共查询到20条相似文献,搜索用时 578 毫秒
1.
Edoardo Cesarotti Maria Grassi Laura Prati
Francesco Demartin
《Journal of organometallic chemistry》1989,370(1-3):407-419The DANTE technique and NOESY two-dimensional method have been employed to observe the isomerization of the chiral cationic complex [Pd(η3-CH2CMeCH2(P-P′)]+ (1a), where P-P′ = the chiral chelating ligand (S)(N-diphenylphosphino)(2-diphenylphosphinoxymethyl)pyrrolidine. The rate constant was found to be 0.5 s−1 in CHCl3 at 295 K and 1.50 s−1 in the presence of added free ligand. In the latter case the epimerization proceeds by a π-σ-π mechanism via the intermediacy of a primary η1-allylpalladium complex. Although the intermediate was not detected, the NMR findings reveal that it has the allylic terminus η1-bonded to palladium. The structure of 1a in its PF6− salt has been determined. The compound crystallizes in the orthorhombic space group P212121 with a 10.029(4) b 19.203(8) c 36.115(6) Å, Z = 8, R = 0.0572 and Rw = 0.0712 for 3716 observed reflections with I > 3σ(I). 相似文献
2.
Liang Oyang Hao-Ling Sun Xin-Yi Wang Jun-Ran Li Dao-Bo Nie Wen-Fu Fu Song Gao Kai-Bei Yu 《Journal of Molecular Structure》2005,740(1-3):175-180
Ternary terbium complexes with p-aminobenzoic acid (HL), [TbL3(DMSO)(H2O)]2 (1), [TbL3(DMF)(H2O)]2 (2) and [TbL3(Bpy)(H2O)]2·2H2O (3) (DMSO=dimethyl sulfoxide, DMF=N, N- dimethylformamide, Bpy=2, 2′- bipyridyl) have been synthesized, and their crystal structures determined. The luminescence properties of these complexes, including both the emission quantum yield and the fluorescence lifetime, have been investigated. The effect of a second ligand on the crystal structure and luminescence property of the ternary terbium p-aminobenzoic acid complexes, and the relationship between luminescence properties and crystal structure, including coordination mode of the L− ligand and the characteristics of a second ligand, are discussed. 相似文献
3.
Judith Bravo Carlos Cativiela Rafael Navarro Esteban P. Urriolabeitia 《Journal of organometallic chemistry》2002,650(1-2):157-172
The chiral bis-imine (1R,2R)-C6H10-[E---N=CH---C6H3---3,4-(OMe)2]2 1 (LH) reacts with [Pd(OAc)2] (1:1 molar ratio; OAc=acetate) giving the orthometallated [Pd(OAc)(C6H2---4,5-(OMe)2---2-CH=N-(1R,2R)-C6H10---N=CH---C6H3-3′,4′-(OMe)2-κ-C,N,N)] 2 (abbreviated as [Pd(OAc)(L-κ-C,N,N)]), through C---H bond activation on only one of the aryl rings and N,N-coordination of the two iminic N atoms. 2 reacts with an excess of LiCl to give [Pd(Cl)(L-κ-C,N,N)] 3. The reaction of 3 with AgClO4 and neutral or anionic ligands L′ (1:1:1 molar ratio) affords [Pd(L-κ-C,N,N)(L′)](ClO4) (L′=PPh3 4a, NCMe 5, pyridine 6, p-nitroaniline 7) or [Pd(I)(L-κ-C,N,N)] 8. Complex 4a reacts with wet CDCl3 giving [Pd(C6H2---4,5-(OMe)2---2-CH=N-(1R,2R)---C6H10---NH2-κ-C,N,N)(PPh3)](ClO4) 4b as a result of the hydrolysis of the C=N bond not involved in