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Inversion Center (inversion + center)
Kinds of Inversion Center Selected AbstractsAb initio structure solution by iterative phase-retrieval methods: performance tests on charge flipping and low-density eliminationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2010Frank Fleischer Comprehensive tests on the density-modification methods charge flipping [Oszlányi & Süt, (2004). Acta Cryst. A60, 134,141] and low-density elimination [Shiono & Woolfson (1992). Acta Cryst. A48, 451,456] for solving crystal structures are performed on simulated diffraction data of periodic structures and quasicrystals. A novel model-independent figure of merit, which characterizes the reliability of the retrieved phase of each reflection, is introduced and tested. The results of the performance tests show that the quality of the phase retrieval highly depends on the presence or absence of an inversion center and on the algorithm used for solving the structure. Charge flipping has a higher success rate for solving structures, while low-density elimination leads to a higher accuracy in phase retrieval. The best results can be obtained by combining the two methods, i.e. by solving a structure with charge flipping followed by a few cycles of low-density elimination. It is shown that these additional cycles dramatically improve the phases not only of the weak reflections but also of the strong ones. The results can be improved further by averaging the results of several runs and by applying a correction term that compensates for a reduction of the structure-factor amplitudes by averaging of inconsistently observed reflections. It is further shown that in most cases the retrieved phases converge to the best solution obtainable with a given method. [source] A list of organic kryptoracematesACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2010László Fábián A list of 181 organic kryptoracemates has been compiled. This class of crystallographic oddities is made up of racemic compounds (i.e. pairs of resolvable enantiomers) that happen to crystallize in Sohnke space groups (i.e. groups that include only proper symmetry operations). Most (151) of the 181 structures could have crystallized as ordered structures in non-Sohnke groups. The remaining 30 structures do not fully meet this criterion but would have been classified as kryptoracemates by previous authors. Examples were found and checked with the aid of available software for searching the Cambridge Structural Database, for generating and comparing InChI strings, and for validating crystal structures. The pairs of enantiomers in the true kryptoracemates usually have very similar conformations; often the match is near-perfect. There is a pseudosymmetric relationship of the enantiomers in about 60% of the kryptoracemate structures, but the deviations from inversion or glide symmetry are usually quite easy to spot. Kryptoracemates were found to account for 0.1% of all organic structures containing either a racemic compound, a meso molecule, or some other achiral molecule. The centroid of a pair of enantiomers is more likely (99.9% versus 99% probability) to be located on an inversion center than is the centroid of a potentially centrosymmetric molecule. [source] A mixed-valence chair-like tetranuclear copper(I,II) cluster with three linking modes of the 3,5-bis(2-pyridyl)-1,2,4-triazole ligandACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010Quan-Guo Zhai In the tetranuclear copper complex tetrakis[,-3,5-bis(2-pyridyl)-1,2,4-triazolido]bis[3,5-bis(2-pyridyl)-1,2,4-triazolido]dicopper(I)dicopper(II) dihydrate, [CuI2CuII2(C12H8N5)6]·2H2O, the asymmetric unit is composed of one CuI center, one CuII center, three anionic 3,5-bis(2-pyridyl)-1,2,4-triazole (2-BPT) ligands and one solvent water molecule. The CuI and CuII centers exhibit [CuIN4] tetrahedral and [CuIIN6] octahedral coordination environments, respectively. The three independent 2-BPT ligands adopt different chelating modes, which link the copper centers to generate a chair-like tetranuclear