共查询到20条相似文献,搜索用时 15 毫秒
1.
Phase diagrams of 3-component lipid bilayer mixtures containing cholesterol reveal major differences among the different types of lipids. Here we report that mixtures of cholesterol together with POPC and a high-melting temperature PC or sphingomyelin show different phase behavior from similar mixtures that contain DOPC or di-phytanoyl-PC instead of POPC. In particular, only one region of macroscopic phase coexistence occurs with POPC, a region of coexisting liquid disordered and solid phases, {Lα + Lβ}. Fluorescence microscopy imaging is useful for these studies, but is subject to artifactual light-induced domain formation, as reported by Ayuyan and Cohen [A.G. Ayuyan, F.S. Cohen, Lipid peroxides promote large rafts: Effects of excitation of probes in fluorescence microscopy and electrochemical reactions during vesicle formation, Biophys. J. 91 (2006) 2172-2183.]. This artifact can be attenuated by decreased illumination and low dye concentration. The use of the free radical scavenger n-propyl gallate can reduce the artifact, but this molecule enters the bilayer and itself perturbs the phase behavior. We suggest that the light-induced domain separation artifact might actually arise from pre-existing lipid clusters that are induced to coalesce, and therefore indicates highly nonrandom mixing of the lipid components. 相似文献
2.
Aims
Cyclooxygenase 2 (COX-2) with the resulting prostaglandin E2 (PGE2) is linked to increased risk of human breast cancer (BC). The aim of this study was to determine COX-2 169C > G and 8473T > C gene polymorphisms and PGE2 level at various stages of BC clarifying the role of COX-2 gene polymorphism and PGE2 in relation to BC.Methods
The study population comprised 160 women at different stages of BC and 150 gender- and age-matched healthy control subjects. Plasma PGE2 was measured by ELISA, the COX-2 gene polymorphisms were determined using PCR-RFLP.Results
The variant alleles COX-2 169G and 8473C were significantly associated with BC susceptibility [OR = 3.1, 95% CI (2.2–4.4), P < 0.001 for 169C>G and OR = 1.74, 95%CI (1.3–2.4), P = 0.005 for 8473C]. However, both COX-2 gene polymorphisms were not associated with breast cancer stage. Plasma PGE2 levels were significantly increased in patients compared to the controls. In early and late stages of BC, there was a significant increase in the plasma PGE2 levels towards the presence of homozygous GG compared with homozygous CC (P < 0.001) for 169 C>G, also towards the presence of CC than TT (P < 0.001) for 8473T>C SNP.Conclusion
The 169C>G and 8473T>C polymorphisms of the COX-2 gene were associated with the BC in Egyptian women. Furthermore, individuals with COX-2 169GG and 8473CC genotypes showed significant increase in plasma PGE2 levels. PGE2 levels may serve as a predictor of poor prognosis in patients with BC. 相似文献3.
Reactions in water between the di-sodium salt of amino terepthalic acid (C8H3NO4Na2) and a lanthanide chloride lead to a family of 3D-coordination polymers with general chemical formula [Ln(C8H3NO4)(C8H4NO4), O]∞ where Ln = La-Eu (except Pm) and 8 ? n ? 11. All these compounds are isostructural. High quality single crystals of [Ln(C8H3NO4)(C8H4NO4), nH2O]∞ with Ln = La-Sm (except Pm) and 8 ? n ? 11 have been obtained by slow diffusion in agar-agar gels. The crystal structure has been solved for the Nd-containing compound. This compound crystallizes in the cubic system, space group Ia-3 (no. 206) with a = 26.8056(5) Å. The crystal structure can be described as the juxtaposition of large channels with square cross-section.The channels are filled by highly disordered crystallization water molecules. The dehydration of the compounds by freeze-drying is possible and most of the crystallization water molecules can be removed without destruction of the molecular skeleton. The partially dehydrated compounds have general chemical formula [Ln(abdc)(Habdc), 2H2O]∞ with Ln = La-Eu except Pm. The porosity of the Nd-containing compound has been estimated by computational methods to 2170 m2 g−1. This dehydrated compound reversibly binds water when exposed to wet atmosphere restoring the initial hydrated phase. 相似文献
4.
