共查询到20条相似文献,搜索用时 29 毫秒
1.
John S. Fossey Mark L. Russell Christopher J. Richards 《Journal of organometallic chemistry》2007,692(22):4843-4848
(S,S)-2,6-bis[(N-α-methylbenzyl)imino]phenylpalladium bromide was synthesised by oxidative addition of palladium(0) to (S,S)-1-bromo-2,6-bis[(N-α-methylbenzyl)imino]benzene. In contrast, (S,S)-2,6-bis[(N-α-methylbenzyl)imino]phenylplatinum chloride was synthesised by direct C-H activation from the reaction of potassium tetrachloroplatinate with (S,S)-1,3-bis[(N-α-methylbenzyl)imino]benzene. The X-ray crystal structures of both pincer complexes were obtained. Treatment of both complexes with silver hexafluoroanimonate gave effective but not stereoselective catalysts for a Michael reaction between methyl vinyl ketone and methyl 2-cyanopropanoate. 相似文献
2.
Qian Dai 《Tetrahedron》2006,62(5):868-871
Rhodium complexes of functionalized bisphospholane ligands (S,S,S,S-Me-ketalphos) 1 and (R,S,S,R-Me-ketalphos) 2 have been used as catalyst precursors for the asymmetric hydrogenation of several different types of functionalized olefins and have achieved high enantioselectivities. 相似文献
3.
Jaime Vázquez Sylvain BernèsPankaj Sharma Javier PérezGuadalupe Hernández Alejandra TovarUlises Peña René Gutiérrez 《Polyhedron》2011,30(15):2514-2522
A set of new diastereopure unsymmetrical α-diimine ligands 2a-d derived from methylglyoxal and optically pure primary amines 1a-d afforded the new chiral Pd(II)-complexes (S,S)-3a, (S,S)-3b, (S,S)-3c, and (1S, 2S, 3S, 5R)-3d. All compounds have been characterized by IR, 1H, and 13C NMR spectroscopies along with MS-FAB+ spectrometry. The crystal and molecular structure for the complexes 3a, 3b and 3d have been fully confirmed by single-crystal X-ray studies. Likewise, complexes 3a-d have also been screened for their in vitro cytotoxicity against different classes of cancer: leukemia (K-562 CML), colon cancer (HCT-15), human breast adenocarcinoma (MCF-7), central nervous system (U-251 Glio) and prostate cancer (PC-3) cell lines. 相似文献
4.
Vesna M. Djinović Verica V. Glodjović Gordana P. Vasić Vladimir Trajković Olivera Klisurić Slobodanka Stanković Tibor J. Sabo Srećko R. Trifunović 《Polyhedron》2010,29(8):1933-1938
The syntheses of two novel platinum(IV) complexes of formula [PtX2(S,S-eddp)]·nH2O (S,S-eddp = ethylenediamine-N,N′-di-S,S-2-propanoate ion, X = chlorido (1) or bromido (2), n = 4, 0) are reported. The complexes have been obtained by direct reaction of corresponding potassium hexahalogenidoplatinate(IV) with neutralized ethylenediamine-N,N′-di-S,S-2-propanoic acid (H2-S,S-eddp). The complexes were characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The spectroscopically predicted geometrical configurations of the obtained complexes were confirmed by X-ray analyses of the crystal structures of the s-cis-[Pt(S,S-eddp)Cl2]·4H2O and uns-cis-[Pt(S,S-eddp)Br2]. These complexes displayed significantly lower in vitro cytotoxicity in comparison to cisplatin. 相似文献
5.
