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Zn Atom (zn + atom)
Selected AbstractsLocal 3D real space atomic structure of the simple icosahedral Ho11Mg15Zn74 quasicrystal from PDF dataCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2003S. Brühne Abstract We present a new complementary strategy to quasicrystalline structure determination: The local atomic structure of simple icosahedral (si) Ho11Mg15Zn74 [a(6D) = 5.144(3)Å in a sphere of up to r = 17Å was refined using the atomic pair distribution function (PDF) from in-house X-ray powder diffraction data (MoK,1, Qmax = 13.5Å,1; R = 20.4%). The basic building block is a 105-atom Bergman-Cluster {Ho8Mg12Zn85}. Its center is occupied by a Zn atom , in contrast to a void in face centred icosahedral (fci) Ho9Mg26Zn65. The center is then surrounded by another 12 Zn atoms, forming an icosahedron (1st shell). The 2nd shell is made up of 8 Ho atoms arranged on the vertices of a cube which in turn is completed to a pentagon dodecahedron by 12 Mg atoms, the dodecahedron then being capped by 12 Zn atoms. The 3rd shell is a distorted soccer ball of 60 Zn atoms, reflecting the higher Zn content of the si phase compared to the fci phase. In our model, 7% of all atoms are situated in between the clusters. The model corresponds to a hypothetical 1/1-approximant of the icosahedral (i) phase. The local coordinations of the single atoms are of a much distorted Frank-Kasper type and call to mind those present in 0/1-Mg2Zn11. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Syntheses, Characterization, and Luminescent Properties of Monoethylzinc Complexes with Anilido,Imine LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2007Qing Su Abstract The syntheses of three anilido,imine ligands of the general formula ortho -C6H4(NHAr,)(CH=NAr, [Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6-Me2C6H3 (2a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (2b); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6- iPr2C6H3 (2c)] and four zinc(II) complexes of the general formula [ortho -C6H4(NHAr,)(CH=NAr,)]ZnEt [Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Me2C6H3 (3a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (3b); Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6- iPr2C6H3 (3c); Ar, = 2,6-Me2C6H3, Ar, = 2,6- iPr2C6H3 (3d)] are described. The complexes were synthesized from the reaction of ZnEt2 with corresponding ligands 2 by alkane elimination. All compounds were characterized by elemental analysis and 1H and 13C NMR spectroscopy. The molecular structures of compounds 2a, 2b, 3b, and 3c were determined by single-crystal X-ray crystallography. The X-ray analysis reveals that complexes 3b and 3c exist in the dimeric form with the N atom in the quinolyl ring coordinating to the other Zn atom to make the Zn atoms four coordinate. Luminescent properties of ligands 2a,2d and complexes 3a,3d in both solution and the solid state were studied. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Zinc Hydrazide and Zinc Alkoxide Hydrazide Cages with Zn4N8 and Zn4N6O Cores , Cluster Isomerism as a Result of Subtle Changes in Ligand SizeEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2006Surajit Jana Abstract The hydrazide cluster [(iPrZn)4(NHNMe2)4] (1) was synthesised by the reaction of diisopropylzinc with N,N -dimethylhydrazine and was characterised by 1H- and 13C NMR and IR spectroscopy, mass spectrometry, elemental analysis and X-ray crystallography. This compound forms asymmetric aggregates containing Zn4N8 cores. The Zn atoms in these aggregates are arranged in topological tetrahedra in which the triangular faces are bridged by NHNMe2 substituents. Each NH group is connected to two Zn atoms and each NMe2 group to one Zn atom. Alkoxide clusters were prepared in one-pot syntheses by treating diisopropylzinc solutions with mixtures of N,N -dimethylhydrazine and ROH (R = Et, iPr). The resulting compounds have the formula [(iPrZn)4(NHNMe2)3(OR)] [R = Et (3), iPr(4)] and contain Zn4N6O cages, such that one NHNMe2 in 1 is replaced by one alkoxide group. Two different aggregation modes were found for these Zn4N6O cages. In compound 3, one Zn atom is bound to two NMe2 groups and one NH group. The other three Zn atoms each have three bonds to NH groups and one dative bond to an NMe2 group. The cage consists of one four-membered and one six-membered ring as well as four five-membered rings. In compound 4, the fourth zinc atom is exclusively bonded to three anionic NH functions in such a way that the rings in the cage are all five-membered. Compounds 3 and 4 were characterised by NMR spectroscopy and single-crystal X-ray diffraction. Hydrazide hydroxide clusters were also obtained through the reaction of a diisopropylzinc solution with N,N -dimethylhydrazine and a small amount of water. The structure of the resulting cocrystalline material, [(iPrZn)4(NHNMe2)4]·[(iPrZn)4(NHNMe2)3(OH)] (2), was also confirmed by X-ray diffraction. The hydroxide cluster in 2 contains a Zn4N6O cage, with a similar aggregation mode to that of 4. