- The synthesis and vibrational spectra of tetrakistrimethylphosphinenickel(0) and -platinum(0), Ni(PMe3)4 and Pt(PMe3)4
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The syntheses of the molecules Ni(PMe3)4 and Pt(PMe3)4 are reported for the first time.The platinum compound is much less stable than the nickel analogue.Raman and i.r. spectra have been obtained for the nickel compound and a complete vibrational assignment is proposed on the basis of Td molecular symmetry.For the platinum compound only the i.r. spectrum has been obtained.
- Edwards, H. G. M.
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- Trivalent Antimony as L-, X-, and Z-Type Ligand: The Full Set of Possible Coordination Modes in Pt-Sb Bonds
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In the course of our investigations of the coordination chemistry of trivalent antimony (Sb) compounds, we studied heteronuclear complexes formed in reactions of the compounds RSb(pyS)2 (R = pyS, Ph; pyS- = pyridine-2-thiolate) with [Pt(PPh3)4], i.e., complexes [(R)Sb(μ-pyS)2Pt(PPh3)] (R = pyS, 1; R = Ph, 2). The reaction of 1 with o-chloranil proceeds cleanly with elimination of 2,2′-dipyridyl disulfide and formation of the salt [(PPh3)Pt(μ-pyS)2Sb(μ-pyS)2Pt(PPh3)]+[Sb(C6Cl4O2)2]- (3III), which features the cation 3+. The charge-neutral, unsymmetrically substituted compound [(PPh3)Pt(μ-pyS)2Sb(μ-pyS)2Pt(κS-pyS)] (4) can be accessed by the reaction of 3+ with LipyS. The oxidation of 2 with o-chloranil furnishes the complex [(κ-O,O-C6Cl4O2)PhSb(μ-pyS)2Pt(PPh3)] (5). The oxidation of 1 with PhICl2 afforded the paddlewheel-shaped complex [Sb(μ-pyS)4PtCl] (6). Moreover, compound 6 was obtained by the reaction of Sb(pyS)3 with [PtCl(pyS)(PPh3)]. The polarization of Pt-Sb bonds of compounds 1-6 was investigated by natural localized molecular orbital (NLMO) calculations, which suggest X-type ligand character (covalent Pt-Sb bonds) for 1 and 2, whereas the Sb ligand of 6 reflects Z-type character (dative Pt→Sb bonds). In 3+, 4, and 5, high contributions of the reverse, i.e., L-type (dative Pt←Sb bonds), were observed. In conjunction with the results of NLMO analyses, 121Sb M?ssbauer spectroscopy proves that complexes 1-6 represent essentially trivalent Sb complexes with either a free lone pair (LP) at the Sb atom (1, 2, and 6) or LP character involved in L-type Pt←Sb coordination (3+, 4, and 5).
- Block, Theresa,Gericke, Robert,P?ttgen, Rainer,W?chtler, Erik,Wagler, J?rg
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- Method for preparing palladium (0) or platinum (0) composite compound from triphenylphosphine
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The invention provides a method for preparing a palladium (0) or platinum (0) composite compound from triphenylphosphine; with use of palladium chloride (PdCl2) or hydrochloroplatinic acid (H2PtCl6.xH2O) as a starting material, preliminary preparation reaction is not needed, and commercially purchased palladium chloride or hydrochloroplatinic acid can be directly used for reaction. The reaction process is simple, all the reactions are carried out in a same reactor, separation of intermediate products is not needed, and the loss is reduced; the yield of target products is high; the recovery problem of reaction residues is simplified. The product has high reactivity and catalytic activity in various reactions, and has broad application prospects.