The title complexes, [M(Diap)2(OAc)2] · H2O (M = Zn,Cd; Diap = 1,3-diazepane-2-thione; OAc = acetate) with an MO2S2 configuration, have been characterized by X-ray crystallography as well as FT-IR, 1H and 13C NMR spectroscopy. In these complexes, the metal atoms lie in a pseudo-tetrahedral environment and are coordinated by the thione sulfur atoms of two neutral 1,3-diazepane-2-thione ligands and one oxygen atom from each of two monodentate acetate anions. In both complexes, there are two intramolecular N-H?O hydrogen bonds, each being between one NH group of a Diap ligand and the uncoordinated O atom of an OAc ligand. The water molecule is also involved in hydrogen bonds, as an acceptor and as a donor twice, linking together three symmetry-related complexes. The Cd complex undergoes a structural phase transition from a monoclinic form at 150 K with Z′ = 2 to a smaller monoclinic cell at room temperature with Z′ = 1 without loss of crystallinity. The Zn complex does not exhibit an equivalent phase transition, and at 150 K is isostructural with the room-temperature form of the Cd complex. All three crystallographically independent molecules found for the Cd complex (two at low temperature and one at room temperature) have essentially the same structure except for small changes in the conformations of the ligands. Tetrahedral coordination with monodentate carboxylate ligands is common for Zn complexes of this kind, but is unusual for Cd complexes, and is the result of the bulky Diap ligands. 相似文献
5.
T.D. Noakes J.P. Dugas L.R. Dugas R. Tucker J. Oksa J. Dunn B.S. van der Merwe J.A. Dirker K. Porvari J. Smolander 《Journal of thermal biology》2009
- 1.
- We report body temperature responses in a single individual to 3 swims of 1000 m or longer in ice-cold water (0–3 °C) during which he swam the normal crawl stroke with his face in the water whilst wearing only a swimming costume, swimming cap and goggles. 相似文献
6.
Mariagiuseppina Pellegrini Barbara Manconi Alessandra Olianas Maria Teresa Sanna Claudia Meloni Monica Pirastru Paolo Mereu Giovanni Leoni Bruno Masala Laura Manca 《Biochimica et Biophysica Acta (BBA)/General Subjects》2011
Background
HbF-Monserrato-Sassari is a newly discovered abnormal fetal hemoglobin observed in an apparently normal newborn baby during a hemoglobinopathies survey at birth in North Sardinian population.Methods
Electrophoretic analysis of the cord blood lysate evidenced for an abnormal tetramer due to a mutated fetal globin chain. Electrospray ionisation-mass spectrometry and gene sequencing were used to identify the mutation. Oxygen binding ability of the variant Hb was determined.Results
Sequencing of the γ globin genes revealed the TGT → CGT transition at codon 93 in one of the two Gγ genes, which leads to the Arg for Cys amino acid replacement at position 9 of the F α-helix. The amino acid substitution was confirmed by mass spectrometric analysis of the globin chains. Since modifications or substitutions at position β93 are known to affect the arrangement of a salt bridge at the α1β2 sliding contacts that are crucial for subunit cooperativity, the functional properties of the variant were studied to evaluate the effect of the replacement at the same position in the γ globin chain. With respect to normal HbF, the variant showed a significant increase in oxygen affinity and a slight decrease of both Bohr effect and cooperativity.General significance
Result indicates a key role of the Cys γ93 residue for subunit cooperativity in the T → R transition of the HbF tetramer. Substitutions at the F9 position of the Gγ globin may result in stabilization of the high affinity R-state of the Hb tetramer. Because of the loss of Cys γ93 residue, this variant is considered to be potentially compromised in nitric oxide transport. 相似文献7.
Takayoshi Tagami Masayuki Okuyama Hiroyuki Nakai Young-Min Kim Haruhide Mori Kazunori Taguchi Birte Svensson Atsuo Kimura 《Biochimica et Biophysica Acta - Proteins and Proteomics》2013,1834(1):329-335
Glycoside hydrolase family 31 α-glucosidases (31AGs) show various specificities for maltooligosaccharides according to chain length. Aspergillus niger α-glucosidase (ANG) is specific for short-chain substrates with the highest kcat/Km for maltotriose, while sugar beet α-glucosidase (SBG) prefers long-chain substrates and soluble starch. Multiple sequence alignment of 31AGs indicated a high degree of diversity at the long loop (N-loop), which forms one wall of the active pocket. Mutations of Phe236 in the N-loop of SBG (F236A/S) decreased kcat/Km values for substrates longer than maltose. Providing a phenylalanine residue at a similar position in ANG (T228F) altered the kcat/Km values for maltooligosaccharides compared with wild-type ANG, i.e., the mutant enzyme showed the highest kcat/Km value for maltotetraose. Subsite affinity analysis indicated that modification of subsite affinities at + 2 and + 3 caused alterations of substrate specificity in the mutant enzymes. These results indicated that the aromatic residue in the N-loop contributes to determining the chain-length specificity of 31AGs. 相似文献
8.
