首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Using ESR and IR spectroscopy, the structures of >Si(O–C·=O)(CH2–CH3) (1) and >Si(CH2–CH·–CH3)(CH2–CH3) (2) radicals were deciphered. The directions and kinetic parameters of reactions of intramolecular rearrangements in these radicals were determined. The reactions of hydrogen atom abstraction in radical (1) from the CH2 and CH3 groups were studied. It was found that the endothermic reaction of hydrogen atom abstraction from the methyl group occurs at a higher rate than the exothermic reaction with the methylene group. The differences are determined by changes in the size of a cyclic transition state. Based on the experimental data, the strengths of separate C–H bonds in surface fragments are compared. The rearrangement >Si(CH2–CH·–CH3)(CH2–CH3) >Si(C·(CH3)2)(CH2–CH3) was discovered and its mechanism was determined. One of its steps is the skeletal isomerization Si- (2)- . (1)Si- (1)- . (2). Experimental data are analyzed using the results of quantum-chemical calculations of model systems.  相似文献   

2.
3.
4.
The migration of the double bond in the allylcarboxamide ligands of (μ-H)Os3(μ-O=CN RCH2CH=CH2) (CO)10 (R=H (1) or CH3 (2)), (μ-D)Os3(μ-O=CNDCH2CH=CH2) (CO)10, and (μ-H)Os3(μ-O=CNHCD2CH=CH2)(CO)10 clusters was studied by1H,2H, and13C NMR spectroscopy. Neither μ-D nor ND groups in the deuterated complexes are directly involved in prototropic processes of allylic rearrangement. Initially, the deuterium atom of the CD2 group migrates to the ψ-carbon atom of the allyl fragment to form the −CD=CH-CH2D propenyl moiety, in which the deuterium and hydrogen atoms are gradually redistributed between the ψ-and β-carbon atoms. The triosmium cluster complexes containing the bridging carboxamide ligands O=CNRR' catalyze the allylic rearrangement ofN-allylacetamide. Based on the data obtained, the probable scheme of the allylic rearrangements in clusters1 and2 was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2182–2186, November, 1999.  相似文献   

5.
The stability of the complex (μ-H)Os3(μ-OCNMe2)(CO)9PPh2CH2CH=CH2 (1), which contains a free unsaturated functional group in the terminal ligand PPh2CH2CH=CH2, with respect to isomerization, chelation of the ligand, and other transformations in solutions was examined. No transformations of complex1 were observed in the course of synthesis from (μ-H)Os3(μ-OCNMe2)(CO)9NMe3 or upon heating in solution. Complex1 as well as complexes (μ-H)Os3(μ-OCNMe2)(CO)9PHPh2 and (μ-H)Os3(μ-OCNMe2)(CO)9PPh3, which were formed as admixtures, were isolated in the solid state and identified by1H,1H-{31P}, and1H-{1H} NMR, IR, and Raman spectroscopy and mass spectrometry. For Part 52, see Ref. 1. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1455–1460, August, 2000.  相似文献   

6.
Crystals of the complexes 2CuBr·C4H3(O)–CH=N–CH2–CH=CH2 (I) and CuBr·C6H5–CH=N–CH2–CH=CH2 (II) were obtained from an ethanol solution of CuBr2 and N-allyl-2-furylaldimine or N-allylbenzaldimine using the alternating current electrochemical procedure. Their crystal structures were determined (DARCH diffractometer, MoK radiation, 1001 (F 2 F) and 911 (F 6 F) reflections; R = 0.029 and 0.063, respectively, for I and II. , -Complex I crystallizes in space group A2/a, a = 13.698(6), b = 17.679(5), c = 10.247(4) , = 114.03(3)°, Z = 8. Crystal data for -complex II: space group P2 1 /a, a = 19.016(5), b = 13.876(2), c = 4.0272(9) , = 92.90(2)°, Z = 4. The structure of I involves separate - and -coordinations of copper(I) in the form of planar trigons similar to those in the analogous nonisostructural -complex with copper(I) chloride. The length of the coordinated C=C bond is 1.35(1) . The structure of II consists of infinite (CuBr) n chains -coordinated to the nitrogen atom of the ligand molecules. The noncoordinated allyl group is disordered.  相似文献   