Patricia Horrillo-Martínez 《Tetrahedron letters》2009,50(18):2054-2207
Reaction of 2 equiv of n-Bu2Mg and Et2Zn with the chiral l-proline-derived axial chiral tetraamines (S,S,S)-1 and (R,S,S)-1 gave the chiral bimetallic complexes [M2{(S,S,S)-DABN(MeProline)2}{R}2] (M=Mg, R=n-Bu ((S,S,S)-2); M=Zn, R=Et ((S,S,S)-3)) and [M2{(R,S,S)-DABN(MeProline)2}{R}2] (M=Mg, R=n-Bu ((R,S,S)-2)); M=Zn, R=Et ((R,S,S)-3)). The magnesium complexes showed moderate to high catalytic activity in the intramolecular hydroamination/cyclization of aminoalkenes, though enantiomeric excess was limited to 14% ee due to protolytic ligand exchange processes. The zinc complexes were less reactive and generally required higher reaction temperatures of 60-100 °C, but achieved slightly higher enantiomeric excess of up to 29% ee. 相似文献
6.
Adedamola S. Arojojoye R. Tyler Mertens Samuel Ofori Sean R. Parkin Samuel G. Awuah 《Molecules (Basel, Switzerland)》2020,25(23)
Herein is reported the synthesis of two Au(III) complexes bearing the (R,R)-(–)-2,3-Bis(tert-butylmethylphosphino)quinoxaline (R,R-QuinoxP*) or (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxaline (S,S-QuinoxP*) ligands. By reacting two stoichiometric equivalents of HAuCl4.3H2O to one equivalent of the corresponding QuinoxP* ligand, (R,R)-(–)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (1) and (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (2) were formed, respectively, in moderate yields. The structure of (S,S)-(+)-2,3-Bis(tert-butylmethylphosphino)quinoxalinedichlorogold(III) tetrachloroaurates(III) (2) was further confirmed by X-ray crystallography. The antiproliferative activities of the two compounds were evaluated in a panel of cell lines and exhibited promising results comparable to auranofin and cisplatin with IC50 values between 1.08 and 4.83 µM. It is noteworthy that in comparison to other platinum and ruthenium enantiomeric complexes, the two enantiomers (1 and 2) do not exhibit different cytotoxic effects. The compounds exhibited stability in biologically relevant media over 48 h as well as inert reactivity to excess glutathione at 37 °C. These results demonstrate that the Au(III) atom, stabilized by the QuinoxP* ligand, can provide exciting compounds for novel anticancer drugs. These complexes provide a new scaffold to further develop a robust and diverse library of chiral phosphorus Au(III) complexes. 相似文献
7.
《Polyhedron》1999,18(6):897-904
Copper(II) quelates with Schiff bases derived from ethylenediamine, 1R,2R-(+)- or 1S,2S-(−)-1,2-diphenylethylenediamine and 5-X-salicylaldehyde (X=OCH3, H, Br, NO2) have been synthesized and characterized by elemental analysis and IR and UV-visible spectroscopies. The ORD and CD spectra of the chiral ligands and their related complexes have also been measured. The absorption and CD spectra of the metal complexes in the visible region are consistent with near square planar coordination geometries. Trends in absorption spectra over the series of complexes can be correlated with electronic effects of the substituents at position 5 of the salicylaldehyde. The sign patterns of the CD spectra in both UV and visible regions suggest the prevalence of δ and λ conformations for the chelate ring in the complexes of Schiff bases derived, respectively, from R,R- and S,S-diamines. Specific features of the CD spectra of the metal complexes are discussed in terms of the exciton chirality method. 相似文献
8.
《Tetrahedron: Asymmetry》2007,18(11):1278-1283
The catalytic asymmetric hydrogenation of prochiral ketones was carried out with Ru(II) complexes prepared from new chiral diphosphine ligands, cis-(R,R)-2,5-bis[(diarylphosphino)]-3-hexenes. These new ligands were prepared from enantiomerically pure (R,R) or (S,S)-(Z)-3-hexene-2,5 diol and enantiomeric excesses up to 85% were obtained in the reduction of 2-benzamidomethyl-3-oxobutanoate, starting material for the synthesis of 4-acetoxy-2-azetidinone. 相似文献
9.
