Electrochemistry and strong near-IR absorption of the [Ni(dphdt)2]n complexes (n =-1, 0; dphdt=5,6-diphenyl-1,4-dithiin-2,3-dithiolate);: X-ray crystal structure of (Ph4P) [Ni(dphdt)2] (CH2Cl2)

Nickel bisdithiolene complexes C-x[Ni(dphdt)(2)] (x = 1 or 0.1, C = tetrabutylammonium (n-Bu4N+); x = 1, C = tetraphenylphosphonium (Ph4P+); dphdt=5,6-diphenyl-1,4-dithiin-2,3-dithiolate) have been synthesized and characterized. The molecular structure of (ph(4)P) [Ni(dphdt)(2)] (CH2CI2) was determined by X-ray analysis. Ni(S2C2S2)(2) core is planar and stacking along the c-axis and the shortest intra-stack S ... S distance is 4.529 Angstrom. According to the cyclic voltammetry of (n-Bu4N) [Ni(dphdt)(2)], two phenyl groups on the dphdt ligand decrease the electron density on the Ni(S2C2S2)(2) core and increase the oxidation potentials compared to those of the (n-Bu4N) [Ni(dddt)(2)] complex (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate). Near-IR spectra of the complexes show that phenyl substitution on the ligand does not give rise to the evident change in transition energy due to the lack of coplanarity with the Ni(S2C2S2)(2) core. (C) 2000 Elsevier Science Ltd All rights reserved.