metallomacrocycle with metal,metal distances of about 4.4 × 6.2,Å disposed about a crystallographic inversion center. Furthermore, strong ,,, stacking interactions and O,H...N hydrogen-bonding systems link the tetracopper clusters into a two-dimensional supramolecular network. [source] Hydrogen-bonded supramolecular networks of N,N,-bis(4-pyridylmethyl)oxalamide and 4,4,-{[oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2010Gene-Hsiang Lee The molecule of N,N,-bis(4-pyridylmethyl)oxalamide, C14H14N4O2, (I) or 4py-ox, has an inversion center in the middle of the oxalamide group. Adjacent molecules are then linked through intermolecular N,H...N and C,H...O hydrogen bonds, forming an extended supramolecular network. 4,4,-{[Oxalylbis(azanediyl)]dimethylene}dipyridinium dinitrate, C14H16N4O22+·2NO3,, (II), contains a diprotonated 4py-ox cation and two nitrate counter-anions. Each nitrate ion is hydrogen bonded to four 4py-ox cations via intermolecular N,H...O and C,H...O interactions. Adjacent 4py-ox cations are linked through weak C,H...O hydrogen bonding between an ,-pyridinium C atom and an oxalamide O atom, forming a two-dimensional extended supramolecular network. [source] Constructor graph description of the hydrogen-bonding supramolecular assembly in two ionic compounds: 2-(pyrazol-1-yl)ethylammonium chloride and diaquadichloridobis(2-hydroxyethylammonium)cobalt(II) dichlorideACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Ilia A. Guzei Covalent bond tables are used to generate hydrogen-bond pattern designator symbols for the crystallographically characterized title compounds. 2-(Pyrazol-1-yl)ethylammonium chloride, C5H10N3+·Cl,, (I), has three unique, strong, charge-assisted hydrogen bonds of the types N,H...Cl and N,H...N that form unary through ternary levels of graph-set interactions. Diaquadichloridobis(2-hydroxyethylammonium)cobalt(II) dichloride, [CoCl2(C2H8NO)2(H2O)2]Cl2, (II), forms five unique charge-assisted hydrogen bonds of the types O,H...Cl and N,H...Cl. These form graph-set patterns up to the quinary level. The Co complex in (II) resides at a crystallographic inversion center; thus the number of hydrogen bonds to consider doubles due to their G -equivalence, and the handling of such a case is demonstrated. [source] Mono- and bis-tolylterpyridine iridium(III) complexesACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Lindsay M. Hinkle The first structure report of trichlorido[4,-(p -tolyl)-2,2,:6,,2,,-terpyridine]iridium(III) dimethyl sulfoxide solvate, [IrCl3(C22H17N3)]·C2H6OS, (I), is presented, along with a higher-symmetry setting of previously reported bis[4,-(p -tolyl)-2,2,:6,,2,,-terpyridine]iridium(III) tris(hexafluoridophosphate) acetonitrile disolvate, [Ir(C22H17N3)2](PF6)3·2C2H3N, (II) [Yoshikawa, Yamabe, Kanehisa, Kai, Takashima & Tsukahara (2007). Eur. J. Inorg. Chem. pp. 1911,1919]. For (I), the data were collected with synchrotron radiation and the dimethyl sulfoxide solvent molecule is disordered over three positions, one of which is an inversion center. The previously reported structure of (II) is presented in the more appropriate C2/c space group. The iridium complex and one PF6, anion lie on twofold axes in this structure, making half of the molecule unique. [source] A copper,polyol complex: [Na2(C2H6O2)6][Cu(C2H4O2)2]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Joseph H. Rivers The ionic title complex, bis(,-ethylene glycol)-,3O,O,:O,;,3O:O,O,-bis[(ethylene glycol-,2O,O,)(ethylene glycol-,O)sodium] bis(ethylene glycolato-,2O,O,)copper(II), [Na2(C2H6O2)6][Cu(C2H4O2)2], was obtained from a basic solution of CuCl2 in ethylene glycol and consists of discrete ions interconnected by O,H...O hydrogen bonds. This is the first example of a disodium,ethylene glycol complex cation cluster. The cation lies about an inversion center and the CuII atom of the anion lies on another independent inversion center. [source] Poly[[aqua(4,4,-diazenediyldibenzoato-,4O,O,:O,,,O,,,)cadmium(II)]: a twofold interpenetrated three-dimensional coordination polymer of PtS topologyACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Ru-Guo