Binary B4S4 Rhombic Clusters as Promising Inorganic Ligands for ­Triple‐Decker Sandwich Complexes

Abstract

AbstractDesigning new forms of ligands and their sandwich‐type analogs is the beginning of building multidecker metallic sandwich clusters and their infinite one‐dimensional molecular wires. Here, we report on two binary B–S clusters: C2v B4S4 (1, 1A1) and D2h B4S4– (2, 2B2u) with rhombic B2S2 as the core are their global minimum structures based upon global searches and electronic structure calculations at the B3LYP and coupled‐cluster theory [CCSD(T)] levels. The global‐minimum structures 1 and 2 can be formulated as B2S2(BS)2 and feature B2S2 four‐membered rings as the core, with two –BS terminal groups attached terminally, closely resembling B2S2H2 with a rhombic B2S2 core and obtainable from the latter by isovalent BS/H substitution. Bonding analyses reveal a 4c–4e o‐bond in C2v B4S4 (1, 1A1), which is 4π systems in the nonbonding/bonding combination, in contrast to the antibonding/bonding combination in a classical 4π antiaromatic hydrocarbon such as cyclobutadiene (C4H4). The electronic properties of the global‐minimum 1 and 2 clusters are predicted. C2v B4S4 (1, 1A1) is predicted to be effective as an inorganic ligand to form triple‐decker sandwich‐type transition‐metal complexes, such as D2h (B4S4)3M2 (M = Ni, Pd, and Pt). These complexes, considering the formation energies, are found to be particularly stable. The sandwich structural pattern developed in this work expands the transition‐metal complexes by introducing inorganic C2v B4S4 (1, 1A1) into traditional triple‐decker sandwich structures and may be extended to form one‐dimensional transition‐metal sandwich polymers [M(B4S4)]∞ (M = Ni, Pd, and Pt).