New Noncentrosymmetric Tetrel Pnictides Composed of Square‐Planar Gold(I) with Peculiar Bonding. Issue 26 (15th March 2021)

• Record Type: Journal Article
• Authors: Lee, Shannon J.; Won, Juyeon; Wang, Lin‐Lin; Jing, Dapeng; Harmer, Colin P.; Mark, Justin; Akopov, Georgiy; Kovnir, Kirill
• Is Part Of: Chemistry. Volume 27:Issue 26(2021)
• Page Start: 7383
• Page End: 7390
• Publication Date: 2021-03-15
• Subjects: electron localization function -- gold -- noncentrosymmetric structures -- tetrel pnictides -- X-ray photoelectron spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202005312
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Three novel isostructural equiatomic gold tetrel pnictides, AuSiAs, AuGeP, and AuGeAs, were synthesized and characterized. These phases crystallize in the noncentrosymmetric (NCS) monoclinic space group Cc (no. 9), featuring square‐planar Au within cis ‐[AuTt2 Pn2 ] units (Tt=tetrel, Si, Ge; Pn=pnictogen, P, As). This is in drastic contrast to the structure of previously reported AuSiP, which exhibits typical linear coordination of Au with Si and P. Chemical bonding analysis through the electron localization function suggests covalent two‐center two‐electron Tt−Pn bonds, and three‐center Au−Tt−Au and Au−Pn−Au bonds with 1.6 e − per bond. X‐ray photoelectron spectroscopy studies support the covalent and nonionic nature of Au−Pn and Au−Tt bonds. The title materials were found to be n ‐type narrow‐gap semiconductors or semimetals, with nearly temperature‐independent electrical resistivities and low thermal conductivities. A combination of the semimetallic properties with tunable NCS structure provides opportunities for the development of materials based on gold tetrel pnictides. Abstract : Bonding natures : Compared with common types of Au I coordination observed in extended solids, square‐planar coordination is rare. Au(I)relia shows off the three‐centered bonding of Au−Tt−Au and Au−Pn−Au (on her feathers; Tt=tetrel, Pn=pnictogen), square‐planar cis ‐[AuTt2 Pn2 ] units (her body), and linear chains of Au (her legs) that are characteristic of equiatomic AuSiAs, AuGeP, and AuGeAs compounds.