Pentagonal pyramidal lead coordination in the crystal structure of dimeric diaquopyridine-2,6-dicarboxylatolead(II) pyridine-2,6-dicarboxylic acid monohydrate

1979 ◽  
Vol 57 (18) ◽  
pp. 2498-2503 ◽  
Author(s):  
A. Beveridge ◽  
W. Bushnell
Keyword(s):  
Crystal Structure ◽  
Dicarboxylic Acid ◽  
Electron Pair ◽  
Solid Angle ◽  
Lone Pair ◽  
Axial Position ◽  
Asymmetric Unit ◽  
Inversion Point ◽  
The Mean ◽  
Lead Complex

The crystal structure of dimeric diaquopyridine-2,6-dicarboxylatolead(II) pyridine-2,6-dicarboxylic acid monohydrate, empirical formula and asymmetric unit C14H14N2O11Pb, has been solved and refined to R = 0.081, Rw = 0.100. The space group was [Formula: see text] with a = 1073.8(3), b = 1123.2(5), c = 705.0(3) pm, α = 101.28(8)°, β = 95.42(6)°, γ = 92.80(7)°, ρ = 2.37 g cm−3 (meas.). Measurements were done on an automatic 4-circle diffractometer ([Formula: see text], λ = 71.069 pm), and corrected for absorption. The lead complex is dinuclear with an inversion point at the centre of the double bridging. Each lead atom has distorted pentagonal pyramidal coordination with a water molecule at the apex. The basal ligands are water and terdentate pyridine-2,6-dicarboxylate. The double bridging is by one of the coordinated carboxylic oxygen atoms and its inverse. The electron pair geometry is assumed to be pentagonal bipyramidal with a stereochemically active lone pair occupying considerable solid angle in an axial position. Bond lengths (±2 pm) are: Pb—OH2 (apex), 259; Pb—OH2 (basal), 273; Pb—O, 251, 258, 273; Pb—N, 259. The mean of the bond angles at Pb involving the apical oxygen is 77°. The unit cell contains two water and two dicarboxylic acid molecules of crystallisation which are involved in an H-bonding network with one bond for each hydrogen attached to oxygen in the structure.

Structural Studies on N-(2,4,6-Trimethylphenyl)-methyl/ chloro-acetamides, 2,4,6-(CH3)3C6H2NH-CO-CH3–yXy (X = CH3 or Cl and y = 0, 1, 2)

2006 ◽  
Vol 61 (10-11) ◽  
pp. 588-594 ◽  
Author(s):  
Basavalinganadoddy Thimme Gowda ◽  
Jozef Kožíšek ◽  
Hartmut Fuess
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structural Data ◽  
The Other ◽  
Side Chain ◽  
Structural Studies ◽  
Asymmetric Unit ◽  
Lattice Constants ◽  
Peptide Linkage ◽  
The Mean

