Cobalt, 1,1-dithio complexes

The 1,1-dithio complexes of cobalt have been studied extensively (1). Most of the literature is concerned with Co(III) compounds, as the complexes with divalent cobalt are extremely air-sensitive and have only been synthesized in acidic solution under rigorously deoxygenated conditions. The recent complexes of cobalt with 1,1-dithio ligands are listed in Table III, together with some of their physical properties. 

Cobalt(III) complexes of formula cis- and trans-[Co(dtc)L4]2+ and [Co(dtc)2L2]+ where dtc = dimethyl-, diethyl- or piperidino-dithiocarbamate were prepared with phosphites P(OMe)3, P(OEt)3 and 4-ethyl-2,6,7-trioxa-l-phophabicyclo[2.2.2]octane as ligands L.1048 Whereas Co—P bonding is found, as defined in the crystal structures of each of the two forms of complexes isolated, a linkage isomer in which the phosphite is O bound was detected for the bis(dithio-carbamate) compounds. 

Further recent papers concerning metal complexes of thio-analogues of j3-diketones deal with the preparation of the cobalt(n) complex of 1,3-diacetylthioacetone, the synthesis and properties of a series of metal complexes of dithioacetylacetone, the synthesis of the nickel(n) complexes of monothio- and dithio-dibenzoylmethane (67) by the nucleophilic cleavage of 1,2-dithiolium salts by hydroxide or mercaptide ions in the presence of nickel(ii) ions, the bromination of the cobalt(m) complex of monothioacetylacetone (68) with iV-bromosuccinimide to yield (69), and the application of monothiodibenzoylmethane as an analytical reagent for quantitative determination of copper. ... 

More recently, widespread use has been made of optical rotatory dispersion as a means for studying configurations. a-Amino acids were investigated as such or as derivatives, notably alkyl dithio-carbamates (116) , copper(n) complexes , and cobalt(m) complexes . From these studies useful though not always straightforward correlations have been obtained, between the shape and location of the dispersion curves and the configuration of the compounds. 

Eventually we formed carbonyls in the liquid phase by redox disproportionation of nickel and cobalt derivatives of organic thioacids. In the reaction between nickel(II) dithiobenzoate and carbon monoxide in the presence of HS ion we assumed the formation of a sulfur-bridged nickel(IV) complex (VII, 32). More recent investigations (84), however, have shown that half the nickel appears as a monomeric nickel(II) complex of the same empirical formulation, formed by insertion of a sulfur atom in the dithio ligand, the other half of the nickel being reduced to nickel(O) by the sulfide. 

Cyclopentadienyl cobalt and rhodium complexes with 1,2-benzenedithiolate or S2C2R2 type ligands readily add unsaturated carbon molecules to form tridentate ligands exhibiting S2C donor sets. When nitrenes are added, dithio-lene derived ligands with S2N donor sets result. Scheme 3 shows examples of... 

Table 99 Preparations Some 1,1-Dithio- and Diseleno-phosphinate Complexes of Cobalt...

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