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Tantalaalkylidene compounds, CHRTaCl3L2 (R=tBu or CMe2Ph, L=THF or 1/2dimethoxyethane) mixed with the cyclopalladated dimer [Pd(2-C6H4CH2NMe2)(μ-Cl)]2, 1, afford good yields of heterodimetallic complexes [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHR=TaCl3L], 3a, 3b, in which the TaC unit is η2-interacting with the palladium atom, while a chloride ligand is bridging the tantalum and the palladium atoms. These compounds are fairly stable in air in the solid state and also in solution at RT. The interaction of the TaC unit with Pd in these bimetallic compounds is weak as shown by the ready formation of [Pd(2-C6H4CH2NMe2)PyCl] and CHRTaCl3Py2 upon treatement with pyridine. Compounds analogous to 3a, b can also be obtained with 12 electrons tantalum complexes. Thus treating the same cyclopalladated dimer 1 with CHRTa(OAr)3 (OAr=2,6-diisopropylphenyloxy) led to a much more stable though electron deficient species: [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHtBu=Ta(OAr)3], 3c. Substitution in 3a of one chloride ion by an alkyl group occurred at the tantalum metal via reaction with ZnR2 (R=CH2CMe2Ph) leading to [Pd(2-C6H4CH2NMe2)(μ-Cl)(μ-CHtBu=TaCl3(CH2CMe2Ph)], 4 for which there is no free rotation around the new TaC bond and in which one of the methylene protons is strongly interacting with the palladium centre. This compound is believed to mimic an intermediate to the formation of tantalacarbyne derivative, which was obtained earlier via reaction of the uncomplexed tantalacarbene compound with dialkylzinc compounds. 相似文献
3.
The reactions of 1,3,5-tris-(trimethylsilylethynyl)benzene (1) with Cu2O and 1,1,1,5,5,5,-hexafluoroacetylacetone in alkyne to Cu ratios 1:0.5, 1:1 and 1:3 in CH2Cl2 at room temperature give copper complexes (η2-1,3,5-tris(trimethylsilylethynyl)benzene)(Cu(hfac)) (2), (η2:η2-1,3,5-tris(trimethylsilylethynyl)benzene)(Cu(hfac))2 (3) and (η2:η2:η2-(1,3,5- tris(trimethylsilylethynyl)benzene))2(Cu(hfac))3(4), respectively. In the same conditions, 2,5-bis-(trimethylsilylethynyl)thiophene (5) reacts with 0.5 or 1 equiv. of Cu2O to give (η2:η2-2,5-bis(trimethylsilylethynyl)thiophene)(Cu(hfac)) (6) and (η2:η2-2,5-bis(trimethylsilylethynyl)thiophene)(Cu(hfac))2 (7), respectively, and 1,4-bis(trimethylsilyl)-1,3-butadiyne (8) with 0.5 equiv. of Cu2O give (η2:η2-1,4-bis(trimethylsilyl)-1,3-butadiyne)(Cu(hfac))2(9). All the new compounds have been characterized by analytical and spectroscopic methods and their thermal properties were examined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). 相似文献
4.
Qunying Chen Yitao Pu Zongkun Zheng Chunzhi Shi Xinzheng Huang 《Carbohydrate research》2010,345(11):1609-426
Water-soluble 2′-O-hydroxypropyltrimethylammoniumchitin chloride (2′-O-HTACCt) was prepared directly from β-chitin and 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) in basic medium. The effect of alkali concentration, reaction temperature, reaction time, and dosage of CTA on yield and degree of substitution (DS) of 2′-O-HTACCt were studied. These quaternized chitin derivatives were characterized by FTIR and 1H NMR spectroscopy, conductometric titration, and elemental analysis methods. Research results indicate that β-chitin can react directly with CTA to produce a water-soluble 2′-O-HTACCt derivative with a high DS. The optimal preparation conditions were determined to be 35-40 wt % (aq NaOH), 40 °C (reaction temperature), 6 h (reaction time), and 4 (molar ratio of CTA to β-chitin unit). 相似文献
5.