7.
Compounds [Cu2(CH2FCOO)4· 2CH3CN](CH3CN) (I) and Ag3(CF3COO)3(CH3CN)2(II) were synthesized and studied by X-ray structural analysis. Crystals Iare monoclinic, space group C2/c, a= 27.854(6), b= 8.286(2), c= 19.428(4) Å, = 106.82(3)°, V= 4292(2) Å3, Z= 8, R 1= 0.0426; crystals IIare triclinic, space group , a= 8.676(2), b= 9.819(2), c= 11.961(2) Å, = 95.27(3), = 109.59(3)°, = 104.60(3)°, V= 911.4(3) Å3, Z= 2, R 1= 0.0252. Structure Iis composed of the structural units (lanterns) typical of copper(II) carboxylates. The presence of an additional acetonitrile molecule noncoordinated by the copper atoms makes it possible to consider compound Ias a lattice clathrate. Structure IIhas no analogs among the silver carboxylates. It simultaneously contains silver atoms with coordination numbers varying from 2 to 4.  相似文献   

8.
The coordination compounds [Cd(CH3COO-κO 1,O 2)2(phenanthroline-kN 1 N 2)(H2O)] · H2O (1) and [Cd{μ-(CH3CH2COO-κO 1,O 2)}2(phenanthroline-κN 1,N 2)]2 · 2CH3CH2COOH (2) were synthesized and characterized by elemental and thermal analysis and IR spectroscopy. Crystal and molecular structures of both compounds were determined. The complexes are air stable and fairly soluble in water. In both compounds the cadmium is seven-coordinate and contains chelating phenanthroline and two chelating carboxylate groups in the inner coordination sphere. The seventh coordinating oxygen belongs to water in 1 and to bridging carboxylate in 2. All carboxylate groups are bonded unsymmetrically to the central atom. The coordination polyhedra can be described as distorted pentagonal bipyramid (compound 1) and distorted capped tetragonal bipyramid (compound 2). In the structure of 1 intermolecular O(water)–H ··· O (water/carboxylate) hydrogen bonds create a two-dimensional net along the crystallographic a0c plane. Each molecule of 2 is connected to two propionic acid molecules via hydrogen bonds. In both compounds exist π-stacking interactions.  相似文献   

9.
林进  张萍  王昭煜  王宏根 《结构化学》1999,18(3):188-191
用X-射线晶体结构衍射法测定了[C5H4C(CH3)2CH2CH=CH2]Sm(OH)Cl·2MgCl2·4THF的晶体结构。它属三斜晶系,空间群为P^-1,a=10.773(2),b=12.836(3),c=15.478(3)A,a=111.46(3),β=107.71(3),γ=92.54(3)°,V=1868(1)A^3,Mr=827.91,Dx=1.472g/cm^3,μ=2.0006mm  相似文献   

10.
The 16-electron fragment (NP3)Rh+ inserts in a highly stereospecific manner across CH bonds from acetylene and 1-alkynes to give the octahedral cis-(alkynyl)hydrides [(NP3)Rh(H)(CCR)]BPh4 (R = H, Ph, COOEt). The structure of the cis-(ethynyl)hydride [(NP3)Rh(H)(CCH)]BPh4 · 1.5 THF has been established by X-ray diffraction. The trigonal bipyramidal rhodium(I) complex [(NP3)RhH], reacts with terminal alkynes to give H2 and the neutral σ-acetylides [(NP3)Rh(CCR)] (R = Ph, COOEt). These undergo metathesis between terminal alkynes and the σ-acetylide ligand through a mechanism involving consecutive breaking and making of CH bonds.  相似文献   