the orthometallated ring. The molecular structure of 4b·CH2Cl2 has been determined by X-ray diffraction methods. Cleavage of the Pd---N bond trans to the Caryl atom can be accomplished by coordination of strongly chelating ligands, such as acetylacetonate (acac) or bis(diphenylphosphino)ethane (dppe), forming [Pd(acac-O,O′)(L-κ-C,N)] 9 and [Pd(L-κ-C,N)(dppe-P,P′)](ClO4) 12, while classical N,N′-chelating ligands such as 1,10-phenantroline (phen) or 2,2′-bipyridyl (bipy) behave as monodentate N-donor ligands yielding [Pd(L-κ-C,N,N)(κ1-N-phen)](ClO4) 10 and [Pd(L-κ-C,N,N)(κ1-N-bipy)](ClO4) 11. Treatment of 1 with PtCl2(DMSO)2 (1:1 molar ratio) in refluxing 2-methoxyethanol gives Cl2Pt[(NH2)2C6H10---N,N′] 13a and [Pt(Cl)(C6H2---4,5-(OMe)2---2-CH=N-(1R,2R)---C6H10---NH2-κ-C,N,N)] 13b, while [Pt(Cl)(L-κ-C,N,N)] 14 can be obtained by reaction of [Pt(μ-Cl)(η3-2-Me---C3H4)]2 with 1 in refluxing CHCl3. Complexes 2 and 3 catalyzed the arylation of methyl acrylate giving good yields of the corresponding methyl cinnamates and TON up to 847 000. Complex 3 also catalyzes the hydroarylation of 2-norbornene, but with lower yields and without enantioselectivity. 相似文献
4.
Edwin C. Constable Catherine E. Housecroft Valrie Jullien Markus Neuburger Ingo Poleschak Sbastien Reymann Sina Saxer Silvia Schaffner 《Polyhedron》2007,26(18):5519-5526
The chiral ligands, 4,4′-bis{(1S,2R,4S)-(−)-bornyloxy}-2,2′-bipyridine, (1S,2R,4S)-1, and 4,4′-bis{(1R,2S,4R)-(+)-bornyloxy}-2,2′-bipyridine, (1R,2S,4R)-1, have been prepared and characterized by spectroscopic techniques and, for (1S,2R,4S)-1, by single crystal X-ray diffraction. Despite the use of enantiomerically pure ligands, the formation of the complexes [Fe((1S,2R,4S)-1)3]2+, [Ru((1S,2R,4S)-1)3]2+, [Ru((1S,2R,4S)-1)(bpy)2]2+ and [Ru((1R,2S,4R)-1)(bpy)2]2+ proceeds without preference for either the Δ or Λ-diastereoisomers. 相似文献
5.
J. Bakos I. T th B. Heil
G. Szalontai
L. P
rk nyi V. Fü l p 《Journal of organometallic chemistry》1989,370(1-3):263-276Rhodium(I) complexes formed by (−)-(2S,4S)-2,4-bis(diphenylphosphino)pentane (BDPP) are efficient catalysts for the hydrogenation of acetophenone and acetophenonebenzylimine. The composition of the solvent mixture and the reaction temperature have a marked influenced on the enantioselectivity. These effects are thought to be related to the enhanced conformational flexibility of six-membered rings when simple substrates without functional groups are coordinated to the rhodium. X-ray crystallographic studies reveal that in [Rh((S,S)-BDPP)NBD]+ (1) the ligand is in a chair conformation, and that in [Rh((S,S)-BDPP)COD]+ (2) the chelate ring is in a δ-skew conformation. Studies of Rh((S,S)-BDPP)(NBD)Cl (3) in solution indicate a trigonal bipyramidal structure with a chair conformation of the ring in aromatic solvents and a conformationally labile ring in methanol. 相似文献
6.
