摘要:

C(1) C(2) C(3) C(4) C(5) C(6) C(7) S(1) S(2) S(3) S(4) S(5) S(6) S(7) S(8) S(9) Ni(1) Ni(2) Ni(3) S(1¢) S(2¢) Ni(2¢) Ni(3¢) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) S(1) S(2) S(3) S(4) S(5) S(6) S(7) S(8) S(9) S(10) S(11) S(12) S(13) S(14) Ni(1) Ni(2) Ni(3) Two new nickel–dmit-based molecular conductors based on heteroleptic polymetallic complexes synthesis structures and electrical properties Tianlu Sheng Xintao Wu,* Wenjian Zhang Quanming Wang Xiancheng Gao and Ping Lin State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fjuian 350002 PR China Two heteroleptic dmit complexes of polynuclear nickel(ii) [NEt4]2[Ni5(edt)4(dmit)2] and [AsPh4]2[Ni3(pdt)2(dmit) 2]·0.5MeOH (dmit = 2-thione-1,3-dithiole-4,5-dithiolate H2edt = ethane-1,2-dithiol H2pdt = propane-1,2-dithiol) are synthesized and characterized by X-ray crystallography and display room-temperature conductivities of 1.75 3 1024 and 1.52 3 1025 S cm21; this is the first report of semiconducting heteroleptic dmit complexes consisting of more than two nickel(II) centres.During the search for new complexes with novel electric properties metal complexes of the dmit ligand have received considerable attention1,2 since some of them were reported to exhibit conductivities and even superconductivities.3–7 Some non-planar metal–dmit complexes have also been reported to exhibit high conductivities.8 Recently it has been shown that intermolecular interactions in transition metal bis(dithiolate) complexes of this type are also important for the assembly of molecular ferromagnets.9 A large number of metal–dmit complexes have been synthesized and structurally characterized but many of them are homoleptic.To our knowledge heteroleptic polymetallic complexes of dmit in particular are rare. These types of complexes reported in the literature are restricted to [NBu4]2[Ni2(C2S4)(dmit)2],10 [Au4(dmit)2- (Ph2PCH2PPh2)2] and [Au3(PPh3)3(dmit)].11 We have now investigated whether dithiolate can be used as a bridging ligand to synthesize heteroleptic polymetallic complexes with dmit. As two examples two heteroleptic nickel(ii) derivatives [NEt4]2[Ni5(edt)4(dmit)2] 1 and [AsPh4]2[Ni3(pdt)2- (dmit)2]·0.5MeOH 2 were formed by using edt or pdt as bridging ligands; this is the first report of heteroleptic dmit complexes consisting of more than two nickel(ii) centres.4,5-Bis(benzoylthio)-1,3-dithiole-2-thione (prepared according to the detailed procedures described by Steimecke et al.12) (0.408 g 1.0 mmol) was dissolved in a methanol solution (30 ml) containing sodium (0.046 g 2.0 mmol). To the resulting purple–red solution of Na2dmit was added H2edt (0.06 ml 1.4 mmol) and then NiCl2·6H2O (0.24 g 1.0 mmol) to give a purple solution. After stirring for 6 h at room temp. a methanol solution (10 ml) of NEt4Br (0.2 g 1.0 mmol) was added leading to the precipitation of a purple product. This was collected by filtration and redissolved in dmf (10 ml); then it was filtered after stirring for several minutes. This filtrate was diffused with Et2O at room temp. for ten days after which 0.12 g of black crystals of 1 were obtained.The preparation of complex 2 was similar to that of 1 H2edt and NEt4Br being replaced by H2pdt and AsPh4Cl respectively. The red precipitate was collected by filtration and redissolved in Me2CO (10 ml) and then filtered after stirring for several min. The filtrate was diffused with Et2O at room temp. for ten days after which 0.35 g of black crystals of 2 were obtained.