Structural variation in silver complexes with N-heterocyclic carbene ligands bearing amido functionality

Abstract

Silver complexes derived from reactions of silver(I) oxide and imidazolium precursors [L 1H 1H 2]Cl and [ L 2 H 2 1 H 2 ] Cl in DMF were reported. The crystallographic analyses confirmed that all these silver complexes are 1:1 Ag/NHC complexes in the solid states with formulae of Ag(L 1H 1)Cl and Ag ( L 2 H 2 1 ) Cl , respectively. The amido proton (H 1) remains intact. Their solid-state structures markedly depend on their N-substitutions on the ligand frameworks. The C–Ag–Cl bond angles are ca. 150° in Ag(L 1H 1)Cl complexes bearing N-benzyl groups, whereas the angle is linear in Ag ( L 2 H 2 1 ) Cl bearing two N-amido functional groups. The obtuse bond angles in Ag(L 1H 1)Cl permit the formation of infinite 1D staircase motifs via bridging Cl and hydrogen bonding interactions. No such motif exists in the structure with the linear bond angle.