全文获取类型
收费全文 | 49篇 |
免费 | 0篇 |
专业分类
化学 | 45篇 |
数学 | 3篇 |
物理学 | 1篇 |
出版年
2020年 | 1篇 |
2016年 | 1篇 |
2012年 | 1篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有49条查询结果,搜索用时 15 毫秒
1.
N. V. Podberezskaya A. V. Virovets Yu. L. Slovokhotov Yu. T. Struchkov V. A. Maksakov V. P. Kirin V. A. Ershova 《Journal of Structural Chemistry》1990,31(6):943-950
Institute of Inorganic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 6, pp. 108–116, November–December, 1990. 相似文献
2.
This paper reports a theoretical investigation of the conformations of triosmium clusters with a chiral pinane ligand (μ-H)Os3(CO)10(μ-NHC10H17). The potential curves of internal rotation of the organic ligand relative to the N-C bond are plotted for the cluster complexes.
The structures of possible conformers are considered, and reasons for their stability are revealed. The barrier of rotation
around the N-C bond of the terpenoid is 186.6 kJ/mol for crystals and ∼140 kJ/mol for solutions. Due to this, the free rotation
of the ligand is hindered in both cases. The effects of the intra-and intermolecular interactions on the conformational state
of the cluster complex are analyzed.
Original Russian Text Copyright ? 2007 by V. A. Potemkin, V. A. Maksakov, and V. S. Korenev
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No. 2, pp. 230–235, March–April, 2007. 相似文献
3.
4.
5.
I. Yu. Prikhod’ko V. P. Kirin V. A. Maksakov A. V. Virovets A. V. Golovin 《Journal of Structural Chemistry》2008,49(4):719-723
The complex Ru4(μ4-S)(μ,η3-C3H5)2(CO)12 is prepared and examined by IR and NMR spectroscopy; its crystal structure is determined (an automatic Bruker-Nonius X8 Apex
four-circle diffractometer equipped with a 2-D CCD-detector, 100 K, graphite-monochromated molybdenum source, λ = 0.71073
?). The crystal belongs to the orthorhombic crystal system with unit cell parameters a = 19.3781(9) ?, b = 12.2898(7) ?, c = 10.1726(4) ?, V = 2422.6(2) ?3, space group Pnma, Z = 4, composition C18H10O12Ru4S, d
x = 2.343 g/cm3. The molecule of point symmetry C
1 is situated on the mirror plane of the space group Pnma, two carbonyl groups at Ru2 and Ru3 atoms overlapping with the allylic ligand with a weight of 50% so that carbon atoms coincide.
Thus, we have a racemic structure with two overlapping enantiomers of the molecule of Ru4(μ4-S)(μ,η3-C3H5)2(CO)12.
Original Russian Text Copyright ? 2008 by I. Yu. Prikhod’ko, V. P. Kirin, V. A. Maksakov, A. V. Virovets, and A. V. Golovin
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 748–752, May–June, 2008. 相似文献
6.
V. A. Maksakov N. V. Pervukhina N. V. Podberezskaya M. Yu. Afonin V. A. Potemkin V. P. Kirin 《Journal of Structural Chemistry》2008,49(5):894-900
The crystal structure of the Os3(μ,η2-O=CC6H5)(η3-C3H5)(CO)9 cluster synthesized by the reaction of the (μ-H)Os3(μ-O=CC6H5)(CO)10 complex with allylamine in chloroform was determined by X-ray analysis. Prolonged storage of the reaction mixture led to
N-C bond cleavage in allylamine and η3-addition of the allyl fragment at one of the Os atoms (Os-C 2.246 ?, 2.248 ?, and 2.273 ?). The unit cell parameters of the
complex are a = 9.494(1) ?, b = 10.479(1) ?, c = 12.474(2) ?, α = 84.55(1)°, β = 70.08(1)°, γ = 70.72(1)°, V = 1255.8(4), ?3, space group P
, Z = 2; C19H10O10Os3; d
calc = 2.922 g/cm3, 3085 I
hkl
> 2σ
I
of 3611 collected reflections; R = 0.0252. The structure of Os3(μ,η2-O=CC6H5)(η3-C3H5)(CO)9 is molecular. The plane of the Os3 triangle and the OsCOOs plane are connected according to the “butterfly” principle with an angle of 103.4° between them.
