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1.
Molecular catalysts for organic synthesis should be constructed to be tailored to target reactions and their desirable conditions. In our search for them, we have studied new types of transition metal molecular catalysts dressed with a tridentate N,C,N modular ligand, which consists of a C2-symmetric side-by-side phenyl group with chiral bis(oxazolinyl) substituents. The ligand, 2,6-bis(oxazolinyl)phenyl abbreviated as Phebox, can connect covalently to transition metals by the central carbon atom. Here, we review our recent work on the chemistry of Phebox and its metal complexes, including preparation, structural analysis, asymmetric Lewis acid catalysis, asymmetric hydrosilylation, asymmetric conjugate reduction, asymmetric reductive aldol reaction, and organometallic reactions. 相似文献
2.
David G. Holah Alan N. Hughes Benjamin C. Hui Pui-Kwan Tse 《Journal of heterocyclic chemistry》1978,15(1):89-96
The reactions between four very simply substituted phospholes and the chlorides of Ni(II), Pd(II) and Pt(II) are described. The phospholes 1-phenylphosphole, 3-methyl-1-phenyl-phosphole and 3,4dimethyl-1-phenylphosphole all readily form bis-complexes of formula L2MCl2 [L = phosphole ligand and M = Ni(II), Pd(II) or Pt(II)] or tris-complexes of formula L3MCI2. 1-n-Butyl-3,4-dimethylphosphole appears to form stable complexes only with Ni(II). Evidence is put forward which indicates that the L2MCl2 complexes exist in a four-coordinate, square-planar monomeric/five coordinate equilibrium while the L3MCl2 complexes are primarily the ionic species [L3MCl]+ Cl? in solution. Comparisons are made with the behaviour of other simple phospholes which do not form Ni(II) complexes and the results are discussed briefly in terms of both aromatic and non-aromatic phosphole models. 相似文献
3.
Phan NT Brown DH Adams H Spey SE Styring P 《Dalton transactions (Cambridge, England : 2003)》2004,(9):1348-1357
Solid-supported catalysts derived from homogeneous nickel(II) and palladium(II) non-symmetrical salen-type coordination complexes have been prepared and shown to be effective in the heterogeneous catalysis of carbon-carbon cross-coupling reactions. The nickel catalyst has been used in room-temperature Tamao-Kumada-Corriu reactions and the palladium catalyst in the Heck reaction at elevated temperatures. The complexes were prepared by improved methods and characterised by spectroscopic techniques. Comparisons between the solid-supported catalysts and their homogeneous analogues are reported. The single-crystal structure determination of the nickel and palladium complexes [M(salenac-OH)][M = Ni, Pd; salenac-OH = 9-(2',4'-dihydroxyphenyl)-5,8-diaza-4-methylnona-2,4,8-trienato](2-)] is reported. 相似文献
4.
Berven BM Koutsantonis GA Skelton BW Trengove RD White AH 《Dalton transactions (Cambridge, England : 2003)》2011,40(16):4167-4174
A variety of Group 10 metal complexes [MXY(dfppp)], M = Ni, X, Y = Cl, Br, M = Pd, Pt, X, Y = Cl or CH(3), containing the recently reported highly fluorous diphosphine ligand, dfppp, 1,3-bis[di(fluoroponytail)phosphino]propane, {(p-F(13)C(6)C(6)H(4))(2)P}(2)(CH(2))(3) have been synthesised. They have been characterised by NMR, mass spectrometry and microanalysis, with two platinum complexes, [PtCl(2)(dfppp)] and [PtClMe(dfppp)], structurally characterised by single crystal X-ray diffraction studies. The highly fluorous nature of the ligands affords the complexes good supercritical CO(2) solubility as measured by supercritical fluid extraction (SFE), and has allowed for the copolymerisation of CO and ethylene using [PdClMe(dfppp)] as the catalyst precursor and CO(2) as the solvent. Additionally, PtCl(2) complexes of the new ligands dfppb, {(p-F(13)C(6)C(6)H(4))(2)P}(2)(CH(2))(4), and dfpop, {(p-F(13)C(6)C(6)H(4)O)(2)P}(2)(CH(2))(3), have also been prepared and characterised. 相似文献
5.
