18421-49-3Relevant academic research and scientific papers
Dichloromethane assisted oxidation of Pt(0) via cleavage of Te-C(aryl) bond of an assymetric telluride leading to the fromation of trans-[PtCl(Ar)(PPh3)2]
Khanna, Anju,Khandelwal, B. L.,Saxena, Ajay K.,Singh, T. P.
, p. 2705 - 2710 (1995)
3-Aminopropyl(aryl)tellurides react with [Pt(PPh3)2(C2H4)] in dichloromethane to form tellurium-free platinum(II) complexes [PtCl(Ar)(PPh3)2] [Ar=Ph(A), C6H4-4-OMe(A')] along with Te(CH2Cl){(CH2)3NH2} (B). The presence of Cl in the products clearly establishes the involvement of dichloromethane in the reaction. A free radical mechanism, involving Cl. and CH2Cl. radicals from dichloromethane has been proposed for the reaction. The products have been characterized by (1)H, (31)P{(1)H} and (195)Pt{(1)H} NMR and IR spectra. The structures of A and A' have been determined byX-ray crystallography. The crystals belong to the orthorhombic crystal system, space group Pbca. The structure of the complex A' has been descr ibed in detail. It adopts a square planar arrangement of the ligands around the Pt atom. The P-Pt-P angle is 173.3(1)°, indicating the trans arrangement of the two triphenylphosphine groups around Pt. The Pt-Cl distance is 2.40(4) ? and the Pt-C(1) distance is 2.01(1) ?, whereas the Pt-P(1) and Pt-P(2) distances are 2.318(5) and 2.306(5) ?, respectively. The square plane formed by P(1)ClP(2)C(1) is inclined at70.0(5)° with respect to the plane of the six-membered ring atta ched to the Pt atom.
Synthesis, Structure, and Reactivity of Arylfluoro Platinum(II) Complexes
Nilsson, Patrik,Plamper, Felix,Wendt, Ola F.
, p. 5235 - 5242 (2008/10/09)
Complexes of the type trans-[PtPhFL2], where L = PPh 3 (4), PMe2Ph (5), were synthesized. Complex 4 was characterized by X-ray crystallography. The equilibrium constant for the substitution of the fluoride trans to phenyl in 4 by Cl- and I - was determined, and the stability sequence follows the normal trend seen in "soft" metal centers: i.e., the Pt has a preference for the halide in the order I > Cl > F; the difference is, however, fairly small. The substitution kinetics follow the usual two-term rate law, and the rate constants for the solvolytic (k1) and the direct (k 2) reaction pathways were determined to be k1 = (9.7 ± 2.4) × 10-5 s-1, k2 = (11.7 ± 0.3) × 10-2 M-1 s-1 and k 1 = (7.1 ± 4.9) × 10-5 s-1, k 2 = (23.0 ± 1.3) × 10-2 M-1 s -1 for Cl- and I-, respectively. Activation parameters for the solvolytic and direct pathways with Cl- as incoming ligand are typical for associative processes and were determined to be δHDagger; = 77.8 ± 5.5 kJ mol-1, δS Dagger; = -56 ± 18 J K-1mol-1 and δH? = 67.6 ± 1.8 kJ mol-1, δS? = -37 ± 6 J K-1mol-1, respectively. Complexes 4 and 5 react with Me3SnPh, and within 2-15 min there is a complete conversion to products. 4 gives a single product, trans-[PtPhMe(PPh3)2], which was characterized by X-ray crystallography. 5 gives two products: trans-[PtPhMe(PMe2Ph) 2] and trans- [PtPh2(PMe2Ph)2]. Steric effects on the reactivity speak in favor of an associative mechanism. The surprisingly high reactivity for the transmetalations, compared to the substitution reactions, can be explained in terms of an associative mechanism, where a strong, bridging Sn-F interaction stabilizes the transition state. Furthermore, only trans products are formed; i.e., we have an exclusive F-for-R (R = Me, Ph) substitution at these platinum fluoro complexes. Treatment of 4 with phenylacetylene in benzene at room temperature gives the alkynyl complex trans-[PtPh(CCPh)(PPh3)2] (8).
Reactions of free radicals with η3-allylpalladium(II) complexes: Phenyl and trityl radicals
Reid, Simon J.,Baird, Michael C.