Reactions of the molybdenum and tungsten precursors [MO2S2]2− with equimolar amounts of benzenedithiol in acetonitrile give the title compounds [M2O2(μ-S)2(bdt)2]2− with M = Mo, W and bdt = benzene-dithiolate. In case a tungsten to ligand ratio of 1:2 is used the dimer forms as well but only as a minor species whereas the monomer [WO(bdt)2]2− is the main product. In both dimeric compounds the syn-isomers are formed referring to the position of the apical oxo ligands with respect to the M2S2 plane. For the molybdenum compound this contrasts with a published crystal structure of the anti-isomer. Both complexes give highly symmetric isomorphous crystals but still show subtle differences in their bond lengths and angles around the central metal. The X-ray crystal structures of both are analyzed in detail and compared with each other and with the isomeric molybdenum compound. Differences and similarities between tungsten and both isomers of molybdenum complexes are shown to be more influenced by the conformation than by the central metal and a reason for the formation of syn- and anti-isomers based on the respective synthetic procedures is proposed. 相似文献
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Stefanie Jäger Natali Gulbahce Peter Cimermancic Joshua Kane Nanhai He Seemay Chou Iván D’Orso Jason Fernandes Gwendolyn Jang Alan D. Frankel Tom Alber Qiang Zhou Nevan J. Krogan 《Methods (San Diego, Calif.)》2011,53(1):13-19
To fully understand how pathogens infect their host and hijack key biological processes, systematic mapping of intra-pathogenic and pathogen–host protein–protein interactions (PPIs) is crucial. Due to the relatively small size of viral genomes (usually around 10–100 proteins), generation of comprehensive host–virus PPI maps using different experimental platforms, including affinity tag purification-mass spectrometry (AP-MS) and yeast two-hybrid (Y2H) approaches, can be achieved. Global maps such as these provide unbiased insight into the molecular mechanisms of viral entry, replication and assembly. However, to date, only two-hybrid methodology has been used in a systematic fashion to characterize viral–host protein–protein interactions, although a deluge of data exists in databases that manually curate from the literature individual host–pathogen PPIs. We will summarize this work and also describe an AP-MS platform that can be used to characterize viral-human protein complexes and discuss its application for the HIV genome. 相似文献
7.
《International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology》1992,19(1):73-78
New tris(β-diketonato) complexes of trivalent 99Tc/99mTc with the ligands hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, and octane-3,5-dione were synthesized by reduction of pertechnetate with dithionite in the presence of excess β-diketone. The complexes were purified by HPLC, identified by elemental analysis and FAB mass spectrometry, and characterized by vis./u.v./i.r. spectrophotometry. The hexane-2,4-dionato complex crystallizes in the monoclinic space group P21/c, isostructurally with pentane-2,4-dionatotechnetium(III). Biodistribution measurements in mice showed the neutral and lipophilic 99mTc-diketonato complexes to penetrate the blood-brain barrier. However, increasing lipophilicity decreased the brain uptake except for the heptane-2,4-dionato complex, which displayed the highest uptake of 0.82% injected dose/g. 相似文献
8.
Jennifer L. Daniels Troy M. Crawford Oleg A. Andreev Yana K. Reshetnyak 《Biochemistry and Biophysics Reports》2017
Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG) and pH Low Insertion Peptide (pHLIP®) were introduced. The presence of a tumor-targeting pHLIP® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ~43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold) were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors. 相似文献
9.
Marina Cindri? Višnja VrdoljakTanja Kajfe? Predrag Novak Ana Brbot-Šaranovi?Neven Strukan Boris Kamenar 《Inorganica chimica acta》2002,328(1):23-32
New dinuclear molybdenum(V) complexes have been obtained by the reaction of [Mo2O3(acac)4] (acac=acetilacetonate ion) with the polydentate ligands, β′-hydroxy-β-enaminones. All prepared complexes consist of Mo2O4 2+ core coordinated by two ligands as in the β-diketonates only through two donor oxygen atoms. Such bonding gives the opportunity for the sixth coordination place around molybdenum to be completed by the monodentate solvent molecule D. All compounds have been characterized by means of elemental analyses, one- and two-dimensional NMR spectroscopy, IR spectroscopy as well as by thermal analyses. The molecular and crystal structures of the molybdenum(V) complexes 1a and 1b coordinated by two different isomeric ligands as well as of the isomer a itself have been determined by a single crystal X-ray diffraction method. 相似文献
10.