Marcial Moreno-Mañas Roser Pleixats Adelina Vallribera 《Journal of organometallic chemistry》2004,689(23):3669-3684
15-Membered macrocycles (E,E,E)-1,6,11-tris(arenesulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes (1) are prepared from arenesulfonamides and trans-1,4-dibromo-2-butene. Macrocycles 1 coordinate palladium(0), platinum(0), and silver(I). The palladium complexes are useful and reutilizable catalysts or precatalysts in Suzuki cross-couplings, butadiene telomerizations, hydroarylation of alkynes, and in the Heck reaction. Structurally related macrocycles are also available by similar synthetic procedures. 相似文献
6.
7.
New data on the structure and reactivity of palladium clusters are surveyed. The mechanisms of stoichiometric and catalytic
reactions of the palladium cluster complexes with alkenes, alcohols, aldehydes, formic acid, CO, and phenol are discussed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 807–815, March, 1998. 相似文献
8.
Summary A novel series of formazan complexes of general formula FoML [H2Fo = 1-(2-hydroxyphenyl)-3,5-diphenylformazan; M = NiII, PdII or PtII; L = NH3, py and Ph3P] are described. The formazan nickel(II) system shows linkage isomerism; one isomer, A, contains an unusual five-membered formazan chelate ring, whereas the other, isomer B, has the usual six-membered ring.13C n.m.r., u.v. and i.r. spectra are presented and interpreted. From these the palladium and platinum complexes appear to contain the six-membered ring of the B type isomer. 相似文献
9.
Neutral complexes of three phthalhydrazidylazo-1,3-diketones [phthalhydrazidylazo-acetylacetone (H2PAA),-benzoylacetone (H2PBA) and-dibenzoylmethane (H2PDM)] with Cu(II), Ni(II), Pd(II) and Fe(III) have been synthesised and characterized on the basis of their analytical data,
magnetic moment, molar conductance and IR and1H NMR spectral data. Dibasic tridentate coordination of the ligands is brought out by the above spectral data. Half-wave potentials
and far IR spectral data of the Cu(II) complexes indicate that the H2PAA complex is the most stable. M?ssbauer spectra of the Fe(III) complexes reveal that delocalisation of the metald electrons with the chelate ring decreases with increasing capability of the pendant groups of the ring for cross conjugation. 相似文献
10.
The upper rim of 1,3,5-triaza-7-phosphaadamantane (PTA) has been modified for the first time. Lithiation of PTA, with n-butyllithium, resulted in deprotonation of an alpha-phosphorus methylene and the formation of 1,3,5-triaza-7-phosphaadamantane-6-yllithium (PTA-Li). The chiral chelating phosphine 6-(diphenylphosphino)-1,3,5-triaza-7-phosphaadamantane (PTA-PPh2) was synthesized, in racemic form, by the reaction of PTA-Li with ClPPh2. PTA-PPh2 has been fully characterized in solution by multinuclear NMR spectroscopy and mass spectrometry and in the solid state by X-ray crystallography. The 31P NMR spectrum contains a pair of doublets at -19.8 and -100.1 ppm (d, (2)J(PP) = 65 Hz). Unlike PTA, the new bidentate phosphine, PTA-PPh2, is insoluble in aqueous solutions. Two group 6 metal carbonyl complexes, [M(CO)4(PTA-PPh2)] (M = W and Mo), were synthesized by the addition of PTA-PPh2 to cis-[M(CO)4(pip)2] and characterized by NMR spectroscopy, IR spectroscopy, and X-ray crystallography. Also reported are the solid-state structures of cis-[W(CO)4PTA2], cis-[W(CO)4(PTA)(PPh3)], and [W(CO)4DPPM] (DPPM = diphenylphosphinomethane). PTA-PPh2 appears to be sterically similar to and slightly more electron-donating than DPPM. 相似文献
11.
