Electronic structure of the two-leg spin ladder (C5H12N)2CuBr4

A density functional theory study of the two-leg spin ladder (C(5)H(12)N)(2)CuBr(4) reveals antiferromagnetic interactions through the rungs and legs, although the latter are significantly smaller. Our work suggests interest in manipulating the physical behavior of this prototypical system by doping or chemical modifications.     

Copper(I) Complexes with N-Allylquinolinium Bromide [C9H7N(C3H5)]CuBr2 and [C9H7N(C3H5)]Cu2Br3: Synthesis and Crystal Structure

Crystals of [₉₇N(₃₅)]uBr₂ (IV) and [₉₇N(₃₅)][u₂Br₃] (V) were prepared by ac electrochemical synthesis from uBr₂, N-allylquinolinium bromide, on copper electrodes in the ethanol–benzene medium. X-ray diffraction study has shown that crystals IV and V are monoclinic: space group A2₁/a, a = 13.776(3) Å, b = 14.304(3) Å, c = 13.147(2) Å, = 107.90(1) Å, V = 2465(2) ų, Z = 8 for IV and space group P2₁/n, a = 13.881(2) Å, b = 15.446(2) Å, c = 7.111(1) Å, = 104.64(1)°, V = 1475.0(8) ų, Z = 4 for V. Structures IV and V are built of the N-allylquinolinium cations and different anions i.e., (CuBr₂) ^n- _n forming infinite chains in IV and peculiar {[Cu^I ₄Br₆]^2–} _n arranged in polymeric chains in V. In the latter case, two independent metal atoms have trigonal–pyramidal and trigonal–planar environments. In the structures of both compounds, the C=C bond of the allyl group is not involved in coordination with the Cu(I) atom.     

吡嗪桥连异三核配合物的合成及晶体结构

Ag(Ⅰ)配合物的几何构型多变,最常见的是配位数为2的线性构型和配位数为4的四面体构型。前者如Ag(NH_3)_2~+及Ag(CN)_2,后者如[Ag(SC(CH_3)NH_2)_4]Cl、[(Ph_3)Ag(Cl)]和[(Ph_3MeP)_3Ag(BH_4]等。配位数为4的平面四方构型却罕见,只在当有一定刚性的四氮杂环十四烷和Ag(Ⅰ)生成配合物时才是平面四方构型。 本文报道一种新型异三核含银配合物的合成及其晶体结构,其中Ag是平面四方构型。     

Unimolecular reactions of the isolated immonium ions CH3CH = NH+C4H9, CH3CH2Ch = NH+C4H9 and (CH3)2C = NH+C4H9

The reactions of ten metastable immonium ions of general structure R¹R²C?NH⁺C₄H₉ (R¹ = H, R² = CH₃, C₂H₅; R¹ = R² = CH₃) are reported and discussed. Elimination of C₄H₈ is usually the dominant fragmentation pathway. This process gives rise to a Gaussian metastable peak; it is interpreted in terms of a mechanism involving ion-neutral complexes containing incipient butyl) cations. Metastable immonium ions ontaining an isobutyl group are unique in undergoing a minor amount of imine (R¹R²C?NH) loss. This decomposition route, which also produces a Gaussian metastable peak, decreases in importance as the basicity of the imine increases. The correlation between imine loss and the presence of an isobutyl group is rationalized by the rearrangement of the appropriate ion-neutral complexes in which there are isobutyl cations to the isomeric complexes containing the thermodynamically more stable tert-butyl cations. A sizeable amount of a third reaction, expulsion of C₃H₆, is observed for metastable n-C₄H₉ ⁺NH?CR¹R² ions; in contrast to C₄H₈ and R¹R²C?NH loss, C₃H₆ elimination occurs with a large kinetic energy release (40–48 kJ mol^?1) and is evidenced by a dish-topped metastable peak. This process is explained using a two-step mechanism involving a 1,5-hydride shift, followed by cleavage of the resultant secondary open-chain cations, CH₃CH⁺ CH₂CH₂NHCHR¹R².     

(C_5H_9C_5H_4)_3NdBrLi(THF)_3和(C_5H_9C_5H_4)_3SmTHF的合成与结构

无水三氯化钕与环戊烷基环戊二烯钠、溴化锂(1:2:1摩尔比)反应,除去不溶物和溶剂后,产物在己烷/四氢呋喃溶剂中冷冻得到兰紫色晶体(C5H9C5H4)3NdBrLi(THF)3(配合物1)。其中心金属Nd3+的配位数为10,以η5与3个环戊二烯基相连,并通过单溴原子桥连锂原子,形成双核结构。该晶体属三斜晶系,P`1空间群。晶体学参数为a=12.048(2)、b=13.498(3)、c=13.831(3);α=104.16(3)、β=104.07(3)、γ=95.96(3); V=2083.3(7)3、Z=2、Dc=1.35Mg/m3、Mr=847.01gmol-1、F(000)=874。无水三氯化钐与环戊烷基环戊二烯钠(1:3)反应,产物在-30oC下的己烷溶剂中结晶得桔红色晶体(C5H9C5H4)3SmTHF(配合物2)。该晶体属正交晶系,Fdd2空间群。晶胞参数a=28.175(5) 、b=46.24(2)、c=9.167(4);V=11943(8)3、Z=16、Dc=1.38Mg/m3、 Mr=622.11 g·mol-1、F(000)=5136。10配位的金属Sm3+与3个环戊二烯基以η5相连,并结合一个四氢呋喃溶剂分子。     