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Paragraph 0033; 0034
(2019/01/08)
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- Mechanistic study of β-hydrogen elimination from organoplatinum(II) enolate complexes
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A detailed mechanistic investigation of the thermal reactions of a series of bisphosphine alkylplatinum(II) enolate complexes is reported. The reactions of methylplatinum enolate complexes in the presence of added phosphine form methane and either free or coordinated enone, depending on the steric properties of the enone. Kinetic studies were conducted to determine the relationship between the rates and mechanism of β-hydrogen elimination from enolate complexes and the rates and mechanism of β-hydrogen elimination from alkyl complexes. The rates of reactions of the enolate complexes were inversely dependent on the concentration of added phosphine, indicating that β-hydrogen elimination from the enolate complexes occurs after reversible dissociation of a phosphine. A normal, primary kinetic isotope effect was measured, and this effect was consistent with rate-limiting β-hydrogen elimination or C-H bond-forming reductive elimination to form methane. Reactions of substituted enolate complexes were also studied to determine the effect of the steric and electronic properties of the enolate complexes on the rates of β-hydrogen elimination. These studies showed that reactions of the alkylplatinum enolate complexes were retarded by electron-withdrawing substituents on the enolate and that reactions of enolate complexes possessing alkyl substituents at the β-position occurred at rates that were similar to those of complexes lacking alkyl substituents at this position. Despite the trend in electronic effects on the rates of reactions of enolate complexes and the substantial electronic differences between an enolate and an alkyl ligand, the rates of decomposition of the enolate complexes were similar to those of the analogous alkyl complexes. To the extent that the rates of reaction of the two types of complexes are different, those involving β-hydrogen elimination from the enolate ligand were faster. A difference between the rate-determining steps for decomposition of the two classes of complexes and an effect of stereochemistry on the selectivity for β-hydrogen elimination are possible origins of the observed phenomena.
- Alexanian, Erik J.,Hartwig, John F.
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supporting information; scheme or table
p. 15627 - 15635
(2009/03/12)
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- Si-H bond activation by (Ph3P)2Pt(η2- C2H4) in dihydrosilicon tricycles that also contain O and N heteroatoms
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Several tricyclic phenoxasilin and phenazasiline heterocycles were synthesized from the corresponding 2,2′-dilithio-diphenyl ether or diphenyl amine precursor and silicon tetrachloride (or trichlorosilane) followed by reduction with lithium aluminum hydride [H2SiAr2: Ar2 = C12H8O (1); Ar2 = C 14H12O (2); Ar2 = C13H11N (3); Ar2 = C15H15N (4); Ar2 = C13H9Br2N (5)]. The reactivity of hydrosilanes 1-5 with (Ph3P)2Pt(η2-C2H 4) (6) was investigated. At room temperature, mononuclear complexes, (Ph3P)2Pt(H)-(SiAr2H) and (Ph 3P)2Pt(SiAr2H)2, were generally observed by NMR spectroscopy but were too reactive or unstable to isolate. Dinuclear and in some cases trinuclear Pt-Si-containing complexes were observed as the major products from the reactions. Symmetrical dinuclear complexes, [(Ph3P)Pt(μ-η2-H-SiAr2)]2 (8 and 22, respectively), were produced from the reaction of 1 or 3 with 6. In contrast, reaction of silane 2 with 6 produced a trinuclear complex, [(Ph 3P)Pt(μ-SiAr2)]3 (16), as the major product. However, reaction of 4 or 5 with complex 6 produced an unsymmetrical dinuclear complex, [(Ph3P)2Pt(H)(μ-SiAr2)(μ- η2-H-SiAr2)Pt(PPh3)] (26 and 30, respectively), as the major component. The molecular structures of a symmetrical (22) and unsymmetrical dinuclear (30) complex as well as a trinuclear (16) complex were determined by X-ray crystallography.
- Braddock-Wilking, Janet,Corey, Joyce Y.,French, Lisa M.,Choi, Eunwoo,Speedie, Victoria J.,Rutherford, Michael F.,Yao, Shu,Xu, Huan,Rath, Nigam P.