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Ab-initio investigation of structural, electronic and optical properties for three phases of ZnO compoundPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 9 2007Z. Charifi Abstract The complex density-functional theory (DFT) calculations of structural, electronic and optical properties for the three phases: wurtzite (B4), zincblende (B3) and rocksalt (B1) of ZnO compound have been reported using the full-potential linearized-augmented plane-wave (FP-LAPW) method as implemented in the WIEN2k code. We employed both the local-density approximation (LDA) and the generalized-gradient approximation (GGA), which is based on exchange,correlation energy optimization to calculate the total energy. Also, we have used the Engel,Vosko GGA formalism, which optimizes the corresponding potential for band-structure calculations. The 3d orbitals of the Zn atom were treated as the valence band. The calculated structural properties (equilibrium lattice constant, bulk modulus, etc.) of the wurtzite and rocksalt phases are in good agreement with experiment. The B4 structure of ZnO is found to transform to the B1 structure with a large volume collapse of about 17%. The phase transition pressure obtained by using LDA is about 9.93 in good agreement with the experimental data. B1-ZnO is shown to be an indirect bandgap semiconductor with a bandgap of 1.47 eV, which is significantly smaller than the experimental value (2.45 ± 0.15 eV). While B3 and B1 phases have direct bandgap semiconductors with bandgaps 1.46 and 1.57 eV, respectively. Also, we have presented the results of the effective masses. We present calculations of the frequency-dependent complex dielectric function , (,) and it zero-frequency limit ,1(0). The optical properties of B4 phase show considerable anisotropic between the two components. The reflectivity spectra has been calculated and compared with the available experimental data. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Charge-density analysis of the ground state of a photochromic 1,10-phenanthroline zinc(II) bis(thiolate) complexACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2010Stephan Scheins The charge density of the title compound was determined at 90,K, using a spherical crystal of 150,µm diameter. The proper treatment of the Zn atom in the pseudo-tetrahedral environment is considered in detail. A satisfactory refinement is only obtained when anharmonic Gram,Charlier parameters are included as variables in the refinement. A successful combined anharmonic/multipole refinement indicates a small polarization of the 4s shell in the anisotropic environment. One of the two toluenethiols is approximately ,-stacked with the phenanthroline ligand. A bond path is found connecting the two ligands. In addition the Zn,S bond to this ligand is slightly extended compared with the same bond to the second toluenethiol. A separate photocrystallographic and theoretical study indicates the long wavelength emission of the title compound to be due to a ligand-to-ligand charge transfer (LLCT) from a toluenethiol to the phenanthroline ligand. The charge-density results do not provide a basis for deciding which of the thiole ligands is the source of the transferred electron density. This result is in agreement with the theoretical calculations, which show comparable oscillator strengths for charge transfer from either of the ligands. [source] Ethyl[tris(3- tert -butyl-5-methylpyrazol-1-yl)hydridoborato]zinc(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2010Mukesh Kumar The X-ray crystal structure of the title compound, [Zn(C2H5)(C24H40BN6)], or TptBu,MeZnEt [TptBu,Me is tris(3- tert -butyl-5-methylpyrazolyl)hydridoborate], reveals a distorted tetrahedral