Intramolecular Rearrangements of >Si(O–C·=O)(CH2–CH3) and >Si(CH2–CH·–CH3)(CH2–CH3) Radicals

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.     

反常蓝移单电子锂键Y…Li-CH3[Y=CH3, CH2CH3, CH(CH3)2, C(CH3)3]体系的结构与性质

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   

Hydrothermal Synthesis,Crystal Structure and Thermal Stability Properties of the Complex [Cd2(phen)2(C14HuO3)4(CH3CH2OH)]·(CH3OH)·(H2O)

T A dinuclear cadmium complex[Cd2(phen)2(C14H11O3)4(CH3CH2OH)]·(CH3OH)·(H2O)has been synthesized with benzilic acid and 1,10-phenanthroline by hydrothermal method.The crystal structure was determined bv X-ray diffraction with crystal parameters as follows:triclinic system with space group P-1,α=1.21298(10),b=1.32586(1 1),c=2.4815(2)nm,α=76.2630(10),β=81.4500(10),γ=69.1700(10)°V=3.6143(5)nm3,Dc=1.438g/cm3,Z=1,F(000)=1600,the final GOOF=0.937,R=0.0521 and wR=0.1328.In the title complex,the dinuclear structure is defined by carboxyl oxygen atoms adopting a monodentate bridged coordination mode.The coordination environment of Cd(Ⅱ)ion is CdO4N2,giving a distorted octahedral coordination geometry.TG analysis shows that the title complex is stable under 140℃.     

Synthesis and Structure of Acetonitrile Solvates of Copper(II) Monofluoroacetate and Silver(I) Trifluoroacetate, [Cu2(CH2FCOO)4· 2CH3CN](CH3CN) and Ag3(CF3COO)3(CH3CN)2

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) ų, 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) ų, 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.     

Synthesis and Crystal Structure of (CH2)3(3, 5-Me2Pz)2·[PhBr2Sn(CH2)SnBr2Ph]·2HBr·2H2O (Pz = pyrazole)

The reaction of bis(dibromophenylstannyl)methane with 1, 3-bis(3, 5-dimethyl- pyrazol-1-yl)propane in a 1:1 or 1:2 ratio yields only 1:1 adduct which partly hydrolyzes to the title complex (C26H38Br6N4O2Sn2, Mr = 1155.42) during crystal growing. The title complex is of triclinic, space group P ī with a = 10.886(1), b = 12.508(1), c = 13.879(1) ?, α = 85.762(2), β = 85.159(2), γ = 84.020(2)°, V = 1868.8(4) ?3, Z = 2, Dc = 2.046 g/cm3, λ(MoKα) = 0.71073 ?, μ = 7.778 mm-1, F(000) = 1088, R = 0.0488 and wR = 0.1157 for 7560 observed reflections with I ≥ 2σ(I). The crystal structure analysis indicates that there is no direct interaction between the ligand and bis(dibromophenylstannyl)methane, and two tin atoms are bridged by two bromide atoms from the partial hydrolysis of this adduct.     

Synthesis, crystal structure, magnetic property and thermal studies of [Ni(CH(3)COO)2·(NH2CH2Ph)4

[Ni(CH(3)COO)(2)·(NH(2)CH(2)Ph)(4)] complex was synthesized using benzylamine and nickel acetate. The molecular structure of this complex was obtained by single crystal X-ray diffraction and characterized by elemental analysis, IR spectrometry and thermal analysis. The complex crystallized in the monoclinic space group P2(1)/n with cell parameters a=11.234(4)?, b=6.459(2)?, c=22.647(8)?, α=90.00, β=91.149(4)°, γ=90.00, V=1642.8(10)?(3), Z=2. The structure has been solved by direct methods and refined to R(1)=0.0876 for 6377 observed reflections I>2σ(I). Magnetic studies for complex show the data over the whole temperature range 5-300 K are well fitted to the Curie-Weiss law with C=1.03 cm(3) K mol(-1) and θ=-1.38 K. This fitting indicates antiferromagnetic interaction between the Ni ions and the metal center exhibits distorted octahedral coordination geometries. The thermal analysis was carried out to understand the thermal stability of the title complex.     

配合物[Ni(IDB)2]2·(SO4)2·3CH3CH2OH·CH3OH·5H2O的合成、晶体结构及其荧光光谱的研究

标题配合物是由三齿配体Ⅳ,Ⅳ-二(2-苯并咪唑甲基)亚胺(IDB)与NiSO4·6H2O在甲醇-乙醇溶液中反应得到的紫色 晶体.X射线衍射测定了其单晶结构.结构分析表明,镍(Ⅱ)分别与两个IDB配体中的苯并咪唑的四个氮和胺基的两个 氮配位形成畸变的八面体构型.研究了纳米金和小牛胸腺DNA对配合物荧光的影响,探讨了配合物的荧光猝灭与恢复 的可能机理.     