11.
The synthesis of 1,5-bis(2-dihydroxyphosphoryl-4-ethylphenoxy)-3-oxapentane [(HO)2(O)P(C6H3CH2CH3)(OCH2CH2)2O(C6H3CH2CH3)P(O)(OH)2] (H4K2) and single crystal X-ray diffraction study of H4K2 · 2H2O (I) are described. The crystals are orthorhombic, a = 33.291(4) Å, b = 8.9374(10) Å, c = 8.1021(9) Å, V = 2410.6(5) Å3, Z = 4, space group Cmc21, R = 0.0484 for 2566 reflections with I > 2σ(I). In I, the molecules of H4K2 are hydrogen-bonded to two crystallographically independent H2O molecules to give neutral conglomerates H4K2 · 2H2O. The electroanalytical characteristics of poly(vinyl chloride) membranes based on H4K2 were tested. Cu2+ and Zn2+ complexes with H4K2 and Er3+, Nd3+, and complexes with H4K2, 1,5-bis[2-(dihydroxyphosphoryl-4-methoxy)phenoxy]-3-oxapentane, 1,5-bis[2-(dihydroxyphosphinyl)phenoxy]-3-oxapentane, and 1,8-bis[2-(dihydroxyphosphinyl)phenoxy]-3,6-dioxaoctane were prepared.  相似文献   

12.
在密度泛函理论B3LYP/6-311++G(d,p)及MP2/6-311++G(d,p)水平上研究了单电子锂键复合物Y…Li—CH3[Y=CH3, CH2CH3, CH(CH3)2, C(CH3)3]的结构与性质. 结果表明, 三种单电子锂键复合物H3CH2C…Li—CH3(II), (H3C)2HC…Li—CH3(III)和(H3C)3C…Li—CH3(IV)单电子锂键强度依II(-26.7 kJ·mol-1)相似文献   

13.
用X-射线衍射法测定了[C5H4C(CH3)(C3H7)CH2CH= CH2]NdMg2(μ3-OH)(μ3-Cl)(μ2-Cl)3(THF)4Cl的晶体结构。它属三斜晶系,空间群为P1- ,a= 12.698(3), b= 13.616(3), c= 13.712(3), α= 68.91(3), β= 84.34(3), γ= 63.07(3)°, V= 1966(1)3, Mr= 849.74, Dx= 1.412 g·cm - 3, μ= 1.7297 m m - 1, F(000)= 840, Z= 2, R= 0.073, w R= 0.086(I≥3σ(I))。分子中Nd(Ⅲ)原子的配位数为八,形成一个严重扭曲的八面体结构。两个Mg 原子的配位情况相似,它们的配位数都是六,构成两个扭曲的八面体。这三个八面体通过三个共用平面联接  相似文献   

14.
The dirhenium(II) complexes [Re2(-X)3(triphos)2]O3SCF3 (X=Cl or Br) have been prepared by anion exchange reactions. These salts show well defined simple electron-transfer redox chemistry (two reversible one-electron oxidations and two one-electron reductions) but the [Re(-X)3Re] unit is remarkably stable to reactions with donor molecules such as monodentate tertiary phosphines which can often induce cleavage of M-X-M bridges. The crystallographic characterization of these two salts show that Re–Re bonds are not present, the Re...Re distances being 3.274(1) Å for X=Cl and 3.277(1) Å for X=Br.  相似文献   

15.
The heats of reaction of HMo(CO)3C5H5 with CX4 (X = Cl, Br) producing XMo(CO)3C5H5 have been measured by solution calorimetry and are −31.8±0.9 and −34.4±2.0 kcal/mole, respectively. The heats of reaction of NaMo(CO)3C5H5 with I2 and CH3I producing IMo(CO)3C5H5 and H3CMo(CO)3C5H5 are −32.3± 1.3 and −7.7± 0.3 kcal/mole. Oxidation with Br2CCl4 yielding Br3Mo(CO)2C5H5 was measured for the following complexes: (C5H5(CO)3Mo)2, (−92.0±1.0 kcal/mole), BrMo(CO)3C5H5 (−24.9± 2.0 kcal/mole) and HMo(CO)3C5H5 (−60.7± 2.0 kcal/mole). These and other data are used to calculate the Mo–X bond strength for X = H, Cl, Br, I, and CH3. These bond strength estimates are compared to those reported for X2Mo(C5H5)2. Iodination of H3CMo(CO)3C5H5, reported in the literature to yield CH3I and IMo(CO)3C5H5, actually produces CH3C(O)I and I3Mo(CO)2C5H5.  相似文献   

