Bis- and tris(2-seleno-1-methylimidazolyl)hydroborato complexes, {[BseMe]ZnX}2 (X = Cl, I), [BseMe]2Zn and [TseMe]Re(CO)3: Structural evidence that the [BseMe] ligand is not merely a “heavier” version of the sulfur counterpart, [BmMe]

Abstract

New bidentate and tridentate ligands that feature selenium donors, namely the bis- and tris(2-seleno-1-methylimidazolyl)hydroborato ligands [Bse^Me] and [Tse^Me], have been constructed via the reaction of MBH₄ (M = Na, K) with 1-methylimidazole-2-selone. Comparison of the structure of {[Bse^Me]ZnI}₂ with its sulfur counterpart, [Bm^Me]ZnI, demonstrates that the seleno ligand exhibits a greater tendency than the mercapto ligand to bridge two metal centers, while comparison of [Tse^Me]Re(CO)₃ and [Tse^Mes]Re(CO)₃ indicates that the [Tse^Me] ligand is more electron donating and less sterically demanding than the [Tse^Mes] ligand.