, p. 3975 - 3980 (2007/10/03)
The compounds (η3-allyl)PdCl(PPh3) and [(η3-allyl)Pd(PPh3)2]Cl react with phenyl and trityl radicals generated from the thermal decomposition of phenylazotriphenylmethane (PhN=NCPh3, PAT) in benzene at 60°C. The products are the palladium phenyl compounds, [PdPhCl(PPh3)]2 and trans-PdPhCl(PPh3)2, respectively, and 4,4,4-triphenyl-1-butene, the latter being the result of coupling of the trityl radical with the allyl ligands. In contrast, [(η3-allyl)PdCl]2 reacts with phenyl and trityl radicals under the same conditions to form palladium metal, trityl chloride and 3-phenylpropene, which is subsequently catalytically isomerized to 1-phenylpropene. These disparate results are interpreted in all cases in terms of initial attack by phenyl radicals on the palladium(II) to give phenyl-palladium(III) intermediates, and it is the secondary reactions, influenced by the presence or absence of coordinated PPh3 ligands, which provide variety in the products. The reaction of [(4-methoxy-1,3-η3-cyclohexenyl)PdCl]2 gives a mixture of trans-3-methoxy-6-phenylcyclohexene and trans-4-methoxy-3-phenylcyclohexene, consistent with initial formation of a phenyl-palladium(III) intermediate followed by phenyl migration to the η3-cyclohexenyl ligand (reductive elimination).
Reactions of organotin(IV) compounds with platinum complexes. Part(III). Reactions of (R2Sn)n, (R = Me or Ph, n = 6; R = Et, n = 9) with platinum complexes
Al-Allaf, Talal A.K
, p. 21 - 28 (2007/10/03)
The R2Sn moieties formed when the cyclic compounds (R2Sn)n, R = Me or Ph, n = 6; R = Et, n = 9, are exposed to light, react with the platinum(II) complexes [PtCl2L2], L = PEt3, PPr3, PBu3, PEtPh2, PPh3 to give new complexes of the general formula [PtCl(SnR2Cl)L2]. Similarly, Et2Sn from (Et2Sn)9 reacts with [PtMe(Cl)L2] to give [PtMe(SnEt2Cl)L2] and Ph2Sn from (Ph2Sn)6 reacts with [PtPh(Cl)L2] or [PtPh2L2] to give [PtPh(SnPh2Cl)L2] or [PtPh(SnPh3)L2] (L = PEt3), respectively. Reactions involving (R2Sn)n and the bridged complex [{Pt(μ-Cl)ClL}2] give a mixture of [PtCl(SnR2Cl)L2] and [PtCl(SnRCl2)L2], R = Me or Et, L = PBu3. It is suggested that these reactions initially involve insertion of R2Sn moieties into Pt-Cl bonds of the complexes [PtX(Cl) L2] or [{Pt(μ-Cl)ClL}2] then generate R2SnXCl (X = Cl, Me, Ph) and the Pt(0)complex [PtL2], which undergoes oxidative-addition of the formed tin(IV) species to give complexes containing Pt-Sn bonds. With (Ph2Sn)6 and [PtPh2L2], the mechanism takes a different course. Reactions under similar conditions involving the Pt(0) complexes [Pt(C2H4(PPh3)2] or [Pt(COD)2], (COD = 1,5-cyclooctadiene) and (R2Sn)6, R = Me or Ph, gave no detectable complexes containing Pt-Sn bonds. The complex [Pt(PEt3)4] and (MeSn)6 likewise gives no species containing Pt-Sn bonds but with (Ph2Sn)6, two complexes, tentatively identified as trans-[PtPh(Sn2Ph5)(PEt3)2] and trans-[PtPh(Sn6Ph11)(PEt3)2], were detected in the solution. In all cases, the products were identified by 31P-NMR spectroscopy.
Reactions of HOSiMe2Ar with Pt-PPh3 complexes leading to Si-C bond activation or formation of a siloxoplatinum complex
Mintcheva, Neli,Nishihara, Yasushi,Mori, Atsunori,Osakada, Kohtaro
, p. 61 - 67 (2007/10/03)
PtI2(PPh3)2 reacts with HOSiMe2(C6H4CF3-4) at 60°C in the presence of AgBF4 to give a mixture of trans-PtI(C6H4CF3-4)(PPh3) 2 (1) and [Pt2(μ-I)2(PPh3)4](BF 4)2 (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or NMR spectroscopy. The 31P{1H}-NMR study of the reaction of AgBF4 with PtI2(PPh3)2 in acetone-d6 revealed the formation of trans-[PtI(PPh3)2(acetone)]BF4 (3) although isolation of the cationic complex was not feasible due to its facile conversion to 2. Addition of HOSiMe2(C6H4CF3-4) and Ag2O to a toluene solution of trans-PtI(Ph)(PPh3)2 causes replacement of the iodo ligand with the siloxo group to afford trans-[Pt(Ph){OSiMe2(C6H4CF 3-4)}(PPh3)2] (4). Crystallographic results of 4 show the coordination of the phenyl, siloxo, and PPh3 ligands to the square-planar Pt center with a large Pt-O-Si angle. Complex 4 does not decompose below 60°C in a toluene solution, but reacts with CH2Cl2 and CHCl3 at room temperature to form trans-PtCl(Ph)(PPh3)2 (5).