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p. 3974 - 3988
(2008/10/09)
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- Reaction of silafluorenes with (Ph3P) 2Pt(η2-C2H4): Generation and characterization of Pt-Si monomers, dimers and trimers
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The reaction of silafluorene (1; H2SiC12H 8) with (Ph3P)2Pt(η2-C 2H4) (2) at room temperature in C7D8 initially provided the mononuclear complex (Ph3P) 2Pt(H)[Si(H)C12H8] (3), followed by the appearance of the unsymmetrical dinuclear complex (Ph3P) 2(H)Pt(μ-SiC12H8)(μ-η2- HSiC12H8)Pt(PPh3) (4) and finally the novel trinuclear complex [(Ph3P)Pt(μ-SiC12H 8)]3 (5). The three complexes were characterized by multinuclear NMR spectroscopy and by X-ray crystallography (5). The molecular structure of 5 exhibits a nonplanar Pt3Si3 core. When the reaction was conducted at low temperature until the silafluorene was consumed and the mixture then warmed to room temperature, the dinuclear complex 4 could be isolated. The related substituted silafluorene system 3,7-di-tert- butylsilafluorene (6; H2SiC20H24) also reacted with 2 to provide both mono- and dinuclear complexes (7 and 8) analogous to 3 and 4. The dinuclear complex 8 was isolated and crystallographically characterized. Each of the two Pt centers in complex 8 exhibits a unique environment. In solution at low temperature 8 is best described as having one platinum center with a terminal hydride, [Pt(H)(PPh3)2], and the second platinum with a nonclassical [Si...H...Pt(PPh 3)] unit. However, in the solid state, the two hydrides may both adopt a bridging environment. Heating a sample of the unsymmetrical dimer 8 led to the formation of several products, one of which was the trimer 9, analogous to 5.
- Braddock-Wilking, Janet,Corey, Joyce Y.,Trankler, Kevin A.,Dill, Kimberly M.,French, Lisa M.,Rath, Nigam P.
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p. 4576 - 4584
(2008/10/09)
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- Reactions of binuclear ruthenium-platinum μ-allenyl complexes with nucleophilic and electrophilic reagents. The characterization of two 1:1 adducts of L(PPh3)Pt(μ-η1:η2α,β-C(Ph)=C=CH2)Ru(CO)Cp (L=PPh3, t-BuNC) and p-toluenesulfonyl isocyanate
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Reactions of (PPh3)2Pt(μ-η1:η2α,β-C(R)=C=CH2)Ru(CO)Cp (R=H (1), Ph (2)) with Ph2PCH2CH2CH2PPh2, PEt3 and t-BuNC in THF at -78°C to room temperature afforded the substitution products L2Pt(μ-η1:η2α,β-C(R)=C=CH2)Ru(CO)Cp (R=H, L2=Ph2PCH2CH2CH2PPh2 (3), R=Ph, L2=Ph2PCH2CH2CH2PPh2 (4), R=H, L2=2PEt3 (5), R=Ph, L2=PPh3 and t-BuNC (6)). No reaction was observed for 1 with Et2NH or C6H11NH2 and 2 with p-TolS(O)2NH2 in THF at reflux temperature. Complex 2 reacted with p-TolS(O)2NCO (TSI) in toluene at -78°C to room temperature to yield two 1:1 addition products of the reactants: the γ-carbon substituted μ-allenyl (PPh3)2Pt(μ-η1:η2α,β-C(Ph)=C=CHC(O)NHS(O)2Tol-p) (7) and the [3+2] cycloadduct (PPh3)2Pt(μ-η1:η2-C=C(Ph)N(S(O)2Tol-p)C(O)CH2)Ru(CO)Cp (8). Complexes 4 and 6 afforded with TSI, under essentially similar conditions, only [3+2] cycloadducts, L2Pt(μ-η1:η2-C=C(Ph)N(S(O)2Tol-p)C(O)CH2)Ru(CO)Cp (L2=Ph2PCH2CH2CH2PPh2 (9), PPh3 and t-BuNC (10)). All products were characterized by a combination of IR and NMR (1H, 13C{1H} and 31P{1H}) spectroscopy, FAB MS and elemental analysis. The structures of 7 (as 7·C3H6O) and 10 were determined by single-crystal X-ray diffraction analysis. Reactions of 2 with trans-NCCH=CHCN (L) and of 1 with the alkynes MeO2CC?CCO2Me, MeO2CC?CMe, PhC?CH and PhC?CPh (L) resulted in the formation of the mononuclear metal complexes Cp(CO)2RuC(R)=C=CH2 (R=H, Ph) and (PPh3)2PtL. The reverse of this fragmentation reaction occurred when Cp(CO)2RuCH=C=CH2 was treated with (PPh3)2Pt(PhC?CPh). No reaction was observed between 2 and each (CN)2C=CPh2 and MeS(O)2NSO in benzene or toluene on heating. The η1-allenyl Cp(CO)2RuC(Ph)=C=CH2, obtained in this study, is a new compound.
