Clustering of auro-acetylenes via C-Au center dot center dot center dot pi interactions: Gold-hydrogen analogy

The structure, stability, electronic and thermochemical properties of small clusters of auro-acetylenes (C2Au2) are investigated using dispersion-corrected density functional theoretical (DFT) method. The studies showed that auro-acetylene clusters are connected mainly via C-Au center dot center dot center dot pi interactions analogous to C-H center dot center dot center dot pi interactions in acetylene clusters. In the most stable structures of trimer and tetramer, each of the constituent unit acts both as a C-Au center dot center dot center dot pi donor and as a C-Au center dot center dot center dot pi acceptor forming cyclic structures akin to acetylene clusters. The studies also revealed that the C-Au center dot center dot center dot pi interactions are stronger than the aurophilic interactions forming the clusters.