Crown compounds for anions: sandwich and half-sandwich complexes of cyclic trimetric perfluoro-o-phenylenemercury with polyhedral closo-[B10H10]2- and closo-[B12H12]2- anions

It has been shown by IR and NMR spectroscopy that cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4-Hg)3 (1) is capable of binding closo-[B10H10]2- and closo-[B12H12]2- anions to form complexes [[(o-C6F4Hg)3](B10-H10)]2- (2), [[(o-C6F4Hg)3]2(B10H10)]2-(3), [[(o-C6F4Hg)3](B12H12)]2- (4), and [[(o-C6F4Hg)3]2(B12H12)]2- (5). According to IR data, the bonding of the [B10H10]2- and [B12H12]2- ions to the macrocycle in these complexes is accomplished through the formation of B-H-Hg bridges. Complexes 2, 3, and 5 have been isolated in analytically pure form and have been characterized by spectroscopic means. X-ray diffraction studies of 3 and 5 have revealed that these compounds have unusual sandwich structures, in which the polyhedral di-anion is located between the planes of two molecules of 1 and is bonded to each of them through two types of B-H-Hg bridges. One type is the simultaneous coordination of a B-H group to all three Hg atoms of the macrocycle. The other type is the coordination of a B-H group to a single Hg atom of the cycle. According to X-ray diffraction data, complex 2 has an analogous but half-sandwich structure. The obtained complexes 2-5 are quite stable; their stability constants in THF/acetone (1:1) at 20 degrees C have been determined as 1.0 x 10(2)Lmol(-1), 2.6 x 10(3)L(2)mol(2), 0.7 x 10(2)Lmol(-1), and 0.98 x 10(3)L(2)mol(-2), respectively.     

Deuteration of closo-1,2- and 1,7-C2B10H12 using C6D6/AlCl3: Mechanistic considerations

Regioselective deuteration of 1-X-C₂B₁₀H₁₂ (X = 2, 7) cage systems with C₆D₆/AlCl₃ is correlated to ab initio calculational results on a [C₂B₁₀H₁₃]⁺ intermediate. Full geometry optimizations of pertinent [C₂B₁₀H₁₃]⁺ isomers, derived from each of the two 1-X-C₂B₁₀H₁₂ carborane isomers, result in cage geometries not unlike the (nearly) icosahedral starting carborane. Each isomer contains a BH₂ group having an acute H-B-H angle, long B–H bonds, and a very short H · · · H distance, hinting that the pertinent boron shares the electrons of a hydrogen molecule σ pair. It is suggested that the structural differences between the BH₂ group of [C₂B₁₀H₁₃]⁺ and the CH₂ group of the benzenium ion, [C₆H₇]⁺ (the intermediate strongly intimated upon protonation of benzene), can be explained, in part, by (a) the availability of the π-ring electrons for bonding to the (extra) proton in the latter and (b) the unavailability of π electrons from the carborane. Thus, the C₂B₁₀H₁₂ cage is most probably very reluctant to give up a cage electron pair in order to assist in bonding to an (externally bound) proton. Instead, it is more probable that “hydridic” B–H sigma electrons could very well play the important role in providing bonding to the attacking proton. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:95–102, 1998     

Crystal and molecular structure of novel 10-membered ring compound: 10-Chloro-1,7-ditosyl-8-phenyl-4,1,7-benzoxadiazecine

10-Chloro-1,7-ditosyl-8-phenyl-4,1,7-benzoxadiazecine is obtained by reacting the sodium salt of N , N ′-ditosyl-2-amino-5-chlorobenzhydrylamine with the ditosylate of bis(hydroxyethyl) ether in DMF. The structure of the title compound was established by X-ray crystal structure analysis. The 10-membered ring that is the core of the molecule is asymmetric and considerably folded. © 1995 John Wiley & Sons, Inc.     

Synthesis and structure of lateral halogenated V-shaped liquid crystal molecules based on a 1,7-naphthalene central core and alkylthio tails

A series of small angle bent-core (V-shaped) mesogens carrying 1,7-naphthalene as a central core linked with lateral halogenated (chlorinated or fluorinated) Schiff-base side wings and alkylthio terminal tails of variable carbon number (n = 12, 16) was synthesised in order to reduce the transition temperature and improve the phase stability of bent-core liquid crystal molecules. Differential scanning calorimetry (DSC), polarising optical microscopy (POM), small-angle X-ray scattering system (SAXS) and two-dimensional X-ray diffractometer were applied to ascertain the mesomorphic structure and phase transition temperatures of the compounds. The results confirm that all the molecules show thermotropic liquid crystalline behaviour and exhibit hexagonal columnar phase (Col_h) in a certain temperature range. Compared with the homologous compounds without lateral halogen, the cleaning point temperature of lateral halogenated V-shaped compounds generally decrease and the Col_h phase ranges are more extensive. The influence of lateral chlorine on the cleaning point temperature is more obvious, as well as the effect of lateral fluorine on the range of Col_h phase.     