Michele Abbate Tiziana Fiore Claudia Pellerito Alberto Spinella 《Journal of organometallic chemistry》2010,695(9):1405-1413
Three new complexes of the steroid sodium fusidate (sodium 2-[(1S,2S,5R,6S,7S,10S,11S,13S, 14Z,15R,17R)-13-(acetyloxy)-5,17-dihydroxy-2,6,10,11-tetramethyl tetracyclo[8.7.0.02,7.011,15] heptadecan-14-ylidene]-6-methylhept-5-enoate = (NaFusidate, NaFA)]), with triorganotin(IV) moieties have been prepared and investigated by conventional techniques as FTIR, Mössbauer, ESI-MS and NMR spectroscopy. The isolated compounds showed stoichiometries organotin(IV)/fusidate 1/1, R3Sn(IV)FA (R = Me, FA1; Bu, FA2; Ph, FA3). The ligand coordination sites were determined by FTIR spectroscopic measurements. In the complexes, the carboxylate group of the fusidate ligand behaves as monodentate monoanionic donor, binding the Sn(IV) through one oxygen atom.On the basis of C-Sn-OCOO angles, calculated through the rationalization of the 119Sn Mössbauer parameter nuclear quadrupole splitting, it has been confirmed that, in all the solid state complexes, the Sn(IV) was tetracoordinated in a distorted tetrahedral structure.Further data from 119Sn CP-MAS spectra confirmed the distorted tetrahedral arrangement.In MeOH solution, 1H, 13C and 119Sn NMR spectroscopy showed monomeric complexes, where the carboxylate group mainly acts as monodentate ester-type ligand, and the occurrence of a coordinated solvent molecule to the tin center, as validated by non-relativistic NMR DFT study. 相似文献
10.
Pt{(S,S)-bdpp}(R)I (bdpp = 2,4-bis(diphenylphosphino)pentane; R = Me, Ph, Bz, 2-Tioph) complexes were formed in alkyl/aryl ligand - iodide ligand-exchange reactions by reacting the corresponding Pt{(S,S)-bdpp}R2 complexes with methyl iodide. The Pt{(S,S)-bdpp}(Me)I complex was isolated and fully characterised. The influence of the X ligand on the platinum-bdpp chelate conformation was investigated in Pt{(S,S)-bdpp}(X)I (X = I, SnCl3, Me) complex series by means of X-ray crystallography. 相似文献
11.
《Journal of organometallic chemistry》2007,692(1-3):408-419
A series of 18-electron alkylruthenium complexes, RuR[κ2(N,N′)-(S,S)-R′SO2NCHPhCHPhNH2](η6-arene) (Ph = C6H5, R′ = p-CH3C6H4 and CH3), bearing a N-sulfonylated diamine ligand was synthesized from the reaction of RuCl[κ2(N, N′)-(S,S)-R′SO2NCHPhCHPhNH2](η6-arene) with alkylzinc reagents, in which transmetalation proceeded smoothly to give the desired alkyl complexes in good yield and selectivity. Although the isolable amine Ru complexes bearing functionalized alkyl ligands were thermally stable, the simple methyl and ethyl Ru complexes underwent intramolecular deprotonation from NH protons to give the amido Ru complexes with release of the alkanes. The reactivity of the alkyl Ru complexes is highly affected by the structures of the arene ligands. 相似文献
12.
