974 resultados para Alkenone, C37:3 C37:2
Resumo:
Through the reaction of Co-2(CO)(8) with four thiuram [R2NC(S)S](2), four new sulfur-capped trinuclear cobalt carbonyl clusters Co-3 (CO)(7) (mu(3)-S) (mu, eta(2)-S* C* NR2) ( I : R = Me; I : R = Et; II : R = i-Pr; IV : NR= -N [GRAPHICS] were prepared and characterized by elementary analysis, IR,H-1 NMR and MS spectroscopy. The crystal structure of the cluster Co-3(CO)(7)(mu(3)-S)[mu, eta(2)-S*C*N (i-Pr)(2)]( III) was determined by X-ray single crystal diffraction method. The crystal of m is monoclinic, belonging to space group P2(1)/n, and the cell parameters are as follows: a = 1, 145 2(2) nm, b = 1. 502 8(3) nm, c = 1, 214 4(2) nmj alpha = 90 degrees, beta = 92, 15(3)degrees, gamma = 90 degrees; V = 2. 088 5(7) nm(3) , Z = 4, F (000) = 1 096, D-c = 1. 747 mg . m(-3), mu = 2. 588 mm(-1), R=0. 040 7, R-w=0. 062 4, The structural analysis shows that cluster II has a pyrimidal Co3S framework and contains a heterocylic bridging bidentate ligand [mu, eta(2)-S* C* N (i-Pr)(2)] linked to the Co2 and Co3 atoms of the cluster by a cobalt-carbon and a cobalt-sulfur bond respectively.
Resumo:
A manganese molybdenum phosphate, (NH3CH2CH2NH3)(10)(H3O)(3)(H5O)Na-2[MnMo12O24(OH)(6) (PO4)(4)(PO3OH)(4)][MnMo12O24 (OH)(6)(PO4)(6)(PO3OH)(2)]. 9H(2)O, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The structure of this compound may be considered to be two [Mo6O12(OH)(3)(PO4)(2)(HPO4)(2)](7-) units bonded together by a manganese atom, although several P-O groups are not protonated on account of coordination to a Na+ cation. One-dimensional tunnels were formed in the solid. A probe reaction of the oxidation of acetaldehyde with H2O2 using this compound as catalyst was carried out in a liquid-solid system, showing that the manganese molybdenum phosphate has high catalytic activity in the reaction.
Resumo:
A nickel molybdenum phosphate, (NH3CH2CH2NH3)(4).(NH3CH2CH2NH2). Na .[Ni2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]. 6H(2)O, invoicing molybdenum present in V oxidation, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a = 12,011(2), b = 14,612(3), c = 21.252(4) Angstrom, alpha = 80.54(2)degrees, beta = 83.10(2)degrees, gamma = 76.29(2)degrees, V = 3561.4(12) Angstrom(3), Z = 2, lambda(MoK alpha) = 0.71073 Angstrom (R(F) = 0.0529 for 9880 reflections), Data mere collected on a Siemens P4 diffractometer at 20 degrees C in the range of 1.75 degrees < theta < 23.02 degrees using the omega-scan technique. The structure was solved by direct methods using the program SHELXTL-93 and refined with the method of fun-matrix least-squares on F-2. The structure of the title compound may be considered to be two [Mo6O15(HPO4)(H2PO4)(3)](5-) units bonded together with a nickel atom, although several P-O groups are not protonated on account of coordination with a Na+ cation, The one-dimensional tunnels were formed in the solid of the title compound. A probe reaction of the oxidation of acetaldehyde with H2O2 using the title compound as catalyst was carried out in a liquid- solid system, showing that the title compound had high catalytic activity in the reaction, (C) 1999 Academic Press.
Resumo:
通过测定 4 5Ca2 +摄取初速度的变化研究了La3+和Gd3+对鼠肝癌H 3 5细胞Ca2 +内流的影响 .发现低浓度La3+和Gd3+能增加肝癌H 3 5细胞Ca2 +内流初速度达 6~ 10倍 .Ca2 +内流的初速度随Ca2 +浓度变化的动力学研究表明 ,肝癌H 3 5细胞中存在 2类Ca2 +亲和部位的通道 ,即高亲和位和低亲和位Ca2 +内流通道 ,而La3+和Gd3+刺激的肝癌H 3 5细胞则只有 1类Ca2 +亲和位通道 ,La3+和Gd3+增加高亲和位Ca2 +结合通道的Km和Vmax,而对于低亲和位的Ca2 +结合通道Ca2 +内流的作用是竞争性的.
