The active and well-designed Schiff base ligands are considered "privileged ligands". The so-called salen ligands, i.e., the tetradentate [O, N, N, O] bis-Schiff base ligands, have also found broad applications in many homogeneous catalytic reactions. Modification of the salen ligands has concentrated on altering the substituents in the phenolate rings and variations in the diamine backbones. Herein, o-carborane-supported salen ligands (2) were designed and prepared. A series of aluminum−salen complexes (3• (sol) 2 ), which were supported by the nido-C 2 B 9 carborane anions, were synthesized. These Al(III) complexes showed high activities (TOF up to 1500 h −1 ) in catalyzing the cycloaddition of epoxides and CO 2 at atmospheric pressure and near room temperature. Complexes 3•(sol) 2 are one of the rare examples of Al-based catalysts capable of promoting cycloaddition at 1 bar pressure of CO 2 . Density functional theory (DFT) studies combined with the catalytic results reveal that the catalytic cycles occur on two axial sites of the Al(III) center.
Metallacarboranes have attracted significant attention due to their unique properties. Considerable efforts have been made on the reactions around the metal centers or the metal ion itself, while transformations of functional groups of the metallacarboranes have been much less explored. We presented here the formation of imidazoliumfunctionalized nickelacarboranes (2), their subsequent conversion to nickelacarborane-supported N-heterocyclic carbenoids (NHCs, 3), and the reactivities of 3 toward Au(PPh 3 )Cl and Se powder, which resulted in the formation of bis-gold carbene complexes (4) and NHC selenium adducts (5). Cyclic voltammetry of 4 shows two reversible peaks, corresponding to the interconversion transformations Ni II ↔ Ni III and Ni III ↔ Ni IV . Theoretical calculations demonstrated relatively high-lying lone-pair orbitals, weak B−H•••H−C interactions between the BH units and the methyl group, and weak B−H•••π interactions between the BH groups and the vacant p-orbital of the carbene.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.