An unexpected '4+2' [N(3)S]:[NS] rhenium(IV) complex formed upon cleavage of a Re(V) imido bond.

The reaction of [Re(NMe)Cl(3)(PPh(3))(2)] with the pentadentate [N(3)S(2)] ligand pyN(2)H(2)S(2)-H(2) [2,6-bis(2-mercaptophenylamino)dimethylpyridine] (1) in the presence of triethylamine did not yield the anticipated six-coordinate complex [Re(NMe)(eta(5)-pyN(2)HS(2))] (2), but rather resulted in cleavage of the Re(V)=NMe bond. A novel six-coordinate Re(IV) [N(3)S]/[NS] complex [Re(eta(4)-SC(6)H(4)-2-NCH(2)-C(5)H(3)N-C=NC(6)H(4)-2-S)(eta(2)-NHC(6)H(4)-2-S)] (4) was thus obtained with the simultaneous coordination of 2-aminothiophenol, a dianionic bidentate [NS] donor resulting from the decomposition of the parent ligand and ligand 3, a dianionic tetradentate [N(3)S] donor formed by partial self-condensation and subsequent oxidation of the parent ligand 1. Crystal data for 4: C(25)H(18)N(4)S(3)Re.CH(2)Cl(2), monoclinic, space group P2(1)/n, a = 9.255(2) A, b = 11.181(2) A, c = 25.316(4) A, beta = 97.434(3) degrees , V = 2587.8(7) A(3) and Z = 4.