Affiliations: Department of Chemistry, The University of Tennessee at Chattanooga, Chattanooga, TN, USA | Department of Chemistry, Clemson University, Clemson, SC, USA
Abstract: The synthesis, spectroscopic data and crystal structures of two new mononuclear Pd(II) heteroleptic complexes with the crown trithioether 1,4,7-trithiacyclononane (9S3) and the arsine ligand, triphenylarsine (AsPh3) are presented. Reaction between [Pd(9S3)Cl2] and AsPh3 (1:2 stoichiometry) in nitromethane followed by metathesis to the hexafluorophosphate salt results in the formation of two different palladium(II) complexes, the expected bis arsine complex [Pd(9S3)(AsPh3)2](PF6)2 as well as, surprisingly, the intermediate mono arsine-chloro complex [Pd(9S3)(AsPh3)(Cl)](PF6). Both complexes exhibit the anticipated structure consisting of a cis square planar array of two sulfur atoms from the 9S3 and either two As donors (bis AsPh3 complex) or one As and one Cl donor (mono AsPh3 complex). The third 9S3 sulfur atom exhibits a long distance interaction with the palladium forming an elongated square pyramidal geometry with a coordination environment around the Pd best described as [S2As2 + S1] or [S2AsCl + S1]. Structural, spectroscopic, and reactivity differences are observed between the arsine and related phosphine complexes due to the poorer donor qualities of AsPh3.