geometry around the Zn atom. The Zn center is coordinated by three N atoms of the borate ligand and by one C atom of the ethyl group. The present structure and other tetrahedral Tp zinc alkyl complexes are compared with similar Ttz ligands (Ttz is 1,2,4-triazolylborate), but no major differences in the structures are noted, and it can be assumed that variation of the substitution pattern of Tp or Ttz ligands has little or no influence on the geometry of alkylzinc complexes. Refinement of the structure is complicated by a combination of metric pseudosymmetry and twinning. The metrics of the structure could also be represented in a double-volume C -centered orthorhombic unit cell, and the structure is twinned by one of the orthorhombic symmetry operators not present in the actual structure. The twinning lies on the borderline between pseudomerohedral and nonmerohedral. The data were refined as being nonmerohedrally twinned, pseudomerohedrally twinned and untwinned. None of the approaches yielded results that were unambiguously better than any of the others: the best fit between structural model and data was observed using the nonmerohedral approach which also yielded the best structure quality indicators, but the data set is less than 80% complete due to rejected data. The pseudomerohedral and the untwinned structures are complete, but relatively large residual electron densities that are not close to the metal center are found with values up to three times higher than in the nonmerohedral approach. [source] Ce20Mg19Zn81: a new structure type with a giant cubic cellACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2008Volodymyr Pavlyuk Icosacerium nonadecamagnesium henoctacontazinc, Ce20Mg19Zn81, synthesized by fritting of the pure elements with subsequent arc melting, crystallizes with an unusually large cubic unit cell [space group F3m, a = 21.1979,(8),Å] and represents a new structure type among the technologically important family of ternary rare earth,transition metal,magnesium intermetallics. The majority of atoms (two Ce and five Zn) display .3m site symmetry, two Ce and one Mg atom occupy three 2.mm positions, one Mg and one Zn have 3m site symmetry, one Mg and three Zn atoms sit in ..m positions, and one Zn atom is in a general position. The Ce20Mg19Zn81 structure can be described using the geometric concept of nested polyhedral units, by which it consists of four different polyhedral units, viz. A (Zn+Zn4+Zn4+Zn12+Ce6), B (Mg+Zn12+Ce4+Zn24+Ce4), C (Zn4+Zn12+Mg6) and D (Zn4+Zn4+Mg12+Ce6), with the outer construction unit being an octahedron or tetrahedron. All interatomic distances in the structure indicate metallic-type bonding. [source] {Bis(3,5-Di- tert -butyl-2-oxidobenzyl)[2-(N,N -dimethylamino)ethyl]amine-,4N,N,,O,O,}zinc(II) and {bis(3- tert -butyl-5-methyl-2-oxidobenzyl)[2-(N,N -dimethylamino)ethyl]amine-,4N,N,,O,O,}(tetrahdyrofuran)zinc(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2006Ruth H. Howard The title zinc(II) complexes, [Zn(C34H54N2O2)], (II), and [Zn(C28H42N2O2)(C4H8O)], (III), were obtained as monomeric 1:1 complexes, in contrast with the calcium complexes supported by the same ligand class. Complex (II) crystallizes with two independent molecules in the asymmetric unit, which have similar geometric parameters. The donor atoms in (II) form a distorted trigonal,pyramidal arrangement around the zinc centre. Complex (III) contains a coordinated tetrahydrofuran molecule, resulting in a five-coordinate trigonal,bipyramidal arrangement around the Zn atom. The electron density provided by the coordination of this tetrahydrofuran molecule elongates the Zn,O and Zn,N bonds by approximately 0.07 and 0.10,Å, respectively, in comparison with (II). Neither (II) nor (III) is active as an ,-caprolactone polymerization catalyst. The data presented here demonstrate that Zn may bind both an ONNO ligand and an additional oxygen-based ligand. The lack of activity is thus not due to steric hinderance at the metal atom. [source] Butane-1,4-diamine zinc(II) hydrogen phosphiteACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2004Lyndsey K. Ritchie The title compound, poly[zinc(II)-,-butane-1,4-diamine-,-(hydrogen phosphito)] (C4H12N2)0.5[ZnHPO3], is a hybrid organic,inorganic solid built up from 1,4-diaminobutane molecules, Zn2+ cations (coordinated by three O atoms and one N atom) and HPO32, hydrogen phosphite groups. The organic