Synthesis and crystal structures of 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran

The title compounds 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline 1 (C₁₉H₁₂ClN₃O, M _r = 333.77) and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran 2 were synthesized and crystallized. The crystals of compound 1 are triclinic, space group P-1, a = 7.488(2), b = 9.127(3), c = 12.252(3) Å, = 73.58(2), = 78.38(2)°, = 75.39(2), Z = 2, V = 769.5(4) ų; The compound 2 crystallizes in space group P2₁/n, with cell parameters a = 13.582(2), b = 8.974(1), c = 16.960(2) Å, = 103.34(1)° and D _calc = 1.352 g/cm^–3 for Z = 4. X-ray analysis reveals that atoms C(1)—C(5) and O form a pyran ring in compound 1, which adopts half-chair conformation. In compound 2 the atoms C(12)—C(16) and O form a pyran ring which adopts boat conformation, another six-membered ring (C(8)—C(13)) adopts a half-chair conformation. In addition, there are intermolecular hydrogen bonds in the crystal structures 1 and 2.     

4-(E)-2-[3-(3-[(E)-2-(4-cyanophenyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-ylmethyl)perhydrobenzo[d]imidazol-1-yl]-1-diazenylbenzonitrile: X-ray crystal structure

4-(E)-2-[3-(3-[(E)-2-(4-Cyanophenyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-ylmethyl) perhydrobenzo[d]imidazol-1-yl]-1-diazenylbenzonitrile (1) has been synthesized by reac- tion of p-cyanobenzene diazonium chloride with a mixture of formaldehyde and trans-1,2-cyclohexanediamine. The crystal structure has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) does not adopt a folded conformation, unlike previously studied ethylenediamine analogues, and there is no indication of -stacking in the crystal packing. The dominant interaction between molecules is the van der Waal's attraction between cyclohexane rings. This result establishes the structure of the product of this diazonium coupling reaction as the 1-(1-imidazolidinylmethyl)imidazolidine derivative and not the alternate tetraazabicyclo[4.4.1]undecane derivative. Crystal data: 1 C₂₉H₃₄N₁₀, orthorhombic, space group Pbca, a = 17.946(1), b = 13.106(1), c = 24.108(1) Å, V = 5670.6(3) ų, for Z = 8.     

Synthesis, structure and characterization of a new inorganic-organic hybrid complex (C3H5N2)2[Cd(C3H4N2)2Nb2O3F8]·2H2O

(C₃H₅N₂)₂[Cd(C₃H₄N₂)₂Nb₂O₃F₈]·2H₂O (C₃H₄N₂=imidazole) (1) was prepared from the hydrothermal reaction of Nb₂O₅, 3CdSO₄·8H₂O, C₃H₄N₂, HF and H₂O at 403 K, and characterized by single crystal X-ray diffraction and IR spectra. 1 crystallizes in the orthorhombic system, space group Pba2, with a=11.0192(9), b=16.8012(14), c=6.8717(6) ?, and Z=2. The crystal is made up of [Cd(C₃H₄N₂)₂Nb₂O₃F₈]²⁻ anions, [C₃H₅N₂]⁺ complex cations and H₂O molecules of crystallization. And the backbone of the compound is a one dimension coordination polymeric chain containing the anions. The complex cations and anions are linked through hydrogen bonding interactions. Co-crystallized water molecules fill in the pores and hydrogen bond to the host. Bond valence sums show that O1, O3 and F3 have much more negative charge, which are in agreement with the crystal structure that they act as bridging atoms.Supplementary material CCDC-606794 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at http://www.ccdc.cam.ac.uk/ const/retrieving.html or from the Cambridge Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223-336033 or e-mail: deposit@ccdc.cam.ac.uk.     

