Synthesis, structure and photophysical properties of binuclear methylplatinum complexes containing cyclometalating 2-phenylpyridine or benzo{h}quinoline ligands: a comparison of intramolecular Pt–Pt and π–π interactions

Abstract

The binuclear cyclometalated complexes [Pt 2 Me 2 (ppy) 2 (m-dppm)], 1a, and [Pt 2 Me 2 (bhq) 2 (m-dppm)], 1b, in which ppy = 2-phenylpyridyl, bhq = benzo{h}quinoline and dppm = bis(diphenylphosphino)-methane, were synthesized by the reaction of [PtMe(SMe 2 )(ppy)] or [PtMe(SMe 2 )(bhq)] with 1/2 equiv of dppm at room temperature, respectively. Complexes 1a and 1b were fully characterized by multinuclear ( 1 H, 31 P, 13 C, and 195 Pt) NMR spectroscopy and were further identified by single crystal X-ray structure determination. A comparison of the intramolecular Pt-Pt and p-p interactions in complexes 1a and 1b has been made on the basis of data on crystal structures and wave functions analysis. The binuclear complexes 1a and 1b are luminescent in the solid state, and showing relatively intense orange-red emissions stemming from 3 MMLCT excited states. The reaction of complex 1b with excess MeI gave the binuclear cyclometalated Pt(IV)-Pt(IV) complex [Pt 2 Me 4 (bhq) 2 (m-I) 2 ], 2. Crystal structure of complex 2 shows intermolecular C-H ◊ ◊ ◊ I and C-H ◊ ◊ ◊ p interactions in solid state.

Kinetics and mechanism of oxidative addition of MeI to binuclear cycloplatinated complexes containing biphosphine bridges: Effects of ligands

“…As has been reported previously [36], on the basis of 31 P NMR studies, reaction of the binuclear Pt(II)ePt(II) complex [Pt 2 Me 2 (bhq) 2 (m-dppm)], 1b, in which dppm, bis(diphenylphosphino)methane, acts as a bridging ligand, with excess MeI first gives a Pt(II)ePt(IV) intermediate which is finally converted to a mixture of two Pt(IV)ePt(IV) binuclear complexes. In this work in an attempt to shed some light on mechanism of the reaction, we investigated kinetics of the reaction using UVevis spectroscopy.…”

“…Benzo{h}quinoline and 1,1 0 -bis(diphenylphosphino)ferrocene were purchased from commercial sources. [PtMe(bhq)(SMe 2 )] [34] and [Pt 2 Me 2 (bhq) 2 (m-dppm)] [36] were prepared as reported. …”

Luminescence properties of some monomeric and dimeric cycloplatinated(ii) complexes containing biphosphine ligands

“…Jamali and coworkers 56 have reported a dimer complex with methyl ligands instead of chloro ligands in complex 5d. Although there is an intramolecular Pt···Pt and π-π interactions in this complex because of small Pt-P-P-Pt torsion angle (33.3°), the anti conformation of similar complex (i.e.…”

The effect of the nature of peripheral platinated and bridging mercapto ligands on the optical and electrochemical properties of binuclear Pt(II) complexes with a metal-metal chemical bond

“…The luminescence spectra and decay kinetics in CH 2 Cl 2 and CH 3 CN solutions (293 K) and in the 1 : 1 2 methoxyethanolethanol mixture (77 K) were recorded on a Fluorat 02 Panorama spectrofluorimeter without correction for its spectral sensitivity. The oxidation and reduction voltammograms of complexes were obtained in a three electrode cell with separated compartments of the working (GC), auxiliary (Pt), and reference (Ag) electrodes in the presence of 0.1 M of [N(C 4 H 9 ) 4 ]PF 6 at 293 K in a toluene-acetonitrile (1 : 1) mixture. The potentials are given with respect to the ferroce nium/ferrocene redox system at a potential scan rate of 100 mV/s.…”

“…The planar structure of cycloplatinated complexes of heterocyclic ligands determines the possibility of inter action of d Z2 orbitals of two metal centers of {Pt(C^N)} fragments with formation of a metal-metal bond in [Pt(C^N)(µ L^L)] 2 binuclear complexes [1][2][3][4][5][6][7]. The phosphorescence of these complexes at room tempera ture provides wide possibilities of their application as components of optoelectronic devices [8][9][10].…”