Synthesis of amidate-hanging platinum mononuclear complexes by base hydrolysis of nitrile complexes

摘要

The "amidate-hanging" Pt mononuclear complexes, which can easily bind a second metal ion with the non-coordinated oxygen atoms in the amidate moieties, have been synthesized and characterized by H-1 NMR, MS, IR spectroscopy, and single crystal X-ray analysis. Five new complexes with various amidate ligands and co-ligands, cis-[Pt(PVM)(2)(en)] center dot 4H(2)O (1, PVM = pivaloamidate, en = ethylenediamine), cis-[Pt(PVM)(2)(NH2CH3)(2)] center dot H2O (2), cis-[Pt(PVM)(2)((NH2Bu)-Bu-t)(2)](3), cis-[Pt(TCM)(2)(NH3)(2)](4, TCM = trichloroacetamidate), and cis-[Pt(BZM)(2)(NH3)(2)] (5, BZM = benzamidate), were successfully synthesized by direct base hydrolysis of the corresponding Pt nitrile complexes, cis-[Pt(NCR)(2)(Am)(2)](2+) (P1, P2, P3, and P5) (NCR = nitrile, Am = amine). These nitrile complexes were obtained by introducing nitriles into the Pt aqua complexes, cis-[Pt(OH2)(2)(AM)(2)](ClO4)(2), whereas introduction of trichloronitrile into [Pt(OH2)(2)(NH3)(2)](ClO4)(2) induced more facilitated water nucleophilic attack to afford [Pt(TCM)(NH(C=OH)CCl3)(NH3)(2)](ClO4) (P4). The base treatments of the precursor complexes (P1-5) lead to produce "amidate-hanging" Pt mononuclear complexes (1-5) without geometry isomerization. The (195)pt chemical shifts for 1-5 exhibit subtle differences of the Pt electron densities among them. (C) 2007 Elsevier B.V. All rights reserved.