Dithioformic acid metal complexes

Insertion of CSj in metal-hydride bonds gives metal dithioformates. Bonding of the ligands to the metal can take place in several ways (a) ionic in alkali and alkaline earth metal compounds (b) symmetric bidentate in most of the transition metal complexes and (c) as a positive symmetrically bonded ligand to (25), in which the HC(S)S has donated two electrons to the two electron-deficient dicarbanonaborane groups.36 Little is known about monothioformic acid and its complexes. 

Unsubstituted phosphino- and arsino-dithioformic acids and their dithioformates have not yet been described. In addition, the monosubstituted primary alkyl and aryl compounds have not been investigated very well. Disubstituted phosphinodithioformates can be prepared easily. Because of the difference in basicity of Ph2PH and Et2PH they react with CS2 in different ways (reactions 14 and 15). By addition of metal ions to the resulting ethyl compound, one CS2 is split off.1 Only the potassium complexes have a second CS2 molecule bonded to the phosphorus atom. 

Alkali dithioformates can be prepared according to reaction (10) in a methanolic medium. The unstable free monomeric add, which trimerizes within a few minutes, is formed when an aqueous solution of these compounds is treated with HC1. The trimeric acid turns into the polymeric product (24) in DMF or DMSO. The alkali metal compounds are light and oxygen sensitive. Its complexes with Cu", Tl1, In1" and PbD are stable, whereas the Ag1, FeD, Co" and Ni compounds decompose and give the metal sulfides.1... 

---