A Cationic (N‐Heterocyclic carbene)silver Complex as Catalyst for Bulk Ring‐Opening Polymerization ofL‐Lactides

Abstract

Synthetic, theoretical, and catalysis studies of a cationic functionalized N-heterocyclic carbene complex of silver, namely, is reported. Specifically, 1b was synthesized by the reaction of 1-isopropyl-3-(N-phenylacetamido)imidazolium chloride (1a) with Ag 2 O in 64 % yield; 1a was synthesized by the alkylation reaction of 1-isopropylimidazole with N-phenyl chloroacetamide in 90 % yield. The molecular structure of 1b was determined by X-ray diffraction studies and was found to be active for polymerization of L-lactide at elevated temperatures under solvent-free melt conditions to give polylactide of moderate molecular weight with narrow molecular weight distribution. Density functional theory studies of the cationic species 2b, derived from NHC silver complex 1b, were employed to obtain an understanding of the structure, bonding, and electronic features of the mole-

The Medicinal Applications of Imidazolium Carbene−Metal Complexes

“…Thus a higher d/b ratio emphasizes the ability of NHC to function as an effective σ-donor, whereas a lower d/b ratio highlights the greater NHC ← metal π-back donation. Interestingly, in the studies conducted by Ghosh, greater NHC ← metal π-back donation was observed in Pd-NHC complexes exhibiting lower d/b ratios ranging between 2.59 – 3.9913,14 and Au-NHC complexes with d/b ratios ranging between 5.23 – 5.8815,16 as compared to the Ag-NHC complexes with d/b ratios ranging between 7.8 – 12.6811,12,16. This observation could attest to why silver-NHC complexes are particularly better transmetallating agents.…”

N‐Phenyl‐substituted carbene precursors and their silver complexes: synthesis, characterization and antimicrobial activities

“…[12][13][14][15][16][17] Using these ligands, their metal complexes have shown high catalytic activity in metathesis, the creation of furan, polymerization, hydrosilylation, hydrogenation and coupling reactions. [1,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Thus NHC-silver complexes have had a significant role in the rapid development of NHC-metal complexes. [1,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Thus NHC-silver complexes have had a significant role in the rapid development of NHC-metal complexes.…”

Experimental and theoretical studies of a silver complex of O-functionalized N-heterocyclic carbene

“…Unlike the neutral monomeric 1:1 complex (NHC ligand to metal) observed in case of [1- [57] having 2:1 NHC ligand to metal ratio was obtained under analogous reaction conditions for a related NHC ligand bearing a N-phenylacetamide substituent. Similar 2:1 cationic monomeric silver complexes have been observed in case of both symmetrically as well as unsymmetrically substituted N-hetercocylic carbene ligands.…”