《Inorganica chimica acta》1988,154(1):41-43
The reaction of [Rh(diene)(acac)] (diene=cyclooctadiene or norbornadiene; acac=acetylacetonate) with bidentate ligands of the type Ph2P(CH2)nSR (n=1, 2 or 3; R=Me, Et, Ph, not all combinations) or cis-Ph2PCHCHPPh2 leads to [Rh(diene)(LL)]+ or [Rh(LL)2]+, depending on the stoichiometry of the reaction. The complexes were fully characterized by 1H and 31P NMR spectroscopy. 相似文献
11.
《Inorganica chimica acta》1986,114(2):141-144
The preparations and properties of tris(dipivaloylmethanato)technetium(III), tris(trifluoroacetylacetonato)technetium(III), and tris(hexafluoroacetonato)technetium(III) are described. The oxidation of the dipivaloyl derivative to tris(dipivaloyl)technetium(IV) hexafluorophosphate was shown to take place readily. Voltammetric studies and magnetic resonance results on the new complexes are reported. The large shifts observed for the complexes seem to be due to a contact interaction. 相似文献
12.
《Inorganica chimica acta》1988,151(1):61-68
Metal complexes of 2-pyridinecarboxaldehyde 2′-pyridylhydrazone (PCPH) and related compounds with manganese(II), iron(II), cobalt(II), nickel(Il), copper(II), zinc(II) and platinum(II) were synthesized and characterized by magnetic susceptibility measurements down to liquid nitrogen temperature and also by electronic, infrared, electron spin resonance and Mössbauer spectra. All the metal(II) complexes appeared to be monomeric, high-spin, five-coordinate (square-pyramidal) (X = Cl− or OAc−), except for Ni(PCPH)Cl2 which is polymeric, high-spin, six-coordinate. Each ligand behaved as a tridentate NNN donor, via the pyridine nitrogen, azomethine nitrogen, and pyridine or quinoline nitrogen. One of the most active agents of this series, Cu(PCPH)Cl2, showed antitumour activity against a variety of transplanted tumours, including Sarcoma 180, Ehrlich carcinoma and L1210 leukaemia sensitive to α(N)-heterocyclic carboxaldehyde thiosemicarbazones. This agent caused inhibition of 3H-thymidine and 3H-uridine incorporation into DNA and RNA, respectively, of Sarcoma 180 ascites cells; protein biosynthesis was relatively insensitive to the action of this agent. 相似文献
13.
Denise Bohrer Vania Gabbi Polli Paulo Cícero do Nascimento Jean Karlo A. Mendonça Leandro Machado de Carvalho Solange Garcia Pomblum 《Journal of biological inorganic chemistry》2006,11(8):991-998
The interaction between aluminium and cysteine and cystine was evaluated by means of ion-exchange experiments and potentiometry. Ion-exchange experiments included other ligands with affinity for aluminium and two kinds of resins, either a Na+-form or an Al3+-form exchanger. The ability of the ligands to keep aluminium in solution in the presence of the Na+ exchanger or to withdraw it from the Al3+-form resin was evaluated. Aluminium quantification was carried out by either graphite-furnace or flame atomic absorption spectrometry. Aluminium extraction isotherms were linearised using the Scatchard plot, and stability constants were obtained from the curves’ slopes. The experiments showed that the ability of the ligands to withdraw aluminium from the Al3+-form resin increased following the order cysteine < oxalate < citrate = cystine < nitrilotriacetic acid < ethylenediaminetetraacetic acid. Potentiometric titrations, carried out in aqueous solution with constant ionic strength and temperature, showed that the predominant species in solution have a metal–ligand proportion of 1:1 for both amino acids. The main species are Al(OH)3L, with log K of 6.2 for cysteine, and AlL and Al(OH)L, with log K of 10.3 and 1.7, respectively, for cystine. Stability constants obtained from the Scatchard plots showed a linear correlation with the stability constants obtained by potentiometry for cystine and cysteine in this work and those collected from the literature for the other ligands. These results show that cysteine and cystine extract and maintain aluminium in solution, which may explain elevated concentrations of aluminium in parenteral nutrition solutions containing these amino acids.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at . 相似文献
14.
