Diverse Post-Metathesis Reactivities of Mixed Amido-Isothiocyanato Molybdenum Complexes.

Attempts to prepare mixed isothiocyanato-bis(imido) Mo VI complexes led to the discovery of post-metathesis rearrangements toward three distinct products ( 1 - 3 ), which feature the NCS-derived chelators [N(NMe 2 )CS] 2- ( L 1 in dinuclear 1 and 2 ) and [N(SiMe 3 )(NMe 2 )CS] - ( L 2 in mononuclear 3 ). Notably, the preparation of bidentate ligand L 1 and its coordination chemistry are unprecedented. Together with computational studies, it is proposed that the putative "mono-substituted" intermediate [Mo(N t Bu) 2 (NMe 2 )(NCS)] serves as the common starting point for the observed molecular transformations. Construction of the [Mo(N t Bu) 2 (NCS) 2 ] core was ultimately possible in the presence of additional stabilizing donors (THF or PMe 3 ), which yielded the complexes [Mo(N t Bu) 2 (NCS) 2 (THF) 2 ] ( 4 ) and [Mo(N t Bu) 2 (NCS) 2 (PMe 3 ) 2 ] ( 5 ).