Crystal structure and reactivity of mononuclear cationic palladium(II) and platinum(II) triphos complexes with phenyltin(IV) anions. The formation of polynuclear platinum-triphos ionic and covalent complexes

M. Inés García-Seijo, Alfonso Castieiras, Bernard Mahieu, László Jánosi, Zoltán Berente, László Kollár, M. Esther García-Fernández

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The ionic complexes [M(triphos)Cl]X [M = Pd, X = Cl (1), SnCl3 (1a), SnPh2Cl3 (1c); M = Pt, X = Cl (3), SnCl3 (3a), SnPh2Cl3 (3c)], [M(triphos)Cl]2X [X = SnPh2Cl4, M = Pd (1b), Pt (3b); X = PtCl4, M = Pt (3d)] and [M(triphos)2]X2 [X = SnPh2Cl3, M = Pd (2), Pt (4)] where triphos = bis(2-diphenylphosphinoethyl)phenylphosphine, were synthesised and characterised by microanalysis, mass spectrometry, IR, 119Sn Mössbauer, NMR (31P, 195Pt and 119Sn) spectroscopies and conductivity measurements. The X-ray crystal structures of compounds 1b, 3b and 3c, where tetrachlorodiphenylstannate(IV) and trichlorodiphenylstannate(IV) act as counterions stabilising cationic metal complexes, are reported. These compounds contain the cation [M(triphos)Cl]+ with distorted square-planar geometry at palladium or platinum, triphos acting as a tridentate chelating ligand. The anions [SnPh2Cl4]2- (1b, 3b) and [SnPh2Cl3]- (3c) have trans-octahedral and distorted trigonal-bipyramidal environments for the metal, respectively. Although the dinegatively charged [SnPh2Cl4]2- is counteracted by the presence of two singularly positively charged [M(triphos)Cl]+ species, interanion contacts via hydrogen bonds were found for 1b and 3b but were absent for compound 3c. The crystalline solids [M(triphos)2][SnPh2Cl3]2 M = Pd (2), Pt (4)] were formed via a chelate ring-opening reaction of [M(triphos)Cl]+ induced by triphos. The formation of heterometallic complexes by reaction of AgCl or Au(I) with the complex [Pt(triphos)2][SnPh2Cl3]2 (4), followed by 31P NMR in solution, did not take place. The presence of dangling arm phosphine oxide groups, on oxidation of complex 4 with H2O2, was detected. Other ring-opening reactions were observed by 31P NMR and conductivity measurements when solutions containing PtCl2(PhCN)2 and triphos in a molar ratio 3:2 were refluxed C6H6. Besides [Pt(triphos)Cl]2[PtCl4] (3d) and the ionic complex with a dinuclear anion, [Pt(triphos)Cl][Pt2(triphos)Cl5] (5), the covalent trinuclear complexes [{PtCl2(Ph2PCH2CH2) 2PPh-P1,P2}2(P3, P3)PtCl2] (6a, 6b) were formed as minor products. These latter diastereomeric species become the dominant species upon heating, being thermodynamically controlled complexes. Mixtures of 3d, 5, 6a and 6b converted to complex [Pt(triphos)Cl]Cl (3) by addition of triphos, chelate ring-closure reactions of 6a, 6b and the complex anion 5 occurring. With an excess of triphos (Pt:triphos = 3:4 or higher ratio), broad peaks reflecting fast equilibria between ring-opened and ring-closed products were found.

Original languageEnglish
Pages (from-to)855-868
Number of pages14
JournalPolyhedron
Volume20
Issue number9-10
DOIs
Publication statusPublished - Apr 30 2001

    Fingerprint

Keywords

  • Diphenyltin(IV) anions
  • NMR spectroscopy
  • Palladium
  • Platinum
  • Triphosphine complexes
  • X-ray structures

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this