Di-platinum complexes containing thiolato-urea ligands: structural and anion binding studies

Abstract

The new di-platinum(II) thiolato-bridged complexes [(dppp)Pt{μ-S(CH₂)_nNHC(O)NHR}]₂(OTf)₂ (n = 2, 3; R = Et, Ph) have been synthesized. The X-ray crystal structures of three of these complexes have confirmed their formulation and highlighted the ability of the urea groups on the thiolato bridges to display hydrogen bonding interactions with anions. The binding of anions by these receptors has been quantitatively determined by ¹H NMR spectroscopy and in a qualitative fashion by indicator displacement assays. These studies have shown the receptors to be selective for inorganic phosphate. In addition we have isolated and structurally characterized an unusual 1D coordination polymer with formula {[(dppp)Pt{μ-S(CH₂)₂NHC(O)NHR}][Pb₂Cl₆]}_n. The X-ray crystal structure of this inorganic polymer has shown that it consists of units of the di-platinum-thiolato cations bridged by [Pb₂Cl₆]²⁻ moieties.