TMPAThe effect of substitutions in the ring and in the side chain on the crystal structure of N- (2,4,6-trimethylphenyl)-methyl/chloro-acetamides of the configuration 2,4,6-(CH3)3C6H2NH-COCH3− yXy (X = CH3 or Cl and y = 0,1, 2) has been studied by determining the crystal structures of N-(2,4,6-trimethylphenyl)-acetamide, 2,4,6-(CH3)3C6H2NH-CO-CH3 (); N-(2,4,6- trimethylphenyl)-2-methylacetamide, 2,4,6-(CH3)3C6H2NH-CO-CH2-CH3 (TMPMA); N-(2,4,6- trimethylphenyl)-2,2-dimethylacetamide, 2,4,6-(CH3)3C6H2NH-CO-CH(CH3)2 (TMPDMA) and N-(2,4,6-trimethylphenyl)-2,2-dichloroacetamide, 2,4,6-(CH3)3C6H2NH-CO-CHCl2 (TMPDCA). The crystallographic system, space group, formula units and lattice constants in Å are: TMPA: monoclinic, Pn, Z = 2, a = 8.142(3), b = 8.469(3), c = 8.223(3), β = 113.61(2)◦; TMPMA: monoclinic, P21/n, Z = 8, a = 9.103(1), b = 15.812(2), c = 16.4787(19), α = 89.974(10)◦, β = 96.951(10)◦, γ =89.967(10)◦; TMPDMA: monoclinic, P21/c, Z = 4, a =4.757(1), b= 24.644(4), c =10.785(2), β = 99.647(17)◦; TMPDCA: triclinic, P¯1, Z = 2, a = 4.652(1), b = 11.006(1), c = 12.369(1), α = 82.521(7)◦, β = 83.09(1)◦, γ = 79.84(1)◦. The results are analyzed along with the structural data of N-phenylacetamide, C6H5NH-CO-CH3; N-(2,4,6-trimethylphenyl)-2-chloroacetamide, 2,4,6-(CH3)3C6H2NH-CO-CH2Cl; N-(2,4,6-trichlorophenyl)-acetamide, 2,4,6-Cl3C6H2NH-COCH3; N-(2,4,6-trichlorophenyl)-2-chloroacetamide, 2,4,6-Cl3C6H2NH-CO-CH2Cl; N-(2,4,6-trichlorophenyl)- 2,2-dichloroacetamide, 2,4,6-Cl3C6H2NH-CO-CHCl2 and N-(2,4,6-trichlorophenyl)- 2,2,2-trichloroacetamide, 2,4,6-Cl3C6H2NH-CO-CCl3. TMPA, TMPMA and TMPDCA have one molecule each in their asymmetric units, while TMPDMA has two molecules in its asymmetric unit. Changes in the mean ring distances are smaller on substitution as the effect has to be transmitted through the peptide linkage. The comparison of the other bond parameters reveal that there are significant changes in them on substitution.

scholarly journals Dibromido(N-phenylbenzamidine-κN′)tin(II)

IUCrData ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Xiuming Ma
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Asymmetric Unit ◽  
Phenyl Rings ◽  
The Mean

The asymmetric unit of the title compound, [SnBr2(C13H12N2)], contains an amidine ligand and tin(II) bromide moiety. In the amidine ligand, the phenyl rings present a head-to-tail configuration mode. The tin atom is coordinated by the terminal N atom of the amidine ligand, and the two Br atoms extend to both sides of the Sn atom in a V-shape. The phenyl rings are twisted from the mean N/C/N plane by 26.14 (18) and 79.50 (8)°. The crystal structure features N—H...Br hydrogen bonds.

Darstellung und Kristallstruktur von Tl4TiS4, TI4SnS4 und Tl4TiSe4 / Preparation and Crystal Structure of Tl4TiS4, TI4SnS4 and Tl4TiSe4

1984 ◽  
Vol 39 (6) ◽  
pp. 705-712 ◽  
Author(s):  
Kurt O. Klepp ◽  
Günther Eulenberger
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Lone Electron Pair ◽  
Electron Pair ◽  
Monoclinic System ◽  
The Mean ◽  
Similar Description ◽  
Oriented Parallel ◽  
Stereochemical Activity

AbstractThe isostructural compounds Tl4TiS4, Tl4SnS4 and Tl4TiSe4 crystallize in the monoclinic system, space group P21/c with a = 8.328, b = 8.191, c = 15.248 Å, β = 104.53°; a = 8.395, b = 8.280, c = 15.398 A, ft = 103.69°, and a = 8.517, b = 8.389, c = 15.672 Å, β = 103.50°, respectively. There are four formula units in the unit cell. The crystal structures were determined and refined from single crystal diffractometer data. They are characterized by isolated tetrahedral thioanions which are connected with each other by Tl+ ions. The mean bond lengths are Ti-S = 2.26 Å, Sn-S = 2.40 Å and Ti -Se = 2.38 Å. The Tl atoms are surrounded by six and seven chalcogen atoms, respectively, in an irregular and polar arrangement, thus indicating stereochemical activity of the lone electron pair of the Tl+ ions. Tl-S distances vary from 2.93 to 3.98 Å, Tl-Se distances from 3.03 to 3.96 Å. The Tl atoms have nearest Tl neighbours at distances ranging from 3.46 to 3.65 Å. The crystal structure can be described as built from pseudotetragonal slabs oriented parallel to (001) which contain the cations and the tetrahedral anions. It is shown that a similar description is valid also for the crystal structures of Tl4GeS4 [1] and Na4SnS4 [2, 3].