四氯合锌酸十四烷铵-四氯合锌酸十六烷铵二元体系相图

合成了四氯合锌酸十四烷铵(C4H29NH3)2ZnCl4(简记为C14ZnCl)和四氯合锌酸十六烷铵(C16H33NH3)2ZnCl4(简记为C16ZnC1),并配制了一系列不同组成的C14ZnCl-C16ZnCl二元体系,通过DSC测试,变温红外光谱法及X-ray粉末衍射法来绘制该二元体系相图。该相图是生成稳定中问化合物的固相部分互溶体系相图。     

Synthesis and structure of anilinium chloranilate (NH3C6H5)2 · (C6O4C12) and acid ammonium chloranilate dihydrate NH4H5O2(C6O4Cl2)

Conclusions The authors have synthesized anilinium chloranilate (NH₃C₆H₅)₂(C₆O₄Cl₂) (I) and acid ammonium chloranilate dihydrate NH₄H₅O₂(C₆O₄C1₂) (II). By x-ray structural analysis they have established their crystal structures. In crystals of NH₄H₅O₂(C₆O₄Cl₂) they find the ion H₅O ₂ ⁺ with the unusual O-H-O bond length of 2.81 A. The anions of chloranilic acid in crystals (I) and (II) have equal charges but different structures.Translated from IzvestiyaAkademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 487–489, March, 1981.     

Dewetting behavior of polystyrene film filled with (C6H5C2H4NH3)2PbI4

The dewetting behavior of thin (about 30 nm) polystyrene (PS) films filled with different amount of (C(6)H(5)C(2)H(4)NH(3))(2)PbI(4) (PhE-PbI(4)) on the silicon substrate with a native oxide layer was investigated. For different additive concentrations, PhE-PbI(4) showed different spatial distributions in the PS films, which had a strong influence on the film wettability, dewetting dynamics, and mechanism. With 0.5 wt % additive, PhE-PbI(4) formed a noncontinuous diffusion layer, which caused a continuous hole nucleation in the film. With about 1 wt % additive, a continuous gradient distribution layer of PhE-PbI(4) formed in the film, which inhibited the dewetting. When the concentration is higher (2 wt %), large PhE-PbI(4) aggregates, in addition to the PhE-PbI(4) continuous layer, formed in the film. These large aggregates (larger than radius of gyration of PS) migrated to the interface, resulting in the hole nucleation and eventually the complete dewetting of the film.     

Thermal behaviour and vibrational spectra of (NH4)3Ga(C2O4)3 · 3H2O and (NH4)3Al(C2O4)3 · 3H2O

The IR and Raman spectra and the thermal behaviour of the isomorphous compounds (NH₄)₃Ga(C₂O₄)₃·3H₂O and (NH₄)₃Al(C₂O₄)₃·3H₂O were investigated. Detailed stoichiometries, sustained by TG, DTA and IR spectroscopic analyses, were found in both cases. Different results, associated with the different polarizing powers of the metal cations, were obtained. The first evidence was found of the formation of basic gallium carbonates.     

Die Kristallstruktur von CuBr · (C2H5)4P2

The crystal structure of CuBr · (C₂H₅)₄P₂ has been determined by single crystal X-ray methods. The crystals are triclinic (space group P 1 ) with two formula units per unit cell (a) = 9,29, b = 9,92, c = 7,57 Å, α = 85,3°, β = 106,6°, γ = 109,1°. The copper atoms are tetrahedrally coordinated by two bromine and two phosphorus atoms (of different biphosphine molecules). The structure has continuous chains running parallel c, in which the copper atoms are linked together by alternating double bridges consisting of two biphosphine molecules and two bromine atoms, respectively.     

A hydrothermal investigation of the 1/2V2O5-H2C2O4/H3PO4/NH4OH system: synthesis and structures of (NH4)VOPO(4).1.5H2O, (NH4)0.5VOPO(4).1.5H2O, (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2](2).3H2O, and (NH4)2[VO(HPO4)]2(C2O4).5H2O

