70516-09-5

Upstream product

• 70423-98-2 cis-dimethylbis[(sulfinyl-κS)bis[methane]]platinum(II) 
• 7688-25-7 1,4-di(diphenylphosphino)-butane 

Downstream Products

• 902775-58-0 [(1,4-bis(diphenylphosphino)butane)Pt(Me)Cl] 

Relevant academic research and scientific papers

Platinum ethylene dimerization catalysts: Diphosphine vs. diimine ancillary ligand effects

Kinetic and mechanistic studies are presented for the (dfepe)Pt(Me)(NC5F5)+ (dfepe = (C2F5)2PCH2CH2P(C2F5)2) ethylene dimerization catalyst system. New labile complexes (dfepe)PtMe(L)+ (L = NC5F5, C6F5CN, C6F5NH2, C6F5NO2) have been prepared. A general extension to a variety of other chelating diphosphine analogues (PP)Pt(Me)(C2H4)+ has been accessed by methyl abstraction from donor (PP)PtMe2 precursors with Ph3C+B(C6F5)4? in the presence of ethylene to cleanly afford (PP)Pt(Me)(C2H4)+ products. Catalysis studies for these more electron-rich diphosphine systems demonstrate moderate dimerization activity which is uniformly higher than reported for (diimine)Pt(Me)(C2H4)+. In several cases allylic catalyst decomposition products (PP)Pt(η3-C3H4Me)+ have been identified. A DFT study of insertion barriers for diimine and diphosphine systems is presented which suggests that weakening of Pt-ethylene ground state binding by strong-field diphosphine ligands is a major contributing factor to the lower ethylene insertion barriers for PP systems.

Mechanistic insight into the protonolysis of the Pt-C bond as a model for C-H bond activation by platinum(II) complexes

The kinetic and NMR features of the protonolysis reactions on platinum(II) alkyl complexes of the types cis-[PtMe2L2], [PtMe 2(L-L)], cis-[PtMeClL2], and [PtMeCl(L-L)] (L = PEt 3, P(Pri)3, PCy3, P(4-MePh) 3, L-L = dppm, dppe, dppp, dppb) in methanol suggest a rate-determining proton attack at the Pt - C bond. In contrast, a multistep oxidative-addition - reductive-elimination mechanism characterizes the methane loss on protonation of the corresponding trans-[PtMeClL2] species. Tools that were particularly diagnostic in suggesting different reaction pathways for the two systems were (i) the different results of kinetic deuterium isotope experiments, (ii) the detection or absence of Pt(IV) hydrido alkyl intermediate species by low-temperature 1H NMR experiments, and (iii) the detection or absence of isotope scrambling and incorporation of deuterium into Pt - CH3, combined with the loss of a range of CH nDn-4 isotopomers. For all systems, the rates of protonolysis are retarded by ligand steric congestion, accelerated by ligand electron donation, and almost unaffected by the chain length along the series of chelate complexes. A straight line correlates the rates of protonolysis of cis-dialkyl and cis-monoalkyl complexes, the difference in reactivity between the two systems being almost 5 orders of magnitude (slope of the line = 6 × 104). Factors controlling the dichotomy of behavior between complexes of different geometry have been taken into consideration. Application of the principle of microscopic reversibility suggests the reason why platinum complexes with nitrogen donor ligands appear to be far more efficient than platinum phosphane complexes in activating the C-H bond.