Crystal structure of 4-[benzylideneamino]-3-thiophen-2-yl-methyl-4,5-dihydro-1H-[1,2,4]triazole-5-one

The crystal structure of the title compound C₁₄H₁₂N₄OS was determined by the X-ray diffraction method. The compound crystallizes in the triclinic space group $P\bar 1$ with Z = 2. The molecule is not planar: the dihedral angle between the triazole and thiophene rings is 73.98(2)°, and that between the triazole and benzene rings is 4.05(2)°. The thiophene ring is disordered over two positions, which are approximately parallel and oppositely oriented. The major component refined to a site-occupancy factor of 0.573(3). An intramolecular C-H...O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked together by two pairs of N-H...O interactions (to the same O atom as acceptor), forming inversion dimers. The crystal packing is also stabilized by π-π interactions [centroid-centroid distance is 3.978 Å].     

Crystal structure of 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethenyl]benzamide : <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethylformamide (1 : 1)

The title compound, 2-(thiophen-2-yl)-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)ethenyl] benzamide:N,N-dimethylformamide (1: 1), (C₁₅H₁₁N₃O₂S₂ · C₃H₇NO), was synthesized, and its structure was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the monoclinic space group P2₁/n with a = 10.8714(7), b = 9.0497(5), c = 19.8347(13) Å, β = 91.093(5)°, Z = 4. The crystal structure is stabilized by N–H···S, C–H···O and N–H···O hydrogen bonds. The π···π interactions are also observed between the rings.     

The hydrogen bonding in 2-amino-3-cyano-4-(3-nitrophenyl)-4,6-dihydro-5H-pyrano[3,2-c]quinolin-5-one N,N-dimethylformamide solvate monohydrate

The crystal structure of 2-amino-3-cyano-4,6-dihydro-4-(3-nitrophenyl)-5H-pyrano[3,2-c]quinolin-5-one N,N-dimethylformamide solvate monohydrate is determined by room temperature X-ray diffraction. The title compound 1, C₂₂H₂₁N₅O₆, is triclinic, space group P-1, a=9.109(2) ?, b=11.340(2) ?, c=12.485(2) ?, α=70.02(1)°, β=69.36(1)°, γ=67.32(1)°, Z=2, V=1081.4(4) ?³. It is interesting that a bridge-like hydrogen bond O–H···O is formed between the title compound and solvent molecules of water with molecular ratio of 2:2 building a bi-layer framework. In addition, there are two other types of classical hydrogen bonds N–H···N and N–H···O in the crystal structure.Supplementary material Crystallographic data for the structure reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-275001. Copies of available material can be obtained, free of charge, on application to the Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, (fax: +44-(0) 1223–336033 or e-mail: deposit@ccdc.cam.ac.uk).     

Crystal and molecular structure of 3,6-dihydro-4,5-dimethyl-2-[2-(methoxymethyl)pyrrolydinesulfonyl]-2-phenyl-2H-thiapyran-1-oxide,C19H27NO4S2

The crystal structure of a dihydrothiapyranS-oxide was determined from single-crystal diffractometer data, C₁₉H₂₇NO₄S₂, MoK radiation: orthorhombic, space groupP2₁2₁2₁, usinga=8.9604(10),b=13.5928(15),c=16.5621(19) Å,z=4. The molecule has theE-geometry, and the absolute configuration isR at C₁ andS at S₁.     

Synthesis and crystal structure of 3-[2-oxo-2-(4-methyloxyphenylsulfonamidophenyl)ethylidene]-3,4-dihydro-1H-quinoxalin-2-one

3-[2-Oxo-2-(4-methyloxyphenylsulfonamidophenyl)ethylidene]-3,4-dihydro-1H-quinox-alin-2-one (4) was synthesized and characterized by ¹H NMR,¹³C NMR, IR, and single-crystal X-ray diffraction techniques. The crystallographic results show that the composition of the title compound is C₂₃H₁₉N₃O₅S. It belongs to triclinic crystal system and P-1 space group, with a=7.273(6) ?, b=9.092(7) ?, c=15.928(13) ?; α=85.135(11)°, β=78.297(10)°, γ=84.619(11)°, V=1024.4(14) ?³, Z=2, D _c=1.457 mg/m³, μ = 0.201 mm⁻¹, F(000)=468, R=0.0597, wR=0.1438. Supplementary material CCDC-281953 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/retrieving.html or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk.     