Water soluble (1 → 3)-β-d-glucan oligosaccharides were prepared by hydrolyzing curdlan with α-amylase. The hydrolysis process was monitored by the DE values of the hydrolysates. Under the optimized conditions (pH, 5.98; temperature, 55.92 °C; α-amylase amount, 31.94 mg α-amylase/500 mL of reaction mixture containing 5 g curdlan; reaction time, 30 min), maximum DE value (15.62%) was obtained. The resulting products were composed of (1 → 3)-β-d-glucan oligosaccharides of DP 2-9. The hydrolysates were filtered, concentrated to ∼20% (w/v), and precipitated with 5 volumes of ethanol, which were then freeze dried to yield a water soluble powder. The (1 → 3)-β-d-glucan oligosaccharides content of the product and the yield were 97.7% and 97.6% (w/w), respectively. 相似文献
9.
Many epidemiological studies have indicated that interleukin-1α (IL-1α) − 899 (+ 4845) C→T polymorphism increases the risk of chronic periodontitis (CP), whereas some studies have reported opposite results. Accordingly, the aim of this meta-analysis is to investigate the association of the IL-1α − 899 (+ 4845) C→T polymorphism with CP. We searched the PubMed database up to May 1, 2013 and finally obtained 23 case–control studies. After data extraction, we performed meta-analysis using Comprehensive Meta-Analysis v2.2 software. The overall result based on the fixed-effect model showed that IL-1α − 899 (+ 4845) C→T polymorphism was significantly associated with increased risk of CP: [odds ratio (OR) = 1.29, 95% confidence interval (CI) = 1.15–1.44, p < 0.001] for T vs. C; (OR = 1.59, 95%CI = 1.22–2.07, p = 0.0005) for TT vs. CC; (OR = 1.30, 95% CI = 1.12–1.51, p = 0.0004) for CT vs. CC; and (OR = 1.40, 95% CI = 1.21–1.61, p < 0.001) for (CT+TT) vs. CC; (OR = 1.47, 95% CI = 1.16–1.87, p = 0.002) for TT vs. (CT+CC). Stratified analyses revealed that there was a significantly increased risk for Caucasians and Asians. In conclusion, current evidence showed that IL-1α − 899 (+ 4845) C→T polymorphism probably increased the risk of CP. 相似文献
10.
Current knowledge about the abundance, growth, and primary production of the seagrass Cymodocea nodosa (Ucria) Ascherson is biased towards shallow (depth <3 m) meadows although this species also forms extensive meadows at larger depths along the coastlines. The biomass and primary production of a C. nodosa meadow located at a depth of 8–11 m was estimated at the time of maximum annual vegetative development (summer) using reconstruction techniques, and compared with those available from shallow meadows of this species. A depth-referenced data base of values at the time of maximum annual development was compiled to that end. The vegetative development of C. nodosa at 8–11 m depth was not different from that achieved by shallow (depth <3 m) meadows of this species. Only shoot density, which decreased from 1637 to 605 shoots m−2, and the annual rate of elongation of the horizontal rhizome, which increased from 23 to 71 cm apex−1 year−1, were different as depth increased from <3 to 8–11 m. Depth was a poor predictor of the vegetative development and primary production of C. nodosa. The biomass of rhizomes and roots decreased with depth (g DW m−2 = 480 (±53, S.E.) − 32 (±15, S.E.) depth (in m); R2 = 0.12, F = 4.65, d.f. = 35, P = 0.0381) which made total biomass of the meadow to show a trend of decrease with depth but the variance of biomass data explained by depth was low. The annual rate of elongation of the horizontal rhizome showed a significant positive relationship with depth (cm apex−1 year−1 = 18 (±5.1, S.E.) + 5.0 (±1.33, S.E.) depth (in m); R2 = 0.50, F = 14.07, d.f. = 14, P = 0.0021). As shoot size and growth did not change significantly with depth, the reduction of shoot density should drive any changes of biomass and productivity of C. nodosa as depth increases. The processes by which this reduction of C. nodosa abundance with depth occur remain to be elucidated. 相似文献
11.