Heather L. Milton Matthew V. Wheatley Alexandra M.Z. Slawin J.Derek Woollins 《Polyhedron》2004,23(18):3211-3220
The synthesis and coordination of 2-diphenylphosphinopicolinamide (dpppa 1) is reported. Coordination complexes with Pd, Pt, Ru, Rh, Ir and Au are described. The ligand behaves as a monodentate P donor in complexes such as [PtCl2(dpppa-P2)], [PdCl(allyl)(dpppa-P)], [RuCl2(p-Cymene)(dpppa-P)], cis-[PtCl2(dpppa-P)(PR3)] and [AuCl(dpppa-P)]. Bidentate P, O coordination was accomplished by reaction of BuLi with [RuCl2(p-Cymene)(dpppa-P)], to give [RuCl(p-Cymene)(dpppa-P,O). P,N donor behaviour was achieved by reaction of a monodentate complex with a halide abstractor [AgBF4] generating [RuCl(p-Cymene)(dpppa-P,N)][ClO4] and[RhCl(η5-C5Me5)(dpppa-P,N)][BF4]. The X-ray structures of dpppa, dpppaO, dpppaS, four monodentate complexes and [RuCl(p-Cymene)(dpppa-P,O) are reported. All of the structures contain intramolecular N–HN hydrogen bonding. 相似文献
7.
A. Scrivanti U. Matteoli V. Beghetto S. Antonaroli R. Scarpelli B. Crociani 《Journal of molecular catalysis. A, Chemical》2001,170(1-2):51-56
In the presence of methanesulfonic acid, the palladium(0)-olefin complexes: [Pd(η2-ol)(P---N)] [ol=dimethyl fumarate or fumaronitrile, P---N=1-(Ph2P)C6H4-2-CH=NR (R=CMe3 or C6H4OMe-4)] catalyse the alkoxycarbonylation of terminal alkynes. Moderately good rates are obtained when the catalysts are promoted with two equivalents of the free P---N ligand and a large excess of acid at 120°C. The catalytic data suggest that derivatives of the type [Pd(alkyne)(P---N)n] (n=2–3) are the active catalytic species. 相似文献
8.
Thermal decomposition of mixed ligand thymine (2,4-dihydroxy-5-methylpyrimidine) complexes of divalent Ni(II) with aspartate, glutamate and ADA (N-2-acetamido)iminodiacetate dianions was monitored by TG, DTG and DTA analysis in static atmosphere of air. The decomposition course and steps of complexes [Ni(C5H6N2O2)(C4H5NO4)2−(H2O)2]·H2O, [Ni(C5H6N2O2)(C5H7NO4)2−(H2O)2]·H2O and [Ni(C5H6N2O2)(C6H8N2O5)2−(H2O)2]·1.5H2O were analyzed. The final decomposition products are found to be the corresponding metal oxides. The kinetic parameters namely, activation energy (E*), enthalpy (ΔH*), entropy (ΔS*) and free energy change of decomposition (ΔG*) are calculated from the TG curves using Coats–Redfern and Horowitz–Metzger equations. The stability order found for these complexes follows the trend aspartate > ADA > glutamate. 相似文献
9.
Vimal K. Jain 《Polyhedron》1985,4(12):2089-2096
The nature of the 8-quinolinato ligand in various forms has been examined by 15N, 13C and 119Sn NMR spectroscopy, with evidence also from electronic spectroscopy. These forms include 8-quinolinol (HQ), 8-quinolinate, the 8-hydroxyquinolinium ion, O- and N-methyl derivatives, 8-methoxyquinoline (MeQ), the zwitterionic N-methylquinolinium-8-olate and the N-methylquinolinium ion, and the chelating ligand in organotin(IV) complexes. The 15N shift from MeQ to HQ affords a measure of the intramolecular hydrogen bonding in HQ. The 15N shifts and 2J(15N1H) couplings afford criteria of chelation, and the O- and N-methyl compounds provide useful reference points for its assessment. Evidence for chelation is demonstrated in three groups of compounds, [SnR2Q2] (R = Me, Et, Bun, Octn or Ph), [SnR3Q] (R = Me, Et, Bun or Ph) and [SnR2ClQ] (R = Me, Et, Bun or Octn), the 15N and 119Sn shielding increasing from the [SnR3Q] to the [SnR2Q2] compounds. 相似文献
10.