Wang In the title coordination compound, [Cd(C14H8N2O4)(H2O)]n, the CdII cation and the coordinated water molecule lie on a twofold axis, whereas the ligand lies on an inversion center. The CdII center is five-coordinated in a distorted square-pyramidal geometry by four carboxylate O atoms from four different 4,4,-diazenediyldibenzoate (ddb) anions and one water O atom. The three-dimensional frameworks thus formed by the bridging ddb anions interpenetrate to generate a three-dimensional PtS-type network. Additionally, the coordination water molecule and the carboxylate O atom form a hydrogen-bonding interaction, stabilizing the three-dimensional framework structure. [source] Diaquadichloridobis(1H -imidazole)manganese(II) at 100 KACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009Barbara Hachu The mononuclear title complex, [MnCl2(C3H4N2)2(H2O)2], is located on a crystallographic inversion center. The MnII ion is coordinated by two imidazole ligands [Mn,N = 2.2080,(9),Å], two Cl atoms [Mn,Cl = 2.5747,(3),Å] and two water molecules [Mn,O = 2.2064,(8),Å]. These six monodentate ligands define an octahedron with almost ideal angles: the adjacent N,Mn,O, N,Mn,Cl and O,Mn,Cl angles are 90.56,(3), 92.04,(2) and 90.21,(2)°, respectively. Hydrogen bonds between the coordinated water molecules and Cl atoms form a two-dimensional network parallel to (100) involving R42(8) rings. The two-dimensional networks link into a three-dimensional framework through weaker N,H...Cl interactions. Thermogravimetric analysis results are in accordance with the water-coordinated character of the substance and its dehydration in two successive steps. [source] Mn3(OAc)6·CH3CN: a porous dehydrated manganese(II) acetateACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009John Fielden The crystal structure of a new form of dehydrated manganese(II) acetate, poly[[hexa-,3 -acetato-trimanganese(II)] acetonitrile solvate], {[Mn3(CH3COO)6]·CH3CN}n, (I), reveals a three-dimensional polymeric structure based on an {Mn3} trimer. The {Mn3} asymmetric unit contains three crystallographically independent Mn positions, comprising a seven-coordinate center sharing a mirror plane with a six-coordinate center, and another six-coordinate atom located on an inversion center. Two of the four crystallographically independent acetate (OAc) ligands, as well as the acetonitrile solvent molecule, are also located on the mirror plane. The Mn atoms are connected by a mixture of Mn,O,Mn and Mn,OCO,Mn bridging modes, giving rise to face- and corner-sharing interactions between manganese polyhedra within the trimers, and edge- and corner-sharing connections between the trimers. The network contains substantial pores which are tightly filled by crystallographically located acetonitrile molecules. This structure represents the first porous structurally characterized phase of anhydrous manganese(II) acetate and as such it is compared with the closely related densely packed anhydrous manganese(II) acetate phase, solvent-free ,-Mn(OAc)2. [source] Dimeric (isoquinoline)(N -salicylidene- d,l -glutamato)copper(II) ethanol solvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Vratislav Langer The title racemic complex, bis[,- N -(2-oxidobenzylidene)- d,l -glutamato(2,)]bis[(isoquinoline)copper(II)] ethanol disolvate, [Cu2(C12H11NO5)2(C9H7N)2]·2C2H6O, adopts a square-pyramidal CuII coordination mode with a tridentate N -salicylideneglutamato Schiff base dianion and an isoquinoline ligand bound in the basal plane. The apex of the pyramid is occupied by a phenolic O atom from the adjacent chelate molecule at an apical distance of 2.487,(3),Å, building a dimer located on the crystallographic inversion center. The Cu...Cu spacing within the dimers is 3.3264,(12),Å. The ethanol solvent molecules are hydrogen bonded to the dimeric complex molecules, forming infinite chains in the a direction. The biological activity of the title complex has been studied. [source] N,N,-Dimethylpyrazinediium bis(tetrafluoroborate) and N,N,-diethylpyrazinediium bis(tetrafluoroborate): new examples