Crystal structure of complexes of bivalent Co,Ni, and Cd with anions of benzoic and 2-(acetylamino)-5-nitrobenzoic acids

The structure of three complexes of bivalent metals (cobalt, nickel, and cadmium) with anions of benzoic (HL ¹) and 2-(acetylamino)-5-nitrobenzoic (HL ²) acids, namely, [Co₂¹ (H₂O)₂(μ-C₄H₄N₂)] _n (I), [NiL²(H₂O)₅]L² · 2H₂O (II), and [Cd(μ-L ²)₂(H₂O)₂] _n · 2nH₂O (III), is determined. In chainlike structure I, cobalt atoms are connected by bridging pyrazine molecules; structure II contains isolated complexes. In structure III, centrosymmetric (CdOCO)₂ cycles and polymeric ribbons are formed due to the coordination of the carboxylate group of the L ² ligand to two cadmium atoms.     

Synthesis,Crystal Structure and DNA Binding Property of Diaquadi(4-methylbenzoyloxy)bis[2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide]cobalt(II)

Abstract  

A novel cobalt(II) complex of [Co(4-MePhCOO)₂(NITpPy)₂(H₂O)₂] (1), where NITpPy is short for 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxy 3-oxide(C₁₂H₁₆N₃O₂), was synthesized and structurally characterized by X-ray diffraction analysis. The X-ray diffraction analysis reveals that 1 crystallizes in the triclinic space group P-1 with a = 6.7910(10) ?, b = 12.4421(15) ?, c = 12.9169(16) ?, α = 89.8470(10)°, β = 89.8480(10)°, γ = 76.991(2)°, and Z = 1. The Co atom in the complex is located on the center of inversion and lies in a distorted octahedral geometry defined by an N₂O₄ donor set. The interaction of 1 with calf thymus DNA (CT-DNA) was investigated by UV–vis absorption and emission spectroscopy, which indicating that 1 could bind to DNA through electrostatic interaction.     

Syntheses,characterization and crystal structures of two structurally similar Schiff bases isonicotinic acid [1-(3-methoxy-2-hydroxyphenyl)methylidene]hydrazide and isonicotinic acid [1-(4-dimethylaminophenyl)methylidene]hydrazide monohydrate

The Schiff base compounds, isonicotinic acid [1-(3-methoxy-2-hydroxyphenyl) methylidene]hydrazide (C₁₄H₁₃N₃O₃, 1) and isonicotinic acid [1-(4-dimethylaminophenyl) methylidene]hydrazide monohydrate (C₁₅H₁₆N₄O·H₂O, 2) have been synthesized by the condensation of equimolar 3-methoxysalicylaldehyde or 4-dimethylaminobenzaldehyde with isonicotinic acid hydrazide in MeOH or EtOH. The compounds were characterized by elemental analysis, IR, ¹HNMR spectra, and single crystal X-ray diffractions. Compound 1 crystallizes in the monoclinic space group P-1 with unit cell dimensions a = 7.662(1) ?, b = 16.249(2) , c = 10.874(2) ?, β = 110.426(3)°, V = 1268.7(3) ′³, Z = 4, R ₁ = 0.0644, and wR ₂ = 0.1283. Compound 2 crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell dimensions a = 7.388(1) ?, b = 11.812(1) ?, c = 17.197(2) ?, V = 1500.7(2) ′³, Z = 4, R ₁ = 0.0585, and wR ₂ = 0.1143. X-ray structure determinations revealed that the molecules of both compounds display trans configurations with respect to the C=N double bonds. In the crystal structure of 1, molecules are linked through N–H···N intermolecular hydrogen bonds, forming layers parallel to the bc plane, while in the crystal structure of 2, molecules are linked through N–H···O, O–H···O, and O–H···N intermolecular hydrogen bonds, forming a network. Supplementary material CCDC-615072 and 620235 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at http://www.ccdccam. ac.uk/const/retrieving.html or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44(0)1223–336033 or e-mail: deposit@ccdc.cam.ac.uk.     