Synthesis and structural characterization of symmetrical closo-4,7-I2-1,2-C2B10H10 and [(CH3)3NH][nido-2,4-I2-7,8-C2B9H10

The boron-atom insertion reaction of nido-9,11-I(2)-7,8-C(2)B(9)H(9)(2-), with the HBCl(2):SMe(2) complex yields closo-4,7-I(2)-1,2-C(2)B(10)H(10), 1, in excellent yield. Although the two boron atoms (B3 and B6) nearest to the carbon atoms in 1 are equally available for attack by nucleophiles, the boron-degradation reaction of 1 with alkoxide ion occurs only at the B6 vertex, yielding regioselectively [(CH(3))(3)NH][nido-2,4-I(2)-7,8-C(2)B(9)H(10)], 2. The molecular structures of 1 and 2 have been determined by X-ray diffraction studies. Crystallographic data are as follows. For 1, monoclinic, space group P2(1)/n, a = 6.9199(19) Angstroms, b = 23.9560(7) Angstroms, c = 7.2870(2) Angstroms, beta = 94.081(4) degrees, V = 1204.9(6) Angstroms(3), Z = 4, rho(calcd) = 2.18 g cm(-3), R = 0.020, R(w) = 0.0610; for 2, orthorhombic, space group Pca2(1), a = 14.1141(7) Angstroms, b = 7.0276(4) Angstroms, c = 16.4602(9) Angstroms, V = 1632.7(15) Angstroms(3), Z = 4, rho(calcd) = 1.81 gcm(-3), R = 0.022, R(w) = 0.0623.     

Crystal structure determination of 2′-nitro-10-phenylphenothiazine

The structure of the titled compound, 4 , has been solved by x-ray analysis. One of the important structural features of 4 is that the 2′-nitrophenyl group is in the plane bisecting the phenothiazine ring which is in contrast to that of 10-(2′-pyrazyl)phenothiazine of 4′-nitro-10-phenylphenothiazine in which the 10-aryl group is perpendicular to the plane bisecting the phenothiazine ring. The structure of 4 is in agreement with its ¹H and ¹³C nmr data which indicate that resonance interactions between the 2′-nitrophenyl group and the lone pair of electrons on N₁₀ are hindered sterically by the 2′-nitro group.     

Synthesis of monohalogeno derivatives of closo-[B9H9]2-. Crystal structures of (Ph4P)2[1-XB9H8].CH3CN (X = Cl, Br, I)

By reaction of Na2[B9H9] with the appropriate N-halogenosuccinimide, the monohalogenated anion [1-XB9H8]2- (X = Cl, Br, or I) is formed. The X-ray diffraction analyses performed on single crystals of (Ph4P)2[1-XB9H8].CH3CN (X = Cl, Br, I) reveal that the tricapped trigonal prismatic geometry of the cluster is retained after substitution in the 1-position. Crystallographic data are as follows for (Ph4P)2[1-XB9H8].CH3CN. X = Cl, Br: monoclinic, space group P2(1), a = 10.7 A, b = 32.9 A, c = 13.8 A, beta = 96 degrees, Z = 4, R1 = 0.038 and R1 = 0.036, respectively. X = I: monoclinic, space group P2(1)/n, a = 10.5 A, b = 13.6 A, c = 33.4 A, beta = 94 degrees, Z = 4, R1 = 0.094. The compounds have been characterized by vibrational and 11B NMR spectroscopy as well.     

Synthesis and IR Spectral Study of MoO2Cl2 Molecular Complexes with Acetoacetanilides. Crystal Structure of MoO2Cl2 Complex with Acetoacet-2-Toluidine

A series of MoO₂Cl₂ complexes with acetoacetanilide derivatives were synthesized and studied by IR spectroscopy. The crystal and molecular structures of the MoO₂Cl₂ complex with acetoacet-2-toluidine (HL) were determined by X-ray diffraction analysis. The monoclinic crystals involved are a = 7.621(7) Å, b = 9.498(3) Å, c = 19.980(9) Å, = 95.16(7)°, V = 1440(2) ų, Z = 4, and space group P2₁/n. The coordination polyhedron of the Mo atom is a distorted octahedron with two O oxoatoms in the cis-position relative to each other, two Cl atoms in the trans-positions, and two O atoms (HL) in the trans-positions to O(oxo).     