of anion,, triadsACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Jianjiang Lu Crystallization of N,N,-dimethylpyrazinediium bis(tetrafluoroborate), C6H10N22+·2BF4,, (I), and N,N,-diethylpyrazinediium bis(tetrafluoroborate), C8H14N22+·2BF4,, (II), from dried acetonitrile under argon protection has permitted their single-crystal studies. In both crystal structures, the pyrazinediium dications are located about an inversion center (located at the ring center) and each pyrazinediium aromatic ring is ,-bonded to two centrosymmetrically related BF4, anions. Strong anion,, interactions, as well as weak C,H...F hydrogen bonds, between BF4, and pyrazinediium ions are present in both salts. [source] 1,1,-Dimethoxy-3,3,-dimethyl-3,3,-(hexane-1,6-diyl)bis(triazen-2-ium-2-olate): a nitric oxide donorACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009Zhengrong Zhou The title compound, C10H24N6O4, is the most stable type of nitric oxide (NO) donor among the broad category of discrete N -diazeniumdiolates (NO adducts of nucleophilic small molecule amines). Sitting astride a crystallographic inversion center, the molecule contains a symmetric dimethylhexane-1,6-diamine structure bearing two planar O2 -methylated N -diazeniumdiolate functional groups [N(O)=NOMe]. These two groups are parallel to each other and have the potential to release four molecules of NO. The methylated diazeniumdiolate substituent removes the negative charge from the typical N(O)=NO, group, thereby increasing the stability of the diazeniumdiolate structure. The crystal was nonmerohedrally twinned by a 180° rotation about the real [101] axis. This is the first N -based bis-diazeniumdiolate compound with a flexible aliphatic main unit to have its structure analyzed and this work demonstrates the utility of stabilizing the N -diazeniumdiolate functional group by methylation. [source] Poly[diaqua(,-4,4,-bipyridine-,2N:N,)bis(,-cyanido-,2C:N)bis(cyanido-,C)nickel(II)copper(II)]: a metal,organic cyanide-bridged frameworkACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2008Olha Sereda The structure of the title compound, [NiCu(CN)4(C10H8N2)(H2O)2]n or [{Cu(H2O)2}(,-C10H8N2)(,-CN)2{Ni(CN)2}]n, was shown to be a metal,organic cyanide-bridged framework, composed essentially of ,Cu,4,4,-bpy,Cu,4,4,-bpy,Cu, chains (4,4,-bpy is 4,4,-bipyridine) linked by [Ni(CN)4]2, anions. Both metal atoms sit on special positions; the CuII atom occupies an inversion center, while the NiII atom of the cyanometallate sits on a twofold axis. The 4,4,-bpy ligand is also situated about a center of symmetry, located at the center of the bridging C,C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the ,Cu,4,4,-bpy,Cu,4,4,-bpy,Cu, chains, which are mutually perpendicular and non-intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)4]2, anions coordinate to successive CuII atoms, forming zigzag ,Cu,N[triple-bond]C,Ni,C[triple-bond]N,Cu, chains. In this manner, a three-dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II),4,4,-bipyridine framework complexes synthesized to date. The coordination environment of the CuII atom is completed by two water molecules. The framework is further strengthened by O,H...N hydrogen bonds involving the water molecules and the symmetry-equivalent nonbridging cyanide N atoms. [source] A novel three-dimensional coordination polymer: poly[di-,3 -acetato-di-,2 -acetato-di-,3 -hydroxido-octa-,3 -triazolato-heptamanganese(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2008Zhe-Hui Weng The title compound, [Mn7(C2H2N3)8(C2H3O2)4(OH)2]n, is composed of centrosymmetric heptanuclear building units with the central Mn atom on an inversion center. In the building block, three MnII ions are held together by one ,3 -hydroxide group, two ,2 -triazolate (trz) ligands and two ,2 -acetate groups, forming an Mn3 cluster. Two Mn3 clusters are bridged by an Mn atom via two ,2 -trz ligands and two ,2 -O atoms from two acetate ions to construct a heptanuclear building block. The heptanuclear building units, lying parallel to each other along the b direction, form one-dimensional