Structure ofp-tetrakis-(4-nitrophenylazo)calix[4]-arene-4-picoline (1∶4) complex

The structure of thep-tetrakis-(4-nitrophenylazo)calix[4]arene-4-picoline (14) complex has been determined by X-ray crystallography. Crystals are monoclinic, space groupC2/c,a=24.9097) Å,b=8.425(6) Å,c=33.81(1) Å, =101.13(2)°,D _c =1.330 g/cm³,Z=4, finalR value =0.067. The cone conformation adopted by this azocalixarene is disturbed by the positions of the picoline molecules. Two of them are inside the macorocycle cavity and the two others are outside. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. Sup. 82190 (32 pages).     

SYNTHESES AND CRYSTAL STRUCTURES OF (Et_4N)_2(Fe_2Se_2(SPh)_4) AND (Et_4N)_2(Fe_4Se_4Cl_4)

<正> Since the discovery of iron-sulfur proteins , a number of analogous compounds of the active sites of iron-sulfur proteins has been synthesized and characterized . Due to the similarity between sulfur and selenium, some selenoproteins with similar active site as iron-sulfur proteins were found . We have synthesized a series of iron-selenium compounds in correlative study with the iron-sulfur compounds. In this paper, we will discuss the syntheses and crystal stuctures of the title compounds. The spectroscopic properties of these compounds have been under investigation.     

Synthesis and mesomorphic properties of 4-(4-bromopropyloxy)-4’-(4-alkyloxybenzylidene)anilines

This article describes the preparation and liquid crystalline properties of a new homologous series of 4-（4-bromopropyloxy）-4’- （4-alkyloxybenzylidene）anilines in which the phenyl ring is armed by a bromopropyloxy chain.The thermal behavior and mesomorphic properties of the synthesized compounds were studied with particular attention given to the correlation between their phase transition temperatures and anisotropic change influenced by molecular structure.All the members displayed enantiotropic smectic phase except for the homologue with the longest alkyloxy chain(R = C₁₈H₃₇),exhibiting only monotropic characteristic. The presence of bromine atom from the propyloxy side chain is found to be capable of altering and influencing the mesomorphic properties.     

Synthesis of Alkyl4(4'-octyloxy-4”-biphenylcarboxy)-benzenesulfonates

Sincethediscoveryoftristableswitching'andthesubsequentidentificationofmesomorphicphasesinMHPOBC2'3I,thesynthesisofnewliquidcrystalshaveattractedmuchattention.Theliquidcrystals,incorporatingtheSatom,suchasthioester4,sulfoxides5andsulfone',havebeenstudied.PrelindnarydatasuggestedthatthisstrUcturalchangefavoredtheformationofsmecticphases.WefirstintroducedsuIfonateintoliquidcrystalsandplannedthesynthesisofthiscategoryinordertostudyitsproperties.Wepresentherethesynthesisandcharacterizationsbase…     

An approach to heterometallic alkoxide-β-diketonate complexes with a M4O4 cubane-like core and new prospects of their application in preparation of solid catalysts. X-ray single crystal study of (Co,Ni)4(acac)4(μ3-OMe)4(MeOH)4, Co2Ni2(acac)4(μ3-OMe)4(OAc)2 and Mg4(acac)4(μ3-OMe)4(MeOH)4

The interaction of the individual M₄(acac)₄(μ₃-OMe)₄(MeOH)₄ complexes, M=Co, Ni in toluene/methanol media provided crystals of (Co,Ni)₄(acac)₄(μ₃-OMe)₄(MeOH)₄ (I) — the product of co-crystallization of isomorphous products. The oxidation of a MeOH solution of I in air in the presence of NaOAc and aminoalcohols as catalysts gave Co₂Ni₂(acac)₄(μ₃-OMe)₄(OAc)₂ (II), an individual heterometallic derivative. The interaction of Mg(OCH(CH₃)CH₂NMe₂)₂ with Cu(acac)₂ in toluene/methanol media produced Mg₄(acac)₄(μ₃-OMe)₄(MeOH)₄ (III) as the only isolatable product. The starting Co and Ni homometallic complexes as well as the heterometallic CoNi complex II were used to prepare the zeolite-supported oxide catalysts which exhibited extremely high activity towards methanol oxidation.     

