The First Systematic Synthesis of Heterobimetallic Dithiolene-Bridged Complexes. Synthesis and Characterization of Metal Complexes of 4-(1‘,2‘-Ethylenedithiolate)-1,3-dithiole-2-one and Dimeric Metal Complexes of 1,2,3,4-Butadienetetrathiolate

The 1,2-dithiolene ligands 4-(1‘,2‘-ethylenedithiolate)-1,3-dithiole-2-one (eddo2-) and 1,2,3,4-butadienetetrathiolate
(bdt4-) are synthesized by the controlled single or double 1,3-dithiole-2-one ring opening of 4,4‘-bis(1,3-dithiole-2-one) (bdo) (1). The synthesis and characterization of the novel transition metal complexes (COD)Pt(eddo) (2),
(diphos)Ni(eddo) (3), [Bu4N][Ni(eddo)2] (4), (COD)Pt(bdt)Pt(COD) (5), and (diphos)Ni(bdt)Pt(COD) (6) (where
COD = 1,5-cyclooctadiene, diphos = 1,2-bis(diphenylphosphino)ethane) are reported. Use of eddo2- and bdt4-
results in the selective systematic synthesis of transition metal monomers and dimers. In addition, the synthesis
of mixed metal dimeric complexes utilizing a “transition metal 1,2-dithiolene” ligand is demonstrated. The single-crystal X-ray structural analyses of the cocrystallized (COD)Pt(eddo)·1/2bdo, monoclinic, P21/n, a = 13.0388(4)
Å, b = 9.2048(3) Å, c = 16.2384(5) Å, β = 97.289(5)°, Z = 4, and [Bu4N][Ni(eddo)2], monoclinic, P21/n, a =
8.3508(2) Å, b = 26.4703(7), c = 15.2778(3) Å, β = 99.8160(10)°, Z = 4, are reported. There is strong evidence
of delocalization through the butadiene backbone of 1 which extends into the sulfur atoms. It also appears that
there is some delocalization through the butadiene backbone of the eddo2- ligands in 2 and 4.