Organometallic Complexes with Terminal Imidazolato Ligands and Their Use as Metalloligands

Compounds [Re(bipy)(CO)3(HIm)]OTf (1) and [Mo(η3-C3H4-R-2)(CO)2(HIm)(phen)]BAr′4 [R = Me (2a), H (2b); Ar′ = 3,5-bis(trifluoromethyl)phenyl; HIm = 1H-imidazole] were prepared from 1H-imidazole and either [Re(OTf)(bipy)(CO)3] or [MoCl(η3-C3H4-R-2)(CO)2(phen)]. Compounds 1, 2a, and 2b were deprotonated to afford the terminal κ-N-imidazolate complexes [Re(bipy)(CO)3(Im)] (3) and [Mo(η3-C3H4-R-2)(CO)2(Im)(phen)] [R = Me (4a), H (4b)], which were fully characterized, including an X-ray structural determination of 3. The topological analysis of the electron density (obtained from the X-ray diffraction study) and its Laplacian were used to characterize the differences in the electron density at the five-membered ring ligand between the imidazole and imidazolate complexes 1 and 3. The reaction of complexes 3, 4a, and 4b with the appropriate organometallic complexes afforded the bimetallic imidazolate-bridged compounds [{Re(bipy)(CO)3}2(μ-Im)]OTf (5), [{Mo(η3-C4H7)(CO)2(phen)}2(μ-Im)]OTf (6), and [{Mo(η3-C3H5)(CO)2(phen)}(μ-Im){Re(phen)(CO)3}]OTf (7). The reaction of [Mo(η3-C4H7)(CO)2(Im)(phen)] (4a) with SnClPh3 led to the formation of the trinuclear complex [{Mo(η3-C4H7)(CO)2(phen)(μ-Im)}2{SnPh3}]BAr′4 (8).