ladder-like chains and are further interlinked, resulting in a three-dimensional framework through Mn,Ntrz bonds. [source] Hydrogen-bonded supramolecule of N,N,-bis(4-pyridylmethyl)oxalamide and a zigzag chain structure of catena -poly[[[dichloridocobalt(II)]-,- N,N,-bis(4-pyridylmethyl)oxalamide-,2N4:N4,] hemihydrate]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2007Gene-Hsiang Lee N,N,-Bis(4-pyridylmethyl)oxalamide, C14H14N4O2, exists as a dimer which is extended into a two-dimensional network with other dimers through pyridine,amide hydrogen bonds. The crystal structure of the title coordination polymer, {[CoCl2(C14H14N4O2)]·0.5H2O}n, features a one-dimensional zigzag chain, in which the cobalt ion sits at a twofold symmetry position and adopts a tetrahedral geometry, and the bridging ligand lies on an inversion center and connects to CoII ions in a bis-monodentate mode. Furthermore, two interwoven chains create a cavity of ca 8.6 × 8.6,Å, which produces a three-dimensional channel. Water molecules are held in the channel by hydrogen bonds. [source] A novel dimeric zinc(II) complex: bis[,-1,2-bis(1H -1,2,4-triazol-1-yl)ethane-,2N4:N4,]bis[diisothiocyanatozinc(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2007Yu-Mei Zhang The coordination geometry of the ZnII atom in the title complex, [Zn2(NCS)4(C6H8N6)2], is that of a distorted tetrahedron, in which the ZnII atom is coordinated by four N atoms from the triazole rings of two symmetry-related 1,2-bis(1,2,4-triazol-1-yl)ethane ligands and two thiocyanate ligands. Two ZnII atoms are bridged by two organic ligands to form a dimer. The dimer lies about an inversion center. [source] The first metalloporphyrin dimer linked by a bridging phenylenedicarbene ligandACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2006Hidetaka Yuge In the first bis[ruthenium(II),porphyrin],dicarbene complex, ,-[1,4-phenylenebis(phenylmethylidene-,C)]bis[(ethanol-,O)(5,10,15,20-tetra- p -tolylporphyrinato-,4N)ruthenium(II)] 1,2-dichloroethane trisolvate, [Ru2(C20H14)(C48H36N4)2(C2H6O)2]·3C2H4Cl2, an inversion center is located at the center of the ,-phenylene group, leading to a parallel arrangement for the pair of porphyrin ring systems. The bond lengths and angles compare favourably with literature values for ruthenium,porphyrin,monocarbene complexes; the Ru=C(carbene) bond length and the C(phenyl),C(carbene),C(phenylene) angle are 1.865,(3),Å and 112.3,(3)°, respectively. The RuII ion is displaced out of the C20N4 porphyrin least-squares plane (by 0.2373,Å) toward the bridging ligand of the Ci -symmetry dimer. The porphyrin ring systems of the dimer thus exhibit mildly domed conformations. [source] Poly[methylammonium tris(,2 -formato-,2O:O,)cobalt(II)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2004Miroslav Bo The structure of the title compound, {(CH6N)[Co(CHO2)3]}n, consists of a three-dimensional net of central CoII ions connected via formate (methanediolate) bridges. The negative charge is compensated by protonated methylamine cations. The CoO6 chromophores form slightly distorted octahedra, which are bridged by C atoms of formate groups. The central Co atom lies on an inversion center and most of the other atoms lie on an m plane. [source] A capped trigonal prismatic cadmium complex with tetra- and tridentate ligands: bis(triethanolamine)-,3N,O,O,;,4N,O,O,,O,,-cadmium(II) squarate monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2004brahim Uçar In the crystal structure of the title compound, [Cd(C6H15NO3)2](C4O4)·H2O, a supramolecular structure is observed. The asymmetric unit consists of one unit of the cationic Cd complex, one water molecule and two half-squarate anions, each sitting on a crystallographic inversion center. The different coordinations of the two triethanolamine (TEA) ligands results in an unusual example of coordination number seven for the CdII ion. Both TEA ligands coordinate to the CdII ion, forming a distorted monocapped trigonal prismatic geometry with approximate C2v symmetry. One of the TEA ligands acts as an N,O,O,-tridentate ligand, whereas the