Synthesis, structure and spectroscopic properties of two new cyanido-bridged trinuclear 9-atom molecular AgNCCuNCAuCN assembly of formula [AgCuAu(CN)3(PPh3)5](H2O)2 and a dinuclear gold–copper one-dimensional coordination polymer of formula [AuCu(CN)2(PPh

•An unprecedented trinuclear 9-atom molecular chain AgNCCuNCAuCN.•A missing member of the coordination polymer [MM′(CN)2(PPh3)2](H2O)2 (M, M′ = Au,Cu).•Linear gold and tetrahedral Ag and Cu form a trinuclear chain with cyanido bridges.

Two new cyanido-bridged coinage metal compounds are presented. A novel hetero trinuclear Ag–Cu–Au compound of formula [AgCuAu(CN)3(PPh3)5](H2O)21 is described with bridging cyanide ligands between the metals, and terminal phosphane ligands for Cu(I) and Ag(I). Silver is tetrahedrally coordinated by 3 phosphane ligands and a bridging cyanido ligand, copper is coordinated tetrahedrally by 2 phosphanes, and 2 bridging cyanide ligands, whereas gold has a linear coordination by 2 cyanido-κC ligands. Under slightly different synthetic conditions, an alternating chain compound [AuCu(CN)2(PPh3)2](H2O)22 was found, isostructural with the related Ag–Cu compound. In 2, Cu(I) is tetrahedrally coordinated by 2 phosphane ligands and 2N atoms of the bridging cyanido ligand to the Au(I). The qualitative solid-state luminescence emission intensity of 1 is reported and compared with that of the related bimetallic Au–Cu, Ag–Cu, Ag–Ag and Ag–Au cyanido-bridged chain compounds. The luminescence of 2 was found somewhat stronger than that of 1. The electronic molecular orbitals were calculated by DFT, where a strong contribution of Cu(I) orbitals in HOMO/LUMO character of the two complexes is observed.

Graphical abstractA rare 9-atom molecular assembly of cyanides bridging a trinuclear Ag–Cu–Au compound with terminal phosphane ligands coordinating to Cu(I) and Ag(I), and a new dinuclear-based cyanide bridged Au–Cu chain compound with phosphanes only coordinating to Cu(I) are presented.Figure optionsDownload full-size imageDownload as PowerPoint slide