《Tetrahedron: Asymmetry》2006,17(19):2743-2753
A new efficient method for the asymmetric synthesis of β-heterocycle substituted (2S,3S)-α-aminobutyric acids through the diastereoselective addition of 5-thioxo-4-allyl-1,2,4-triazoles, containing various substituents at the 3-position, to the CC double bond of (E)- and (Z)-dehydroaminobutyric acid in the NiII complexes of their Schiff base with chiral auxiliaries (S)-N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide [(S)-BPB], (S)-N-(2-benzoylphenyl)-1-(3,4-dichlorobenzyl)pyrrolidine-2-carboxamide [(S)-3,4-DCBPB], (S)-N-(2-benzoylphenyl)-1-(3,4-dimethylbenzyl)pyrrolidine-2-carboxamide [(S)-3,4-DMBPB], and (S)-N-(2-benzoylphenyl)-1-(2-chlorobenzyl)pyrrolidine-2-carboxamide [(S)-2-CBPB] has been elaborated upon. The nucleophilic addition proceeds with high diastereoselectivity with a preferential formation of (S,S,S)-diastereoisomers. After decomposition of a mixture of diastereomeric complexes, optically active β-heterocycle substituted (2S,3S)-α-aminobutyric acids with high diastereomeric purity (de >98%) were isolated. 相似文献
13.
《Tetrahedron letters》2004,45(41):7723-7726
New ligands and their complexes with iron(III) chloride have been suggested and prepared: (R,S)-, (R,R)- and (S,S)-2,6-bis(1-benzyl-4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-on-2-yl) pyridines. Both the ligands and their complexes were characterised by 1H and 13C NMR spectroscopy, optical rotation and X-ray diffraction. 相似文献
14.
《Journal of molecular catalysis. A, Chemical》2007,261(1):64-72
The enantiomerically and diastereomerically pure dinitrogen-bridged complexes [{TpRu(L)}2(μ-N2)][PF6]2 (L = R,R- or S,S-1,2-bis(diphenylphosphinoamino)cyclohexane (R,R- or S,S-dppach)) were prepared by reaction of the corresponding chloro-complexes [TpRuCl(L)] with NaPF6 in dichloromethane under dinitrogen. The dinitrogen adducts react with neat methacrolein furnishing the labile complexes [TpRu(methacrolein)(L)][PF6] (L = R,R- or S,S-dppach). Both the dinitrogen and methacrolein derivatives are catalysts for the solvent-free regio- and enantioselective Diels–Alder reactions between methacrolein and cyclopentadiene or pentamethylcyclopentadiene, with moderate enantiomeric excesses ranging from 36 to ca. 70%. The metal complex can be easily recovered and re-utilised for further reactions. The dinitrogen complexes also catalyse the 1,3-dipolar cycloaddition reaction between methacrolein and benzylidenephenylamine N-oxide to yield 5-methyl-2-N-3-diphenyl-isoxazolidine-5-carbaldehyde with very high regioselectivity and 32% enantiomeric excess. 相似文献
15.
W. Y. Lu Y. H. Hu S. H. Yang 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,40(1):40-43
The resonant two-photon ionization technique (R2PI) is used to study jet-cooled van der Waals (vdW) complexes o, p, m-xylene...Ar n (n = 1, 2) through the S 1 ← S 0 transition around the origin band. We have tentatively assigned the main spectral features of these vdW complexes. The transitions of these complexes are red-shifted from those of the monomers. The influence of the substituent positions on the vdW vibrations is investigated. 相似文献
16.
Abel Ros Manuel Alcarazo David Monge Eleuterio Álvarez Rosario Fernández José M. Lassaletta 《Tetrahedron: Asymmetry》2010,21(11-12):1557-1562
The synthesis of two different types of chiral C/S ligands based upon N-(N,N-dialkylamino)-substituted N-heterocyclic carbenes and thioether functionalities, along with their neutral [RhCl(CNH)(COD)] and cationic [Rh(I)(NHC/S)(COD)]+ complexes, has been accomplished. (S)-2-[(Phenylthio)methyl]pyrrolidine, carrying the thioether moiety, and (2S,5S)-2,5-diphenylpyrrolidine, combined with a thioether functionalized side chain, were studied as potential stereodirecting groups. Only the latter provided high selectivity in the formation of the neutral complex, leading to a single atropoisomer (de >98%) of the newly formed, configurationally stable C(NHC)–Rh bond. The synthesis of the corresponding cationic [Rh(I)(NHC/S)(COD)]+ complexes, however, resulted in the formation of single (Ra,SS) and (Sa,SS) diastereomers, respectively, of the four possible complexes in each case [combinations of the (Ra/Sa) C(NHC)–Rh axis and the (Ss/Rs) stereogenic S center formed upon coordination]. For the proline derivative, the resolution of the mixture of (Ra/Sa)-[RhCl(CNH)(COD)] neutral complexes proceeds via dynamic kinetic resolution through coordinatively unsaturated Rh(I) intermediates formed after halide abstraction. The absolute configurations of both types of cationic complexes were unequivocally assigned on the basis of X-ray diffraction analysis. 相似文献
17.
