Acta Crystallographica Section B-structural Science最新文献_第8页

Site occupancy and lattice parameters in sigma-phase Co-Cr alloys. sigma相Co-Cr合金中的位占率和晶格参数。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-04-01 Epub Date: 2012-03-20 DOI: 10.1107/S0108768112006234

Jakub Cieslak, Stanislaw M Dubiel, Michael Reissner

引用次数: 18

Two novel Zn-MOFs: structures and characterization. 两种新型zn - mof:结构与表征。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-04-01 Epub Date: 2012-03-20 DOI: 10.1107/S0108768112007999

Ran Zheng, Lei Han, Qinhe Pan, Kirsten E Christensen, Tiezhen Ren

{"title":"Two novel Zn-MOFs: structures and characterization.","authors":"Ran Zheng, Lei Han, Qinhe Pan, Kirsten E Christensen, Tiezhen Ren","doi":"10.1107/S0108768112007999","DOIUrl":"https://doi.org/10.1107/S0108768112007999","url":null,"abstract":"Two novel three-dimensional Zn-MOFs (zinc metal-organic frameworks), Zn(5)(μ(3)-OH)(BTC)(3)(Phen)(4)·5H(2)O (denoted as HUT-11) and Zn(4)(μ(4)-O)(BTC)(2)(Phen)(2)·4H(2)O (denoted as HUT-12), have been synthesized by metal-ligand-directed assembly under hydrothermal conditions. Here, BTC and Phen are denoted as 1,3,5-benzenetricarboxylate and phenanthroline. HUT-11 contains two kinds of secondary building units (SBUs), Zn(3)(μ(3)-OH)(COO)(5) clusters and Zn(2)(COO)(4) clusters. This material exhibits a new three-dimensional (3,4,5)-connected topology with the Schläfli symbol (4·6·8)(2)(4·8(2))(4·6(4)·8(5))(4(2)·6(2)·8(2)). Two perpendicular planes cross at five coordinated Zn1-Zn3-Zn5 nodes, giving a new three-dimensional network. HUT-12 is composed of Zn(4)(μ(4)-O)(COO)(6) clusters as the secondary building units and displays a two-dimensional (3,6)-connected TiS(2) related net topology with the Schläfli symbol (4(2)·6)(4(4)·6(2)·8(8)·10). Both MOFs show blue light emission and a high thermal stability above 673 K.","PeriodicalId":7107,"journal":{"name":"Acta Crystallographica Section B-structural Science","volume":"68 Pt 2","pages":"158-63"},"PeriodicalIF":1.9,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1107/S0108768112007999","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30518015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Sagrario Martínez-Carrera (1925-2011). 萨格拉里奥·马丁内斯-卡雷拉（1925-2011）。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-04-01 Epub Date: 2012-03-20 DOI: 10.1107/S0108768112003540

Martín Martínez-Ripoll

引用次数: 0

Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study. 具有σ-受体和σ-供体取代基的环丙烷衍生物的几何和构象:理论和晶体结构数据库研究。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-04-01 Epub Date: 2012-02-25 DOI: 10.1107/S0108768111054991

Aurora J Cruz-Cabeza, Frank H Allen

{"title":"Geometry and conformation of cyclopropane derivatives having σ-acceptor and σ-donor substituents: a theoretical and crystal structure database study.","authors":"Aurora J Cruz-Cabeza, Frank H Allen","doi":"10.1107/S0108768111054991","DOIUrl":"https://doi.org/10.1107/S0108768111054991","url":null,"abstract":"The structures of cyclopropane rings which carry σ-acceptor or σ-donor substituents have been studied using density-functional theory (DFT), and mean bond lengths and conformational parameters retrieved from the Cambridge Structural Database. It is confirmed that σ-acceptor substituents, e.g. halogens, generate positive ring bond-length asymmetry in which there is lengthening of the distal bond (opposite to the point of substitution), and shorterning of the two vicinal bonds. This is due to withdrawal of electron density from the cyclopropane 1e'' orbitals, which are bonding for the distal bond and antibonding for the vicinal bonds. For σ-donor substituents such as SiH(3) or Si(CH(3))(3), the DFT and crystal structure data show negative ring bond-length asymmetry (distal bond shortened, vicinal bonds lengthened), owing to electron donation into the 4e' ring orbital, which are also bonding for the distal bond and antibonding for the vicinal bonds. The results also show that -OH substituents induce weak positive asymmetry, but that the effects of methyl or amino substituents are either non-existent or extremely small, certainly too small to measure using crystal structure information.","PeriodicalId":7107,"journal":{"name":"Acta Crystallographica Section B-structural Science","volume":"68 Pt 2","pages":"182-8"},"PeriodicalIF":1.9,"publicationDate":"2012-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1107/S0108768111054991","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30518018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

High-precision absolute lattice parameter determination of SrTiO3, DyScO3 and NdGaO3 single crystals. SrTiO3、DyScO3和NdGaO3单晶绝对晶格参数的高精度测定。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-06 DOI: 10.1107/S0108768111046738