† The structures of 1 and 2 were established by single-crystal X-ray diffraction analysis‡ and reveal the edt or pdt ligands in bridging modes chelated to Ni atoms and dmit ligands coordinated to edge Ni atoms. The anions of 1 and 2 together with selected bond parameters are depicted in Figs. 1 and 2. In 1 the anion occupies a crystallographic inversion center the five Ni atoms are bridged by four edt ligands Ni(1) Ni(2) and Ni(2A) are square-planar coordinated to four S atoms of edt ligands and both the edge Ni atoms are square-planar coordinated to two S atoms of edt ligands and to two S atoms from one dmit ligand.From the configuration of the five Ni atoms and two dmit ligands the anion can be described as consisting of an Ni3(edt)4 22 unit to which are trans attached two Ni(dmit)2 fragments the angle Ni(1)–Ni(2)–Ni(3) [Ni(1)–Ni(2A)–Ni(3A)] being 102.83°. The Ni···Ni bond distances are 2.852(1) and 2.817(1) Å and are slightly shorter than that in [PPh4]2[Ni2(edt)3] 317 [2.914(1) Å] and comparable to the distances in [PPh4]2[Ni3(edt)4] 418 [2.856(1) Å]. The Ni–S bond distances vary from 2.151(3) to 2.227(3) Å which are comparable to the Ni–S bond distances in 317 [2.158(2)–2.221(2) Å] and 418 [2.174(1)–2.210(1) Å] as well as Fig.1 ORTEP diagram of the anion of 1 (25% displacement ellipsoids). Selected bond lengths (Å) and angles (°) Ni(1)–Ni(2) 2.852(1) Ni(2)– Ni(3) 2.817(1) Ni(1)–S(1) 2.213(3) Ni(1)–S(2) 2.215(3) Ni(2)–S(1) 2.169(3) Ni(2)–S(2) 2.151(3) Ni(2)–S(3) 2.159(3) Ni(2)–S(4) 2.160(3) Ni(3)–S(3) 2.222(3) Ni(3)–S(4) 2.227(3) Ni(3)–S(5) 2.174(3) Ni(3)–S(6) 2.171(3); Ni(1)–Ni(2)–Ni(3) 102.83. Fig. 2 ORTEP diagram of the anion of 2 (25% displacement ellipsoids). Selected bond lengths (Å) and angles (°) Ni(1)–Ni(3) 2.792(2) Ni(1)– Ni(2) 2.812(2). Ni(1)–S(1) 2.143(3) Ni(1)–S(2) 2.149(3) Ni(1)–S(3) 2.156(3) Ni(1)–S(4) 2.184(3) Ni(2)–S(5) 2.161(3) Ni(2)–S(6) 2.167(3) Ni(2)–S(1) 2.244(3) Ni(2)–S(3) 2.245(3) Ni(3)–S(11) 2.151(3) Ni(3)– S(10) 2.176(3) Ni(3)–S(2) 2.223(3) Ni(3)–S(4) 2.240(3); Ni(3)–Ni(1)– Ni(2) 102.47(5).Chem. Commun. 1998 263 a b c 0 in [AsPh4]2[Ni2(S2C4){S2C2S2C2(CO2Me)2}2]19 and [NBu4]2[Ni2(C2S4)(dmit)2].10 As shown in Fig. 2 the geometry around the Ni atoms in 2 is similar to those in 1 the three Ni atoms adopt a V shape with the angle Ni(2)–Ni(1)–Ni(3) being 102.47°. In contrast to 1 complex 2 can be achieved as an Ni(pdt)22 unit to which two Ni(dmit)2 fragments are cis bonded. Compared to 1 the Ni···Ni bond distances [Ni(1)–Ni(2) 2.812(2) Ni(1)–Ni(3) 2.792(2) Å] are slightly shorter whereas the Ni–S bond lengths are almost the same as those in 1. In the crystal of complex 1 (as shown in Fig. 3) the anions interact with each other through S···S contacts of < 3.7 Å between the thiole and