Hildebrand A Sárosi I Lönnecke P Silaghi-Dumitrescu L Sárosi MB Silaghi-Dumitrescu I Hey-Hawkins E 《Inorganic chemistry》2012,51(13):7125-7133
Heteropolytopic arsanylthiolato ligands 1-AsPh(2)-2-SHC(6)H(4) (AsSH), PhAs(2-SHC(6)H(4))(2) (AsS(2)H(2)), and As(2-SHC(6)H(4))(3) (AsS(3)H(3)) have been prepared by lithiation-electrophilic substitution procedures. The 2:1 reaction of AsSH with NiCl(2)·6H(2)O, Na(2)[PdCl(4)], and [PtI(2)(cod)] (cod = 1,5-cyclooctadiene) in the presence of NEt(3) afforded the square-planar complexes trans-[Ni{(AsS)-κ(2)S,As}(2)] (1), cis-[Pd{(AsS)-κ(2)S,As}(2)] (2), trans-[Pd{(AsS)-κ(2)S,As}(2)] (3), and cis-[Pt{(AsS)-κ(2)S,As}(2)] (4). In the cases of nickel and platinum, only one isomer was isolated. With palladium, initially the cis isomer 2 is formed and undergoes slow isomerization to the trans isomer 3 in solution. Small amounts of the trinuclear complex [{PtI(1-AsPh(2)-μ-2-S-C(6)H(4)-κ(2)S,As)}(3)] (5) are also formed besides the mononuclear platinum bis-chelate complex 4. Density functional theory calculations support a dissociative mechanism for the isomerization of the palladium(II) complexes. 相似文献
12.
Palladium and nickel complexes with tetrabenzoporphine were synthesized by reacting tetrabenzoporphine and cadmium tetrabensoporphine with palladium and nickel chlorides in boiling dimethylformamide and identified. 相似文献
13.
Six copper(II) complexes with N,O-donor ligand 2-methyl-2-(2-pyridyl)-1,3-propan-diol (H2ppdo) were synthesized and characterized. Treatment of CuCl2 or Cu(OTf)2 with H2ppdo led to the formation of bis(H2ppdo) monomers [Cu(H2ppdo)2][CuCl4] (1) and [Cu(H2ppdo)2](OTf)2 (2), respectively. Both 1 and 2 are comprised of the copper atom coordinated by two ligands in an axially-compressed tetragonal geometry with the pyridyl N atoms in the axial positions and the alcohol O atoms in the equatorial plane. The treatment of 1 or 2 with Et3N produced copper(II) complexes of varying nuclearity. Treatment of 1 with excess Et3N generated two binuclear Cu(II) clusters [Cu2(Hppdo)2Cl2] (3) and [Cu2(Hppdo)2Cl2(CH3OH)2] (4), where only one alcohol OH group per ligand has been deprotonated, while similar treatment of 2 with excess Et3N afforded the trimeric copper(II) species [Cu3(Hppdo)4](OTf)2 (5). The structures of 3 and 4 are similar, with alkoxo-O ligand atoms bridging between two square pyramidal copper atoms, and the alcohol-O ligand atoms either coordinating in the axial position in 3, or uncoordinated in 4. Treatment of CuCl2 with H2ppdo and Et3N afforded the trinuclear Cu(II) complex, [Cu3(Hppdo)4]Cl2 (6). Complexes 5 and 6 are made up of one square-planar copper sandwiched between two tetragonally distorted six-coordinate Cu(Hppdo)2 moieties, where the bridging alkoxo-O atoms link the copper atoms. 相似文献
14.
The chemistry of binuclear palladium(II) and platinum(II) complexes has been reviewed. This review deals with complexes derived from various classes of ligands and covers various aspects, viz. synthesis, spectroscopic and structural features and chemical reactivity, of these complexes. Applications of these complexes are briefly described in the respected sections. 相似文献
15.
Mª José Camazón Amparo Alvarez-Valdés José R. Masaguer M. Carmen Navarro-Ranninger 《Transition Metal Chemistry》1986,11(6):226-229
Summary The preparation of two new tetracoordinated complexes of palladium(II) with 2-methylimidazole, 2-MeIm, and chloride as ligands is described. 相似文献
16.