12-Ring Network Coordination Polymer——{[Cu(C_4N_2H_(10))_4]_2·H_4V_4O_(14)}_n Formed by Linking cyclo-[H_4V_4O_(14)]~(4-) with Cu(C_4N_2H_(10))~(2+)_4 Cation Clusters

IntroductionThe interest in polyoxometalates that are widelyused in medical chemistry, catalyst reactions, and ma-terial sciences stems from their complicated aggregatesformed by means of corner-, edge- and face-sha-ring[1—4]. The exploitation of new str…     

Like (CO)4, Do (CS)4 and (CSe)4 Have a Triplet Ground State?

Cyclobutane‐1,2,3,4‐tetraone, (CO)₄, was computationally predicted and, subsequently, experimentally confirmed to have a triplet ground state, in which a b_2g σ MO and an a_2u π MO were each singly occupied. In contrast, the (U)CCSD(T) calculations reported herein found that cyclobutane‐1,2,3,4‐tetrathione, (CS)₄, and cyclobutane‐1,2,3,4‐tetraselenone, (CSe)₄, both had singlet ground states, in which the b_2g σ MO was doubly occupied and the a_2u π MO was empty. Our calculations showed that both the longer C?X distances and smaller coefficients on the carbon atoms in the b_2g and a_2u MOs of (CS)₄ and (CSe)₄ contributed to the difference between the ground states of these two molecules and the ground state of (CO)₄. An experimental test of the prediction of a singlet ground state for (CS)₄ is proposed.     

Electronic structure and low temperature thermoelectric properties of In₂₄M₈O₄₈ (M = Ge(4+), Sn(4+), Ti(4+), and Zr(4+))

The electronic structure and transport properties of In₂₄M₈O₄₈ (M = Ge⁴⁺, Sn⁴⁺, Ti⁴⁺, and Zr⁴⁺) have been studied by using the full‐potential linearized augmented plane‐wave method and the semiclassical Boltzmann theory, respectively. It is found that the magnitude of powerfactor with respect to relation time follows the order of In₂₄Sn₈O₄₈ > In₂₄Zr₈O₄₈ > In₂₄Ge₈O₄₈ > In₂₄Ti₈O₄₈. The largest powerfactor is 2.7 × 10¹² W/K²ms for In₂₄Sn₈O₄₈ at 60 K, which is nearly thirty times larger than those of conventional n‐type thermoelectric materials. The origin of the different thermoelectric behavior for these compounds is discussed from the electronic structure level. It is found that, at low temperature, the dopant strongly affect the bands near the Fermi level, which consequently leads to their different thermoelectric properties. The electronic configuration and the difference in atomic number between the dopant and the host atom also play an important role on the thermoelectric properties of In₂₄M₈O₄₈. Our calculations give a valuable insight on how to enhance the thermoelectric performance of In₃₂O₄₈. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011     

Rh2(CO)4(μ-Cl)2和Rh4(μ-CO)3(CO)4的简正振动分析

金属簇合物具有独特的结构和成键方式。本文对铑簇合物的简正振动分析进行了研究。通过红外光谱用石蜡油糊涂KBr和聚乙烯窗口, 在Nicolet 200SXV FT-IR光谱上测定了Rh2(CO)4(μ-Cl)2的构型, 并使用分子振动全分析程序MVTA(Basic语言), 在PC机上进行计算。     

(Tetragermacyclobutadiene)ruthenium tricarbonyl [η4-(But 2MeSi)4Ge4]Ru(CO)3

Tetrakis(di-tert-butylmethylsilyl)tetragermacyclobutadiene]ruthenium tricarbonyl [η⁴-(Bu^t ₂MeSi)₄Ge₄]Ru(CO)₃ is synthesized. This analogue of well-known cyclobutadiene transition metal complexes bears a tetragermacyclobutadiene derivative as ligand. The structure and spectroscopic parameters of the complex are compared with those of its iron-containing analogue [η⁴-(Bu^t ₂MeSi)₄Ge₄]Fe(CO)₃. Based on experimental data and results of quantum chemical calculations, it is shown that the π-donating ability of ligands increases upon replacement of carbon atoms in the cyclobutadiene moiety by silicon or germanium atoms, tetrasilacyclobutadiene and tetragermacyclobutadiene being comparable in π-donating activity.     