[C5H4C(CH3)2CH2CH=CH2]Sm(OH)Cl·2MgCl2·4THF的晶体结构分析

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     

Structure, IR and Mössbauer spectra, and magnetic properties of [Fe2CoO(CH3COO)6(3-CI-Py)3]· 1/4· 3-Cl-Py· 1/4(CH3)2CO· 1/2H2O

The structure of the hetemnuclear iron acetate [Fe₂CoO(CH₃COO)₆(3-Cl-Py)₃]·1/4· 3-Cl-y× 1/4(CH₃)₂CO· 1/2H₂O was determined by X-ray structure analysis. The crystal has a molecular structure and is monoclinic with lattice parameters a = 21.034(4). b = 8.398(2), c = 23.360(5) Å, β= 98.28(3)?, R = 0.0656. space group P2₁/c. The trinuclear complex [Fe₂CoO(CH₃COO)₆(H₂O)₃] has a structure typical for iron(III) μ₃-O compounds with iron atoms hing at the vertices of the equilateral triangle centered by an oxygen atom. The metal atoms are each coordinated to four oxygen atoms of the four bridging carboxy groups, the bridging oxygen atom (μ₃-O), and the coordinated 3-chloropyridine molecule which is trans relative to the latter atom. According to Mössbauer spectroscopy data, the iron(III) ions are in the high-spin state. The value of (μ_ef)_mole/μ₃ at room temperature and its temperature dependence suggest that the resulting magnetic exchange interaction between the paramagnetic centers of the cluster is antiferromagnetic.     

A cobalt molybdenum phosphate with a tunnel: Hydrothermal synthesisand structure of (NH3CH2CH2NH3)4·(NH3CH2CH2NH2)·Na·[Co2Mo12O30(PO4)(HPO4)4(H2PO4)3]·5H2O

Transition Metal Chemistry -     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.     

Synthesis,characterization, and crystal structure of a 2-D metal diphosphonate: Cu3(H2O)2[HO3PCH2N(CH3)CH2PO3]2 · 2H2O

Hydrothermal reaction of N-methyl-iminobis(methylenephosphonic acid), CH₃N(CH₂PO₃H₂)₂, (H₄L) with copper(II) acetate afforded a new layered Cu(II) amino diphosphonate, Cu₃(H₂O)₂(HL)₂?·?2H₂O (1). Compound 1 was studied by IR spectroscopy, TGA/DTA data, and X-ray diffraction (XRD) techniques. The XRD patterns are the same for the hydrated and the dehydrated complexes. A single-crystal X-ray crystallographic determination reveals copper in two different coordination environments. Cu1 has a distorted elongated tetragonal octahedral geometry, whereas Cu2 has a square-pyramidal distorted geometry. The HL trianion is a pentadentate ligand with a deprotonated nitrogen atom and two oxygen atoms of each phosphonate binding to copper. Hydrogen bonds between lattice water molecules in interlayer spaces and the non-coordinated phosphonate oxygen atoms as well as water ligands leads to a 3-D supramolecular network structure.     

Chlorine reaction with platinum triamine [Pt(N,N-DimeTm)PyCl3]Cl (N,N-DimeTm = (CH3)2N(CH2)3NH2). Crystal structure of [Pt(N,N-DimeTm)Cl2], [Pt(N,N-DimeTm(Py)Cl3]Cl · H2O and [Pt{(CH3)2N(CH2)2C(O)NH}(Py)Cl3]

Treatment of platinum(II) diamine [Pt(N,N-DimeTm)Cl₂] (I) with pyridine gave tetramine [Pt(N,N-DimeTm)Py₂]Cl₂ (II); by oxidation with chlorine this was converted to Pt(IV) triamine, [Pt“(N,N-DimeTm(Py)Cl₃]Cl (III) with a six-membered chelate ring. According to X-ray diffraction data, the reaction of complex II with chlorine is accompanied by removal of the pyridine molecule from the trans-position to the NH₂ group of N,N-dimethyltrimethylenediamine. The reaction of complex III with chlorine at 20°C afforded a mixture of compounds (IV) and the complex [Pt“(CH₃)₂N(CH₂)₂C(O)NH”(Py)Cl₃] (V) with an amidate six-membered metal ring, dimethylpropioamide, which was also isolated upon refluxing a mixture of IV in an aqueous solution. The UV/Vis and IR spectra of the obtained complexes were studied, and X-ray diffraction analysis of I, III, and V was performed. The crystals of I are triclinic, space group P $ \bar 1 $ ; a = 7.6526(4) Å, b = 11.5571(6) Å, c = 12.4432(7) Å, α = 113.85(1)°, β = 96.54(2)°, γ = 106.78(2)°; Z = 4; R _hkl = 0.051. The crystals of III are monoclinic, space group C2/c; a = 36.715(2) Å, b = 7.8179(4) Å, c = 29.721(16) Å, β = 127.80(1)°; Z = 16; R _hkl = 0.036. The crystals of V are monoclinic, space group P2₁/n; a = 7.0398(6) Å, b = 27.458(2) Å, c = 7.687(6) Å, β = 106.270(1)°; Z = 4; R _hkl = 0.052.     