Phimphaka Harding David J. Harding Wasinee Phonsri Hirihattaya Phetmung 《Inorganica chimica acta》2009,362(1):78-2745
The reaction of [Ni(tmhd)2] and [Ni(dbm)2] with N-donor chelating ligands in dichloromethane and acetone, respectively, yields the complexes [Ni(tmhd)2(L-L)] (L-L = 2,2′-bpy 1, phen 2 and dmae 3) and [Ni(dbm)2(L-L)] (L-L = 2,2′-bpy 4, phen 5, dmae 6). UV-Vis spectroscopy shows very strong bands in the UV region consistent with ligand centred π → π∗ transitions. The electrochemical studies of 1-6 reveal oxidation to Ni(III). The [Ni(tmhd)2(L-L)] 1-3 are more easily oxidized by ca. 300 mV and are quasi-reversible whereas for the [Ni(dbm)2(L-L)] series only complex 6 shows significant reversibility. X-ray crystallographic studies have been conducted in the case of [Ni(dbm)2(phen)] 5 and [Ni(dbm)2(dmae)] 6. The structures both show that the nickel metal centre is octahedral with an O4N2 coordination environment. In the structures the β-diketonate ligands exhibit a cis-arrangement, with the metal displaced out of the planar chelate ring. 相似文献
15.
I-Ping Hsieh Hon Man Lee Jui-Hsien Huang Hong-I Lee Gene-Hsiang Lee 《Inorganica chimica acta》2006,359(2):497-504
The reactions of InCl3 with two and three equivalents of lithium (2-dimethylaminomethyl)pyrrolate (1) in diethyl ether solutions afford In[C4H3N(CH2NMe2)]2Cl (2) and In[C4H3N(CH2NMe2)]3 (3) in 92% and 50% yield, respectively. Subsequent reactions of 2 with MeLi and Li(CCPh) yield In[C4H3N(CH2NMe2)]2Me (4) and In[C4H3N(CH2NMe2)]2(CCPh) (5), respectively. All compounds were confirmed by 1H and 13C NMR spectroscopy and compounds 3, 4, and 5 were further characterized by single-crystal X-ray crystallography. Compounds 2, 3, and 4 showed moderate catalytic activity toward the ring-opening polymerization of ε-caprolactone. 相似文献
16.
The polymeric [PdCl(dithiocarbamate)]n complexes, in which the ligand ion is dimethyldithiocarbamate (DMDT), pyrrolidine dithiocarbamate (PyDT, (CH2)4NCS2−) and sarcosine ethyl ester dithiocarbamate (ESDT, EtO2CCH2N(CH3)CS2−), have been reacted with chelating diamines, like ethylenediamine (en) or 1,3-diaminopropane (dap) and long chain diamines, like 1,4-diaminobutane (dab) or 1,7-diaminoheptane (dah). The reaction products depend on either diamine chain length or molar ratio. By operating at PdCl(dithiocarbamate)/diamine molar ratio 1:1 chelating diamines yielded the ionic [Pd(dithiocarbamate)(diamine)]Cl species (diamine = en or dap), whereas with long chain diamines species of the type [Pd(dithiocarbamate)(diamine)]nCln (diamine = dab or dah) were obtained, in which each Pd(dithiocarbamate)+ unit binds to the NH2 group of two different molecules, in a network of bridging diamines. At molar ratio 1:0.5, the long chain diamines yielded the binuclear [Pd2Cl2(dithiocarbamate)2(diamine)] complexes (diamine = dab or dah), whereas exchange reactions take place generally in the presence of en or dap. The reaction trend is described on the basis of IR and proton NMR spectra. The new dithiocarbamate complexes were preliminarily tested for their cytotoxicity on human cancer cells. 相似文献
17.
