1,721,004 research outputs found
Isocyanide insertion into platinum-oxygen bonds
No full textThe reaction of isocyanides, CNR, with hydroxy- and methoxy-alkyl complexes of platinum(II), PtOH(R)(Ph2PCH=CHPPh2)_and PtOCH3(R)(Ph2PCH=CHPPh2) (R = CF3, CH2 CN) affords insertion products Pt(CONHR)(R)(Ph2PCH=CHPPh2) and Pt[C(OCH3)=NR] (R)(Ph2PCH=CHPPh2) containing the carboxamido and imidoyl moiety, respectively
Hydridocyanomethyl complexes of platinum(II)
No full textThe preparation and spectroscopic properties are described of some novel platinum(II) complexes having a hydride ligand cis or trans to an sp3 carbon, vis. PtH(CH2CN)(PPh3)2 and PtH(CH2CN)(L-L) with L-L = bis(diphenylphosphino)-ethene, -ethane, -propane and bis(diphenylarsino)ethane
Photoinduced reductive elimination of cyanoalkanes from hydridocyanoalkyl complexes of platinum(II)
No full textThe photoinduced reductive elimination of cyanoalkanes (CH3CN, CH3CH2CN and CH3(CH2)2CN) from trans-hydridocyanoalkyl complexes of platinum(II), [PtH(R)(PPh3)2] (R = CH2CN, (CH2)2CN, (CH2)3CN) has been studied. The three trans complexes undergo isomerization to cis forms in the initial step before the reductive elimination. The elimination from the cis isomers is intramolecular as shown by the absence of crossover with the [PtH(CH2CN)(Ph2PCH=CHPPh2)] analogue and of the failure to detect the presence of free radicals during the reaction. The monomeric [Pt(PPh3)2] complex has been identified as the initial product of reductive elimination. Several reactions of this mechanistically important compound are also described
Hydrido trifluoromethyl Platinum(II) complexes
No full textSynthesis, characterization and properties of hydrido trifluoromethyl Platinum(II) complexes
Alkoxo and hydroxo complexes of platinum(II). Novel insertion reactions into platinum-oxygen bonds and condensations with compound containing active hydrogen atoms
No full textHydroxo and alkoxo alkyl complexes of the general formula cis- and transPt(OR)(Rx)L2 (R = H, CH3; Rx = CH2CN, CF3, CH2CF3; L2 = 2 PPh3, diphosphine) were prepared by metathesis of PtCl(Rx)L2 or [Pt(Rx)L2]BF4 with NaOR. The platinum-oxygen bonds undergo facile insertion of CO, COS, CS2 and SO2. The hydroxo complexes react with a variety of acids, including fairly weak carbon or nitrogen acids, such as phenylacetylene, acetamide and methylaniline, to give the corresponding condensation complexes
Hydrido- and hydroxo-cyanoalkyl complexes of platinium(II). Reactivity of the Pt-H and Pt-OH bonds towards nucleophiles and electrophiles
No full textReactions of the Pt-H and/or Pt-C bonds of the hydridocyanoalkyl complexes cis- or trans-PtH[(CH2)nCN]L2 (n = 1, 3; L2 = 2 PPh3, Ph2PCH=CHPPh2) are described, viz. reductive elimination induced by CO, PhCCPh, PEt3, PPhMe2, cis-Ph2PCH=CHPPh2 to give Pt(CO)2L2, PtL2(PhCCPh), PtL2, PtL(PPhMe2)3, PtL2(Ph2PCH=CHPPh2) (L = PPh3), respectively, and cleavages by acids, halogens and alkyl halides.
The monomeric hydroxo complexes cis-Pt(OH)[(CH2)nCN]L2 were shown to be intermediates in the synthesis of PtH[(CH2)nCN]L2 from cationic cyanoalkyl complexes in alcoholic NaOH. Their characterisation and the reactions of the Pt-OH bond with activated methyl groups are reported
Protonolysis of the Pt-C bond in trans-[PtH(CH2CN)(PPh3)2]
No full textThe protonolysis of the Pt-C bond in trans-[PtH(CH2CN)(PPh3)2] in methanol/1,2- dichloroethane is shown to take place by a two step mechanism involving oxidative addition to the metal center followed by reductive elimination of CH3CN to give trans-[PtHCl(PPh3)2]
Reactions of trans-hydridocyanoalkylplatinum(II) complexes with isocyanides. Preparation of novel platinum(II) compounds with adjacent Pt-H and Pt-C bonds
No full textThe hydridocyanopropyl complex of platinum(II) trans-[PtH(CH2CH2CH2CN)-(PPh3)2] reacts with an excess of isocyanide RNC (R = t-Bu or 2,6-Me2C6H3) to yield platinum(O) isocyanide complexes of the type [Pt(CNR)2(PPh3)2] through reductive elimination of 1-cyanopropane. In contrast the cyanomethyl complex trans-[PtH(CH2CN)(PPh3)2] reacts with RNC to give the novel platinum(II) complexes [PtH(CH2CN)(CNR)(PPh3)] (R = CH3; t-Bu; 2,6-Me2C6H3;p-MeOC6H4) by displacement of one phosphine ligand.
Spectroscopic evidence shows these complexes to contain the cyanoalkyl group adjacent to the hydride and opposite to the phosphine. Heating of these complexes in the presence of equimolar amounts of PPh3 and RNC gives the corresponding platinum(O) species [Pt(CNR)2(PPh3)2]
Cationic cyanobenzylpalladium(II) complexes. Synthesis and reactivity of the CN group towards nucleophiles
No full textThe addition of alcohols, thiols, water and amines to the σ-coordinated CN group of cis-[Pd(o-CH2C6H4CN)L2]2(BF4)2(L2 = 2PPh3, 1,2-bis(diphenylphosphino)ethene or -ethane) yields stable N-bonded iminoether, iminothioether, amide and amidine complexes,respectively. Thiophenols, ArSH (Ar = p-C6H4CH3, p-C6H4Br) break the σ-Pd-C bond, forming o-cyano toluene and complexes of the type [Pd(SAr)L2]2(BF4)2. The azido complex PdN3(o-CH2C6H4CN)(Ph2PCH2CH2PPh2) is stable in the solid state but in solution it undergoes an intramolecular 1,3-cycloaddition yielding the corresponding tetrazolate complex
Hydridocyanoalkyl complexes of platinum(II). Insertion of olefins into the Pt-H bond
No full textThe preparation and spectroscopic properties are described of some platinum(II) complexes having a hydride ligand cis or trans to an sp3 carbon, viz. trans-PtH(YCN)(PPh3)2 and cis-PtH(YCN)(L-L) with YCN = C2H4CN, n-C3H6CN, o-CH2C6H4CN and L-L = bis(diphenylphosphino)-ethene or -ethane. The complexes trans-PtH(YCN)(PPh3)2 can add a fifth ligand in solution; the resulting five-coordinate complex was observed by 31P NMR in the case of PtH(C3H6CN)(PPh3)3. Insertion of olefin (ethen, 1-cyanoethene, norbornadiene, allen) into the Pt-H bond of the trans-hydrido complexes occurs to give cis-dialkyl complexes, but the cis-hydrido complexes are unreactive. The mechanism of insertion is discussed in terms of the kinetics and the geometries of reactants and products
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