Wolfdieter A. Schenk Michael Stubbe Michael Hagel 《Journal of organometallic chemistry》1998,560(1-2):257-263
The P–Ph cleavage of phenyldibenzophosphole (1) with lithium in THF gives lithium dibenzophospholide (2). Reaction of 2 with ethyleneglycol ditosylate produces the known chelate ligand 1,2-bis(dibenzophospholyl)ethane (3) in good yield. Similarly, 2 and (2R,3R)-butanediol ditosylate give the new chiral chelate ligand (2S,3S)-bis(dibenzophospholyl)butane (4). Ligand exchange of [CpRu(PPh3)2Cl] with 3 or 4 yields the halfsandwich complexes [CpRu(C12H8PC2H4PC12H8)Cl] (5) and [CpRu((S,S)-C12H8PCHMeCHMePC12H8)Cl] (6). Complex 6 was characterized crystallographically (monoclinic, space group P21 (no. 4), a=820.6(4), b=1501.0(3), c=1172.8(6) pm, β=108.87(2)°, V=1.367(1)×109 pm3, Z=2). The most conspicuous feature of the structure of 6 is the perfect coplanarity of the two dibenzophosphole moieties imposed by their steric interaction with the Cp ligand. Complex 6 and the thiophene complex [CpRu((S,S)-C12H8PCHMeCHMePC12H8)(SC4H4)]BF4 (7) derived therefrom are remarkably unreactive with regard to ligand substitutions. A possible explanation is the lack of intramolecular –C stabilization en route to the transition state of ligand substitution. The enantiomeric purity of 6 and 7 could nevertheless be demonstrated by conversion to diastereomerically pure [CpRu((S,S)-C12H8PCHMeCHMePC12H8)((S)-CNCHMePh)]BF4 (8). 相似文献
11.
Two Schiff bases N,N′-(bis(pyridin-2-yl)benzylidene)propane-1,3-diamine (pbpd) and N,N′-(bis(pyridin-2-yl)formylidene)butane-1,4-diamine (pfbd) have been prepared and used to synthesize copper(II) complexes. Four complexes of the type [Cu(L)(N3)]X (1–4) [L = pbpd; X = ClO4 (1); L = pbpd; X = PF6 (2); L = pfbd; X = ClO4 (3); L = pfbd; X = PF6 (4)] have been synthesized and characterized on the basis of microanalytical, spectroscopic, magnetic, electrochemical, luminescence and other physicochemical properties. Two representative complexes of the series, 2 and 3, have been characterized by single crystal X-ray diffraction measurements which reveal that in each complex the copper(II) ion assumes a distorted trigonal bipyramidal environment through coordination of the metal centre by two pyridine N atoms and two imine N atoms of the Schiff base with the fifth position occupied by a N atom of a terminal . They display intraligand 1(π–π*) fluorescence at room temperature and intraligand 3(π–π*) phosphorescence in glassy solutions (MeOH at 77 K). A band (492 nm) observed for the complexes in their solid-state emission spectra is an excimeric emission arising due to an aromatic π–π interaction. Electrochemical electron transfer study reveals CuII–CuI reduction in methanolic solutions. 相似文献
12.
The synthesis and characterization of the [M(dmit)(phen)] complexes [M = Pd(II), Pt(II); H2dmit = 4,5-dimercapto-1,3-dithiole-2-thione; PHEN = 1,10-phenanthroline) and of the iodinated [M(dmit)(phen)]I compounds are described. The conductivity of [M(admit)(phen)] increases upon oxidation by a factor of 106, and is ca. 5 × 10−3 ohm− cm− for the [M(admit)(phen)]I compounds. The nature of the iodine species in these solids is determined by UV-visible and resonance Raman spectroscopies. The only polyiodide present is I−3 and, thus, the charge distribution can be expressed as [M(dmit) (phen)0.33+[I−3]0.33. 相似文献
13.
钯(Ⅱ)三元配合物稳定性及其与DNA作用研究 总被引:3,自引:0,他引:3
合成了[Pd(bipy)(DL-gly)]Cl•2H22O(2)两个钯三元配合物. 配合物1和2的稳定常数对数值lgβ分别为13.81和13.71, 表征常数ΔlgK、lgX高于统计值, 表明在配合物分子内存在d-p π电子协同效应. 紫外光谱、荧光光谱结果表明, 配合物1和2与鱼精DNA主要以插入方式键合, 键合常数分别为2.37×106(1)和4.57×106(2). CD光谱图也显示, 配合物与DNA分子之间发生了作用. 质粒pBR322 DNA的凝胶电泳图表明, 配合物浓度在3.00×10-3~7.50×10-4 mol •L-1范围内对DNA分子有切割作用, 配合物浓度低于3.75×10-4 mol •L-1时则主要以插入方式与DNA键合. 相似文献
14.