The 1/2V2O5-H2C2O4/H3PO4/NH4OH system was investigated using hydrothermal techniques. Four new phases, (NH4)VOPO(4).1.5H2O (1), (NH4)0.5VOPO(4).1.5H2O (2), (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O (3), and (NH4)2[VO(HPO4)]2(C2O4).H2O (4), have been prepared and structurally characterized. Compounds 1 and 2 have layered structures closely related to VOPO(4).2H2O and A0.5VOPO4.yH2O (A = mono- or divalent metals), whereas 3 has a 3D open-framework structure. Compound 4 has a layered structure and contains both oxalate and phosphate anions coordinated to vanadium cations. Crystal data: (NH4)VOPO(4).1.5H2O, tetragonal (I), space group I4/mmm (No. 139), a = 6.3160(5) A, c = 13.540(2) A, Z = 4; (NH4)0.5VOPO(4).1.5H2O, monoclinic, space group P2(1)/m (No. 11), a = 6.9669(6) A, b = 17.663(2) A, c = 8.9304(8) A, beta = 105.347(1) degrees, Z = 8; (NH4)2[VO(H2O)3]2[VO(H2O)][VO(PO4)2]2.3H2O, triclinic, space group P1 (No. 2), a = 10.2523(9) A, b = 12.263(1) A, c = 12.362(1) A, alpha = 69.041(2) degrees, beta = 65.653(2) degrees, gamma = 87.789(2) degrees, Z = 2; (NH4)2[VO(HPO4)]2(C2O4).5H2O, monoclinic (C), space group C2/m (No. 12), a = 17.735(2) A, b = 6.4180(6) A, c = 22.839(2) A, beta = 102.017(2) degrees, Z = 6.     

Canted antiferromagnetism and spin reorientation transition in layered inorganic-organic perovskite (C6H5CH2CH2NH3)2MnCl4

This work presents the synthesis, structure determination and magnetic properties of a new complex, phenethylammonium tetrachloromanganate(II), (C(6)H(5)CH(2)CH(2)NH(3))(2)MnCl(4) (Mn-PEA). Single crystals of Mn-PEA were obtained from methanol solution using the solvent-evaporation method at room temperature. The crystal structure of Mn-PEA was determined by single-crystal X-ray diffraction (orthorhombic, space group Pbca, a = 7.2075(9), b = 7.3012(14), c = 39.413(6) ? and Z = 4). The structure consisted of an extended [MnCl(4)](2-) network and two phenethylammonium cations to form a two-dimensional halide perovskite structure. Temperature-dependent magnetization measurements indicated that Mn-PEA acted as a weak ferromagnet below T(C) = 44.3 K due to spin canting. Below T(C), the magnetic behavior differed significantly from the behavior commonly observed among weak ferromagnets. The susceptibility depended strongly on the crystal orientation, the external magnetic field strength, and the magnetic history. The isothermal magnetization for two orientations revealed a ferromagnetic moment with a spin-canting angle of 0.04° and a spin-flop transitions with H(sf) = 3.5 T. The weak ferromagnetism, which manifested as spontaneous magnetization and magnetic hysteresis near a field strength of zero, was driven by interplay between the easy axis and the antisymmetric Dzyaloshinsky-Moriya (DM) interaction, leading to directional dependent magnetic behavior.     

Strandberg型杂多化合物(C_6H_(11)NH_3)_5H(P_2Mo_5O_(23))4H_2O的水热合成及结构

利用水热合成法合成了分子组成为(C6H11NH3)5H(P2Mo5O23)4H2O的杂多化合物, 用单晶X-ray衍射方法测定了它的结构,该晶体属于单斜晶系,空间群P21/c, a = 12.830(3), b = 14.848(3), c = 25.258(5) ? b = 92.95(3), Mr = 1483.62, V = 4805.1(17) 3, Z = 4, Dc = 2.051 g/cm3, m = 1.431 mm-1, F(000) = 3000, I >2s(I) 的可观察衍射点4426个, 最终结构偏差因子R = 0.0464, wR = 0.0801, S = 0.731。在[P2Mo5O23]6-杂多阴离子中5个MoO6八面体通过共边和共角相连, 形成1个近似的五角平面骨架, 2个PO4四面体加在五角平面的两侧。热性质研究表明杂多阴离子骨架在547.4 ℃左右分解。     

Exciton transfer in the two-dimensional antiferromagnet (C2H5NH3)2MnCl4

Exciton transfers in the two-dimensional and spin-canted antiferromagnet (C₂H₅NH₃)₂MnCl₄ were studied by investigating the absorption spectra ⁶A_1g → ⁴T_2g(⁴D) of Mn²⁺. A magnon side band (exciton–magnon simultaneous excitation) which has an anomalous shape with the cutoffs at the low-energy as well as the high-energy sides was observed. This anomalous shape could be reproduced in calculation as magnon side band, considering both the intersublattice and intrasublattice exciton transfers. From the analysis of this band shape, the magnitudes of the intersublattice and intrasublattice exciton transfers are estimated to be 10.2 and 6.8 cm^?1, respectively. In the case of simple antiferromagnets without spin canting, the intersublattice exciton transfer process is forbidden because of the spin angular momentum. However, in the case of (C₂H₅NH₃)₂MnCl₄, the prohibition of the intersublattice exciton transfer is removed by the canted-spin arrangement.     

Raman study of phase transitions in (n-C4H9NH3)2BiCl5

The Raman spectra of (n-C₄H₉NH₃)₂BiCl₅ were recorded and analysed from 4 K to 390 K. The phase transition (α → β) at 370 K to the metastable form is manifested by changes in the low-frequency Raman spectra, indicating the changes in the anionic structure of the crystal. The phase transition at 215 K is clearly manifested by the temperature evolution of the internal modes of the butylammonium cation. The phase transition is likely to be due to a reorientational motion of the cation.