other behaves as an N,O,O,,O,,-tetradentate donor. The anions and cations are linked to one another by hydrogen bonds between hydroxy H atoms of the TEA ligands and squarate O atoms. The crystal structure is stabilized by O,H,O hydrogen bonds between the unligated water molecule and a squarate O atom, together with a weak ,,ring interaction between the ethylene group of a TEA ligand and a squarate anion. [source] Polymeric hexa-,-nicotinato-tricadmium(II) tetrahydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2003Hong-Ji Chen The title polymeric complex, poly[tetraaquatricadmium(II)-hexa-,-nicotinato], [Cd3(C6H4NO2)6(H2O)4]n, exhibits two types of metal centers, i.e. a seven-coordinated Cd atom and a six-coordinated Cd atom located on an inversion center. The seven-coordinated Cd atoms are linked by ,3N:O,O,-nicotinate bridges into one-dimensional chains that are further linked by ,2N,O -nicotinate,Cd2,,2N,O -nicotinate bridges into a two-dimensional network which is parallel to the xy plane and which contains large 24- and 36-membered rings. [source] 1,2,4,5-Tetrakis(2-vinylpyridyl)benzene,dichloromethane (1/2)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2003Brian T. Holmes The title compound, C34H26N4·2CH2Cl2, lies about an inversion center. The solvent molecules interact with the benzene molecule both through C,H,N hydrogen bonding to span pyridine N atoms of adjacent vinyl groups, possibly stabilizing the rotational conformation observed, and through a , interaction between a dichloromethane Cl atom and a pyridyl ring C,C bond of a c -glide-related molecule. The benzene molecules form stacks along the a axis such that two of the four olefin groups are properly oriented for photoreactivity (2+2 cyclodimerization). [source] Ni(bipy)2Ni(CN)4, a new type of one-dimensional square tetracyano complexACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2000Juraj, ernák The one-dimensional structure of catena -poly[[bis(2,2,-bipyridyl-1,2N,N,)-,-cyano-1:2,2N:C -dicyano-2,2C -dinickel(II)]-,-cyano- C:N], [Ni2(CN)4(C10H8N2)2]n, consists of infinite zigzag chains running parallel to the c axis. The chains are composed of paramagnetic [Ni(bipy)2]2+ cations (bricks; nickel on a twofold axis) linked by diamagnetic [Ni(CN)4]2, anions (mortar; nickel on an inversion center) via bridging cyano groups. The bridging cyano groups occupy cis positions in the cation and trans positions in the anion, giving rise to a new previously unknown CT-type chain (i.e. cis,trans -type) among square tetracyano complexes. The coordination polyhedron of the paramagnetic Ni atom (twofold symmetry) is a slightly deformed octahedron with the two Ni,N(bipy) bonds in cis positions being somewhat longer [2.112,(3),Å] than the remaining four Ni,N bonds with a mean value of 2.065,(6),Å. The bond distances and angles in the anion have typical values. [source] Analysis of lattice-translocation disorder in the layered hexagonal structure of carboxysome shell protein CsoS1CACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2009Yingssu Tsai Lattice-translocation or crystal order,disorder phenomena occur when some layers or groups of molecules in a crystal are randomly displaced relative to other groups of molecules by a discrete set of vectors. In previous work, the effects of lattice translocation on diffraction intensities have been corrected by considering that the observed intensities are the product of the intensities from an ideal crystal (lacking disorder) multiplied by the squared magnitude of the Fourier transform of the set of translocation vectors. Here, the structure determination is presented of carboxysome protein CsoS1C from Halothiobacillius neapolitanus in a crystal exhibiting a lattice translocation with unique features. The diffraction data are fully accounted for by a crystal unit cell composed of two layers of cyclic protein hexamers. The first layer is fully ordered (i.e. has one fixed position), while the second layer randomly takes one of three alternative positions whose displacements are related to each other by threefold symmetry. Remarkably, the