16.
The reaction of 1-phenacylimidazole with W(CO)6 in a 1:1 molar ratio under irra- diation with a high-pressure Hg lamp mainly yielded the title compound (C29H26N4O7W, Mr = 726.39), which is of orthorhombic, space group Pbca with a = 27.665(4), b = 7.7807(12), c = 27.803(4) (A), V = 5984.8(16) (A)3, Z = 8, Dc = 1.612 g/cm3, λ(MoKα) = 0.71073 (A), μ = .3.911 mm-1, F(000) = 2864, R = 0.0583 and wR = 0.1502 for 3356 observed reflections (I > 2σ(I)). The crystal structural analysis indicates that in the coordination geometry of tungsten, 1-phenacylimidazole acts as a monodentate ligand and two imidazole ligands locate in a cis-position.  相似文献   

17.
The reaction of Sn[CH(SiMe3)2]2 and ethyne at ambient temperature affords a mixture of products, from which the title compound has been separated and identified by IR, 1H, and 13C NMR spectroscopy.  相似文献   

18.
Complexes \(\rm[{Ph_{3}PR]_2^+[RuCl_6]^{2-}}\), where R = C2H5 (I), CH=CHCH3 (II), CH2CH=CHCH3 (III), and CH2OCH3 (IV), have been prepared by the reaction between ruthenium(III) chloride hydrate and triphenylorganylphosphonium chlorides in dimethylsulfoxide in the presence of hydrochloric acid. A hydrochloric acid solution of ruthenium(III) chloride hydrate when mixed with an aqueous solution of 2-butylene-1,4- bis(triphenylphosphonium dichloride) followed by recrystallization from dimethylsulfoxide results in complex \(\rm[{Ph_{3}PCH_2CH=CHCH_2{PPh_3}]_2^{2+}[Ru_2Cl_{10}O]^{4-}}\)· 4H2O (V). According to X-ray diffraction data, phosphorus atoms in mono- and binuclear cations have slightly distorted tetrahedral coordination (CPC 105.54(13)°?113.00(8)°, P?C 1.758(9)?1.839(7) Å). In slightly distorted octahedral anions [RuCl6]2? of complexes I–IV, the Ru?Cl bond lengths vary in the range 2.3222(6)?2.340(2) Å; the cis-ClRuCl and trans-ClRuCl angles are 89.133(18)°–90.867(18)° and 179.53(13)°–180°, respectively. In the binuclear [(RuCl5)2O]4? anion of complex V, RuCl5 fragments are bonded by a bridging oxygen atom. The Ru–Cl bond lengths fall in the range 2.3375(8)?2.3957(8) Å; the Ru–O bond length is 1.7832(2) Å. The cis-ClRuCl, trans-ClRuCl, cis-ORuCl, and trans-ORuCl angles are 86.67(3)°?91.28(3)°, 174.60(3)°?174.83(3)°, 91.49(2)°?93.65(2)°, and 178.39(2)°, respectively. In crystals I–V, interionic hydrogen bonds Cl···Hcation (2.63?2.95 Å), Cl··· \({\rm{H}_{{H_2}O}}\) (2.35?2.79 Å), and Hcation···\({\rm{O}_{{H_2}O}}\) (1.72?1.93 Å) (for V) are found.  相似文献   

19.
The reactions of mononuclear carbene complexes of W and Fe of the type CO)mMC(OR)(CH2nCHCR′″ (M  = FE, W; m = 4 and 5; n = 0, 2, 3; R′, R″ = C, CH3, OEt) with Fe(CO)5 have been studied. In all cases the reaction leads to new hetero (WFe) or homo (FeFe) μ-alkylidene complexes, the position of the double bond depending strongly on n.  相似文献   

20.
1 INTRODUCTION Recently, the researches on inorganic-organic hy-brid compounds represent an advanced field in mate-rial science[1]. At the molecular level, the combina-tion of two extremely different components providesan avenue to design new hybrid materials as well asthe ability to modulate properties of one or more ofthe components[2~6]. Some attractive properties, suchas efficient luminescence[2~4], ideal thermal and me-chanical stability, interesting magnetic[5], non-linearoptical[…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号