Dithiolato ligands

Table I outlines the major types of 1,1-dithiolato ligands. Table lA shows the related dithio acid complexes derived from dithiophosphinic, dithiocacodylic (dithioarsinic), dithioarsenate, and dithiophosphoric acids. The complexes most intensively studied to date are those of the dithiocarbamates and dithiophosphates.

The literature concerning the chemistry of transition-metal complexes containing 1,1-dithiolato ligands was extensively reviewed, up to 1968, by Coucouvanis (1). We attempt here to update that excellent account. 

Relatively few complexes of the early transition metals with 1,1-dithiolato ligands have been prepared and characterized. This is consistent with their classification as "hard or "class a acceptors. Thus,... 

The only technetium complex has been reported (226) is [Tc(CO)4(R2dtc)]. There appear to be few reports of rhenium or technetium complexes with 1,1-dithiolato ligands. 

Very few studies on complexes of palladium and platinum with 1,1-dithiolato ligands have been reported recently. The electronic absorption spectra of the Et2dtc complexes of Pd and Pt, as well as Zn, Cu, Fe, Co, and Mn, have been measured in MeCN, EtOH, and -heptane, with diffuse-reflectance spectra also being determined (401). In 1969 and... 

Dithiolato Ligands and Related Selenium and Tellurium Compounds... 

The 1,1-dithiolato ligands and their complexes have been reviewed rather extensively in earlier publications. Reviews on various aspects of dithiophosp-hato,2 dithiophosphinato,3 xanthato,4 dithiocarboxylato,5 and dithiocarba-mato6 ligands are available. In this section, only the more recent literature (basically after 1990) will be considered because of space limitations. 

Monodentate (monometallic monoconnective) phosphor-1,1-dithiolato ligands are rare. Bidentate (monometallic biconnective) form chelate rings and three sub-types can be distinguished according to the degree of asymmetry (Scheme 2). The most asymmetric type (anisobidentate) occurs when a covalent bond is associated with a secondary bond this takes place mostly in main-group metal complexes. The second type is rare and is the result of the association between a covalent and a dative coordinate bond. The symmetric bidentate bonding (isobidentate) is found mainly in transition metal complexes. 

---