Copper Complexes with (2,7‐Di‐tert‐butylfluoren‐9‐ylidene)methanedithiolate: Oxidatively Promoted Dithioate Condensation

Abstract

AbstractThe reaction of [Cu(NCMe)4]PF6 with piperidinium 2,7‐di‐tert‐butyl‐9H‐fluorene‐9‐carbodithioate (pipH)[S2C(tBu‐Hfy)] (1; tBu‐Hfy = 2,7‐di‐tert‐butylfluoren‐9‐yl), affords [Cun{S2C(tBu‐Hfy)}n] (2), which reacts with various P ligands to give [Cu{S2C(tBu‐Hfy)}L2] [L = PPh3 (3a), PCy3 (3b), PiPr3 (3d); L2 = 1,1′‐bis(diphenylphosphanyl)ferrocene (dppf, 3c), bis(diphenylphosphanyl)methane (dppm, 3e)]. Compounds 3a–c react with atmospheric oxygen and moisture in the presence of NEt3 to give the dinuclear complexes [Cu2{[SC=(tBu‐fy)]2S}L2] [tBu‐fy = 2,7‐di‐tert‐butylfluoren‐9‐ylidene; L = PPh3 (4a), PCy3 (4b); L2 = dppf (4c)], which contain a new dithiolato ligand formally resulting from the condensation of two dithioato ligands with loss of a sulfide ion and two protons. Neutral CuI dithiolate complexes of the type [Cu4{S2C=(tBu‐fy)}2L4] [S2C=(tBu‐fy) = [2,7‐di‐tert‐butylfluoren‐9‐ylidene)methanedithiolate; L = PPh3 (5a), P(C6H4OMe‐p)3 (5b), PiPr3 (5d) or L2 = dppf (5c)] were obtained by treating 1 with [Cu(NCMe)4]PF6, the corresponding phosphane, and piperidine in a 1:2:2:1 molar ratio. The reaction of 1 with Cu(ClO4)2·6H2O and (Pr4N)OH in a 2:1:2 molar ratio gives the CuII complex (Pr4N)2[Cu{S2C=(tBu‐fy)}2] [(Pr4N)26], which readily oxidizes to the CuIII complex Pr4N[Cu{S2C=(tBu‐fy)}2] (Pr4N7) in the presence of atmospheric oxygen and moisture. The salt PPN7 [PPN+ =(Ph3P)2N+] was obtained from 1, CuCl2·2H2O, PPNCl, and piperidine in a 2:1:1:2 molar ratio under aerobic conditions. The crystal structures of 3a, 3c·CH2Cl2, 4a·4Me2CO, and 4c·CH2Cl2 have been determined by X‐ray diffraction studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)