Resumo:
研究了金属离子Ca2+和Tb3+对长白山白眉蝮蛇蛇毒磷脂酶A2(phospholipase A2)荧光光谱的作用,发现Ca2+浓度的增加能够增强磷脂酶A2的荧光发射强度.而且Ca2+ 浓度的增大能够明显加快磷脂酶A2与其相应反应底物DPPC的反应速率.稀土离子Tb3+在低浓度条件下对磷脂酶A2起荧光淬灭作用, 而在浓度较高时能够提高磷脂酶A2荧光发射强度.
Resumo:
Lutetium(III) and lanthanum(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP), 3',5'-cyclic deoxyadenosine monophosphate (dcAMP) and 2',3'-cyclic adenosine monophosphate (2',3'-cAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. 2',3'-cAMP is converted to 3'-AMP and 2'-AMP, the ratio of 3'-AMP to 2'-AMP produced being 1.4.
Resumo:
The crystal structure of the title compound, bis[tris(2,2'-bipyridyl-N,N')nickel(II)] cyclo-tetravanadate undecahydrate, contains a centrosymmetric [V4O12](4-) anion, which has an eight-membered ring structure formed by four VO4 tetrahedra sharing vertices, and two complex cations containing octahedrally-coordinated Ni-II ions. The anion and coordinated Ni-II ions are isolated and make up anion and cation layers, respectively. The Ni-N distances range from 2.077(3) to 2.112(2)Angstrom and the V-O distances range from 1.621(2) to 1.803(2)Angstrom.
Resumo:
The reaction of anhydrous PrCl3 with Na(C9H7) in 1.2 mole ratio in THF gives [(C9H7)(2)PrCl(THF)](2)1. 1 crystallized in monoclinic system, space group P2(1)/c with a = 7.808(2), b = 17.796(6), c = 14.070(4) Angstrom, beta = 93.97(2)degrees, V= 1950.3(9) Angstrom(3), Dcalcd = 1.63 g/cm(3) and Z = 2. Each Pr ion is surrounded by two indenyl, two Cl and one THF in a roughly trigonal bipyramid arrangement with average Pr-C(ring) and Pr-Cl distances of 2.81 and 2.84 Angstrom. The reaction of LaCl3 with Na(C9H7) in 1:3 mole ratio gives (C9H7)(3)LaTHF 2, which crystallizes in the monoclinic space group P2(1)/a with unit cell constants a = 21.871(8), b = 10.585(3), c = 23.652(7) Angstrom,beta = 114.62(2)degrees, V = 4977.9 Angstrom(3) and Z = 8. (C) 1997 Elsevier Science S.A.
Resumo:
[La(OH2)(5)(phen)(2)]Cl-3 4H(2)O.phen is centric, Pnna, with a = 19.946(7), b = 16.458(5), c = 12.207(4)Angstrom and D-calc = 1.57 g cm(-3) for Z = 4. The La(III) ion resides on a crystallographic twofold axis and is coordinated to four nitrogen atoms (fr
Resumo:
对具d-f和f-f两种跃迁形式的Eu~(2+)和具d-f跃迁特征的Ce~(3+),讨论了它们在ABF_3(A=K~(+),Ba~(2+);B=Li~(+),Mg~(2+),Ca~(2+))中的光谱特征。根据Eu~(2+)、Ce~(3+)在KCaF_3基质中的能级关系,实现了在复合氟化物中Ce~(3+)对Eu~(2+)能量传递,探讨了能量传递机理,并计算了传递量子效率。
Resumo:
本文讨论了BaYF_5中Eu~(2+)和Ce~(3+)的光谱特征及浓度对光谱的影响。Eu~(2+)和Ce~(3+)均表现为d—f跃迁的特征激发和发射。由于Eu~(2+)—Eu~(2+),Ce~(3+)—Ce~(3+)能量迁移的存在,两者猝灭浓度偏低,其猝灭机理为偶极-偶极相互作用。根据BaYF_5基质中Eu~(2+)和Ce~(3+)的能级关系,发现Ce~(3+)对Eu~(2+)的发射具有明显的敏化作用。其机理主要为非辐射多极子作用,但也存在辐射传递。
Resumo:
The solid-state structures of a series of seven substituted 3-methylidene-1H-indol-2(3H)-one derivatives have been determined by single-crystal X-ray diffraction and are compared in detail. Six of the structures {(3Z)-3-(1H-pyrrol-2- ylmethylidene)-1H-indol-2(3H)-one, C13H10N2O, (2a); (3Z)-3-( 2-thienylmethylidene)-1H-indol-2(3H)-one, C13H9NOS, (2b); (3E)-3-(2-furylmethylidene)-1H-indol-2(3H)-one monohydrate, C13H9NO2 center dot H2O, (3a); 3-(1-methylethylidene)-1H-indol- 2(3H)-one, C11H11NO, (4a); 3-cyclohexylidene-1H-indol- 2(3H)-one, C14H15NO, (4c); and spiro[1,3-dioxane-2,3'-indolin]- 2'-one, C11H11NO3, (5)} display, as expected, intermolecular hydrogen bonding (N-H center dot center dot center dot O=C) between the 1H-indol-2(3H)-one units. However, methyl 3-(1-methylethylidene)- 2-oxo-2,3-dihydro-1H-indole-1-carboxylate, C13H13NO3, (4b), a carbamate analogue of (4a) lacking an N-H bond, displays no intermolecular hydrogen bonding. The structure of (4a) contains three molecules in the asymmetric unit, while (4b) and (4c) both contain two independent molecules.