species bonds to the Zn atom as an unprotonated ligand, resulting in it acting as a bridge between infinite ZnHPO3 layers, which propagate in (100). The complete butane-1,4-diamine species is generated from a H2N(CH2)2, half molecule by inversion symmetry. The zincophosphite sheets contain polyhedral four- and eight-membered rings in a 4.82 topology. [source] (2,2,-Bipyridine-,2N)bis[N -(2-pyridyl-,N)- p -toluenesulfonamido-,N]zinc(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2000Santiago Cabaleiro The structure of the title compound, [Zn(C12H11N2O2S)2(C10H8N2)], consists of monomeric molecules in which the central ZnN2N,N,, unit has a distorted tetrahedral geometry, with bond lengths ranging from 2.020,(3) to 2.109,(3),Å. The anionic ligands are potential bidentate donors and thus there are two secondary Zn,N interactions. The shorter of these is 2.317,(3),Å and completes at the Zn atom an irregular five-coordinated geometry, which can be described as a square pyramid showing 30% distortion towards the trigonal bipyramid; the other Zn,N contact is much longer at 2.549,(3),Å. [source] Local 3D real space atomic structure of the simple icosahedral Ho11Mg15Zn74 quasicrystal from PDF dataCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2003S. Brühne Abstract We present a new complementary strategy to quasicrystalline structure determination: The local atomic structure of simple icosahedral (si) Ho11Mg15Zn74 [a(6D) = 5.144(3)Å in a sphere of up to r = 17Å was refined using the atomic pair distribution function (PDF) from in-house X-ray powder diffraction data (MoK,1, Qmax = 13.5Å,1; R = 20.4%). The basic building block is a 105-atom Bergman-Cluster {Ho8Mg12Zn85}. Its center is occupied by a Zn atom , in contrast to a void in face centred icosahedral (fci) Ho9Mg26Zn65. The center is then surrounded by another 12 Zn atoms, forming an icosahedron (1st shell). The 2nd shell is made up of 8 Ho atoms arranged on the vertices of a cube which in turn is completed to a pentagon dodecahedron by 12 Mg atoms, the dodecahedron then being capped by 12 Zn atoms. The 3rd shell is a distorted soccer ball of 60 Zn atoms, reflecting the higher Zn content of the si phase compared to the fci phase. In our model, 7% of all atoms are situated in between the clusters. The model corresponds to a hypothetical 1/1-approximant of the icosahedral (i) phase. The local coordinations of the single atoms are of a much distorted Frank-Kasper type and call to mind those present in 0/1-Mg2Zn11. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Syntheses, Characterization, and Luminescent Properties of Monoethylzinc Complexes with Anilido,Imine LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2007Qing Su Abstract The syntheses of three anilido,imine ligands of the general formula ortho -C6H4(NHAr,)(CH=NAr, [Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6-Me2C6H3 (2a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (2b); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6- iPr2C6H3 (2c)] and four zinc(II) complexes of the general formula [ortho -C6H4(NHAr,)(CH=NAr,)]ZnEt [Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Me2C6H3 (3a); Ar, = 7-(2,4-Me2)C9H4N, Ar,= 2,6-Et2C6H3 (3b); Ar, = 7-(2,4-Me2)C9H4N, Ar, = 2,6- iPr2C6H3 (3c); Ar, = 2,6-Me2C6H3, Ar, = 2,6- iPr2C6H3 (3d)] are described. The complexes were synthesized from the reaction of ZnEt2 with corresponding ligands 2 by alkane elimination. All compounds were characterized by elemental analysis and 1H and 13C NMR spectroscopy. The molecular structures of compounds 2a, 2b, 3b, and 3c were determined by single-crystal X-ray crystallography. The X-ray analysis reveals that complexes 3b and 3c exist in the dimeric form with the N atom in the quinolyl ring coordinating to the other Zn atom to make the Zn atoms four coordinate. Luminescent properties of ligands 2a,2d and complexes 3a,3d in both solution and the solid state were studied. