Nickel complexes phosphorus sulfide

Schrauzer, Mayweg and Heinrich have reported the preparation of the complex 5 from the reaction of aqueous nickel(ll) chloride with a reaction mixture of benzoin in dioxane and phosphorus(V) sulfide. The parent acid and its salts have not been characterized. The only other closed ring complex, 6, was isolated in low yield (3%) subsequent to the reaction of nickel (II) acetate with the mixture resulting from the reaction of 1,3-propanediol with phosphorus(V) sulfide. As for 5, the parent acid and its salts were not... 

On the basis of complexes which were found to contain sulfur donors one can draw the conclusion that the coordination of SR-, S2- and S2 species to nickel(II) in complexes with triphos, pp3 and np2 is possible only in coordination sites unoccupied by phosphine donors which are able to form strong covalent bonds as sulfur does. Moreover, the phenyl groups on the phosphorus atoms surround the sulfur atoms, preventing their non-bonded electron pairs from forming bonds with nickel atoms and forming polynuclear sulfides. 

In oxides or sulfides of low-valent phosphorus with their cage-type stmctures, like P4O6 or P4S3, the phosphorus atoms have very significant donor character and consequently the molecules can be introduced as ligands into metal complexes. Classical examples are the 1 1 complexes with nickel carbonyls, (P406)Ni(C0)3 (57) or (P406)[Ni(C0)3]2, in which one or two P-donor sites are occupied by Ni(CO)3 acceptors. 

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