Tin(IV) complexes with 2-hydroxybenz-(2-hydroxynaphth)aldehyde picolinoylhydrazones (H2Ps, H2Pnf). Crystal structure of [SnCl3(Ps · H)] · CH3OH and [SnCl3(Pnf · H)] · CH3OH

The reactions of SnCl₄ with picolinoylhydrazones of 2-hydroxybenz-(2-hydroxynaphth)aldehydes (H₂Ps, H₂Pnf) in CH₃OH gave non-electrolyte complexes [SnCl₃(Ps · H)] · CH₃OH (I) and [SnCl₃(Pnf · H)] · CH₃OH (II). The imide form of the ligand coordinated to Sn(IV) through the azomethine nitrogen atom and oxyazine and oxy oxygen atoms was proved by UV/Vis, IR, and ¹H NMR spectroscopy. The negative charge on the coordination unit thus arising is counterbalanced by the positive charge caused by the protonation of ligands at the pyridine nitrogen atom of the heterocycle. It was shown that dehydrochlorination of the complexes affords tin-containing species, which correlates with the presence of the corresponding peaks [SnCl₂(Ps)]⁺ and [SnCl₂(Pnf)]⁺ in their mass spectra. The molecular and crystal structures of complexes I and II were determined by X-ray diffraction.     

Ab initio study of Eu3+–L (L=H2O,H2S,NH2CH3, S(CH3)2, imidazole) complexes

The ground states and binding energies of Eu³⁺–L (L=H₂O,H₂S,NH₂CH₃,S(CH₃)₂, imidazole) complexes has been determined using ab initio techniques. The binding is mostly electrostatic as expected. The empty f orbital is different for the S compounds, being a π-like orbital, while for the O and N containing ligands it is a σ-like orbital. However, the range in the binding energies for the different f holes is small.     

Reaction of chlorine with platinum(IV) triamine containing N,N-dimethylethylenediamine. The crystal structure of [Pt{(CH3)2N(CH2)2NH2}PyCl3]Cl·H2O[Pt{(CH3)2N(CH2)2NCl}PyCl3], and [Pt{(CH3)2N(CH2)2NH2}PyCl4]

The Platinum(II) diamine with N,N-dimethylethylenediamine (N,N-dimeEn) [Pt{(CH₃)₂N(CH₂)₂NH₂}Cl₂] (I) was synthesized. The reaction of the diamine with pyridine gave Pt(II) tetramine [Pt{(CH₃)₂N(CH₂)₂NH₂}Py₂]Cl₂ (II), which was oxidized with chlorine to give Pt(IV) triamine Pt{[(CH₃)₂N(CH₂)₂}PyCl₃]Cl · H₂O (III). The reaction of III with chlorine (chloroamidation) yielded chloroimide [Pt{(CH₃)₂N(CH₂)₂NCl}PyCl₃] (IV). The IR spectra of complexes I–IV and UV/Vis spectra of III and IV were studied. X-Ray diffraction analysis was performed for III (monoclinic crystals, space group P2₁/c, a = 7.7437(6), b = 8.1100(7), c = 28.52992(2) Å, β = 93.7280(10)°, Z = 4, R _hkl = 0.0420) and IV (orthorhombic crystals, space group Pna2₁, a = 15.7825(12), b = 7.4447(6), c = 12.3099(6) Å, Z = 4, R _hkl = 0.0539). During oxidation of Pt(II) tetramine with chlorine, the pyridine molecule is removed from the cis position relative to the (CH₃)₂N group (trans position relative to the NH₂ group) of N,N-dimethylethylenediamine. The reaction of chloroimide complex IV with concentrated HCl (dechloroamidation) at 20°C afforded the initial complex III; that at 100°C, gave triamine III together with Pt(IV) diamine [Pt(N,N-dimeEn)Cl₄] (V) (monoclinic crystals, space group P2₁/n, a = 7.1278(5), b = 11.5384(8), c = 12.7501(9) Å, β = 93.23(10)°, Z = 4, R _hkl = 0.0239).     