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Zinc Hydrazide and Zinc Alkoxide Hydrazide Cages with Zn4N8 and Zn4N6O Cores , Cluster Isomerism as a Result of Subtle Changes in Ligand SizeEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2006Surajit Jana Abstract The hydrazide cluster [(iPrZn)4(NHNMe2)4] (1) was synthesised by the reaction of diisopropylzinc with N,N -dimethylhydrazine and was characterised by 1H- and 13C NMR and IR spectroscopy, mass spectrometry, elemental analysis and X-ray crystallography. This compound forms asymmetric aggregates containing Zn4N8 cores. The Zn atoms in these aggregates are arranged in topological tetrahedra in which the triangular faces are bridged by NHNMe2 substituents. Each NH group is connected to two Zn atoms and each NMe2 group to one Zn atom. Alkoxide clusters were prepared in one-pot syntheses by treating diisopropylzinc solutions with mixtures of N,N -dimethylhydrazine and ROH (R = Et, iPr). The resulting compounds have the formula [(iPrZn)4(NHNMe2)3(OR)] [R = Et (3), iPr(4)] and contain Zn4N6O cages, such that one NHNMe2 in 1 is replaced by one alkoxide group. Two different aggregation modes were found for these Zn4N6O cages. In compound 3, one Zn atom is bound to two NMe2 groups and one NH group. The other three Zn atoms each have three bonds to NH groups and one dative bond to an NMe2 group. The cage consists of one four-membered and one six-membered ring as well as four five-membered rings. In compound 4, the fourth zinc atom is exclusively bonded to three anionic NH functions in such a way that the rings in the cage are all five-membered. Compounds 3 and 4 were characterised by NMR spectroscopy and single-crystal X-ray diffraction. Hydrazide hydroxide clusters were also obtained through the reaction of a diisopropylzinc solution with N,N -dimethylhydrazine and a small amount of water. The structure of the resulting cocrystalline material, [(iPrZn)4(NHNMe2)4]·[(iPrZn)4(NHNMe2)3(OH)] (2), was also confirmed by X-ray diffraction. The hydroxide cluster in 2 contains a Zn4N6O cage, with a similar aggregation mode to that of 4. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] The new ternary phases of La3(Zn0.874Mg0.126)11 and Ce3(Zn0.863Mg0.137)11ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Volodymyr Pavlyuk The new ternary intermetallic title compounds, namely trilanthanum undeca(zinc/magnesium), La3(Zn0.874Mg0.126)11, (I), and tricerium undeca(zinc/magnesium), Ce3(Zn0.863Mg0.137)11, (II), are isostructural and crystallize in the orthorhombic La3Al11 structure type. These three phases belong to the same structural family, the representative members of which may be derived from the tetragonal BaAl4 structure type by a combination of internal deformation and multiple substitution. Compared to the structure of La3Al11, in (I), a significant decrease of 11.9% in the unit-cell b axis and an increase in the other two directions, of 3.6% along a and 5.2% along c, are observed. Such an atypical deformation is caused by the closer packing of atoms in the unit cell due to atom shifts that reflect strengthening of metallic-type bonding. This structural change is also manifested in a significant difference in the coordination around the smaller atoms at the 8l Wyckoff position (site symmetry m). The Al atom in La3Al11 is in a tricapped trigonal prismatic environment (coordination number 9), while the Zn atoms in (I) and (II) are situated in a tetragonal antiprism with two added atoms (coordination number 10). [source] A double-layered zinc(II) coordination polymer with the ligand 3,5-bis(carboxylatomethoxy)benzoateACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2009Zhong-Min Cen In the title compound, poly[hexaaquabis[,4 -3,5-bis(carboxylatomethoxy)benzoato]trizinc(II)], [Zn3(C11H7O8)2(H2O)6]n, there are two crystallographically distinct ZnII cations which are bridged by polycarboxylate ligands in a ,4 -bridging mode. A pair of ligands bridges adjacent Zn atoms to give centrosymmetric dimetal building blocks which act as four-connected nodes to be further interlinked into a two-dimensional double-layered framework with (4,4) topology. Other Zn atoms, lying on inversion centres, occupy the cavities of this topological structure. This submission shows a versatile polycarboxylate ligand with rigid and flexible functional groups, the co-operation and complementarity of which would meet the coordination requirements of a variety of topological structures. [source] Ce20Mg19Zn81: a new structure type with a giant cubic cellACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2008Volodymyr Pavlyuk Icosacerium nonadecamagnesium henoctacontazinc, Ce20Mg19Zn81, synthesized by fritting of the pure elements with subsequent arc melting, crystallizes with an unusually large cubic unit cell [space group F3m, a = 21.1979,(8),Å] and represents a new structure type among the