Tin(II) Halide Insertion or Halogen Exchange in the Reactions of Dihaloplatinum(II) Complexes with Tin(II) Halide

Abstract

Reactions of SnCl 2 with the complexes cis-[PtCl 2 (P 2 )] (P 2 ¼ dppf (1,1'-bis(diphenylphosphino)ferrocene), dppp (1,3-bis(diphenylphosphino)resulted in the insertion of SnCl 2 into the PtÀCl bond to afford the cis-[PtCl(SnCl 3 )(P 2 )] complexes. However, the reaction of the complexes cis-[PtCl 2 (P 2 , dppp, dppb, and dpppe; P ¼ Ph 3 P and (MeO) 3 P) with SnX 2 (X ¼ Br or I) resulted in the halogen exchange to yield the complexes [PtX 2 (P 2 )]. In contrast, treatment of cis-[PtBr 2 (dppm)] with SnBr 2 resulted in the insertion of SnBr 2 into the PtÀBr bond to form cis-[Pt(SnBr 3 ) 2 (dppm)], and this product was in equilibrium with the starting complex cis-[PtBr 2 (dppm)]. Moreover, the reaction of cis-[PtCl 2 (dppb)] with a mixture SnCl 2 /SnI 2 in a 2 : 1 mol ratio resulted in the formation of cis-[PtI 2 (dppb)] as a consequence of the selective halogen-exchange reaction. 31P-NMR Data for all complexes are reported, and a correlation between the chemical shifts and the coupling constants was established for mono-and bis(trichlorostannyl)platinum complexes. The effect of the alkane chain length of the ligand and Sn II halide is described.

Force-Modulated Reductive Elimination from Platinum(II) Diaryl Complexes

“…The one-bond platinum-phosphorous coupling constant of electronically and sterically homologous bis(phosphine) platinum complexes is highly sensitive to perturbation of ligand geometry. [68][69][70] For example, 1 JP-Pt for the structurally characterized platinum dichloride complexes [Ph2P(CH2)xPPh2]PtCl2 (X = 3-5) increased by >230 Hz with a ~12° increase in the P-Pt-P bond angle (approximately 19 Hz/°). 69,70 This analysis strongly suggests that the geometries of the primary coordination spheres of Pt in all 5 complexes of the series are very similar regardless of the force exerted on the biphenyl moiety by stiff stilbene.…”

Force-modulated reductive elimination from platinum(ii) diaryl complexes

“…The conclusion is based on the high sensitivity of 1 J P-Pt of electronically and sterically homologous bis(phosphine) platinum complexes to the P-Pt-P angle. [75][76][77] For example, 1 J P-Pt varies by >230 Hz for the $12 increase in the P-Pt-P angle ($19 Hz/ ) across the structurally characterized platinum dichloride complexes [Ph 2 P(CH 2 ) x PPh 2 ] PtCl 2 (x ¼ 3-5). 76,77 Solutions of (P-P)PtAr 2 (16 mM) and dibenzylidene acetone (DBA; 1 equiv.)…”

“…[75][76][77] For example, 1 J P-Pt varies by >230 Hz for the $12 increase in the P-Pt-P angle ($19 Hz/ ) across the structurally characterized platinum dichloride complexes [Ph 2 P(CH 2 ) x PPh 2 ] PtCl 2 (x ¼ 3-5). 76,77 Solutions of (P-P)PtAr 2 (16 mM) and dibenzylidene acetone (DBA; 1 equiv.) in toluene-d 8 were heated at 85 C and analyzed periodically by 1 H NMR spectroscopy (Scheme 1).…”

Bismuth–Halide Oxidative Addition and Bismuth–Carbon Reductive Elimination in Platinum Complexes Containing Chelating Diphosphine Ligands

“…The complexes [PtMe 2 (dppm)] and [PtMe 2 (dppe)] were prepared as reported. The Pt(II) compounds [PtMe(X)(P–P)] (PP = dppm or dppe), 2 , [Pt(X) 2 (P–P)], 3 , and [Pt 2 Me 2 (μ-X)(μ-dppm) 2 ]X, 4 , , were characterized by comparing their 1 H and 31 P NMR spectra with those of the authentic samples. The byproducts of the reactions were BiMeX 2 and BiMe 2 X which were identified from their reported 1 H NMR data …”