Ligands dithiolene complexes

Neutral nickel bis(dithiolene) complexes undergo ligand substitution reactions with a variety of amines to form mixed-ligand dithiolene complexes (52, 60). Dance and Miller (60) pointed out that reduction of electron-poor bis(dithiolene) complexes ( i/2 > 0 V vs. SCE) by halides or pseudo-halides, unhindered amines, or common weakly Lewis basic solvents (such as acetonitrile)... 

A number of structures with S-rich dianion ligands have been determined (297-299).831 832 For example, (297) can be synthesized by the reaction of [Ni(CN)4]2 with polysulfide.833 Upon further reaction with CS2 or substituted acetylenes it forms perthiocarbonato and dithiolene complexes, respectively. 

Dithiolene complexes with the maleonitriledithiolate (mnt) ligand form highly delocalized systems and are widespread in studies of conducting and magnetic materials. The electronic properties have been extensively studied with various computational methods including Hiickel and extended Hiickel approaches to identify the nature of the orbitals involved in intramolecular and intermolecular interactions. These structural properties allow the complexes to interact in the solid state via short stacking S, S and short interstack S---S contacts.10 4-1048... 

Dithiolene complexes [ Pd(PPh3)2 ra S2C=CCHC(0)R ] are mononuclear or homodinuclear derivatives of ferrocenyl-substituted dithiolene ligands.530 2,2-Diacetyl-1,1-ethylenedithiolato complexes of palladium can be used to prepare dinuclear PdAg and PdAu complexes 531... 

One of the earliest series of metal complexes which showed strong, redox-dependent near-IR absorptions is the well-known set of square-planar bis-dithiolene complexes of Ni, Pd, and Pt (Scheme 4). Extensive delocalization between metal and ligand orbitals in these non-innocent systems means that assignment of oxidation states is problematic, but does result in intense electronic transitions. These complexes have two reversible redox processes connecting the neutral, monoanionic, and dianionic species. 

This makes it difficult to assign clearly separated formal charges to the metal and to the ligand, which would not be meaningful as a consequence of the noninnocent nature of 1,2-dithiolene ligands.53,54 In Scheme 5, the case of neutral diamagnetic square-planar Zw(l,2-dithiolene) complexes is illustrated. 

Dichalcogenolene ligands form complexes with main group and d transition metal ions.103 Bis( 1,2-dithiolene) complexes have been obtained for metals, such as Cr, Mn, Ni, Cu, Zn, for the first row, Pd, Ag, and Cd for the second row, and Pt, Au, and Hg for the third row. Homoleptic /ra(l,2-dithiolcnc) complexes have been obtained for Ti, V, Cr, Zr, Nb, Mo, Tc, Ru, Ta, W, Re, and Os. Fe and Co have been found both in bis and /ra(l,2-dithiolene) complexes, although /ra(l,2-dithiolene) complexes containing these metal ions... 

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