1749-77-5Relevant articles and documents
Computational and Experimental Insights into Asymmetric Rh-Catalyzed Hydrocarboxylation with CO2
Pavlovic, Ljiljana,Pettersen, Martin,Gevorgyan, Ashot,Vaitla, Janakiram,Bayer, Annette,Hopmann, Kathrin H.
, p. 663 - 670 (2021)
The asymmetric Rh-catalyzed hydrocarboxylation of α,β-unsaturated carbonyl compounds was originally developed by Mikami and co-workers but gives only moderate enantiomeric excesses. In order to understand the factors controlling the enantioselectivity and to propose novel ligands for this reaction, we have used computational and experimental methods to study the Rh-catalyzed hydrocarboxylation with different bidentate ligands. The analysis of the C?CO2 bond formation transition states with DFT methods shows a preference for outer-sphere CO2 insertion, where CO2 can undergo a backside or frontside reaction with the nucleophile. The two ligands that prefer a frontside reaction, StackPhos and tBu-BOX, display an intriguing stacking interaction between CO2 and an N-heterocyclic ring of the ligand (imidazole or oxazoline). Our experimental results support the computationally predicted low enantiomeric excesses and highlight the difficulty in developing a highly selective version of this reaction.
Catalytic conversion of 2,4,5-trisubstituted imidazole and 5-substituted 1H-tetrazole derivatives using a new series of half-sandwich (η6-p-cymene)Ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazone ligands
Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Archana, Govindhasamy,Alves, Luis G.,Martins, Ana M.,Shanmuga Bharathi, Kuppannan
, (2020/11/16)
A new series of half-sandwich (η6-p-cymene) ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazide derivatives [Ru(η6-p-cymene)(Cl)(L)] [L = N'-(naphthalen-1-ylmethylene)thiophene-2-carbohydrazide (L1), N'-(anthracen-9-ylmethylene)thiophene-2-carbohydrazide (L2) and N'-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (L3)] were synthesized. The ligand precursors and their Ru(II) complexes (1–3) were structurally characterized by spectral (IR, UV–Vis, NMR and mass spectrometry) and elemental analysis. The molecular structures of the ruthenium(II) complexes 1–3 were determined by single-crystal X-ray diffraction. All complexes were used as catalysts for the one-pot three-component syntheses of 2,4,5-trisubstitued imidazole and 5-substituted 1H-tetrazole derivatives. The catalytic studies optimized parameters as solvent, temperature and catalyst. The catalysts revealed very active for a broad range of aromatic aldehydes presenting either electron attractor or electron donor substituents and, although less active, moderate to high activities were observed for alkyl aldehydes.
Aicd-base behavior, electrochemical properties and DFT study of redox non-innocent phenol-imidazole ligands and their Cu complexes
Parween, Arfa,Mandal, Tarun Kanti,Guillot, Régis,Naskar, Subhendu
, p. 34 - 46 (2015/07/15)
Abstract Three Cu complexes (1, 2, 3) with N, O donor ligands having imidazole-phenol moieties 2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (L1H), 4-bromo 2-(4,5-diphenyl-1H-imidazol-2-yl)phenol (L2H) and 1-(4,5-diphenyl-1H-imidazol-2-yl)
