Square planar platinum(II) complexes. Crystal structures of cis-bis(triphenylphosphine)hydro (triphenylstannyl)platinum(II) and cis-bis(triphenylphosphine)hydro(triphenylsilyl)platinum(II)

Si–H Bond Activation of a Primary Silane with a Pt(0) Complex: Synthesis and Structures of Mononuclear (Hydrido)(dihydrosilyl) Platinum(II) Complexes

“…The observation of P-P coupling indicates a large deviation of the P-Pt-P angle from 90° of the ideal square planar geometry around the Pt(II) center (vide infra). In contrast, the 31 …”

“…In the 1 H NMR spectrum of 2, the characteristic signals of the platinum hydride were observed at δ = −2.15, which were split by 19 and 157 Hz of 31 The molecular structure of 2 was determined unambiguously by X-ray crystallographic analysis, as depicted in Figure 1. The X-ray crystallographic analysis of 2 revealed that the platinum center attains a distorted square-planar environment, which was probably due to the steric requirement of the cis-coordinated PPh3 ligands and the bulky 9-triptycyl group on the silicon atom.…”

“…In the 1 H NMR spectrum of 2, the characteristic signals of the platinum hydride were observed at δ = −2.15, which were split by 19 and 157 Hz of 31 [35] and [cis-PtH(SiH 2 Si t Bu 2 Me)(dcpe)] (δ = −0.89) [36]. The SiH 2 resonance appeared as a multiplet at δ = 4.68 ppm.…”

“…The 31 P{ 1 H} NMR spectrum of 5 at 298 K exhibited two nonequivalent broad singlet signals at δ = −22.9 and 37.4, with two sets of 195 Pt satellites of 2115 and 1833 Hz. The former signal was assigned to the PMe 3 trans to the hydrido ligand using a non 1 H-decoupled 31 P NMR technique at 253 K. The 29 Si{ 1 H} NMR spectrum of 5 at 223 K featured one 29 Si resonance as a broad doublet signal at δ = −43.9 ( 2 J Si-P = 151 Hz). The broadening of NMR signals possibly implies the existence of the Si-H σ-complex intermediate 6 in the NMR time scale [38,41,42].…”

“…Among these catalytic conversions, the oxidative addition of hydrosilanes with platinum(0) complexes is an efficient method for the generation of the platinum(II) hydride species, which has been proposed as a key intermediate in platinum-catalyzed hydrosilylations [2][3][4][5][6] and bis-silylations [7,8], as well as the dehydrogenative couplings of hydrosilanes [9][10][11][12][13]. While a number of reactions of hydrosilanes with platinum(0) complexes affording mononuclear bis(silyl) [14][15][16][17][18] and silyl-bridged multinuclear complexes [19][20][21][22][23][24][25][26][27][28][29] have been described so far, the isolation of mononuclear hydrido(silyl) complexes has been less well studied due to the high reactivity of a Pt-H bond [30][31][32][33][34]. In particular, the synthesis of hydrido(dihydrosilyl) platinum(II) complexes, which are anticipated as the initial products in the Si-H bond activation reactions of primary silanes with platinum(0) complexes, is quite rare.…”