. (b) Azócar, M. I.; Mikelsons, L.; Ferraudi, G.; Moya, S.; Guerrero, J.; Aguirre, P.; Martinez, C. Organometallics 2004, 23, 5967. (c) Yam, V. W. W.; Lo, W. Y.; Lam, C. H.; Fung, W. K. M.; Wong, K. M. C.; Lau, V. C. Y.; Zhu, N. Coord. Chem. Rev. 2003, 245, 39. (17) Liu, W.; Xiong, J.; Wang, Y.; Zhou, X. H.; Wang, R.; Zuo, J. L.; You, X. Z. Organometallics 2009, 28, 755. (18) (a) Martí, A. A.; Mezei, G.; Maldonado, L.; Paralitici, G.; Raptis, R. G.; Colón, J. L. Eur. J. Inorg. Chem. 2005, 118. (b) Li, M. J.; Ko, C. C.; Duan, G. P.; Zhu, N.; Yam, V. W. W. Organometallics 2007, 26, 6091. (c) Qin, J.; Hu, L.; Li, G. N.; Wang, X. S.; Xu, Y.; Zuo, J. L.; You, X. Z. Organometallics 2011, 30, 2173. (19) Le Derf, F.; Mazari, M.; Mercier, N.; Levillain, E.; Richomme, P.; Becher, J.; Garín, J.; Orduna, J.; Gorgues, A.; Sallé, M. Inorg. Chem. 1999, 38, 6096. (20) Gachot, G.; Pellon, P.; Roisnel, T.; Lorcy, D. Eur. J. Inorg. Chem. 2006, 2604. (21) (a) Benkstein, K. D.; Hupp, J. T.; Stern, C. L. J. Am. Chem. Soc. 1998, 120, 12982. (b) Dinolfo, P. H.; Hupp, J. T. J. Am. Chem. Soc. 2004, 126, 16814. (c) Dinolfo, P. H.; Williams, M. E.; Stern, C. L.;

potentials (ECP) such as LANL2DZ for Re atoms. All geometries were characterized as minima by frequency analysis (Nimag = 0).

■

ASSOCIATED CONTENT

* Supporting Information S

Figures and tables giving additional characterization and theoretical data and CIF files giving crystal data for 1−3. This material is available free of charge via the Internet at http://pubs.acs.org.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Fax: +86-25-83314502. Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This work was supported by the Major State Basic Research Development Program (No. 2011CB808704) and the National Natural Science Foundation of China (Nos. 51173075 and 21021062).

■

REFERENCES

(1) (a) Wudl, F.; Smith, G. M.; Hufnagel, E. J. Chem. Commun. 1970, 1435. (b) Wudl, F.; Wobschall, D.; Hufnagel, E. J. J. Am. Chem. Soc. 1972, 94, 670. (2) TTF Chemistry: Fundamentals and Applications of Tetrathiafulvalene; Yamada, J., Sugimoto, T., Eds.; Springer-Verlag: Berlin, 2004. (3) (a) Bendikov, M.; Wudl, F.; Perepichka, D. F. Chem. Rev. 2004, 104, 4891. (b) Kobayashi, H.; Cui, H.; Kobayashi, A. Chem. Rev. 2004, 104, 5265. (4) (a) Hansen, J. A.; Becher, J.; Jeppesen, J. O.; Levillain, E.; Nielsen, M. B.; Petersen, B. M.; Petersen, J. C.; Şahin, Y. J. Mater. Chem. 2004, 14, 179. (b) Dumur, F.; Gautier, N.; Gallego-Planas, N.; Şahin, Y.; Levillain, E.; Mercier, N.; Hudhomme, P.; Masino, M.; Girlando, A.; Lloveras, V.; Vidal-Gancedo, J.; Veciana, J.; Rovira, C. J. Org. Chem. 2004, 69, 2164. (c) Ho, G.; Heath, J. R.; Kondratenko, M.; Perepichka, D. F.; Arseneault, K.; Pézolet, M.; Bryce, M. R. Chem. Eur. J. 2005, 11, 2914. (d) Martín, N.; Sánchez, L.; Herranz, M. A.; Illescas, B.; Guldi, D. M. Acc. Chem. Res. 2007, 40, 1015. (e) Guégano, X.; Kanibolotsky, A. L.; Blum, C.; Mertens, S. F. L.; Liu, S. X.; Neels, A.; Hagemann, H.; Skabara, P. J.; Leutwyler, S.; Wandlowski, T.; Hauser, A.; Decurtins, S. Chem. Eur. J. 2009, 15, 63. (5) (a) Lorcy, D.; Bellec, N.; Fourmigué, M.; Avarvari, N. Coord. Chem. Rev. 2009, 253, 1398. (b) Rabaça, S.; Almeida, M. Coord. Chem. Rev. 2010, 254, 1493. (c) Shatruk, M.; Ray, L. Dalton Trans. 2010, 11105. (6) (a) Uzelmeier, C. E.; Smucker, B. W.; Reinheimer, E. W.; Shatruk, M.; O’Neal, A. W.; Fourmigué, M.; Dunbar, K. R. Dalton Trans. 2006, 5259. (b) Shin, K. S.; Jung, Y.; Lee, S. K.; Fourmigué, M.; Barrière, F.; Bergamini, J. F.; Noh, D. Y. Dalton Trans. 2008, 5869. (c) Nguyen, T. L. A.; Demir-Cakan, R.; Devic, T.; Morcrette, M.; Ahnfeldt, T.; Auban-Senzier, P.; Stock, N.; Goncalves, A. M.; Filinchuk, Y.; Tarascon, J. M.; Férey, G. Inorg. Chem. 2010, 49, 7135. (7) (a) Massue, J.; Bellec, N.; Chopin, S.; Levillain, E.; Roisnel, T.; Clérac, R.; Lorcy, D. Inorg. Chem. 2005, 44, 8740. (b) Bakhta, S.; Guerro, M.; Kolli, B.; Barrière, F.; Roisnel, T.; Lorcy, D. Tetrahedron Lett. 2010, 51, 4497. (c) Wu, J. C.; Liu, S. X.; Keene, T. D.; Neels, A.; Mereacre, V.; Powell, A. K.; Decurtins, S. Inorg. Chem. 2008, 47, 3452. (d) Wu, J. C.; Dupont, N.; Liu, S. X.; Neels, A.; Hauser, A.; Decurtins, S. Chem. Asian J. 2009, 4, 392. (e) Jaggi, M.; Blum, C.; Dupont, N.; Grilj, J.; Liu, S.-X.; Hauser, J.; Hauser, A.; Decurtins, S. Org. Lett. 2009, 11, 3096. (f) Jaggi, M.; Blum, C.; Marti, B. S.; Liu, S. X.; Leutwyler, S.; Decurtins, S. Org. Lett. 2010, 12, 1344. (8) (a) Han, Y. F.; Zhang, J. S.; Lin, Y. J.; Dai, J.; Jin, G. X. J. Organomet. Chem. 2007, 692, 4545. (b) Pointillart, F.; Maury, O.; Le 3945


