63372-08-7Relevant articles and documents
Synthesis of some alkyl phosphite complexes of platinum and their structural and spectral characterization
Solar, José M.,Rogers, Robin D.,Mason, W. Roy
, p. 373 - 377 (2008/10/08)
In order to explain why Pt(II) products were frequently observed, the synthetic procedure for Pt(0) alkyl phosphite complexes has been reexamined. According to the procedure the Pt(0) complexes [Pt(P(OEt)3)4], [Pt(P(OMe)3)4], and [Pt(ETPB)4] (ETPB = 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane) are formed initially by ligand reduction of PtCl42- accompanied by Cl- displacement. Subsequently, the Pt(0) complexes are found to undergo a reoxidation to Pt(II) if O2 is not excluded from the reaction mixture. The oxidation is accelerated by H+, but the nature of the Pt(II) product depends on the counterion. When [Pt(P(OEt)3)4] in alcoholic solution is treated with HClO4 and the solution saturated with air, [Pt(P(OEt)3)4](ClO4)2 can be isolated. In the presence of HCl, [Pt(P(OR)3)4] is converted to [Pt(P(OH)(OR)2)2(P(O)(OR)2)2] for R = Et or Me. These latter complexes contain four equivalent P atoms by 31P NMR and exhibit a low-field proton resonance (δ 16.5 (Me4Si) for Me and δ 16.6 (Me4Si) for Et) assigned to bridging hydrogens linking the (RO)2POH and (RO)2PO- ligands together in the complex. The structure of [Pt(P(OH)(OMe)2)2(P(O)(OMe)2)2] has been determined by X-ray diffraction techniques. It crystallizes in the monoclinic space group P21/c with unit cell parameters a = 7.147 (1) A?, b = 15.204 (2) A?, c = 10.680 (4) A?, β = 116.53 (2)°, and Dcalcd = 2.02 g cm-3 for Z = 2. The Pt atom resides on a crystallographic center of inversion and is bonded in a square-planar geometry to the four P atoms. The two unique P ligands are equivalent, bridged by a symmetric O?H?O hydrogen bond.