scholarly journals Crystal structure of 3-amino-5,5-dimethyl-2-[(E)-2-nitroethenyl]cyclohex-2-en-1-one

2014 ◽  
Vol 70 (11) ◽  
pp. 379-381
Author(s):  
Brigita Vigante ◽  
Dmitrijs Stepanovs ◽  
Andrejs Pelss ◽  
Anatoly Mishnev
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Asymmetric Unit ◽  
Envelope Conformation ◽  
Compound C ◽  
The Mean ◽  
Independent Molecules

The asymmetric unit of the title compound, C10H14N2O3, contains two independent molecules with similar conformations. In the both molecules, the cyclohexene rings adopt the same envelope conformation with the flap C atoms lying 0.658 (3) and 0.668 (3) Å from the mean planes formed by the remaining atoms. In the crystal, adjacent molecules are connectedviaN—H...O hydrogen bonds and weak C—H...O interactions, forming supramolecular layers parallel to (-101).

scholarly journals Crystal structure ofN-[(4-ethoxyphenyl)carbamothioyl]cyclohexanecarboxamide

2015 ◽  
Vol 71 (11) ◽  
pp. o820-o821
Author(s):  
G. Vimala ◽  
J. Haribabu ◽  
S. Srividya ◽  
R. Karvembu ◽  
A. SubbiahPandi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Compound C ◽  
The Mean ◽  
Independent Molecules ◽  
Ring Motif

The asymmetric unit of the title compound, C16H22N2O2S, contains two crystallographically independent molecules (AandB). In moleculeA, the cyclohexane ring is disordered over two orientations [occupancy ratio 0.841 (10):0.159 (10)]. In each molecule, the central carbonyl thiourea unit is nearly planar (r.m.s. deviations for all non-H atoms of 0.034 Å in moleculeAand 0.094 Å in moleculeB). In both molecules, the cyclohexane ring adopts a chair conformation. The mean plane of the cyclohexane ring makes dihedral angles of 35.8 (4) (moleculeA) and 20.7 (3)° (moleculeB) with that of the benzene ring. Each molecule features an intramolecular N—H...O hydrogen bond, which closes anS(6) ring motif. In the crystal, molecules are linkedviapairs of weak N—H...S interactions, forming inversion dimers with anR22(8) ring motif for both molecules. The crystal structure also features weak C—H...π ring interactions.

The inner-salt zwitterion, the dihydrochloride dihydrate and the dimethyl sulfoxide disolvate of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid

2012 ◽  
Vol 68 (11) ◽  
pp. o431-o435 ◽  
Author(s):  
Yi Wang ◽  
Helen Stoeckli-Evans
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dicarboxylic Acid ◽  
Dimethyl Sulfoxide ◽  
Three Dimensional ◽  
Boat Conformation ◽  
Pyrazine Ring ◽  
Supramolecular Architectures ◽  
Carboxylate Groups ◽  
The Mean