Two isostructural photoluminescent metal-organic coordination polymers, namely, [M(H-mpypdc)(Cl)(H2O)3]n (mpypdc = 2,6-dimethyl-4-(pyridin-4-yl)pyridine-3,5-dicarboxylate; M = Co (2) and Ni (3)), were synthesized from H2mpypdc (1), and characterized by single crystal X-ray analyses. New ligand 1 is an inner salt. In the metal-organic coordination polymeric chains, two distinct S- and R-atropisomeric units are generated from the axially prochiral 1 through C-H?X (X = O, Cl) hydrogen bonds. There have interesting 2D supramolecular networks [M(Cl)(H2O)2]n in the crystal structures of title compounds. The photoluminescence of new compounds are also investigated in solid state at ambient temperature. 相似文献
12.
PPARβ mRNA expression,reduced by n − 3 PUFA diet in mammary tumor,controls breast cancer cell growth
Ramez Wannous Emeline Bon Karine Mahéo Caroline Goupille Julie Chamouton Philippe Bougnoux Sébastien Roger Pierre Besson Stephan Chevalier 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2013,1831(11):1618-1625
The effect of numerous anticancer drugs on breast cancer cell lines and rodent mammary tumors can be enhanced by a treatment with long-chain n − 3 polyunsaturated fatty acids (n − 3 PUFA) such as docosahexaenoic acid (DHA, 22:6n − 3) which is a natural ligand of peroxisome proliferator-activated receptors (PPAR). In order to identify the PPAR regulating breast cancer cell growth, we tested the impact of siRNA, selected to suppress PPARα, PPARβ or PPARγ mRNA in MDA-MB-231 and MCF-7 breast cancer cell lines. The siPPARβ was the most effective to inhibit breast cancer cell growth in both cell lines. Using PPARα, PPARβ and PPARγ pharmacological antagonists, we showed that PPARβ regulated DHA-induced inhibition of growth in MDA-MB-231 and MCF-7 cells. In addition, the expressions of all 3 PPAR mRNA were co-regulated in both cell lines, upon treatments with siRNA or PPAR antagonists. PPAR mRNA expression was also examined in the NitrosoMethylUrea (NMU)-induced rat mammary tumor model. The expressions of PPARα and PPARβ mRNAs were correlated in the control group but not in the n − 3 PUFA group in which the expression of PPARβ mRNA was reduced. Although PPARα expression was also increased in the n − 3 PUFA-enriched diet group under docetaxel treatment, it is only the expression of PPARβ mRNA that correlated with the regression of mammary tumors: those that most regressed displayed the lowest PPARβ mRNA expression. Altogether, these data identify PPARβ as an important player capable of modulating other PPAR mRNA expressions, under DHA diet, for inhibiting breast cancer cell growth and mammary tumor growth. 相似文献
13.
A mixed ligand and dimeric CuII complex [(phen)2Cu(μ-L)Cu(phen)2]L · 12.5H2O (H2L = succinic acid) containing bridging succinate moiety and also non-coordinated succinate dianion was prepared from polymeric Cu(II) succinate by nucleophilic reaction with o-phenanthroline (phen) followed by depolymerization. The dimeric product was characterized by crystallographic, spectroscopic and thermoanalytical studies. The complex crystallizes in triclinic crystal system and is composed of succinate bridged [(phen)2Cu(μ-L)Cu(phen)2]2+ complex cations, non-coordinated succinate anions and hydrogen bonded water molecules. Within the dimeric cationic unit, each of the Cu atoms is octahedrally coordinated by four N atoms of both phen ligands and both O atoms of a carboxylate moiety of the bridging succinate group in chelating form. Through intermolecular π-π stacking interactions, the complex cations form positively charged 2-D layers, between which the non-coordinating succinate anions and water molecules are sandwiched. Both the electronic and EPR studies indicate that the dimeric complex undergoes partial dissociation in solution state to exist in two structural forms. The kinetic and thermodynamic parameters involved in three stage thermal decompositions of the dimeric complex could also be evaluated using Coats-Redfern method. 相似文献
14.
A one-dimensional polymeric-chain iron(II)-nickel(II) cyanido-bridged complex of the composition {[Fe(abpt)2(μ-Ni(CN)4)]·0.5H2O}n (1·0.5H2O), where abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4-triazole, was prepared and characterized by elemental and thermal analyses, FTIR and 57Fe Mössbauer spectroscopies, and magnetic measurements. The incomplete spin crossover phenomenon was observed with approximately 12% of the frozen high-spin fraction at low temperatures and with the spin transition critical temperature above room temperature. 相似文献
15.