The reaction of 4-aminodiphenylamine or 2-aminofluorene with two equivalents of PPh2Cl in the presence of Et3N gives new bis(diphenylphosphino)amines N,N-bis(diphenylphosphino)-4-aminodiphenylamine 1 and N,N-bis(diphenylphosphino)-2-aminofluorene 2 in good yields. Oxidation of 1 or 2 with hydrogen peroxide, elemental sulfur or gray selenium affords the corresponding chalcogen derivatives. The palladium
and platinum complexes of these P–N–P donor ligands were prepared by the reaction of the bis(phosphino)amines with MCl2(cod) (M = Pd or Pt, cod = cycloocta-1,5-diene). All the new compounds have been characterized by analytical and spectroscopic
methods, including 1H-31P NMR, 1H-13C HETCOR, or 1H-1H COSY correlation experiments. The Pd(II) complexes were investigated as catalysts in the Suzuki and Heck reactions; both
showed good catalytic activity affording high yields of the desired products. 相似文献
17.
K. K. Aravindakshan K. Muraleedharan 《Journal of Thermal Analysis and Calorimetry》1991,37(4):791-801
The thermal analysis of Ni(II) and Pd(II) complexes with thiophene-2-carboxaldehyde thiosemicarbazone have been studied using TG technique. Their decompositions are subjected to critical evaluation using the equations of Coats-Redfern, Horowitz-Metzger and modified Horowitz-Metzger and the kinetic parameters (non-isothermal method) have been evaluated for each step of decomposition by the method of weighted least-squares. 相似文献
18.
Brief treatment of azuliporphyrins 5 with nickel(II) or palladium(II) acetate in refluxing DMF afforded excellent yields of the related chelates; these novel organometallic compounds retain cross-conjugated borderline aromatic structures as judged by UV-Vis and NMR spectroscopy, and X-ray crystallography. 相似文献
19.
Copper(II) and nickel(II) complexes of 2-(benzylthio)ethylamine have been isolated and characterized by elemental analysis, i.r., solid state electronic spectra and magnetic susceptibility measurements. 相似文献
20.
Walmsley JA Zhu S Matilla A Donowick TG Cramp JE Tercero JM Dalrymple T 《Inorganic chemistry》2007,46(23):9945-9953
Cyclic tetrameric complexes have been prepared by the reaction of Pd(en)Cl2 or Pd(dapol)Cl2, or their nitrato analogues, with Na2(5'GMP) in aqueous solution, where en=1,2-diaminoethane, dapol=1,3-diamino-2-propanol, and 5'GMP=guanosine 5'-monophosphate. Addition of certain small molecules containing hydrophobic groups resulted in the expansion of the tetramer to a cyclic hexamer with strong bonding of one guest per hexameric host. At pH 5-6, the guest molecule can be a cation, anion, or neutral, and those species containing trimetylsilyl and t-butyl groups bonded the most strongly. The size of the central cavity of the [Pd(en)(5'GMP)]6 host has been estimated to be 5.2 A. Formation of the host-guest complex caused a large upfield shift (Deltadelta) of 2.5-2.9 ppm in the 1H NMR spectrum of the most highly affected guest protons, which were those in closest proximity to the guanine nucleobases. NOESY spectra were used to determine the interaction sites between the host and the guest. Apparent association constants determined at 26 degrees C and pD 5.4 for the [Pd(en)(5'GMP)]6-DSS and [Pd(en)(5'GMP)]6-t-butanol systems, where DSS is 3-(trimethylsilyl)-1-propanesulfonate anion, were 1.36+/-0.11x10(4) and 2.74+/-0.95x10(4) M(-3/2), respectively. The Pd(dapol)-5'GMP system forms hexameric host-guest complexes, similar in nature to those of the Pd(en)-5'GMP system. The molecular and crystal structures of Pd(dapol)Cl2 are also reported. 相似文献