highest symmetry present in the crystal is P3, yet the intensity data (and the Patterson map) obey 6/m instead of symmetry; the intensities exceed the symmetry expected from combining the crystal space group with an inversion center. The origin of this rare phenomenon, known as symmetry enhancement, is discussed and shown to be possible even for a perfectly ordered crystal. The lattice-translocation treatment described here may be useful in analyzing other cases of disorder in which layers or groups of molecules are shifted in multiple symmetry-related directions. [source] Crystal Structures and Characterizations of Bis (pyrrolidinedithiocarbamato) Cu(II) and Zn(II) ComplexesCHINESE JOURNAL OF CHEMISTRY, Issue 1 2003Jian Fang-Fang Abstract The structures of [Cu (S2CN (CH2)4)2] (1) and [Zn2(S2CN-(CH2)4)4] (2) have been determined by X-ray crystallography analysis. They are all isomorphous and triclinic, space group of P1,, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, , = 75.912(2)°, , = 78.634(2)° and , = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, , = 74.813(2)°, , = 73.048(2)° and , = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square-planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability. [source] Intermolecular ,-stacking and F...F interactions of fluorine-substituted meso -alkynylporphyrinACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Yuta Marushima Two C2-symmetric meso -alkynylporphyrins, namely 5,15-bis[(4-butyl-2,3,5,6-tetrafluorophenyl)ethynyl]-10,20-dipropylporphyrin, C50H42F8N4, (I), and 5,15-bis[(4-butylphenyl)ethynyl]-10,20-dipropylporphyrin, C50H50N4, (II), show remarkable ,,, stacking that forms columns of porphyrin centers. The tetrafluorophenylene moieties in (I) show intermolecular interactions with each other through the F atoms, forming one-dimensional ribbons. No significant ,,, interactions are observed in the plane of the phenylene and tetrafluorophenylene moieties in either (I) or (II). The molecules of both compounds lie about inversion centers. [source] Benzene-1,4-diboronic acid,4,4,-bipyridine,water (1/2/2)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Araceli Vega In the presence of water, benzene-1,4-diboronic acid (1,4-bdba) and 4,4,-bipyridine (4,4,-bpy) form a cocrystal of composition (1,4-bdba)(4,4,-bpy)2(H2O)2, in which the molecular components are organized in two, so far unknown, cyclophane-type hydrogen-bonding patterns. The asymmetric unit of the title compound, C6H8B2O4·2C10H8N2·2H2O, contains two 4,4,-bpy, two water molecules and two halves of 1,4-bdba molecules arranged around crystallographic inversion centers. The occurrence of O,H...O and O,H...N hydrogen bonds involving the water molecules and all O atoms of boronic acid gives rise to a two-dimensional hydrogen-bonded layer structure that develops parallel to the (01) plane. This supramolecular organization is reinforced by ,,, interactions between symmetry-related 4,4,-bpy molecules. [source] catena -Poly[[aqua(11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline-,2N4,N5)cadmium(II)]-,-benzene-1,4-dicarboxylato-,3O1,O1,:O4]: an inclined interpenetrating (6,3) networkACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Zhi-Guo Kong The asymmetric unit of the title compound, [Cd(C8H4O4)(C17H8ClN5)(H2O)]n, contains one CdII atom, two half benzene-1,4-dicarboxylate (1,4-bdc) anions, one 11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline (L) ligand and one coordination water molecule. The 1,4-bdc ligands are on inversion centers at the centroids of the arene rings. The CdII atom is six-coordinated by two N atoms from one L ligand, three carboxylate O atoms from two different 1,4-bdc ligands and one water O atom in a distorted octahedral coordination sphere. Each CdII center is bridged by the 1,4-bdc dianions to give a one-dimensional chain. ,,, stacking interactions between L ligands of neighboring chains extend adjacent chains into a two-dimensional supramolecular (6,3) network. Neighboring (6,3) networks are interpenetrated in an unusual inclined mode, resulting in a