60158-99-8Relevant academic research and scientific papers
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
Mechanistic insight into the protonolysis of the Pt-C bond as a model for C-H bond activation by platinum(II) complexes
Romeo, Raffaello,D'Amico, Giuseppina
, p. 3435 - 3446 (2008/10/09)
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.
Reactions of coordinatively unsaturated platinum(II)-η1-allyl complexes with the electrophilic reagents sulfur dioxide, chlorosulfonyl isocyanate, and hexafluorophosphoric acid etherate
Hu, Yeh-Rom,Wojcicki, Andrew,Calligaris, Mario,Nardin, Giorgio
, p. 1561 - 1568 (2008/10/08)
New platinuma(II)-η1-allyl complexes of the type trans-(η1-C3H5)Pt(PR3) 2Cl (PR3 = PMe2Ph, P(i-Pr)3, P(t-Bu)3) have been synthesized by reaction of [(C3H5)PtCl]4 with 8 equiv of PR3. These and known complexes trans-(η1-C3H5)Pt(PR3) 2Cl (PR3 = PEt3, PCy3) and trans-(η1-CH2CH=CHMe)Pt(PEt3)2Cl have been investigated with respect to their behavior toward the electrophiles SO2, ClSO2NCO, and HPF6·Et2O. The complexes trans-(η1-C3H5)Pt(PR3) 2Cl react with SO2 in benzene solution at 25°C to afford trans-(CH2=CHCH2S(O)2)Pt(PR3) 2Cl, the order of reactivity as a function of PR3 being PEt3, PMe2Ph > P(i-Pr)3 > P(t-Bu)3 (no reaction). The crotyl isotopomers trans-(CH2CH=C*HMe)Pt(PEt3)2Cl (*H = H, D) insert SO2 with rearrangement of the η1-allyl fragment to give trans-(CH2=CHC*H(Me)S(O)2)Pt(PEt3) 2Cl. These sulfinato-S products were characterized by chemical analysis and IR and 1H and 31P{1H} NMR spectroscopy, and the structure of trans-(CH2=CHCH2S(O)2)Pt(PMe 2Ph)2Cl was determined by X-ray crystallography. Treatment of trans-(η1-C3H5)Pt(PR3) 2Cl (PR3 = PEt3, PCy3) and trans-(η1-CH2CH=CHMe)Pt(PEt3)2Cl with HPP6·Et2O in diethyl ether or toluene affords the η2-propene and η2-1-butene complexes [trans-(η2-CH2=CHMe)Pt(PR3) 2Cl]PF6 and [trans-(η2-CH2=CHEt)Pt(PEt3) 2Cl]PF6, respectively. The reactions with SO2 and HPF6·Et2O have been rationalized to proceed by attack of the electrophile at the allyl C=C; they appear to be analogous to the corresponding reactions of the 18-electron transition-metal-η1-allyl carbonyls and of related complexes. Treatment of trans-(η1-C3H5)Pt(PR3) 2Cl (PR3 = PEt3, P(i-Pr)3, PCy3) with ClSO2NCO in toluene at 25°C affords trans-Pt(PR3)2Cl2; in contrast, when these reactions are conducted at -78°C with gradual warming, trans-Pt(PR3)2Cl2 and/or another product, tentatively formulated as the cycloadduct trans-CH2N(SO2Cl)C(O)CH2CHPt(PR 3)2Cl, are obtained. The presumed cycloadduct could not be separated from trans-Pt(PR3)2Cl2 and was only characterized by 31P{1H} NMR spectroscopy and FAB mass spectrometry in the mixture. When L = PEt3, a precursor of trans-Pt(PEt3)2Cl2, possibly (η1-C3H5) Pt(PEt3)2Cl2(SO2NCO), is observed. The reactions with ClSO2NCO are provisionally explained by competing [3 + 2] cycloaddition and oxidative addition-reductive elimination pathways. Crystallographic data: monoclinic, space group P21/n, a = 10.633 (2) A?, b = 16.830 (4) A?, c = 13.745 (3) A?, β = 112.77 (2)°, Z = 4, R = 0.032, and Rw = 0.038.
Chemistry of Metal-Diene Complexes: 31P NMR Studies of the Reaction of (COD)PtCl2 with Tertiary Phosphines in Methanol
Goel, Anil B.,Goel, Sarla
, p. 141 - 144 (2007/10/02)
Reactions of (COD)PtCl2 with tertiary phosphine ligands in methanol have been studied by 31P nmr spectroscopy.The formation of cationic complex +Cl-, (L = Pri3P, Ph2ButP, But2MeP, Cy3P and But3P) as the only product in the equimolar reaction between (COD)PtCl2 and tertiary phosphines has been defined.In the reaction of (COD)PtCl2 with two mole equivalent of tertiary phosphines, formation of various intermediate complexes including by the nucleophilic attack of methoxyl-anion on the coordinated cyclo-octadiene has been observed.
Preparation, characterization, and some reactions of tri-tert-butylarsine complexes of platinum(II) and palladium(II) chlorides
Goel, Ram G.,Ogini, William O.,Srivastava, Ramesh C.
, p. 3611 - 3616 (2008/10/08)
As(t-Bu)3 reacts with platinum(II) chlorides to afford either trans-PtCl2[As(t-Bu)3]2 or the dinuclear complex Pt2(μ-Cl)2Cl2[As(t-Bu)3] 2. With palladium(II) chloride, however, only the dinuclear complex Pd2(μ-Cl)2Cl2[As(t-Bu)3] 2 is formed even in the presence of excess As(t-Bu)3. These complexes undergo substitution and/or bridge-cleavage reactions with CO, py, AsPh3, Cl-, or tertiary phosphines.
Reactivity of platinum diolefin complexes. 2. Reactions with bulky and chelating group 5B ligands and studies relating to carbonyl insertion
Anderson,Clark,Davies
, p. 3607 - 3611 (2008/10/08)
Reactions of [PtXY(cod)] (X = Y = Cl, Me, Ph; X = Cl, Y = Ph, COPh) with bulky monodentate and chelating group 5B ligands have been examined by 31P{1H} NMR spectroscopy. The molecularity of the products is a function of steric bulk with monodentate ligands and a function of chelate bite with bidentate ligands. The geometry of the products is controlled largely by the trans influence of both neutral and anionic groups. Where the steric constraints involved in nucleophilic attack of the complexes by bulky ligands are dominant, olefin displacement can be prevented entirely. Reactions of [PtXYL2] (X = Y = Ph, Cl; X = Ph, Y = Cl; L = monodentate ligand, L2 = bidentate ligand) with carbon monoxide have been studied by 31P{1H} and 13C{1H} NMR and infrared spectroscopies. The mechanism of carbonyl insertion at platinum(II) is discussed in terms of the chelate effect and the trans influence of the anionic ligands.