SYNTHESIS OF (4S)-ETHOXYSILATRANE-4-CARBOXYLIC ACIDS

ＳＹＮＴＨＥＳＩＳＯＦ（４Ｓ）－ＥＴＨＯＸＹＳＩＬＡＴＲＡＮＥ－４－ＣＡＲＢＯＸＹＬＩＣＡＣＩＤＳ￥ＺｈｅｎｇＲｏｎｇＬＵ；ＣｈｕｎＹｕａｎＴＡＯ；ＣｈｕｍＹｕａｎＴＡＯ；ＲｅｎＸｉＺＨＵＯ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＷｕｈａｎＵｎ...     

The molecular and crystal structure of N-(4-n-butyloxybenzylidene)-4′-ethylaniline (4O.2) and N-(4-n-heptyloxybenzylidene)-4′-hexylaniline (7O.6)

Abstract

The molecular and crystal structure of N-(4-n-butyloxybenzylidene)-4′-ethylaniline (4O.2) and the homologue N-(4-n-heptyloxybenzylidene)-4′-hexylaniline (7O.6) have been solved (at room temperature) by direct methods. The crystals of both compounds belong to the triclinic system with space group P1 with two molecules per unit cell. 4O.2: a = 5·531(2), b = 7·592(3), c = 19·746(7) Å, α = 86·66(2), β = 88·15(2), γ = 90·29(2)° 7O.6: a = 5·420(2), b = 8·307(3), c = 28·057(7) Å, α = 91·69(2), β = 89·76(2), γ = 108·02(2)°. The structures were refined by full-matrix least-squares calculations to R = 0·036 for 2297 observed reflections for 4O.2 and to R = 0·037 for 2150 reflections for 7O.6. The conformations in the asymmetric units of the two compounds differ considerably: The planes of the two phenyl rings of 4O.2, forming the mesogenic core of the molecule, are twisted at 61·2° to each other and the butoxy group contains a gauche conformation. In contrast the heptoxy chain of 7O.6 forms an all trans-conformation which lies almost in one plane with the two coplanar phenyl rings. The hexyl group also exists in an extended form, in a plane which is rotated against the plane of the mesogenic unit. The packing in the crystalline state of the two homologues exhibits a layered structure along c*; in 4O.2 these layers are separated, but in 7O.6 they are interdigitated. The compensation of the dipole moments of the C?O?C and C?N?C bonds occurs similarly in both structures: molecular orientations parallel to the a, c-plane in which the long axes of the molecules points in the same direction are packed in antiparallel fashion along b*.     

SYNTHESIS AND STRUCTURE OF (Et_4N) [Fe_4S_4 (Et_2NCS_2)_4 ]

<正> INTRODUCTION. The Fe_4S_4 cubane-like clusters have been extensively studied as the model compounds for the active center of the Fe-S proteins in the last fifteen years. Coucouvains et al. have recently reported the syntheses and structures of a few Fe_4S_4 cluster compounds containing R_2NCS_2(R_2dtc) and RS (or Cl) mixed terminal ligands and having [Fe_4S_4]~(2+) core oxi-     

Mesogenic 4-(ω-Hydroxyalkoxy)-4'-formylazobenzenes

Homologs from a series of 4-(-hydroxyalkoxy)-4'-formylbenzenes (C₂,C₃,C₄,C₆ ,C₈) were synthesized. All compounds obtained show properties of thermotropic nematic liquid crystals. The effect of the terminal hydroxy group of the end substituent on the mesomorphous properties of the compounds was analyzed.     

3-(N)-4-(Pyrazolo-4′,5′)-chinolin

Zusammenfassung Da bei Wiederholung der vonK. Eiter undMaria Nagy angegebenen Darstellung der Verbindung I diese in 59% iger Ausbeute erhalten werden konnte, wurde die Behauptung vonD. W. Ockenden undK. Schofield, wonach die Verbindung I nach unseren Angaben nicht herzustellen war, widerlegt.Weiters konnte bewiesen werden, daß eine vonSchofield undTheobald als 3-(Pyridyl-x)-lepidin bezeichnete Verbindung in Wirklichkeit die Verbindung I ist.