The non‐isomorphous crystal structures of NHC—Au—Cl and NHC—Au—Br (NHC is 1, 3‐dibenzyl‐4, 5‐diphenylimidazol‐2‐ylidene). Issue 11 (6th October 2016)

• Record Type: Journal Article
• Authors: Tacke, Matthias; Dada, Oyinlola; O'Beirne, Cillian; Zhu, Xiangming; Müller-Bunz, Helge
• Is Part Of: Acta crystallographica. Volume 72:Issue 11(2016)
• Page Start: 857
• Page End: 860
• Publication Date: 2016-10-06
• Subjects: gold complexes -- crystal structure -- anticancer drug candidate -- N‐heterocyclic carbene; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229616015205
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : The chemically analogous chloride and bromide complexes NHC–Au–Cl and NHC–Au–Br (NHC is an N‐heterocyclic carbene) have significantly different crystal structures, and the bromide compound displays variability in its metal–ligand distances. Abstract : Gold monochloride and monobromide can be transformed into monomeric complexes by ligands such as CO, PPh3 or Me2 S, and such ligand‐stabilized gold monochloride compounds have been investigated as catalysts, luminescent materials and anticancer drugs, especially when coordinated to a lipophilic benzyl‐substituted N‐heterocyclic carbene (NHC) ligand. The triclinic structures of NHC–Au–Cl {chlorido(1, 3‐dibenzyl‐4, 5‐diphenylimidazol‐2‐ylidene)gold, [AuCl(C29 H24 N2 )]} and NHC—Au—Br {bromido(1, 3‐dibenzyl‐4, 5‐diphenylimidazol‐2‐ylidene)gold, [AuBr(C29 H24 N2 )]}, determined by X‐ray crystallography at 100 K, have one and four molecules, respectively, in their asymmetric units. The chloride compound shows an almost linear C—Au—Cl fragment [179.76 (8)°], with an Au—C distance of 1.976 (3) Å and an Au—Cl distance of 2.3013 (6) Å, while the bromide compound shows surprisingly large geometry deviations, from 1.969 (12) to 2.016 (10) Å for the Au—C distance and from 2.4279 (14) to 2.4796 (12) Å for the Au—Br distance, in the four independent molecules.