The Os-Os distances in the cluster core vary from 2.836(1) ? to 2.844(1) ?; the Os-Ccarb distances are 1.88(1)–1.97(1) ?; the distances to the atoms of the bridging ligands are Os-C 2.11(1) ?, Os-O 2.14(1) ?; the
O-C bridging bond is 1.24(1) ?. of the Os3(μ,η2-O=CC6H5)(η3-C3H5)(CO)9 triosmium cluster were studied theoretically. The potential curve of the internal rotation of the allyl ligand relative to
the Os(1)-C(9) bond was determined. The rotation barrier of the allyl ligand in crystal relative to the Os(1)-C(9) bond is
8.38 kJ/mol, and the rotation of the ligand is not hindered. The effects of the intra-and intermolecular interactions on the
conformation state of the cluster complex are considered.
Original Russian Text Copyright ? 2008 by V. A. Maksakov, N. V. Pervukhina, N. V. Podberezskaya, M. Yu. Afonin, V. A. Potemkin,
and V. P. Kirin
__________
Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 5, pp. 926–932, September–October, 2008. 相似文献
7.
The reactions of cluster (-H)Os3(CO)10(-OH) with ethyl and isopropyl esters ofl-oxyproline were studied. In the presence of Me3NO intermediate complex (-H)Os3(CO)9(-OH)L (L — isopropyl ester ofl-oxyproline) is formed, which slowly converts to the more stable cluster (-H)Os3(CO)9
. Cluster complexes containing chelate-bridging heterocycles were also obtained by heating (-H)Os3(CO)10(-OH) with esters ofl-oxyproline. In both cases, only one of the possible diastereomeric complexes (-H)Os3(CO)9
(R = Et, Pri) is formed, which indicates that the reactions are stereospecific. Based on analysis of Dreiding's models, an attempt to determine the absolute configuration of the obtained clusters was made.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2021–2025, October, 1995. 相似文献
8.
S. N. Konchenko A. V. Virovets V. A. Varnek S. V. Tkachev N. V. Podberezskaya V. A. Maksakov 《Journal of Structural Chemistry》1996,37(2):295-304
The cluster anion [Fe3(μ3-Se)(CO)9]2- (I) was isolated as a salt (Et4N)2[I] by the reaction of Fe(CO)5 with Na2Se in isopropanol. The protonated form, (μ-H)2Fe3(μ3-Se)(CO)9 (II), was obtained by acidifying the reaction mixture and used for the synthesis of the heterometallic cluster FeMo2(μ3-Se)(CO)7Cp2 (III), CP=η5-C5H5. The structure of I and III was established by X-ray diffraction analysis. Crystals I are monoclinic, a=14.210(3), b=11.547(3), c=19.831(2), Å, β=90.92(2)°, Vcell=3254(1) Å3, space group P2/c, Z=4, dcalc=1.550 g/cm3, Syntex P21, λCuKα, R(F)=0.1333 for 1264 Fhkl>6σ(Fhkl). Crystals III are monoclinic, a=20.440(5), b=12.771(3), c=16.342(4) Å, β=113.80(2)°, Vcell=3903(2) Å3, space group P21/c, Z=8, dcalc=2.222 g/cm3, Syntex P21, λCuKα, R(F)=0.0734 for 1116 Fhkl>4σ(Fhkl). The structure of II was inferred from the Mössbauer, IR, and1H and77Se NMR spectroscopy data. 相似文献
9.
V. P. Kirin I. Yu. Prikhod’ko V. A. Maksakov A. V. Virovets A. M. Agafontsev B. A. Golovin 《Russian Chemical Bulletin》2009,58(7):1371-1382
The reactions of Ru3(CO)12 with oximes of α-substituted caran-4-one, lemonen-5- and pinan-3-one derivatives were studied. The reactions at elevated
temperatures yield binu-clear complexes Ru2(CO)4L2, with two ruthenium atoms bridging two terpenoid ligands (L) through the oxime groups and coordinated additionally to a nitrogen
or sulfur atom of the NR2 or SR groups respectively. The reactions carried out at room temperature in the presense of Me3NO yield trinuclear complexes Ru3(CO)8L2 with analogous coordination of the terpenoid ligands. In a solution at room temperature these clusters readily transform
to binuclear complexes. The NMR spectroscopy shows the stereochemical nonrigidity of the complexes with the S-CH2-Ph fragment: at room temperature in a solution the benzyl radical undergoes slow rotation about the S-C bond and a change
of the conformation of carane and pinane carbocycles occurs more rapidly. The reactions with pinane and carane derivatives
are stereospecific yielding only one of the possible diastereoisomers. More flexible limonene derivative form both diastereoisomers. 相似文献
10.
Mathematical Notes - In the paper, the notion of an $$\mathfrak F^{\omega}$$ -abnormal (and $$\mathfrak F^{\omega}$$ -normal) maximal subgroup of a finite group is introduced, where $$\mathfrak F$$... 相似文献