The reaction of (R) or (S)-N4,N5-bis(t-butoxycarbonyl)-4,5-diaminopentanoic acid (6) with (R) or (S)-N3,N4-bis(t-butoxycarbonyl)-3,4-diaminobutylisocyanate (8) catalyzed by 4-dimethylamino pyridine (DMAP), leads to the synthesis of (R,R), (S,S), (R,S) and (S,R) isomeric amides (11 a — d) The addition of adipic acid monomethyl ester to (R) or (S) isocyanate, followed by saponification, acidification and subsequent reaction with the second molecule of (R) or (S) isocyanate allows isolation of the (R,R), (S.S) and the meso isomers of N,N′-bis[3,4-bis(t-butoxycarbonylamino) butyl]hexanediamide (17) Removal of protecting groups with HCl/EtOH affords chiral non-racemic molecules having two free vicinal diamine units. 相似文献
15.
Subrata Maity Ramkrishna Roy Chittaranjan Sinha Wen-Jyh Sheen Kaliyamoorthy Panneerselvam Tian-Huey Lu 《Journal of organometallic chemistry》2002,650(1-2):202-209
Binuclear chloro-bridged cyclopalladated azobenzenes [Pd(A)Cl]2 (A=ortho-metallated azobenzene or its derivatives) have been reacted with aqueous (aq.) AgNO3 followed by the addition of 2-hydroxypyridine (2-PyOH; donor centres of deprotonated form abbreviated N,O)/2-mercaptopyridine (2-PySH; donor centres of deprotonated form abbreviated N,S) in presence of Et3N to synthesise bridged dinuclear compound [Pd(A)(μ-N,O)]2–[Pd(A)(μ-N,S)]2. The compositions of the complexes have been established by elemental analyses, IR, UV–vis, 1H and 13C-NMR spectral data. The structural confirmation has been carried out by X-ray crystallography. The structures show anti-symmetric metallacycle in the dimer and N,O/N,S bridging arrangement. The dimer [Pd(A1)(μ-N,X)]2 shows strong PdPd interaction (A1=2-(phenylazo)benzene). The coordination mode in [Pd(A1)(μ-N,O)]2 shows trans pyridine-N to Pd---N(azo) bond while in [Pd(A1)(μ-N,S)]2 pyridine-N is trans to the Pd---C bond. The square planes are convergent towards heterocyclic bridging side. 相似文献
16.
Rob van Asselt Kees Vrieze Cornelis J. Elsevier 《Journal of organometallic chemistry》1994,480(1-2):27-40
Zerovalent complexes of the type Pd(Ar-BIAN)(alkene), i.e. complexes containing the rigid bidentate nitrogen ligands bis(arylimino) acenaphthene (Ar = p-Tol, p-MeOC6H4, o-Tol,o,o′-Me2C6H3, o,o′-iPr2C6H3) and an electron-poor alkene have been shown to react with a variety of (organic) halides RX, including methyl, benzyl, aryl, acyl and allylic halides, to give the corresponding square planar divalent Pd(R)X(Ar-BIAN) or [Pd(η3-allyl)(Ar-BIAN)]X complexes. The new complexes obtained have been fully characterized and their fluxional behaviour in solution studied by 1H NMR spectroscopy. The rate of oxidative addition of iodomethane to Pd(p-Tol-BIAN)(alkene) complexes was found to decrease with increasing Pd-alkene bond strength, i.e. dimethyl fumarate fumaronitrile, but oxidative addition to the fumaronitrile complex was accelerated by irradiation with a mercury lamp. Oxidative addition of allylic ha 相似文献
17.
