Gold(I) Chloride Complexes with 4-Halo-Substituted Phenyl Isocyanide Ligands

A series of gold(I) monoisocyanide [AuCl(CNC₆H₄-4-X)] (X = Cl (IIa), Br (IIb), I (IIc) and bis-isocyanide [Au(CNC₆H₄-4-X)₂](PF₆) (X = Cl (IIIa), Br (IIIb), I (IIIc) complexes were prepared by the reaction of [AuCl(Tht)] (Tht = tetrahydrothiophene) with the specified isocyanide. The molecular structure of IIa–IIc was established by X-ray diffraction (CCDC no. 2253450 (IIa), 2253447 (IIb), 2253448 (IIc)). The crystals of IIb and IIc are isostructural; they were found to have several types of intermolecular interactions, particularly, C–X⋯Cl–Au halogen bonds, π-hole (C_CNR)··· \(~{{d}_{{{{z}^{2}}}}}\) (Au) interactions, and Au⋯Au aurophilic contacts, which form together a two-layer 2D supramolecular polymer. The crystals of IIb, IIc and IIIa, IIIb exhibit phosphorescence at room temperature; compounds IIa and IIIc do not possess luminescent properties; and mechanical grinding of IIa‒IIc and IIIa‒IIIc powders does not change the photophysical properties.