In the inner-salt zwitterion of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid, (I), namely 5-carboxy-3-(pyridin-1-ium-2-yl)-6-(pyridin-2-yl)pyrazine-2-carboxylate, [C16H10N4O4, (Ia)], the pyrazine ring has a twist–boat conformation. The opposing pyridine and pyridinium rings are almost perpendicular to one another, with a dihedral angle of 80.24 (18)°, and are inclined to the pyrazine mean plane by 36.83 (17) and 43.74 (17)°, respectively. The carboxy and carboxylate groups are inclined to the mean plane of the pyrazine ring by 43.60 (17) and 45.46 (17)°, respectively. In the crystal structure, the molecules are linkedviaN—H...O and O—H...O hydrogen bonds, leading to the formation of double-stranded chains propagating in the [010] direction. On treating (Ia) with aqueous 1 MHCl, the diprotonated dihydrate form 2,2′-(3,6-dicarboxypyrazine-2,5-diyl)bis(pyridin-1-ium) dichloride dihydrate [C16H12N4O42+·2Cl−·2H2O, (Ib)] was obtained. The cation lies about an inversion centre. The pyridinium rings and carboxy groups are inclined to the planar pyrazine ring by 55.53 (9) and 19.8 (2)°, respectively. In the crystal structure, the molecules are involved in N—H...Cl, O—H...Owaterand Owater—H...Cl hydrogen bonds, leading to the formation of chains propagating in the [010] direction. When (Ia) was recrystallized from dimethyl sulfoxide (DMSO), the DMSO disolvate 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid dimethyl sulfoxide disolvate [C16H10N4O4·2C2H6OS, (Ic)] of (I) was obtained. Here, the molecule of (I) lies about an inversion centre and the pyridine rings are inclined to the planar pyrazine ring by only 23.59 (12)°. However, the carboxy groups are inclined to the pyrazine ring by 69.0 (3)°. In the crystal structure, the carboxy groups are linked to the DMSO molecules by O—H...O hydrogen bonds. In all three crystal structures, the presence of nonclassical hydrogen bonds gives rise to the formation of three-dimensional supramolecular architectures.

Pentacoordination and ionic character: crystal structure of Ph4SbBr

1989 ◽  
Vol 67 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Osvald Knop ◽  
Beverly R. Vincent ◽  
T. Stanley Cameron
Keyword(s):  
Crystal Structure ◽  
Axial Position ◽  
Ionic Character ◽  
High Symmetry ◽  
Trans Effect ◽  
Bond Lengths ◽  
Axial Bond ◽  
The Mean ◽  
High Degree ◽  
Very High

Ph4SbBr (P21/n, a = 12.282(2) Å, b = 10.656(1) Å, c = 16.156(1) Å, β = 104.92(7)°, Z = 4) crystallizes with the same space group as Ph4SbCl, but the two compounds are not isostructural. The structure of Ph4SbBr consists of layers of Ph4SbBr molecules with the Br atoms almost exactly in the [Formula: see text] planes. The coordination figure of the Sb atom is a trigonal bipyramid (TBP) with Br in an axial position. The Sb—Br distance, 2.950(1) Å is the longest reported for Sb(V) to date. The Sb(V)—Hal bond lengths and the Ph4SbBr and Ph4SbCl structures are compared in detail. Analysis of a large sample of Ph4EX (E = P, As) structures and of all the available R4EX (E = Sb, Bi; R = Ph, Me) structures shows that the former are always ionic, R4E+X−, whereas in the latter the observed coordination figures represent R4EX trigonal bipyramids with various degrees of axial distortion. The inverse variation of the axial bond lengths (the trans effect) in the TBP Sb compounds can be quantified as Sb—Cax ~ 2.4(Sb—X)−1/9 to a very high degree of correlation. This and other geometric relationships show that there exists a limiting E—X bond length (~3.3 Å for E = Sb and ~3.5 Å for E = Bi when X is oxygen) at which the TBP coordination becomes unstable and changes over to a tetrahedral R4E. This change is accompanied by a rearrangement of the structure to an ionic R4E+X− solid (of high symmetry where permitted by the size and shape of the anion) with [Formula: see text] separations no smaller than ~4 Å when E = Sb or Bi and X = O. The distribution of the CEC angles in the Ph4EX (E = P, As) sample is analyzed; the mean (uncorrected) P—C and As—C bond lengths in Ph4E+ are found to be 1.789(11) and 1.902(12) Å, respectively. Keywords: crystal structure, organoantimony compounds, Ph4SbBr, pentacoordination, tetraphenylantimony bromide.

scholarly journals Crystal structure of (E)-N-cyclohexyl-2-(2-hydroxy-3-methylbenzylidene)hydrazine-1-carbothioamide