Synthesis and Crystallographic Characterization of Complex [(CH3)3NCH2CH2N(CH3)3][HgI4]·H2O Containing Novel Cation

The title compound has been synthesized by the reaction of HgI2 and [(CH3)3- NCH2CH2N(CH3)3]I2 with pH = 7.5 at room temperature, and its crystal structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in monoclinic system, space group P21/c with a = 8.3075(8), b =15.8084(19), c =15.390(2)(°A), β = 95.192(4)o, V = 2012.9(4)(°A)3, Z = 2, Dc = 2.824 g/cm3, F(000) = 1502, C14H39N4O2Hg2I8, Mr = 1711.87, μ(MoKα) = 13.768 mm-1, the final R = 0.0465 and wR = 0.1293 for 3046 observed reflections with I > 2(I). The title compound consists of cations ([C8H22N2]2+) and anion (HgI42-), which are combined by static attracting forces to form the so-called organic-inorganic hybrid material.     

The distonic ion ·CH2CH2CH+OH,keto ion CH3CH2CH=O +·, enol ion CH3CH=CHOH+·, and related C3H6O+· radical cations. Stabilities and isomerization proclivities studied by dissociation and neutralization-reionization

Metastable ion decompositions, collision-activated dissociation (CAD), and neutralization-reionization mass spectrometry are utilized to study the unimolecular chemistry of distonic ion ^·CH₂CH₂CH^?OH (2^+·) and its enol-keto tautomers CH₃CH=CHOH^?· (1 ^+·) and CH₃CH₂CH=O ^+· (3^+·). The major fragmentation of metastable 1^+·–3^+· is H^· loss to yield the propanoyl cation, CH₃CH₂C≡O⁺. This reaction remains dominant upon collisional activation, although now some isomeric CH₂=CH-CH⁺ OH is coproduced from all three precursors. The CAD and neutralization-reionization (⁺NR⁺) spectra of keto ion 3 ^+· are substantially different from those of tautomers 2^+· and 1^+·. Hence, 3^+· without sufficient energy for decomposition (i. e. , “stable” 3^+·) does not isomerize to the ther-modynamically more stable ions 2^+· or 1^+·, and the 1,4-H rearrangement H-CH₂CH₂CH=O^+·(3 ^+·) → CH₂CH₂CH⁺ O-H (2 ^+·) must require an appreciable critical energy. Although the fragment ion abundances in the ⁺ NR ⁺ (and CAD) spectra of 1 ^+· and 2 ^+· are similar, the relative and absolute intensities of the survivor ions (recovered C₃H₆O^+· ions in the ⁺NR⁺ spectra) are markedly distinct and independent of the internal energy of 1 ^+· and 2 ^+·. Furthermore, 1 ^+· and 2 ^+· show different MI spectra. Based on these data, distonic ion 2 ^+· does not spontaneously rearrange to enol ion 1 ^+· (which is the most stable C₃H₆O^+· of CCCO connectivity) and, therefore, is separated from it by an appreciable barrier. In contrast, the molecular ions of cyclopropanol (4 ^+·) and allyl alcohol (5 ^+·) isomerize readily to 2 ^+·, via ring opening and 1,2-H^? shift, respectively. The sample found to generate the purest 2 ^+· is α-hydroxy-γ-butyrolactone. Several other precursors that would yield 2 ^+· by a least-motion reaction cogenerate detectable quantities of enol ion 1 ^+·, or the enol ion of acetone (CH₂=C(CH₃)OH^+·, 6 ^+·), or methyl vinyl ether ion (CH₃OCH=CH ₂ ^+· , 7 ^+·). Ion 6 ^+· is coproduced from samples that contain the —CH₂—CH(OH)—CH₂— substructure, whereas 7 ^+· is coproduced from compounds with methoxy substituents. Compared to CAD, metastable ion characteristics combined with neutralization-reionization allow for a superior differentiation of the ions studied.     

二维配位聚合物(NH3+CH2CH2NH3+)(NH2CH2CH2NH3+)2[(VO)4(PO4)4(H2O)2]·2H2O的水热合成及晶体结构

无机-有机杂化钒氧酸盐由于其结构的多样性以及在催化、医药、光、电、磁等材料领域中的应用前景而受到人们的广泛关注。近年来这一研究领域的重大进步是将有机氮配体或者过渡金属配合物直接连接到矾氧骨架上以获得各种新奇结构。合成出许多属于L/V/O、MXLY/V/O、L/P/V/O和MXLY