55664-33-0Relevant academic research and scientific papers
Thermodynamic control of oxidative addition and reductive elimination processes in cis-bis(dimethoxyboryl)-bis(tricyclohexylphosphine)platinum(ii)
Braunschweig, Holger,Damme, Alexander
, p. 5216 - 5218 (2013)
cis-[(Cy3P)2Pt{B(OMe)2}2] (1) was obtained in quantitative yield and fully characterised. The thermal stability of 1 was investigated in solution using multinuclear NMR spectroscopy revealing a hitherto unknown temperature-dependent equilibrium between 1 and the corresponding starting materials [Pt(PCy3)2] and free B2(OMe)4.
An Adaptable Chelating Diphosphine Ligand for the Stabilization of Palladium and Platinum Carbenes
Barrett, Brittany J.,Iluc, Vlad M.
, p. 730 - 741 (2017/04/21)
Group 10 metal carbenes are proposed in catalytic transformations; however, their isolation remains difficult without the presence of a heteroatom donor. The adaptable cis and trans coordinating ligand PterP (1,2-bis(2-(diisopropylphosphino)phe
A B-C double bond unit coordinated to platinum: An alkylideneboryl ligand that is isoelectronic to neutral aminoborylene ligands
Brand, Johannes,Braunschweig, Holger,Hupp, Florian,Phukan, Ashwini K.,Radacki, Krzysztof,Sen, Sakya S.
, p. 2240 - 2244 (2014/03/21)
The reaction of [Pt(PCy3)2] with Br 2B-CH(SiMe3)2 resulted in generation of the first alkylideneboryl complex, trans-[Br(Cy3P)2Pt{B= CH(SiMe3)}], with concomitant elimination of Me3SiBr. The trans bromide ligand of the alkylideneboryl complex was readily substituted by a methyl group upon treatment with methyllithium, leading to another alkylideneboryl complex, trans-[Me(Cy3P)2Pt{B=CH(SiMe 3)}]. Various spectrochemical techniques, single-crystal X-ray crystallography, and quantum chemical calculations confirmed the formulation of a double bond between the boron and the carbon atom. The theoretical studies also provided evidence for the stronger trans influence of the alkylideneboryl ligand over iminoboryl and oxoboryl ligands. Copyright
Reactivity of Lewis basic platinum complexes towards fluoroboranes
Bauer, Juergen,Braunschweig, Holger,Dewhurst, Rian D.,Radacki, Krzysztof
, p. 8797 - 8805 (2013/07/26)
We herein report detailed investigations into the interaction of Lewis acidic fluoroboranes, for example BF2Pf (Pf=perfluorophenyl) and BF2ArF (ArF=3,5-bis(trifluoromethyl)phenyl), with Lewis basic platinum complexes such as [Pt(PEt3)3] and [Pt(PCy3)2] (Cy=cyclohexyl). Two presumed Lewis adducts could be identified in solution and corresponding secondary products of these Lewis adducts were characterized in the solid state. Furthermore, the concept of frustrated Lewis pairs (FLP) was applied to the activation of ethene in the system [Pt(BPf3)(CH2CH2)(dcpp)] (dcpp=1,3-bis(dicyclohexylphosphino)propane; Pf=perfluorophenyl). Finally, DFT calculations were performed to determine the interaction between the platinum-centered Lewis bases and the boron-centered Lewis acids. Additionally, several possible mechanisms for the oxidative addition of the boranes BF 3, BCl3, and BF2ArF to the model complex [Pt(PMe3)2] are presented. Still elusive: Several attempts to yield the elusive, unsupported Lewis adduct between a Lewis basic transition-metal complex and a Lewis acidic borane are presented, including NMR spectroscopic characterization at low temperatures, isolation of secondary products and detailed DFT calculations (see figure). Copyright
Competing C-F activation pathways in the reaction of Pt(0) with fluoropyridines: Phosphine-assistance versus oxidative addition
Nova, Ainara,Erhardt, Stefan,Jasim, Naseralla A.,Perutz, Robin N.,Macgregor, Stuart A.,McGrady, John E.,Whitwood, Adrian C.
, p. 15499 - 15511 (2009/03/12)
A survey of computed mechanisms for C-F bond activation at the 4-position of pentafluoropyridine by the model zero-valent bis-phosphine complex, [Pt(PH3)(PH2Me)], reveals three quite distinct pathways leading to square-planar Pt(II) products. Direct oxidative addition leads to cis-[Pt(F)(4-C5NF4)(PH3)(PH2Me)] via a conventional 3-center transition state. This process competes with two different phosphine-assisted mechanisms in which C-F activation involves fluorine transfer to a phosphorus center via novel 4-center transition states. The more accessible of the two phosphine-assisted processes involves concerted transfer of an alkyl group from phosphorus to the metal to give a platinum(alkyl)(fluorophosphine), trans-[Pt(Me)(4-C5NF 4)(PH3)(PH2F)], analogues of which have been observed experimentally. The second phosphine-assisted pathway sees fluorine transfer to one of the phosphine ligands with formation of a metastable metallophosphorane intermediate from which either alkyl or fluorine transfer to the metal is possible. Both Pt-fluoride and Pt(alkyl)(fluorophosphine) products are therefore accessible via this route. Our calculations highlight the central role of metallophosphorane species, either as intermediates or transition states, in aromatic C-F bond activation. In addition, the similar computed barriers for all three processes suggest that Pt-fluoride species should be accessible. This is confirmed experimentally by the reaction of [Pt(PR 3)2] species (R = isopropyl (iPr), cyclohexyl (Cy), and cyclopentyl (Cyp)) with 2,3,5-trifluoro-4-(trifluoromethyl)pyridine to give cis-[Pt(F){2-C5NHF2(CF3)}(PR3) 2]. These species subsequently convert to the trans-isomers, either thermally or photochemically. The crystal structure of cis-[Pt(F){2-C 5NHF2(CF3)}(PiPr3)2] shows planar coordination at Pt with r(F-Pt) = 2.029(3) A and P(1)-Pt-P(2) = 109.10(3)°. The crystal structure of frans-[Pt(F){2-C5NHF 2(CF3)}(PCyp3)2] shows standard square-planar coordination at Pt with r(F-Pt) = 2.040(19) A.