- Willis, Richard R.,Calligaris, Mario,Faleschini, Paolo,Gallucci, Judith C.,Wojcicki, Andrew
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p. 465 - 478
(2007/10/03)
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- Unexpected substitution reactions of bis(phosphine)platinum ethene complexes
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Reaction of [Pt(C2H4)(PR3)2] (R = Ph or C6H4Me-4) with moderately bulky phosphines at low temperatures did not give the expected tris- or tetrakis-phosphine complexes. Instead, mixed-phosph
- Chaloner, Penny A.,Broadwood-Strong, Gillian T. L.
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p. 1039 - 1043
(2007/10/03)
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- Thermal analysis of coordination compounds. Part 3. Thermal decomposition of platinum complexes containing triphenylphosphine, triphenylarsine and triphenylstibine
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Studies by thermogravimetric analysis (TG) and differential thermal analysis (DTA) of the complexes [PtCl2L2] (L is PPh3, AsPh3, SbPh3), [PtLn] (n = 3, L is SbPh3; n= 4, L is PPh3, AsPh3); [(PtL3)2N2]; [(PtL3)2C2] and [Pt(CO)2L2] (L is SbPh3) are described. Analysis of the TG and DTA curves showed that Pt(II) complexes of the type [PtCl2L2] have a higher thermal stability than the corresponding Pt(0) complexes of the type [PtLn], with the exception of [Pt(SbPh3)3], which is more stable than [PtCl2(SbPh3)2]. Thermal stabilities of each of the complexes are compared with those of the others in the series. Mechanisms of thermal decomposition of complexes of the types [PtCl2L2] and [PtLn] are proposed. Residues of the samples were characterized by chemical tests and IR spectroscopy. The residue from the thermal decomposition of [PtCl2L2] (L is PPh3, AsPh3)and [Pt(PPh3)4] is metallic platinum. For [Pt(AsPh3)4] the residue is a mixture of Pt and As, whereas for the complexes containing SbPh3 the re sidues are mixtures of Pt and Sb. In these cases, the proportional contents of Pt and As or Pt and Sb correspond to the stoichiometry of these elements in the respective complexes. The complexes [Pt(SbPh3)3]2N2, [Pt(SbPh3)3]2C2 lose N2 or the ethynediyl group at 130-150°C are transformed into [Pt(SbPh3)3].
- Barbieri, Roberto Santos,Bellato, C. R.,Massabni, A. C.
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p. 277 - 286
(2008/10/09)
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- Synthesis and Reactivity of N-Acetylamino acidate(2-) and Related Complexes of Platinum(II)
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Treatment of the complexes (L = P-donor ligand) with the N-acetyl derivatives of the amino acids glycine, DL-alanine, DL-methionine or L-phenylalanine in the presence of an excess of silver(I) oxide in refluxing dichloromethane affords PtN(COM
- Kemmitt, Raymond D. W.,Mason, Simon,Fawcett, John,Russell, David R.
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p. 1165 - 1176
(2007/10/02)
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- Synthesis, Reactions and Structure of a Highly Basic Platinum(II) Di(μ-oxo) Dimer with an Unusual Lithium Tetrafluoroborate Interaction
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The reaction chemistry and X-ray crystal structure of the platinum(II) oxo complex 2*LiBF4 (L = PPh3) reveal the presence of a highly basic oxo ligand and an unusual oxo-LiBF4 interaction.
- Li, Wei,Barnes, Charles L.,Sharp, Paul R.