Resumo:
The X-ray crystal structures of two crystalline forms of 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine, C10H7Cl3N4 (code name BW1003C87) (I) and (II), have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are centrosymmetric, with structure (I) in the triclinic space group P (1) over bar unit cell a = 6.4870(10), b = 9.216(2), c = 12.016(2) angstrom, alpha = 75.78(3)degrees, beta = 89.95(3)degrees, gamma = 83.45(3)degrees, V = 691.5(2) angstrom(3), Z = 2 and density (calculated) = 1.544 Mg/m(3); and (II) in the monoclinic space group P2(1)/c, unit cell a = 12.000(2), b = 7.518(2), c = 13.450(3) angstrom, beta = 97.87(3)degrees, V = 1202.0(5) angstrom(3), Z = 4, Density (calculated) = 1.600 Mg/m(3). Structure (I) includes a solvated CH3OH in the lattice. Final R indices [I > 2sigma(I)] are R1 = 0.0427, wR2 = 0.1075 for (I) and R1 = 0.0487, wR2 = 0.1222 for (II). R indices (all data) are R1 = 0.0470, wR2 = 0.1118 for (I) and R1 = 0.0623, wR2 = 0.1299 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. Both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW1003C87), the subject of the present study, are anticonvulsant as well as neuroprotective in models of brain ischaemia and in a model of white matter ischaemia. BW1003C87 is a sodium channel blocker which also reduces the release of the neurotransmitter glutamate. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this drug family and their biological activities.
Resumo:
The Heck arylation of 2-methylprop-2-en- I -ol in ionic liquids and organic solvents is reported using a range of homogeneous and heterogeneous palladium catalysts. Higher activity is observed in the ionic liquid media compared with N-methyl pyrrolidinone and under solventless conditions. The ionic liquid-catalyst system may be recycled easily with little loss in activity, although significant palladium leaching from the heterogeneous catalyst was observed. In the case of Trans-bis(2,3-dihydro-3-methylbenzothiazole-2-ylidene)diiodopalladium (11) reported to be highly active for this transformation, significant induction petiods were observed indicating that nanoparticles may be responsible for the catalysis. Using the ionic liquid Heck reaction, a recyclable synthesis for the fragrance beta-Lilial((R)) has been developed. (c) 2004 Elsevier B.V. All rights reserved.
Resumo:
The new ammonium iodomercurates(II), (NH4)(7)[HgI4](2)[Hg2I7](H2O) (1) and (NH4)(3)[Hg2I7] (2) contain isolated tetrahedra and vertex-sharing double tetrahedra as the anions. The crystal structures were determined from single-crystal X-ray diffraction data: 1: orthorhombic, Pnma (no. 62), a = 2175.9(2), b = 1781.8(2), c = 1256.2(2) pm, Z = 4. R-1 [I-0 > 2 sigma(I-0)] = 0.0520; 2: monoclinic, P2(1)/c (no. 14), a = 1259.0(2), b = 773.2(1), c = 2172.4(3) pm, beta = 101.18(2)degrees, Z = 4, R, [I-0 > 2 sigma(I-0)] = 0.0308.