《Journal of steroid biochemistry》1983,18(1):81-87
The α- and β-anomers of the 17β-d-glucuronide conjugate of ethynylestradiol were synthesized by the SnCl4-promoted reaction between β-acetoxy GAM and the t-17β-hydroxyl group of EE2-3-acetate. The conjugates were resolved by crystallization and HPLC. Positive identification was established by u.v. spectrophotometry, i.r. and mass spectrometry and 1H- and 134C-n.m.r. The structure of the β-anomer was confirmed by X-ray crystallographic analysis. In addition, the α-anomer was refractory to hydrolysis by bovine β-glucuronidase, establishing a biochemical difference between the conjugate pair. 相似文献
18.
Carolina Jullian Constanza Cifuentes Muriel Alfaro Sebastián Miranda Germán Barriga Claudio Olea-Azar 《Bioorganic & medicinal chemistry》2010,18(14):5025-5031
The inclusion complexes of Luteolin (LU) with cyclodextrins (CDs) including β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD) and dimethyl-β-cyclodextrin (DMβCD), Scheme 1, have been investigated using the method of steady-state fluorescence. The stoichiometric ratio of the three complexes was found to be 1:1 and the stability constants (K) were estimated from spectrofluorometric titrations, as well as the thermodynamic parameters. Maximum inclusion ability was obtained in the case of HPβCD followed by DMβCD and βCD. Moreover, 1H NMR and 2D NMR were carried out, revealing that LU has different form of inclusion which is in agreement with molecular modeling studies. These models confirm that when LU–βCD and LU–DMβCD complexes are formed, the B-ring is oriented toward the primary rim; however, for LU–HPβCD complex this ring is oriented toward the secondary rim. The ESR results showed that the antioxidant activity of luteolin was the order LU–HPβCD > LU–DMβCD > LU–βCD > LU, hence the LU-complexes behave are better antioxidants than luteolin free. 相似文献
19.
Stefan I. Pretorius Wilma J. Breytenbach Carmen de Kock Peter J. Smith David D. N’Da 《Bioorganic & medicinal chemistry》2013,21(1):269-277
The aim of this study was to synthesize a series of quinoline–pyrimidine hybrids and to evaluate their in vitro antimalarial activity as well as cytotoxicity. The hybrids were brought about in a two-step nucleophilic substitution process involving quinoline and pyrimidine moieties. They were screened alongside chloroquine (CQ), pyrimethamine (PM) and fixed combinations thereof against the D10 and Dd2 strains of Plasmodium falciparum. The cytotoxicity was determined against the mammalian Chinese Hamster Ovarian cell line. The compounds were all active against both strains. However, hybrid (21) featuring piperazine linker stood as the most active of all. It was found as potent as CQ and PM against the D10 strain, and possessed a moderately superior potency over CQ against the Dd2 strain (IC50: 0.157 vs 0.417 μM, ~threefold), and also displayed activity comparable to that of the equimolar fixed combination of CQ and PM against both strains. 相似文献
20.
《Inorganica chimica acta》1988,147(1):77-85
Polarographic half-wave potentials for two reduction steps of 49 cyclopentadienyliron complexes of substituted arenes or heterocycles in dimethylformamide were determined. A fast cyclic voltammetry (10–40 V/s) was used to study the electron transfer kinetics of some of these complexes. After correction for the double layer effects, the rate constants of all the complexes studied show that the transfer of electrons in the second reduction step occurs significantly faster than in the first one. This was interpreted as a result of greater delocalization of electrons in the 20-electron complexes of iron compared to the 19-electron complexes. 相似文献