作者:W. Kuchen、W. Peters、M. Sünkeler、R. Wiskemann、H. Wunderlich
DOI:10.1002/(sici)1521-3749(1998120)624:12<1956::aid-zaac1956>3.0.co;2-n
日期:1998.12
Metathesis of [NiCl2(PPh3)(2)] with Li salts of the potentially tetradentate ligands [R2P(S)N-R'-NP(S)R-2](2-) (= L) affords monomeric complexes NiL containing the chromophore NiN2S2 (1: R = Et; a, b: R' = Me2C-(CH2)(2)-CMe2, o-Phenylen; 2: R = t-Bu, R' = (CH2)(n); a-c: n = 2, 3, 4). According to the results of magnetic measurements and VIS as well as NMR spectroscopy (H-1, P-31) these complexes are planar except la that is tetrahedral. In case of 1a and 2c this was confirmed by the results of crystal structure analyses. In toluene, however, 1a and 2c form an equilibrium of planar (diamagnetic) and tetrahedral (paramagnetic) conformers. VT-H-1-NMR including H-1,H-1-COSY showed a hindered Delta,Lambda-inversion of 1a below 330 K. Only with 1b a pentacoordinate adduct 1b.PPh3 was obtained that completely dissociates in its components on dissolving in benzene. 1a and 2c crystallize in the monoclinic space group P2(1)/c containing 4 molecules in the unit cell of the dimensions la: a = 8.774(1), b = 12.335(2), c = 21.339(3) Angstrom, beta = 92.33(1)degrees and 2c: a = 13.374(8), b = 16.197(8), c = 12.814(6) Angstrom, beta = 109.20(4)degrees. The coordination of the Ni atom yields in 1a a dihedral angle epsilon of 41.7(1)degrees and thus a geometry intermediate between planar and tetrahedral while in 2c the angle of 4.5(1)degrees reveals a nearly planar chromophore NiN2S2.