Preparation and structure of a new dipalladium complex with bridging diphenylgermyl ligands. Diverse reactivities of Pd(PCy3)2 and Pt(PCy3)2 toward Ph2GeH2
Tanabe, Makoto,Ishikawa, Naoko,Osakada, Kohtaro
, p. 796 - 798 (2008/10/09)
A dinuclear palladium complex having bridging diphenylgermyl ligands, [{Pd(PCy3)}2(μ-HGePh2)2] (1), was obtained from the reaction of Ph2GeH2 with [Pd(PCy 3)2]. X-ray
Platinum bis(tricyclohexylphosphine) silyl hydride complexes
Chan, Danny,Duckett, Simon B.,Heath, Sarah L.,Khazal, Iman G.,Perutz, Robin N.,Sabo-Etienne, Sylviane,Timmins, Philippa L.
, p. 5744 - 5756 (2008/10/09)
A series of platinum metal silyl hydride complexes were prepared in solution by reaction of Pt(PCy3)2 with the appropriate silane, HSiR2R′. The complex was characterized using x ray crystallography at -100°C. The platinum center was found to exhibit a distorted-square-planar geometry with angles P(1)-Pt-P(2)=113.55(3)°, P(1)-Pt-Si=146.83(3)°, and P(2)-Pt-Si=99.37(3)°. The reaction of Pt(PCy3)2 with chlorinated hydrosilanes at -78°C was also found to yield analogues complexes which isomerized to their trans isomers on warming at room temperatures.
PALLADIUM AND PLATINUM COMPLEXES OF α-KETOESTERS. CRYSTAL STRUCTURE OF
Grassi, A.,Longo, P.,Musco, A.,Porzio, W.,Scrivanti, A.
, p. 439 - 448 (2007/10/02)
The reactions of M(PCy3)2 (3) (a, M=Pd; b, M=Pt; Cy=cyclohexyl) and trans-PtH2(PCy3)2 (4) with the α-ketoesters diethyloxomalonate (1) and ethylpyruvate (2) have been investigated.At room temperature 1 coordinates strongly to 3, whereas 2 yields labile adducts.At higher temperatures 2 reacts with 3b to yield the enolate (8), the structure of which has been determined by X-ray diffraction.The ester 1 behaves like CO2 in undergoing rapid insertion into the Pt-H bond of 4.Unexpectedly reaction of 2 with 1 does not yield an insertion product, but again gives complex 8.
Reductive Elimination of a Carbon-Carbon Bond from Bis(trialkylphosphine)-3,3-dimethylplatinacyclobutanes Produces Bis(trialkylphosphine)platinum(0) and 1,1-Dimethylcyclopropane
DiCosimo, Robert,Whitesides, George M.
, p. 3601 - 3607 (2007/10/02)
The thermal decompositions of several platinacyclobutanes-bis(triethylphosphine)-(1), bis(triisopropylphosphine)-(2), and bis(tricyclohexylphosphine)-3,3-dimethylplatinacyclobutane (3) -have been examined in cyclohexane solution.Decomposition of 1 proceeds heterogeneously: it products platinum metal, neopentane, 1,1-dimethylcycloprorane, and ethilene and seems to be autocatalytic.Decompositions conducted using reaction mixtures containing mercury(0) proceed homogeneously and produce predominately 1,1-dimethylcyclopropane; any platinum metal produced is apparently amalgamated by Hg(0) and rendered catalytically inactive.Thermal decompositions of 2 and 3 proceed homogeneously, even in the absence of Hg(0), and yield 1,1-dimethylcyclopropane, bis(trialkylphosphine)platinum(0), and small quantity of neopentane.The rates of the decomposition decreases by addition of trialkylphosphine, and a study of these dependence of the rate on concentration of added phosphine for 2 indicates that one phosphine dissociates to produce a three-coordinate platinum(II) intermediate prior to reductive elimination of 1,1-dimethylcyclopropane.The Arrhenius activation parameters for decomposition of 2 and 3 are respectively Ea=46+/-3 kcal mol-1, log A=23+/-2 and Ea=42+/-2 kcal mol-1, log A=21+/-1.Substitution of deuterium for hydrogen in the triisopropylphosphine groups of 2 produces no change in the rate of the reaction.We cannot distinguish between mechanisms in which reductive elimination of 1,1-dimethylcyclopropane occurs directly from the three-coordinate intermediate and those in which oxidative addition of a C-H bond to platinum bycyclometalation of the phosphine produces a Pt(IV) intermediate in a step preceding rate-limiting reductive elimination of 1,1-dimethylcyclopropane.