The title complexes were obtained as MIIM′II species [(bpy)2M(μ-abpy)M′(bpy)2](PF6)4, M,M′ = Ru or Os, using the new mononuclear precursor [(bpy)2Os(abpy)](PF6)2 for the osmium-containing dinuclear complexes. One-electron reduction produces radical complexes [(bpy)2M(μ-abpy)M′(bpy)2]3+ and [(bpy)2M(abpy)]+ with significant contributions from the metals, as evident from the EPR effects on successive replacement of ruthenium by osmium with its much higher spin-orbit coupling constant. The diruthenium and diosmium radical complexes were also studied by EPR at high-frequency (285 GHz), the latter shows an unusually large g anisotropy g1 − g3 = 0.25 in frozen solution. Further reduction was monitored by UV/Vis spectroelectrochemistry. Oxidation produced OsIII EPR signals for [(bpy)2Os(abpy)]3+ and [(bpy)2Os(μ-abpy)Ru(bpy)2]5+, indicating a RuIIOsIII species for the latter. The diosmium(III,II) and diruthenium(III,II) mixed-valent species remained EPR silent at 4 K, however, they exhibit weak inter-valence charge transfer (IVCT) bands at about 1460 nm. Whereas the cyclic voltammetric response towards reduction is only marginally different for the three dinuclear complexes, successive replacement of ruthenium by osmium causes the first oxidation potential to decrease. The much higher comproportionation constant Kc for the mixed valent diosmium(III,II) state (Kc > 1015) in comparison to the diruthenium(III,II) analogue with Kc = 1010 confirms the electron transfer alternative for the valence exchange mechanism, in contrast to the hole transfer established for analogous dinuclear complexes with the formally related diacylhydrazido(2−) bridging ligands. 相似文献
16.
Barbara Manconi Maria Cristina De Rosa Maria Pia Cappabianca Alessandra Olianas Cristiana Carelli Alinovi Fabrizio Mastropietro Donatella Ponzini Antonio Amato Mariagiuseppina Pellegrini 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Haemoglobin Roma [β115(G17)Ala → Val] is a new adult haemoglobin variant found in a patient presenting a mild hypochromia and microcytosis. We studied this previously uncharacterised variant in order to evaluate the effect on the structural and funcional properties of the Ala → Val substitution at the α1β1 interface.Methods and results
The variant chain was identified by direct DNA sequencing of the β-globin gene, which revealed a GCC → GTC mutation in codon 115. This mutation was confirmed by mass spectrometric analysis of the tetramers and peptides. The oxygen-binding properties of the haemoglobin A/haemoglobin Roma mixture, in which the variant makes up 25% of the haemoglobins, showed a significant increase in oxygen affinity with respect to normal haemoglobin A, both in the absence and presence of 2,3-bisphosphoglycerate. The role of the βG17 position, situated at the α1β1 interface, has been examined using computational models of haemoglobin Roma and other known βG17 variants, in comparison with normal haemoglobin A.Conclusions
This study suggests that the β115(G17)Ala → Val substitution at the α1β1 interface is responsible for increased oxygen affinity and mild destabilisation of the haemoglobin Roma.General significance
An amino acid substitution at the G17 position of the α1β1 interface may result in stabilisation of the high affinity R-state of the haemoglobin molecule. 相似文献17.
Rajagopal N. Aravalli M. Behnan Sahin Clifford J. Steer 《Biochemical and biophysical research communications》2010,391(1):56-62
Liver-derived progenitor cells (LDPCs) are recently identified novel stem/progenitor cells from healthy, unmanipulated adult rat livers. They are distinct from other known liver stem/progenitor cells such as the oval cells. In this study, we have generated a LDPC cell line RA1 by overexpressing the simian virus 40 (SV40) large T antigen (TAg) in primary LDPCs. This cell line was propagated continuously for 55 passages in culture, after which it became senescent. Interestingly, following transformation with SV40 TAg, LDPCs decreased in size significantly and the propagating cells measured 1 μm in diameter. RA1 cells proliferated in vitro with a doubling time of 5-7 days, and expressed cell surface markers of LDPCs. In this report, we describe the characterization of this novel progenitor cell line that might serve as a valuable model to study liver cell functions and stem cell origin of liver cancers. 相似文献
18.
