Functionalization of Tetraphosphido Ligands by Heterocumulenes.

Although numerous polyphosphido complexes have been accessed through the transition-metal-mediated activation and functionalization of white phosphorus (P 4 ), the selective functionalization of the resulting polyphosphorus ligands in these compounds remains underdeveloped. In this study, we explore the reactions between cyclotetraphosphido cobalt complexes and heterocumulenes, leading to functionalized P 4 ligands. Specifically, the reaction of carbon disulfide (CS 2 ) with [K(18c-6)][(Ar*BIAN)Co(η 4 -P 4 )] ([K(18c-6)] 1 , 18c-6 = [18]crown-6) affords the adduct [K(18c-6)][(Ar*BIAN)Co(η 3 :η 1 -P 4 CS 2 )] ([K(18c-6)] 3 ), in which CS 2 is attached to a single phosphorus atom (Ar* = 2,6-dibenzhydryl-4-isopropylphenyl, BIAN = 1,2-bis(arylimino)acenaphthene diimine). In contrast, the insertion of bis(trimethylsilyl)sulfur diimide S(NSiMe 3 ) 2 into a P-P bond of [K(18c-6)] 1 yields [K(18c-6)][(Ar*BIAN)Co(η 3 :η 1 -P 4 SN 2 (SiMe 3 ) 2 )] (K(18c-6)] 4 ). This salt further reacts with Me 3 SiCl to form [(Ar*BIAN)Co(η 3 :η 1 -P 4 SN 2 (SiMe 3 ) 3 ] ( 5 ), featuring a rare azatetraphosphole ligand. Moreover, treatment of the previously reported complex [(Ar*BIAN)Co(η 3 :η 1 -P 4 C(O) t Bu)] ( 2 ) with isothiocyanates results in P-C bond insertion, yielding [(Ar*BIAN)Co(η 3 :η 1 -P 4 C(S)N(R)C(O) t Bu)] ( 6a , b ; R = Cy, Ph).