2019 ◽  
Vol 75 (7) ◽  
pp. 1065-1068
Author(s):  
Md. Azharul Arafath ◽  
Huey Chong Kwong ◽  
Farook Adam
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Title Compound ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Asymmetric Unit ◽  
Compound C ◽  
The Mean ◽  
Independent Molecules ◽  
Ring Motif

The asymmetric unit of the title compound, C15H21N3OS, comprises of two crystallographically independent molecules (A and B). Each molecule consists of a cyclohexane ring and a 2-hydroxy-3-methylbenzylidene ring bridged by a hydrazinecarbothioamine unit. Both molecules exhibit an E configuration with respect to the azomethine C=N bond. There is an intramolecular O—H...N hydrogen bond in each molecule forming an S(6) ring motif. The cyclohexane ring in each molecule has a chair conformation. The benzene ring is inclined to the mean plane of the cyclohexane ring by 47.75 (9)° in molecule A and 66.99 (9)° in molecule B. The mean plane of the cyclohexane ring is inclined to the mean plane of the thiourea moiety [N—C(=S)—N] by 55.69 (9) and 58.50 (8)° in molecules A and B, respectively. In the crystal, the A and B molecules are linked by N—H...S hydrogen bonds, forming `dimers'. The A molecules are further linked by a C—H...π interaction, hence linking the A–B units to form ribbons propagating along the b-axis direction. The conformation of a number of related cyclohexanehydrazinecarbothioamides are compared to that of the title compound.

scholarly journals Crystal structure of bis[trans-dichloridobis(propane-1,3-diamine-κ2N,N′)chromium(III)] dichromate from synchrotron data

2016 ◽  
Vol 72 (9) ◽  
pp. 1293-1296 ◽  
Author(s):  
Dohyun Moon ◽  
Keon Sang Ryoo ◽  
Jong-Ha Choi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Complex Cation ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Intermolecular Hydrogen Bonds ◽  
Distorted Octahedral Coordination ◽  
Distorted Octahedral ◽  
The Mean ◽  
Cl Atoms

The structure of the title compound, [CrCl2(tn)2]2[Cr2O7] (tn = propane-1,3-diamine; C3H10N2), has been determined from synchrotron data. The asymmetric unit contains one CrIIIcomplex cation and half a [Cr2O7]2−anion. In the complex cation, the CrIIIion is coordinated by the four N atoms of two propane-1,3-diamine (tn) ligands in the equatorial plane and by two Cl atoms in atransconfiguration, displaying a distorted octahedral coordination sphere. The two six-membered rings in the complex cation have anantichair–chair conformation with respect to each other. The mean Cr—N(tn) and Cr—Cl bond lengths are 2.09 (1) and 2.320 (2) Å, respectively. The slightly bent dichromate anion is disordered over two sets of sites (occupancy ratio = 0.7:0.3) and has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the NH2groups of the tn ligands as donors and the O atoms of the [Cr2O7]2−anion and chlorido ligands as acceptors.

scholarly journals The crystal structure of 1-(2-hydroxy-5-methoxyphenyl)ethanone 4,4-dimethylthiosemicarbazone

2015 ◽  
Vol 71 (11) ◽  
pp. o811-o812
Author(s):  
Brian J. Anderson ◽  
Michael B. Freedman ◽  
Victoria A. Smolenski ◽  
Jerry P. Jasinski
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Methyl Groups ◽  
Asymmetric Unit ◽  
Compound C ◽  
Thioamide Group ◽  
The Mean ◽  
Independent Molecules ◽  
The Individual

The asymmetric unit of the title compound, C12H17N3O2S, contains two independent molecules,AandB. Both molecules are nearly planar with the dihedral angle between the mean planes of the thioamide group and benzene ring being 7.5 (1)° inAand 4.3 (2)° inB. In each molecule, the hydroxy group participates in intramolecular O—H...N hydrogen bonding, while the amino H atom is not involved in hydrogen bonding because of the steric hinderence caused by two neighboring methyl groups. In the crystal, the individual molecules are linked by weak C—H...O hydrogen bonds, formingA–AandB–Binversion dimers. The dimers are linkedviaC—H...π interactions which help stabilize the packing.

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