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p. 1634 - 1636
(2007/10/02)
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- NMR and kinetic studies on phosphine-induced coupling of (η3-methallyl) (acetylacetonato) palladium and -platinum: Uniquely facile C-C bond formation with an (η3-allyl) platinum complex
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Low-temperature 1H NMR measurements on a mixture of M(η3-CH2CMeCH2) (acac) (1, M = Pt; 2 M = Pd) and 2 equiv of PPh3 or 1 equiv of (Z)-Ph2PCH=CHPPh2 in dichloromethane gave unambiguous evidence for the formation of the ion pair [M(η3-CH2CMeCH2)(PR3) 2]+[CH(COMe)2]-. On warming these solutions to room temperature, the formation of moderate to good yields of the C-C coupling product CH2-CMeCH2CH(COMe)2 and zerovalent metal-phosphine complexes occurred. The kinetics of this process were examined by means of UV-visible spectroscopy to give evidence for almost exclusive participation of [M(η3-CH2CMeCH2)(PR3) 2]+[CH(COMe)2]- (M = Pt, PR3 = PPh3; M = Pd, PR3 = 1/2Ph2PCH2CH2PPh2) in the rate-determining step. The collapse of these ion pairs to the product was estimated to be faster in benzene than that in dichloromethane, the latter in turn having been found to be faster than that in acetonitrile/THF. The platinum analogue 1 reacted more slowly than the palladium analogue 2, but the rate difference was not so remarkable as was the case in the reductive elimination of dialkylmetal complexes of these two metals. The origin of this unique metal effect found in the reaction of 1 and 2 is discussed in terms of the nature of the η3-allyl-metal bonding.
- Kurosawa, Hideo,Ishii, Koichiro,Kawasaki, Yoshikane,Murai, Shinji
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p. 1756 - 1760
(2008/10/08)
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- Interaction of (Ph3P)4Pt with alkynylvinyl triflates: Stereochemistry and mechanism of formation of σ-enynyl and σ-butatrienyl cationic platinum(II) complexes
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Reaction of alkynylvinyl triflates with (Ph3P)4Pt results in σ-enynyl or σ-butatrienyl cationic platinum(II) complexes as reasonably stable microcrystalline solids in 63-84% isolated yields. Only hindered triflates give σ-butatrienyl complexes. Stereochemical studies established that a multistep process, involving initial π-acetylene formation, subsequent rearrangement to a σ-butatrienyl complex and attack by a second Pt species, to give the final σ-enynyl complexes best accounts for the observed results. Formation of the σ-butatrienyl complexes occurs stereospecifically with inverted olefin geometry whereas the formation of the enyne complexes occurs with partial stereoconvergence. These results are discussed and compared to the related reactions of iridium.
- Stang, Peter J.,Datta, Arun K.
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p. 1024 - 1029
(2008/10/08)
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- Study of the interaction of platinum hydride complex + with carbon monoxide and ethylene in trifluoroacetic acid solutions
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The most probable intermediate formed by interaction of CO and C2H4 with + (I), in the synthesis of diethylketone from C2H4, CO and H2 under action of the catalytic system (PPh3)2Pt(OAc)2/PPh3/CF3COOH has been studied by 1H, 13C, 31P NMR spectroscopy.Complex I readily reacts with CO in CF3COOH solutions to form a carbonyl hydride complex trans-+ (II).In contrast to I, II undergoes ethylene insertion at the Pt-H bond in the presence of a catalytic additive Sn(OAc)2.The carbonyl ethyl complex trans+ (III) formed quantitatively from this insertion is stable to isomerization to the corresponding complex indicating that the carbonylation of the Pt-ethyl bond is the rate-determining step of the diethyl ketone synthesis.
- Chinakov, V. D.,Il'inich, G. N.,Zudin, V. N.,Likholobov, V. A.,Nekipelov, V. M.
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p. 421 - 425
(2007/10/02)
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- Electrochemical Behaviour of Mixed Tetrametallic Clusters with Pd2M2 and Pt2M2 Cores (M = Cr, Mo, W)
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Tetrametallic clusters 1M2(μ3-CO)(μ2-CO)2(C5H5)(PPh3)>2 (M1 = Pd, Pt; M2 = Cr, Mo, W) exhibit an unexpected irreversible two-electron reduction leading to the rupture of the metallic core
- Jund, Rodolphe,Lemoine, Paul,Gross, Maurice,Bender, Robert,Braunstein, Pierre
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