Synthesis and dynamic NMR studies of Rhenium(I) tricarbonyl bromide complexes of benzimidazolylpyridine ligands. Crystal structure of [ReBr(CO)3{2,6-bis(1′,5′,6′-trimethylbenzimidazol-2′-yl)pyridine}]
摘要:
Pentacarbonylbromorhenium(I) reacted with 2,6-bis(benzimidazol-2'-yl)pyridine (bbip), 2,6-bis(1'-methylbenzimidazol-2'-yl)pyridine (bmbip), 2,6-bis(5',6'-dimethylbenzimidazol-2'-yl)pyridine (bdmbip), and 2,6-bis(1',5',6'-trimethylbenzimidazol-2'-yl)pyridine (btmbip) to form stable octahedral complexes of type fac[ReBr(CO)(3)L] (L = bbip, bmbip, bdmbip or btmbip) in which L is acting as a bidentate chelate ligand. At above-ambient temperatures in solution the complexes are fluxional with the nitrogen ligand oscillating between equivalent bidentate bonding modes. Rates and activation energies for these fluxions have been investigated by NMR methods. At low temperatures rotation of the uncoordinated benzimidazolyl unit is restricted and for fac-[ReBr(CO)(3)(btmbip)] in CD2Cl2 solution, two preferred rotamers exist in 89:11% relative abundances. A rotational energy barrier has been estimated. The X-ray crystal structure of fac-[ReBr(CO)(3))(btmbip)] confirms the bidentate chelate bonding of btmbip with a N-Re-N angle of 74.2 degrees. The pendant benzimidazole unit is inclined at an angle of 60.7 degrees to the pyridine ring. (C) 1998 Elsevier Science Ltd. All rights reserved.
Synthesis, Characterization, and Ethylene Oligomerization and Polymerization of [2,6-Bis(2-benzimidazolyl)pyridyl]chromium Chlorides
作者:Wenjuan Zhang、Wen-Hua Sun、Shu Zhang、Junxian Hou、Katrin Wedeking、Steven Schultz、Roland Fröhlich、Haibin Song
DOI:10.1021/om050805l
日期:2006.4.1
employed as the cocatalyst, the chromium complexes showed high activity for ethyleneoligomerization and polymerization. Oligomers were produced with high selectivity for α-olefins, and polyethylenes were generated with extremely broad molecular weight distributions. In the presence of diethylaluminum chloride (Et2AlCl), these chromium complexes showed moderate activity for ethylene polymerization and
Investigation of the effect of alkyl substitution on DSSC efficiency of Ru(II) complexes bearing tridentate benzimidazole ligands
作者:Melek Tercan、Osman Dayan
DOI:10.1080/24701556.2020.1720732
日期:2020.7.2
Abstract In this study, tridentate 2,6-bis(5,6-dimethyl-1H-benzimidazol-2-yl)pyridine ligand (L1) and eight derivatives (L2–9) were prepared by substitution with alkyl chains and Ru(II) complexes of these ligands (C1–9) were synthesized. The synthesized ligands and their Ru(II) complexes were characterized by FTIR, UV–vis, 1H-NMR, and ESI/MS spectroscopic methods. The absorption and the emission spectra