Electrochemical generation and reactivity of bis(tertiary phosphine)platinum(0) complexes: A comparison of the reactivity of [Pt(PPh3)2] and [Pt(PEt3)2] equivalents
Davies, Julian A.,Eagle, Cassandra T.,Otis, Deborah E.,Venkataraman, Uma
, p. 1080 - 1088 (2008/10/08)
Electrochemical reduction of cis-[PtCl2(PR3)2] (R = Ph, Et) in CH3CN/C6H6 containing NBu4ClO4 at a Hg pool electrode generates [Pt(PR3)2] equivalents in solution. Where R = Ph, the [Pt(PR3)2] equivalent may be trapped by O2, O2/CO2, HCl, MeI, C6H5COCl, and RC≡CR (R = Ph, COOMe) but not by the less reactive substrate PhCl. Where R = Et, the [Pt(PR3)2] equivalent reacts with the NBu4+ cation to ultimately generate trans-[PtH(Cl)(PEt3)2]. Prolonged electrolyses cause reduction of trans-[PtH(Cl)(PEt3)2] leading to hydride attack on the CH3CN solvent and ultimately forming trans-[PtH(CH2CN)(PEt3)2]. In the presence of bases such as NBu3, trans-[PtH(CH2CN)(PEt3)2] is isomerized in CH3CN solution producing trans-[PtCN(CH3)(PEt3)2]. The use of electroinactive trapping agents such as PhCl or PhCN as cosolvents for the reduction of cis-[PtCl2(PEt3)2] allows trapping of the [Pt(PEt3)2] equivalents as trans-[PtPh-(X)(PEt3)2] (X = Cl, CN).
REDOX-DEMERCURATION OF PHENYLMERCURY 4-FLUOROTHIOPHENOXIDE BY TETRAKIS(TRIPHENYLPHOSPHINE)PLATINUM(0)
Pombrik, S. I.,Bezrukova, A. A.,Golovchenko, L. S.,Peregudov, A. S.,Rubezhov, A. Z.,Kravtsov, D. N.
, p. C1 - C4 (2007/10/02)
A method for the synthesis of organoplatinum compounds containing a Pt-S ?-bond has been found.PhPt(PPh3)2SC6H4F-4 and 4-FC6H4Pt(PPh3)2SPh was obtained by redox-demercuration of PhHgSC6H4F-4 under the action of Pt(PPh3)4.
Aryl(halogeno)bis(triphenylphosphane)platinum(II) Compounds. Syntheses and cis-trans Isomerizations
Ertl, Josef,Grafl, Dieter,Brune, Hans Albert
, p. 1082 - 1090 (2007/10/02)
The syntheses of the platinum-organic compounds cis- (X = H, 3-H3C-, 3-H3CO-, 4-H3C-, 4-H3CO-) and cis- (X = H, 3-H3C-, 3-H3CO-, 3-(H3C)2N-, 4-H3C-, 4-H3CO-) are described; their thermal isomerization in crystalline phase are studied and the resulting trans-isomers characterized. - Key words: Platinum(II) Complexes, Syntheses, Isomerizations
Synthesis of Platinum(II) Alkyl and Aryl Complexes from K2 and Tetraorganotin Compounds in Dimethyl Sulphoxide
Eaborn, Colin,Kundu, Kalipada,Pidcock, Alan
, p. 933 - 938 (2007/10/02)
Complexes cis- and cis-(dmso=dimethyl sulphoxide) are readily obtained from K2 and SnMe3R (R=aryl or Me) in dmso at 70-90 deg C.Hydrogen-1 n.m.r. spectra show that the dmso ligands are bound through sulphur in solution an
POLYCHLOROPHENYL-PLATINUM(II) COMPLEXES CONTAINING TRIPHENYLPHOSPHINE
Rossell, O.,Sales, J.,Seco, M.
, p. 133 - 137 (2007/10/02)
A new method to prepare compounds of the type trans- (R = C6H5; 2,5-C6H3Cl2; 2,3,4-, and 2,4,6-C6H2Cl3; 2,3,4,5-, 2,3,4,6- and 2,3,5,6-C6HCl4 and C6Cl5) by reaction of cis- and HgR2 in the molten state is described.The reactions of the complexes with HCl, Cl2 and I2 have been examined in order to give information about the relative ease of cleavage of the various Pt- aryl bonds.The replacement of Cl by NCS suggests an associative mechanism even for the complexes in which the polychlorophenyl ligand has chlorine atoms in both ortho positions.