Anika Heiss 《Experimental cell research》2009,315(12):2115-2125
δ-Opioid receptor (DOR) agonists possess cytoprotective properties, an effect associated with activation of the “pro-survival” kinase Akt. Here we delineate the signal transduction pathway by which opioids induce Akt activation in neuroblastoma × glioma (NG108-15) hybrid cells. Exposure of the cells to both [D-Pen2,5]enkephalin and etorphine resulted in a time- and dose-dependent increase in Akt activity, as measured by means of an activation-specific antibody recognizing phosphoserine-473. DOR-mediated Akt signaling is blocked by the opioid antagonist naloxone and involves inhibitory Gi/o proteins, because pre-treatment with pertussis toxin, but not over-expression of the Gq/11 scavengers EBP50 and GRK2-K220R, prevented this effect. Further studies with Wortmannin and LY294002 revealed that phophoinositol-3-kinase (PI3K) plays a central role in opioid-induced Akt activation. Opioids stimulate Akt activity through transactivation of receptor tyrosine kinases (RTK), because pre-treatment of the cells with inhibitors for neurotrophin receptor tyrosine kinases (AG879) and the insulin-like growth factor receptor IGF-1 (AG1024), but not over-expression of the Gβγ scavenger phosducin, abolished this effect. Activated Akt translocates to the nuclear membrane, where it promotes GSK3 phosphorylation and prevents caspase-3 cleavage, two key events mediating inhibition of cell apoptosis and enhancement of cell survival. Taken together, these results demonstrate that in NG108-15 hybrid cells DOR agonists possess cytoprotective properties mediated by activation of the RTK/PI3K/Akt signaling pathway. 相似文献
19.
《Inorganica chimica acta》2006,359(7):2309-2313
Deprotonated 3-(2-fluorophenyl)-1-(4-acetylphenyl)triazene reacts with Hg(CH3COO)2 in tetrahydrofuran to give light yellow crystals of [HgII(RPhNNNPhR′)2]n (R = acetyl, R′ = F). The new polymeric triazenide complex of Hg(II) belongs to the monoclinic space group C2/c. The lattice of [HgII(RPhNNNPhR′)2]n can be viewed as a bidimensional assembly of planar tectons [HgII(RPhNNNPhR′)2], occurring through metallocene alike Hg(II)-η2,η2-arene π-interactions along the crystallographic axis b and non classical C-H?O bonding along the axis a. 相似文献
20.
Konrad Herbst Emma Söderhjelm Ebbe Nordlander Michael Brorson 《Inorganica chimica acta》2007,360(8):2697-2703
The versatility of cuboidal Mo3S4Co clusters for the preparation of complexes with different numbers of valence shell electrons (VSE) in the cluster is described. The reaction of the geometrically incomplete cuboidal cluster salt [(η5-Cp′)3Mo3S4][pts] (pts = p-toluenesulfonate) with one molar equivalent of [Co2(CO)8] afforded almost quantitatively the electroneutral 60 VSE cluster [(η5-Cp′)3Mo3S4Co(CO)] (1), which previously has been prepared in low yield by Curtis et al. in autoclave syntheses [M.D. Curtis, U. Riaz, O.J. Curnow, J.W. Kampf, Organometallics 14 (1995) 5337]. Cluster 1 was also obtained in high yield by reaction of [(η5-Cp′)3Mo3S4][pts] with [(η5-Cp∗)Co(CO)2]. Reaction of [(η5-Cp′)3Mo3S4][pts] with two molar equivalents of [Co(I)(CO)3(PPh3)] led to a complex mixture of products, of which the electron deficient 58 VSE cluster salt [(η5-Cp′)3Mo3S4Co(I)][Co(I)3(thf)] ([2][Co(I)3(thf)]) was isolated as single crystals. In the crystal structures of 1 and [2][Co(I)3(thf)], the Co-Mo bond lengths are almost identical, indicating a delocalization of the electron deficiency in [2]+. The reduced form of [2]+, [(η5-Cp′)3Mo3S4Co(I)] (2), was prepared by oxidative substitution of the carbonyl ligand in 1 by I2. Further reactions of 1 with PPh3 and NO leading to the 60 and 61 VSE cluster complexes [(η5-Cp′)3Mo3S4Co(PPh3)] (3) and [(η5-Cp′)3Mo3S4Co(NO)] (4), respectively, enabled the preparation of Mo3S4Co clusters in altogether four different oxidation states. 相似文献