Organometallics

Article

Hupp, J. T. J. Am. Chem. Soc. 2004, 126, 12989. (d) Dinolfo, P. H.; Coropceanu, V.; Brédas, J. L.; Hupp, J. T. J. Am. Chem. Soc. 2006, 128, 12592. (e) Christinat, N.; Scopelliti, R.; Severin, K. Angew. Chem., Int. Ed. 2008, 47, 1848. (22) Hansen, T. K.; Jørgensen, T.; Jensen, F.; Thygesen, P. H.; Christiansen, K.; Hursthouse, M. B.; Harman, M. E.; Malik, M. A.; Girmay, B.; Underhill, A. E.; Begtrup, M.; Kilburn, J. D.; Belmore, K.; Roespstorff, P.; Becher, J. J. Org. Chem. 1993, 58, 1359. (23) (a) Avarvari, N.; Fourmigué, M. Chem. Commun. 2004, 2794. (b) Bendikov, M.; Wudl, F.; Perepichka, D. F. Chem. Rev. 2004, 104, 4891. (c) Iyoda, M.; Hasegawa, M.; Miyake, Y. Chem. Rev. 2004, 104, 5085. (d) Loosli, C.; Jia, C. Y.; Liu, S. X.; Haas, M.; Dias, M.; Levillain, E.; Neels, A.; Labat, G.; Hauser, A.; Decurtins, S. J. Org. Chem. 2005, 70, 4988. (e) Segura, J. L.; Martín, N. Angew. Chem., Int. Ed. 2001, 40, 1372. (f) Vacher, A.; Barrière, F.; Roisnel, T.; Piekara-Sady, L.; Lorcy, D. Organometallics 2011, 30, 3570. (g) Danila, I.; Biaso, F.; Sidorenkova, H.; Geoffroy, M.; Fourmigué, M.; Levillain, E.; Avarvari, N. Organometallics 2009, 28, 3691. (24) Koch, W.; Holthausen, M. A Chemist’s Guide to Density Functional Theory; Wiley-VCH: Weinheim, Germany, 2001. (25) (a) Lau, J.; Blanchard, P.; Riou, A.; Jubault, M.; Cava, M. P.; Becher, J. J. Org. Chem. 1997, 62, 4936. (b) Xiong, J.; Li, G. N.; Sun, L.; Li, Y. Z.; Zuo, J. L.; You, X. Z. Eur. J. Inorg. Chem. 2011, 5173. (26) Frisch, M. J. et al. Gaussian 03, revision B.04; Gaussian, Inc., Wallingford, CT, 2004. The full citation is given in the Supporting Information. (27) (a) Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B 1988, 37, 785. (b) Miehlich, B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett. 1989, 157, 200. (c) Becke, A. D. J. Chem. Phys. 1993, 98, 5648.

3946


Tricarbonyl Mono- and Dinuclear Rhenium(I) Complexes with Redox

Recommend Documents