thione groups or the thiole and thiole groups of the dmit ligands on adjacent molecules to form a twodimensional molecular interaction net.However in the crystal of complex 2 no S···S contacts < 3.7 Å are observed (the shortest intermolecular S···S distance is 3.92 Å); this may result from using the larger AsPh4 + ion. The electrical conductivities of complexes 1 and 2 were measured with pressed pellets (two probe). Both complexes show semiconducting behaviour with room-temperature conductivities of 1.75 3 1024 and 1.52 3 1025 S cm21 respectively. The fact that the conductivity of 1 is higher than that of 2 may be the result of shorter intermolecular non-bonded S···S contacts. This research was supported by State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter the Chinese Academy of Sciences and the Science Foundation of Nation and Fujian Province.Footnotes and References * E-mail wxt@ms.fjirsm.ac.cn † Spectroscopic data for 1 IR (KBr pellet n/cm21) n(Ni–S) 338.2s 316.7m 472.1s 514.6s; n(C–S) and n(CNS) 838.3s 911.1s 998s 1024.2s 1049s. UV–VIS (dmf solution) lmax/nm (e/dm3 mol21 cm21) 275 (4.2 3 104) 290 (4.62 3104) 320 (4.09 3104) 430 (1.12 3104) 530 (2.2 3104) (Found C 26.53; H 4.18; N 2.82; Ni 22.20. Calc. for C30H56N2Ni5S18 C 27.39; H 4.29; N 2;13; Ni 22.31%.) For 2 IR (KBr pellet n/cm21) n(Ni–S) 364.4m 465.9s 476.0s 515.8m; n(C–S) and n(CNS) 857.3w 857.4m 915.1s 997.3s 1023.6s 1049.1s 1079.7s. UV–VIS (dmf solution) lmax/nm (e/dm3 mol21 cm21) 293 (3.3 3 104) 310 (3.4 3 1024) 366 (1.4 3 104) 424 (2.2 3 103) 517 (1.7 3 104).(Found C 46.76; H 3.62; Ni 11.21. Calc. for C60.5H54As2Ni3O0.5S14 C 46.47; H 3.48; Ni 11.26%). ‡ Crystal data 1 C30H56N2Ni5S18 Mr = 1315.32 triclinic space group P1 a = 9.407(4) b = 11.665(3) c = 12.777(3) a = 106.45(2) b = 101.54(3) g = 100.79(3)° U = 1272(1) Å3 Z = 1 Dc = 1.72 g cm23 T = 296 K l(Mo-Ka) = 0.710 73 Å q range 0–25°. Enraf-Nonius CAD4 diffractometer w–2q scans. 4468 reflections are unique 2821 reflections with I > 3.0s(I) were used in the refinement and used to calculate R and Rw. The last successful full-matrix least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms (250 variables) converged to R = 0.058 Rw = 0.062 {w = [s2(Fo)2 + (0.020Fo)2 + 1.000]21} the final maximum residual electron density is 0.80 e Å23.The positions of hydrogen atoms were calculated in ideal positions and not used in the least-squares refinement. The structure was solved by direct methods and the positions of Ni atoms were obtained from E maps. The remaining non-H atoms were located from successive difference Fourier maps. The refinement of the structure was performed by full-matrix least-squares techniques on F using MolEN.13 Data were corrected for absorption with program DIFABS.14 2 C60.5H54As2Ni3O0.5S14 Mr = 1563.85 triclinic space group P1 a = 14.3284(2) b = 14.9487(3) c = 17.2496(3) a = 102.886(1) b = 101.898(1) g = 102.687(1)° U = 3385(2) Å3 Z = 2 Dc = 1.534 g cm23 T = 293 K l(Mo-Ka) = 0.710 73 Å q range 1.90–23.2°. Siemens Smart CCD diffractometer w scans. 