Synthesis and characterization of (ethylenediamine)/(diammine)platinum(II) coordinated to seleno ligands containing carboxylic acid functionality

The reaction of [Pt(N^N)(ONO2)2] with seleno ethers, Se{(CH2)nCOOH)}2 (n = 1 or 2) in the presence of NaOH afforded complexes of composition [Pt(N^N)(OOC(CH2)nSe(CH2)nCOOH)][OH] (N^N = en or 2NH3; n = 1 or 2). Similar reactions with diselenides, [Se(CH2)nCOOH]2 gave complexes of the type [Pt(en){OOC(CH2)nSe}2]. These complexes were characterized by microanalyses and NMR spectroscopy (1H, 13C{1H}, 77Se{1H} and 195Pt{1H}). The seleno ligand in [Pt(N^N)(OOC(CH2)nSe(CH2)nCOOH)][OH] is coordinated to platinum through one carboxylate group and a selenium atom. The molecular structure of [Pt(en)(OOCCH2SeCH2COOH)][OH] was established by single crystal X-ray diffraction analysis. The reactivity of [Pt(N^N)(OOC(CH2)nSe(CH2)nCOOH)][OH] with mononucleotide 5′-guanosine monophosphate (5′-GMP) has been studied in aqueous solution by 195Pt{1H} NMR spectroscopy.