technologically important family of ternary rare earth,transition metal,magnesium intermetallics. The majority of atoms (two Ce and five Zn) display .3m site symmetry, two Ce and one Mg atom occupy three 2.mm positions, one Mg and one Zn have 3m site symmetry, one Mg and three Zn atoms sit in ..m positions, and one Zn atom is in a general position. The Ce20Mg19Zn81 structure can be described using the geometric concept of nested polyhedral units, by which it consists of four different polyhedral units, viz. A (Zn+Zn4+Zn4+Zn12+Ce6), B (Mg+Zn12+Ce4+Zn24+Ce4), C (Zn4+Zn12+Mg6) and D (Zn4+Zn4+Mg12+Ce6), with the outer construction unit being an octahedron or tetrahedron. All interatomic distances in the structure indicate metallic-type bonding. [source] A novel O,Zn bridging polymer complex of 2,6-bis[bis(carboxylatomethyl)aminomethyl]-4-methylphenolateACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2008Yuan-Yuan Zhang A new one-dimensional coordination polymer, catena -poly[[acetatohexaaqua{,4 -2,6-bis[bis(carboxylatomethyl)aminomethyl]-4-methylphenolato}trizinc(II)] octahydrate], [Zn3(C17H17N2O9)(C2H3O2)(H2O)6]·8H2O, is a trinuclear complex consisting of three zinc centers joined by a phenolate bridge and Zn(H2O)4 units. In each complex polymer unit, the three Zn atoms have different coordination modes. Of the two phenolate-bridged Zn ions, one adopts a distorted octahedral coordination composed of two carboxylate ligands, one tertiary N atom, two water molecules and the bridging phenolate ligand, while the other adopts a pyramidal geometry composed of two carboxylate ligands, one tertiary N atom from another coordination arm, one acetate anion as the counter-anion and the bridging phenolate ligand. The third type of Zn centre is represented by two independent Zn atoms lying on inversion centres. They both have an octahedral coordination consisting of four O atoms from four water molecules and two acetate carbonyl O atoms from the ligand. The latter Zn atoms join the above-mentioned binuclear complex units through O atoms of the carboxylate groups into an infinite chain. Neighboring aromatic rings are distributed above and below the chain in an alternating manner. Between the coordination chains, the Zn...Zn separations are 5.750,(4) and 6.806,(4),Å. The whole structure is stabilized by hydrogen bonds formed mainly by solvent water molecules. [source] Two one-dimensional zinc(II) coordination polymers: catena -poly[[bis(pentane-2,4-dionato-,2O,O,)zinc]-,-1,4-bis(x -pyridyl)-2,3-diazabuta-1,3-diene] (x = 3, 4)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2006Juan Granifo The structures of the two title isomeric compounds, [Zn(C5H7O2)2(C12H10N4)]n, are built up around two non-equivalent symmetry centres, one of them at the cation position and the other bisecting the N,N bond in the 1,4-bis(3/4-pyridyl)-2,3-diazabuta-1,3-diene (3pdb/4pdb) units. Both Zn cations have the Zn atoms an inversion centres and present tetragonally distorted octahedral environments, but differences in their linkage through the 3pdb and 4pdb ligands give rise to differently shaped weakly interacting chains. [source] Crystallization of FLINC4, an intramolecular LMO4,ldb1 complexACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2003Janet E. Deane LMO4 is the most recently discovered member of a small family of nuclear transcriptional regulators that are important for both normal development and disease processes. LMO4 is comprised primarily of two tandemly repeated LIM domains and interacts with the ubiquitous nuclear adaptor protein ldb1. This interaction is mediated via the LIM domains of LMO4 and the LIM-interaction domain (LID) of ldb1. An intramolecular complex, termed FLINC4, consisting of the two LIM domains from LMO4 linked to the LID domain of ldb1 via a flexible linker has been engineered, purified and crystallized. The trigonal crystals, which belong to space group P312 with unit-cell parameters a = 61.3, c = 93.2,Å, diffract to 1.3,Å resolution and contain one molecule of FLINC4 per asymmetric unit. Native and multiple-wavelength anomalous dispersion (MAD) data collected at the Zn X-ray absorption edge have been recorded to 1.3 and 1.7,Å resolution, respectively. Anomalous Patterson maps calculated with data collected at the peak wavelength show strong peaks sufficient to determine the positions of four Zn atoms per asymmetric unit. [source] | |||||||||||||