9438 unique reflections were used in the refinement and 6615 reflections with I > 2.0s(I) used to calculate R and Rw.The last successful full-matrix least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms except solution molecule (720 variables) converged to R = 0.0739 Rw = 0.2085 {w = [s2(Fo)2 + (0.1355P)2 + 4.7414P]21 where P = [(Fo)2 + 2(Fc)2]/3}. The solvent molecule is disordered. The final maximum residual electron density is 2.477 e Å23 lying 1.073 Å from Ni(1). The positions of hydrogen atoms were calculated in ideal positions and not used in the least-squares refinement. The structure was solved by direct methods and the positions of three Ni atoms were obtained from E maps. The remaining non-H atoms were located from successive difference Fourier maps. The refinement of the structure was performed by full-matrix least-squares techniques on F2 using SHELXL-93.15 Data were corrected for absorption with SADABS.16 CCDC 182/702.1 P. Cassoux L. Valade H. Kobayashi A. Kobayashi R. A. Clark and A. E. Underhill Coord. Chem. Rev. 1991 110 115. 2 R. M. Olk B. Olk W. Dietzsch R. Kirmse and E. Hoyer Coord. Chem. Rev. 1992 117 99. 3 M. Bousseau L. Valade J. P. Legros P. Cassoux M. Garbauskas and L. V. Interrante J. Am. Chem. Soc. 1986 108 1908. 4 L. Brossard M. Ribault L. Valade and P. Cassoux Physica B 1986 143 378. 5 L. Brossard H. Hurdequint M. Ribault L. Valade J.-P. Legros and P. Cassoux Synth. Met. 1988 27 1315. 6 A. Kobayashi H. Kobayashi A. Miyamoto R. Kato R. A. Clark and A. E. Underhill Chem. Lett. 1991 2163. 7 H. Tajima A. Inokuchi A. Kobayashi T. Ohta R. Kato H.Kobayashi and H. Kuroda Chem. Lett. 1993 1235. 8 T. Imakubo H. Sawa and R. Kato J. Chem. Soc. Chem. Commun. 1995 1097; W. E. Broderick E. M. McGhee M. R. Godfrey B. M. Hoffman and J. A. Ibers Inorg. Chem. 1989 28 2902; G. Matsubayashi K. Akiba and T. Tanaka Inorg. Chem. 1988 27 4744; J. D. Martin E. Canadell and P. Batail Inorg. Chem. 1992 31 3176. 9 A. T. Coomber D. Beljonne R. H. Friend J. L. Bredas A. Charlton N. Robertson A. E. Underhill M. Kurmoo and P. Day Nature 1996 380 144. 10 A. E. Pullen R.-M. Olk S. Zeltner E. Hoyer K. A. Abboud and J. R. Reynolds Inorg. Chem. 1997 36 958. 11 E. Cerrada A. Laguna M. Laguna and P. G. Jones J. Chem. Soc. Dalton Trans. 1994 1325. 12 G. Steimecke H.-J. Sieler R. Kirmse and E. Hoyer Phosphorus Sulfur 1979 7 49. 13 MolEN An Interactive Structure Solution Procedure Enraf-Nonius Delft The Netherlands 1990.14 N. Walker and D. Stuart DIFABS Acta Crystallogr. Sect. A 1983 39 159. 15 G. M. Sheldrick SHELXTL93 Program for the Refinement of Crystal Structure University of G�ottingen 1993. 16 G. M. Sheldrick SADABS University of G�ottingen 1996. 17 B. S. Snyder C. P. Rao and R. H. Holm Aust. J. Chem. 1986 39 963. 18 W. Tremel M. Kriege B. Krebs and G. Henkel Inorg. Chem. 1988 27 3886. 19 X. Yang D. D. Doxsee T. B. Rauchfuss and S. R. Wilson J. Chem. Soc. Chem. Commun. 1994 821. Received in Cambridge UK 23rd September 1997; 7/06685I Fig. 3 The packing of 1 in the crystal. Dashed lines indicate non-bonded S···S contacts < 3.7 Å the cations are omitted for clarity. 264 Chem. Commun.

ISSN:1359-7345    

DOI:10.1039/a706885i

出版商:RSC    

年代:1998

数据来源: RSC