Synthesis and Structure of a Molecular Metal Propeller with Three Leaves, a Tetranuclear Silver(I) Cluster Formed by 2-Mercaptobenzoate and Triphenylphosphine Ligands

A tetranuclear silver(I) cluster, [Ag(2-Hmba)(PPh 3 )] 4 . 0.5CHCl 3 .0.5C 2 H 5 OH 1 (2-H 2 mba = 2-mercaptobenzoic acid), was prepared using the silver(I)-oxygen bonding precursor [Ag 2 (R-Hpyrrld)(S-Hpyrrld)] (H 2 pyrrld = 2-pyrrolidone-5-carboxylic acid), PPh 3 and 2-H 2 mba in an organic solvent. The crystal structure of 1 was composed of a racemic mixture of a propeller cluster having three "leaves" constructed with three Ag(μ 3 -S)(μ 2 -S)P units and one Ag(μ 2 -S) 3 P unit. The Hpyrrld - ligand in the precursor plays an important role in the formation of 1, although this ligand disappeared from the product.