《Tetrahedron: Asymmetry》2006,17(7):1049-1055
The new diastereomeric complexes of two oligo-N-methylpyrrole peptides, linked by a methano[1,5]-diazocin scaffold with DNA, were prepared. The specificity of the binding modes of (4S,9S)- and (4R,9R)-bis-distamycins derivative with ct-DNA explains the observed optical activity of the racemic mixture of distamycin if DNA is present. The bis-distamycin derivative possesses a clear sequence selectivity for A-T rich sequences of DNA, although a nonspecific binding mode with low affinity was also seen for G-C rich sequences. The reversibility of ECD spectra at 5 °C after heating to 90 °C was established. 相似文献
18.
The reactions of a series of 5-alkyl-2-thiophenedithiocarboxylates with nickel(II) chloride afforded two types of complexes, blue nickel(II) complexes with two terminal dithiocarboxylate ligands, [Ni(S2CTR)2] and violet nickel(II) complexes with perthio- and dithiocarboxylate ligands, [Ni(S2CTR)(S3CTR)] (where T = 2,5-disubstituted thiophene, R = CnH2n+1, n = 4, 6, 8, 12, 16). The blue monomers are preferred for the shorter chains (C4 and C6) and the violet compounds form exclusively for the longer chains (C8, C12, and C16) in the alkylthiophene complexes. In addition to the above series, [Ni(S2CTCH3)2], was prepared in a one-pot reaction in THF and both the blue and violet products were isolated. It was possible to convert the blue complexes [Ni(S2CTR)2] (R = butyl, hexyl) into the corresponding violet complexes [Ni(S2CTR)(S3CTR)] after stirring in THF solutions for prolonged periods of time. Liquid-crystalline properties of these complexes were examined by DSC and POM. The violet complexes with C8 and C12 alkyl chains showed liquid-crystalline properties. 相似文献
19.
The synthesis of ( - ) 2S,3S,11S,12R-2, 3,11,12-tetraphenyl [18]-crown-6 from (-)-1S,2S-hydrobenzoin and meso-hydrobenzoin is described. Chemical shifts and vicinal coupling constants of the benzylic protons in the 2 S, 3 S and 11 S,12 R substructures in the free ligands and in complexes with KSCN and 1-phenylethylammonium bromides and a brief discussion of the related conformational changes are also presented. A detailed procedure for the resolution of racemic hydrobenzoin is given. 相似文献
20.
A new series of four-coordinated Pd(II) and Pt(II) complexes in which the Lewis-acid (14-electron) {M(S2CNHR)(PR3′)} group is combined with a variety of other ligands (such as RHNCS2?, I?, SCN?, SnCl2I?) has been synthesised and studied. The structures of the new compounds are discussed in relation to their specroscopic, magnetic and thermal properties. In the case of [M(S2CNHR)2(PR3′)] complexes both the spectroscopic data (IR, 1H NMR, UV-Vis) and their thermal behaviour strongly suggest the coexistence of two kinds of gem-disulphide ligands, one acting as a bidentate ligand and the other one as a unidentate. Also it was confirmed that the chemical behaviour of the bis(N-alkyldithiocarbamato) complexes of Pd(II) and Pt(II) towards tertiary phosphines is similar to that of the isoelectronic xanthate complexes rathe than to the bis(N,N-dialkyldithiocarbamato) complexes. 相似文献