Martin Schmidbauer, Albert Kwasniewski, Jutta Schwarzkopf

引用次数: 80

Structural phase transition to disorder low-temperature phase in [Fe(ptz)6](BF4)2 spin-crossover compounds. [Fe(ptz)6](BF4)2自旋交叉化合物的结构相变到无序低温相。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-18 DOI: 10.1107/S0108768111053298

Joachim Kusz, Maciej Zubko, Reinhard B Neder, Phillipp Gütlich

{"title":"Structural phase transition to disorder low-temperature phase in [Fe(ptz)6](BF4)2 spin-crossover compounds.","authors":"Joachim Kusz, Maciej Zubko, Reinhard B Neder, Phillipp Gütlich","doi":"10.1107/S0108768111053298","DOIUrl":"https://doi.org/10.1107/S0108768111053298","url":null,"abstract":"In the spin-crossover compound [Fe(ptz)(6)](BF(4))(2) (where ptz=1-n-propyltetrazole) six different phases are observed. When a single crystal is slowly cooled from high temperatures to those below 125 K, the reflections broaden into diffuse maxima and split into two maxima along the c* direction [Kusz, Gütlich & Spiering (2004). Top. Curr. Chem. 234, 129-153]. As both maxima are broad along the c* direction, the short-range order exists only along the c direction and in the ab plane the structure remains long-range ordered. In this disordered phase additional satellite reflections appear. Upon heating above 135 K, the diffuse maxima return to their previous shape and this process is completely reversible. Rapidly cooled samples, on the other hand, do not show such splitting and the symmetry remains Rbar 3, despite a jump in lattice parameters. We use a special technique to analyse the disorder model of the slowly cooled samples, which consists of layered domains shifted in the hexagonal ab plane. The low-spin disordered phase was solved in a novel approach to accommodate the very unusual twinning and refined in the non-standard space group Cbar 1. In contrast to the ordered low-spin phase, the Fe ion is in a non-centrosymmetric coordination polyhedron and two of the six propyl groups change their conformation.","PeriodicalId":7107,"journal":{"name":"Acta Crystallographica Section B-structural Science","volume":"68 Pt 1","pages":"40-56"},"PeriodicalIF":1.9,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1107/S0108768111053298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30406052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 21

An order-disorder phase transition in the structure of C60·4benzene. C60·4苯结构的有序-无序相变。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-06 DOI: 10.1107/S0108768111046593

Marilyn M Olmstead, Alan L Balch, Hon Man Lee

引用次数: 11

Hydrogen-bridged chelate ring-assisted π-stacking interactions. 氢桥螯合环辅助π-堆积相互作用。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-06 DOI: 10.1107/S0108768111052608

Hasan Karabıyık, Hande Karabıyık, Nazan Ocak İskeleli

{"title":"Hydrogen-bridged chelate ring-assisted π-stacking interactions.","authors":"Hasan Karabıyık, Hande Karabıyık, Nazan Ocak İskeleli","doi":"10.1107/S0108768111052608","DOIUrl":"https://doi.org/10.1107/S0108768111052608","url":null,"abstract":"A salicylideneaniline (SA) derivative, (6Z)-6-({[2-(hydroxymethyl)phenyl]amino}methylidene)-3,5-dimethoxycyclohexa-2,4-dien-1-one monohydrate, has an increased aromaticity within its hydrogen-bridged chelate ring owing to its NH character. In the reported crystal structure, nonconventional π-stacking interactions, which are referred to as hybrid π-stacking interactions, are observed between a quasiaromatic chelate ring, formed as a result of the resonance-assisted intramolecular hydrogen bond and ordinary aromatic rings. Besides, π-stacking interactions are also seen between two hydrogen-bridged quasiaromatic chelate rings, which are referred to as pure π-stacking interactions. A CSD search has revealed that both kinds of interactions are frequently observed in molecular crystals of SA derivatives in fully or partially NH tautomeric form, and aromaticity levels of certain fragments of SA derivatives have dramatic effects on their stacking arrangements. These interactions are distinguished from the usual π···π interactions by their formation character, i.e. both σ- and π-deficient and σ-deficient character of pure interactions is more pronounced than that of the hybrid ones.","PeriodicalId":7107,"journal":{"name":"Acta Crystallographica Section B-structural Science","volume":"68 Pt 1","pages":"71-9"},"PeriodicalIF":1.9,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1107/S0108768111052608","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30406055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

Structure of the new mineral sarrabusite, Pb5CuCl4(SeO3)4, solved by manual electron-diffraction tomography. 新矿物Pb5CuCl4(SeO3)4的结构用人工电子衍射层析分析。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-06 DOI: 10.1107/S010876811104688X

Mauro Gemmi, Italo Campostrini, Francesco Demartin, Tatiana E Gorelik, Carlo Maria Gramaccioli

引用次数: 35

Lattice constants and thermal expansion of H2O and D2O ice Ih between 10 and 265 K. Addendum. H2O和D2O冰Ih在10 ~ 265 K间的晶格常数和热膨胀。附录。

IF 1.9 3区化学

Acta Crystallographica Section B-structural Science Pub Date : 2012-02-01 Epub Date: 2012-01-06 DOI: 10.1107/S0108768111046908

K Röttger, A Endriss, Jörg Ihringer, S Doyle, W F Kuhs

引用次数: 140