An unexpected ‘4+2’ [N3S]/[NS] rhenium(IV) complex formed upon cleavage of a Re(V) imido bond

The reaction of [Re(NMe)Cl3(PPh3)2] with the pentadentate [N3S2] ligand pyN2H2S2H2 [2,6-bis(2-mercaptophenylamino)dimethylpyridine] (1) in the presence of triethylamine did not yield the anticipated six-coordinate complex [Re(NMe)(η5-pyN2HS2)] (2), but rather resulted in cleavage of the Re(V)NMe bond. A novel six-coordinate Re(IV) [N3S]/[NS] complex [Re(η4-SC6H42-NCH2C5H3NCNC6H42-S)(η2-NHC6H4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 [N3S] donor formed by partial self-condensation and subsequent oxidation of the parent ligand 1. Crystal data for 4: C25H18N4S3Re·CH2Cl2, monoclinic, space group P21/n, a=9.255(2) Å, b=11.181(2) Å, c=25.316(4) Å, β=97.434(3)°, V=2587.8(7) Å3 and Z=4.