Two types of iron(III) carbodithioate complexes, (i) normal complexes, Fe(R2NCS2)3 with R2N = 4-methyl-, 4-phenyl-, or 2-methyl-piperazyl, piperidyl and thiomorpholyl and (ii) zwitterionic complexes, Fe(R2NCS2H)3X3 with R2N = 4-methyl- or 4-phenyl-piperazyl and X = Cl or Br have been synthesized. The complexes have been characterized by elemental analyses, IR spectral studies, variable-temperature magnetic susceptibility and in three cases by variable-temperature Mössbauer spectral studies. All the complexes exhibit the 2T2 (low spin, S =
) 6 A1 (high spin, S =
) spin equilibrium process. The zwitterionic carbodithioate ligands have a weaker ligand field strength than their normal ligand analogues. 相似文献
18.
Members of the series of bridging diphosphine clusters [Os3(CO)10(diphos)] where diphos = Ph2P(CH2nPPh2 [dppm (n = 1), dppe (n = 2), dppp (n = 3), or dppb (n = 4)] show interesting differences in their reactivity towards H+ and H2. Protonation leads to [Os3(μ-H)(CO)10(diphos)]+ with the hydrides bridging the same osmium atoms as the diphos ligand when diphos is dppe, dppp, or dppb, whereas the hydride and dppm bridge different edges in [Os39μ-H)(CO)10(dppm)]+. Hydrogenation of the 1,2-diphos compounds leads to [Os3(μ-H)2(CO)8(diphos)] (diphos = dppm, dppe, dppp) in good to excellent yield but the dppb analogue could not be made. Geometric and electronic factors affecting the ability to incorporate hydride ligands in these clusters are discussed. 相似文献
19.
Pablo Espinet Paloma Gomez-Elipe Fernando Villafae 《Journal of organometallic chemistry》1993,450(1-2):145-150
The first carbonyl molybdenum-(O) and -(II) complexes with phenylbis(2-pyridyl)phosphine (PPhpy2) have been synthesized. PPhpy2 reacts with [Mo(CO)5(NCMe)] to give [Mo(CO)5(PPhpy2-P)]. With [Mo(CO)4(NBD)] (NBD = norbornadiene) it gives [Mo(CO)4(PPhpy2-P)2] when a 2 : 1 ratio is used, or [MO(CO)4(py2PhP---N,N′)] for a 1 : 1 ratio. Decarbonylation of any of these pyridylphosphine complexes leads to an oligomer of formula {MO(CO)3(μ-PPhpy2)}n, which is also obtained after heating [MO(CO)6] in solution with an equimolar amount of PPhpy2. The oligomer undergoes oxidative addition by iodine or allylbromide to give [MoI2(CO)3(py2PhP---N,N′)], or [MoBr(η3-CH2CHCH2)(CO)2(py2PhP---N,N′)], respectively. These complexes are also obtained by addition of equimolar amounts of PPhpy2 to solutions of [MoI2(CO)3(NCMe)2] and MoBr(η3-CH2CH CH2)(CO)2(NCMe)2, respectively. The ligand tends to act as a P-donor towards molybdenum(O) substrates, and as a chelating N,N′-donor in molybdenum (II) complexes. 相似文献
20.
Tetsuro Murahashi Hideo Kurosawa Nobuko Kanehisa Yasushi Kai 《Journal of organometallic chemistry》1997,530(1-2):187-189
An η1-butadienyl complex [trans-η1-CH2=C(Me)C=CH2Pd(PPh3)2Cl] (1) reacted with [(μ-η2:η2-1,3-butadiene)Pd2(PPh3)(μCl)Cl] (2) to result in displacement of the diene ligand of 2 accompanied by exchange of PPh3 of 1 with Cl anion of 2 producing a butadienyl tripalladium cluster [(μ-CH2=C(Me)C=CH2)Pd(PPh3)Cl2 · Pd2(PPh3)2(μ-Cl)] (3) stabilized by the zwitterionic structure in moderate yield. The X-ray structure analysis of 3 revealed rigid binding of [Pd2(PPh3)2(μ-Cl)]+ and [CH2 =C(Me)C=CH2Pd(PPh3)Cl2]− through the π-bond coordination of the butadienyl group to the dipalladium cation. 相似文献