Hydrothermal Synthesis,Crystal Structure and Thermal Analyses of Pyrazine-2,3-dicarboxylic Acid Bridged Co(II) Coordination Polymer of _∞~2[Co(phen)(μ-L)_(3/3)]·H_2O (H_2L = Pyrazine-2,3-dicarboxylic Acid)

1 INTRODUCTION Molecular assembly and supramolecular che-mistry are young and rapidly growing subjects andhave attracted great attention. Microporous materialsbuilt up by organic ligands and metal ions have po-tential applications in catalysis, chemical absorption,magnetism and electronic conductivity[1～3]. Multi-dentate organic ligands are good building blocks,such as 1,2,4,5-benzene tetracarboxylic acid (BT-CA), 1,3,5-benzene tricarboxylic acid, terephthalicacid, 1,10-phenanthrol…     

Dumb-bell Structures of Nonstoichiometric La（Ni, Sn）5＋x Alloys and Their Relationships with the Preparation Methods

Crystal structures of nonstoichiometric La(Ni, Sn)5 x (x = 0.1～0.4) alloysprepared by different methods were investigated by using powder X-ray diffraction and Rietveldrefinement analysis. Space group of this type of alloys belongs to P6/mmm, in which Sn onlyoccupies the 3g sites. It has been demonstrated that some of the la sites of the nonstoichiometricalloy are replaced by the Ni-Ni dumb-bells which have a strong correlation with the anisotropicthermal parameter B33. The preparation methods have an effect on the number of dumb-bells thatcan substitute the l a sites. It was found that the annealed alloys have more Ni-Ni dumb-bells inthe structure than the rapid solidified and as-cast alloys have while still keep good crystallinity.     

Crystal Structure of the 1:2 Stoichiometric Nd: [α-SiW_(11)O_(39)]~(8-): K_5Na_5H_3[Nd(α-SiW_(11)O_(39))_2]·6H_2O

Single-crystal X-ray structural analysis of K5Na5H3[Nd(α-SiW11O39)2]·6H2O (triclinic, space group P1, a = 13.7738(10), b = 19.722(2), c = 20.6647(15) , α = 111.0090(10), β = 105.1740(10), γ = 98.6870(10)o, Z = 2, V = 4867.2(8), Mr = 5914.40, Dc = 4.026, μ = 26.754 mm-1, F(000) = 5076, R = 0.0750 and wR = 0.2077) reveals that two [α-SiW11O39]8- moieties are connected through one Nd atom which is in a square antiprismatic coordination environment by eight oxygen atoms from two [α-SiW11O391]8- moieties. The Nd(Ⅲ ) ion is substituted for a [WO]4+ unit in the "cap" region of the tungsten-oxygen framework of the parent Keggin ion. Disordered Na+ cations and water molecules reside outside these channels, leaving empty pores with an intersecting slot (13 × 10 ).     

Crystal Structure Analysis of Tetras[L-tris(ethylenediamine) cobalt(Ⅲ)] tris[hexacyanoruthenate(Ⅱ)]

1 INTRODUCTION The tris(ethylenediamine) cobalt (Ⅲ) complex in which there are L and D configurations is one of the very interest cations due to the chirality among research complexes and the characterization of reaction on the ion-pair charge-transfer transitions. It has been mentioned in a lot of examples on the chirality and the structure, such as [L-Co(en)3]- [?Co(edta)]2Cl?0H2O[1], [(+)DCo(en)3]Cl3稨2O[2], [(+)-Co(en)3?-)-Cr(en)3]Cl?.1H2O[3], [()-Co(en)3] (SCN)3[4], [(+)D…     

Synthesis,Spectroscopic Properties and Crystal Structural Characterization of a Triphenyltin(IV) Complex with 5-Bromonicotinic Acid

1 INTRODUCTION Organotin esters of carboxylic acids are widely used as biocides, fungicides and homogeneous ca- talysts in industry[1～3]. Recently, pharmaceutical pro- perties of organotin esters of carboxylic acids have been investigated for their antitumour activity[4, 5]. Studies on organotin compounds containing car- boxylate ligands with additional donor atoms (e.g. N, O or S) that are available for coordination to the tin atom have revealed that new structural types may lead to di…     

Theoretical Studies on Intermolecular Interactions of 4-Amino-5-nitro-1,2,3-triazole Dimers

1 INTRODUCTION Triazole, a five-membered heterocyclic compound with three nitrogen atoms, is an important interme- diate product of medicine and chemical industry as well as insecticide [1]. Due to its small volume and high nitrogenous density, triazole holds more and more attraction for the material researchers, espe- cially the researchers of high-energy insensitive explosive. It is reported that its nitro and amino deri- vatives are a sort of important high-energy mate- rials[2]. Previ…     

Synthesis and Crystal Structure of a New One-dimensional Zn(II) Nitronyl Nitroxide Complex Bridged by Pyridine-2,4-dicarboxylate Anion

1 INTRODUCTION The synthesis and study of transition metal com- pounds incorporating organic free radicals directly bound to their coordination sphere are a major re- search aim in the field of molecular magnetism[1]. Exceptional stability, ease of chemical modification and versatility in their coordination properties have made nitroxide free radicals one of the most attrac- tive spin carriers for the design of molecular magne- tic materials[2, 3]. The structures and magnetic prope- rties …     

Synthesis and Crystal Structure of 3-（2-Hydroxy-phenyl）-5-（2-methylphenyl）-6-thoxycarbonyl-cyclohexen-2-one

1 INTRODUCTION The molecular assembly of one- or multi-dimen-sional aggregation by hydrogen bonds is now an im-portant subject of supramolecular chemistry and crys-tal engineering[1, . Supramolecular structures formed 2]via intermolecular hydrogen bonds X–H…X or C–H…X (X = O, Cl, N, et al.) are very common inorganic compounds[3~12], and they generally possessdifferent properties due to these hydrogen bonds. Concerning about the spectra of benzene-contai-ning…     

Synthesis and Crystal Structure of N-（1-Phenyl-3-methyl-4-benzal-pyrazolone-5）-furoic Hydrazide

1 INTRODUCTION In recent years, investigations on the com- pounds containing hydrazide or hydrazone moieties have been increased considerably because of their potentially biological activities, especially as poten- tial inhibitors for many enzymes[1～5]. The presence of weak molecular interactions such as hydrogen- bonding controls the conformational and structural features which are important to the drug action[6, 7]. We have synthesized the photochromic compounds of pyrazolone thiosemi…     

Evolution of Er^3＋ Distribution in the Oxyfluoride Glass Ceramics with Heating

The distribution characteristics of Er3+ ions doped in the oxyfluoride glass ceramics containing LaF3 nanocrystals heat-treated at 650 ℃ for different durations were investigated. The results of the integral absorption cross-section analysis demonstrated that the partition fraction of Er3+ in LaF3 nanocrystals increases with prolonging of heating time. The anomalous phenomena of Er3+ emissions in the up-and the down-conversion fluorescence spectra are well explained based on the calculated results.