three-dimensional framework. Additionally, the water,carboxylate O,H...O hydrogen bonds observed in the network consolidate the interpenetrating nets. [source] Two new cobalt(II) fumarates and a redetermination of tetraaquacobalt(II) fumarate monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2009Sándor L. Bekö Poly[triaqua-,4 -fumarato-cobalt(II)], [Co(C4H2O4)(H2O)3]n, (I), contains two symmetry-independent octahedrally coordinated Co2+ ions, both on inversion centers. One Co2+ ion is coordinated by two water molecules and four fumarate dianions, whereas the other Co2+ ion is surrounded by four water molecules and two fumarate dianions. Each fumarate dianion is bonded to three Co2+ ions, leading to a two-dimensional structure. The fumarate dianions are nonplanar; the angle between the planes of the two carboxylate groups is 54.9,(2)°. The cobalt(II) fumarate layers are connected by hydrogen bonding into a three-dimensional network. Compound (I) is not isostructural with calcium(II) fumarate trihydrate [Gupta et al. (1972). Acta Cryst. B28, 135,139]. In poly[,4 -fumarato-dimethanolcobalt(II)], [Co(C4H2O4)(CH4O)2]n, (II), the Co2+ ions are octahedrally coordinated by four fumarate dianions and two methanol molecules, leading to a three-dimensional structure. The fumarate group is planar. The Co2+ ions and the fumarate dianions both lie on inversion centers. Additionally, the one-dimensional structure of catena -poly[[[tetraaquacobalt(II)]-,2 -fumarato] monohydrate], {[Co(C4H2O4)(H2O)4]·H2O}n, (III), was redetermined at a higher resolution, and the space group C2/c was confirmed. [source] Structural effects on the solid-state photodimerization of 2-pyridone derivatives in inclusion compoundsACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Marina Telzhensky The structures of six crystalline inclusion compounds between various host molecules and three guest molecules based on the 2-pyridone skeleton are described. The six compounds are 1,1,-biphenyl-2,2,-dicarboxylic acid,2-pyridone (1/2), C14H10O4·2C5H5NO, (I,a), 1,1,-biphenyl-2,2,-dicarboxylic acid,4-methyl-2-pyridone (1/2), C14H10O4·2C6H7NO, (I,c), 1,1,-biphenyl-2,2,-dicarboxylic acid,6-methyl-2-pyridone (1/2), C14H10O4·2C6H7NO, (I,d), 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol,1-methyl-2-pyridone (1/2), C30H22O2·2C6H7NO, (II,b), 1,1,6,6-tetraphenyl-2,4-hexadiyne-1,6-diol,4-methy-2-pyridone (1/2), C30H22O2·2C6H7NO, (II,c), and 4,4,,4,,-(ethane-1,1,1-triyl)triphenol,6-methyl-2-pyridone,water (1/3/1), C20H18O3·3C6H7NO·H2O, (III,d). In two of the compounds, (I,a) and (I,d), the host molecules lie about crystallographic twofold axes. In two other compounds, (II,b) and (II,c), the host molecules lie across inversion centers. In all cases, the guest molecules are hydrogen bonded to the host molecules through O,H...O=C hydrogen bonds [the range of O...O distances is 2.543,(2),2.843,(2),Å. The pyridone moieties form dimers through N,H...O=C hydrogen bonds in five of the compounds [the range of N...O distances is 2.763,(2),2.968,(2),Å]. In four compounds, (I,a), (I,c), (I,d) and (II,c), the molecules are arranged in extended zigzag chains formed via host,guest hydrogen bonding. In five of the compounds, the guest molecules are arranged in parallel pairs on top of each other, related by inversion centers. However, none of these compounds underwent photodimerization in the solid state upon irradiation. In one of the crystalline compounds, (III,d), the guest molecules are arranged in stacks with one disordered molecule. The unsuccessful dimerization is attributed to the large interatomic distances between the potentially reactive atoms [the range of distances is 4.027,(4),4.865,(4),Å] and to the bad overlap, expressed by the lateral shift between the orbitals of these atoms [the range of the shifts from perfect overlap is 1.727,(4),3.324,(4),Å]. The bad overlap and large distances between potentially photoreactive atoms are attributed to the hydrogen-bonding schemes, because the interactions involved in hydrogen bonding are stronger than those in ,,, interactions. [source] | ||||||||||