4-异丁氧基-10-羟基-1,7-二氮杂菲-2,8-二羧酸甲酯的合成、表征及晶体结构

报道了4-异丁氧基-10-羟基-1,7-二氮杂菲-2,8-二羧酸甲酯(1)的选择性合成.化合物1是以间苯二胺(3)为起始原料,经三步反应合成得来.间苯二胺和1,4-二羧酸二甲酯丁炔(4)反应生成了1,3-二-(1,2-二甲氧羰基-乙烯氨基)苯(5),随后化合物5在二苯醚中加热回流,生成4,10-二羟基-1,7-邻二氮杂菲-2,8-二羧酸甲酯(6)和4,5-二羟基-1,8-二氮杂蒽-2,7-二羧酸甲酯(7).从核磁共振氢谱中可以估算出,化合物6的产率是化合物7的7～9倍.化合物6和7的混合物通过Mitsunobu反应生成了化合物1和4,5-二异丁氧基-1,8-二氮杂蒽-2,7-二羧酸甲酯(2),其中化合物1的产率是化合物2的5～7倍.晶体结构清楚地表明化合物1中10位上的羟基与1位上的氮原子之间形成了六元环分子内氢键,而在化合物2中却没有发现分子内氢键,此现象很好的说明了氢键的形成与选择性合成之间存在着重要的联系.     

Crystal structure of uranyl tungstate Cs2U2WO10

A representative of uranyl tungstates Cs₂U₂WO₁₀ has been synthesized. A single crystal X-ray diffraction experiment has been performed for the compound prepared and its crystal structure has been solved. It is monoclinic, space group P2₁/n, a = 8.4611(5) Å, b = 28.691(2) Å, c = 9.6499(6) Å; β = 107.073(1)°, R ₁ = 0.086 for 4599 independent reflections with I > 2σ(I). The crystalline structure of the compound is formed by infinite negatively charged layers [U₂WO₁₀] _2∞ ^δ? interleaved with cesium cations which bond the layers. The compound has been studied with IR spectroscopy, and absorption bands of its spectrum have been assigned.     

Crystal structure and dynamics of Mg(ND3)6Cl2

The crystal structure and dynamics of Mg(ND(3))(6)Cl(2) have been investigated by powder neutron diffraction and molecular dynamics. The powder diffraction data can be well described by 4 partly occupied deuterium sites in a square arrangement around the N atoms, which is seemingly inconsistent with the 3-fold symmetry of the ND(3) molecule. Molecular dynamics show highly correlated rotational and translational motion of the ND(3) molecules which explains the apparent 4-fold symmetry of the deuterium arrangement. A more disordered structure model based on the molecular dynamics results gives a better fit to the experimental data and is in agreement with the 3-fold symmetry of ND(3).     

Synthesis,Crystal Structure and Property of CuPb2(OH)2Cl3

A new copper(I)-lead(II) oxyhalide, Cu Pb2(OH)2Cl3, has been prepared by hydrothermal reaction and structurally characterized by single-crystal X-ray analysis. The compound crystallizes in tetragonal, space group I4(1)/acd with a = b = 13.77(1), c = 15.38(1) , V = 2916.2(2), Z = 4, Mr = 618.29, Dc = 5.633 g/cm3, μ = 49.97(2) mm-1, F(000) = 4192, the final R = 0.0204 and w R = 0.0452 for 757 observed reflections with I 2σ(I). The structure of Cu Pb2(OH)2Cl3 contains one-dimensional helical chains built by Cu Cl4 tetrahedra with corner-sharing along the c-axis, in which the Pb2+ and OH- ions are located at the voids between chains. Optical reflectance spectrum measurements indicate that it is a semiconductor with a band-gap of 3.23 e V.     

Crystal structure determination of 10-trifluoroacetylphenothiazine

The structure of the title compound has been determined by single crystal X-ray methods. The crystals are monoclinic, space group P2₁/n with four molecules in a cell of dimensions a = 14.365(4), b = 5.942 (2), c = 17.359(3) Å, β = 119.88(2)° and V = 1298.0(6) Å. The structure has been refined by full-matrix least-squares to R = 0.043 using 1650 observed reflections. This study shows that the folding angle between the two benzo planes is 131.8(1)°, one of the smallest values observed in phenothiazine derivatives. Also, the trifluoroacetyl group is perpendicular to the plane bisecting the tricyclic ring, in contrast to most 10-aryl-substituted phenothiazines where the substituent is approximately parallel to the plane bisecting the tricyclic ring.