Synthesis, Structural Characterization and Spectroscopic Properties of 1,2-Bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene

Abstract  

The crystal structure of the title compound C₂₂H₃₀N₄O₂·H₂O (L), has been determined using X-ray diffraction at 293 K. The crystal of 1,2-bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene is in triclinic crystal system with space group P(−1) (Z = 2), lattice parameters a = 8.225(6) ?, b = 10.967(6) ?, c = 12.903(6) ?, V = 1119.1(11) ?³. Analyses of single crystals of L, crystallized from dichloromethane/diethyl ether (1:1), revealed that the molecules are arranged in couples, which adopt a pseudo chair conformation, by means of intermolecular O–H···N hydrogen bonding interactions. Moreover, the extended structure revealed a 1D chain caused by several C–H···N intermolecular interactions.     

Crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF2(C16H13O3)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C16H13O3)2]

The crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF₂(C₁₆H₁₃O₃)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C₁₆H₁₃O₃)₂], have been determined by single-crystal X-ray diffraction methods. The structures were solved by direct methods and electron density calculations and were refined by the full-matrix least-squares method. Difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]-boron(III) crystallizes as yellow rhombs in the monoclinic space groupP2₁/c witha=11.429(3),b=11.364(4),c=11.412(4) Å,=92.19(2)°,V=1481.0(8) ų andZ=4. A total of 2754 unique reflections were collected. Of these 1342 were considered observed [I>3(I)] leading to a finalR-value of 0.045. Boron is tetrahedrally coordinated to the two fluorine atoms and to two oxygen atoms of the bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligand, C₁₆H₁₃O ₃ ^– . Average bond distances: C-C (aromatic) 1.378(10) Å, B-O 1.473(7) Å and B-F 1.343(4) Å. bis[2-(4-Methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II) crystallizes as dark yellow-green plates in the monoclinic space groupC2/c witha=23.410(7),b=13.856(3),c=8.039(3) Å,=101.79(2)°,V=2553(1) ų andZ=4. Of the unique set of 3076 scanned reflections 2401 hadI>3(I) for whichR became 0.040. Copper is coordinated to four oxygen atoms, two from each of the two bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligands, in a distorted square planar manner. The molecule hasC ₂ symmetry. Average bond distances: C-C (aromatic) 1.383(6) Å and Cu-O 1.896(8) Å. The crystals of both compounds consist of monomeric molecular complexes held together by van der Waals forces.     

Structure of 4,6-dimethylisothiazolo[5,4-b]pyridin-3(2H)-one and its 2-[4-(2-methylphenyl) piperazin-1-ylmethyl] derivative

The crystal and molecular structures of 4,6-dimethylisothiazolo[5,4-b]pyridin-3(2H)-one, C₈H₈N₂OS, 1, and its 2-[4-(2-methylphenyl)piperazin-1-ylmethyl] derivative, C₂₀H₂₄N₄OS, 2c, are described. These compounds crystallize in the monoclinic system in the space group P2 ₁/c. The cell constants for compound 1 are a = 5.049(1), b = 14.897(1), c = 11.330(1) Å, = 98.07(1)°, Z = 4, T = 293 K, and D _cal = 1.419 g cm^–3, and for compound 2c are a = 15.525(1), b = 12.021(1), c = 10.911(1) Å, = 106.42(1)°, Z = 4, T = 293 K, and D _cal = 1.253 g cm^–3 The structures were solved by direct methods and refined to R values of 0.0411 and 0.0380 for 1640 and 3504 reflections for 1 and 2c, respectively. The analysis of the geometry and difference electron density map reveal that the dimethylisothiazolopyridine 1 exists in the amino tautomeric form in the crystalline state. The conformation of the o-methylphenylpiperazine part of the molecule 2c strongly depends on the substituents effect in the phenyl ring and is very similar to those observed in crystals for other investigated arylopiperazine derivatives of the isothiazolopyridine.     

An X-ray Crystallographic Study of the Related Triazenes, 1,4-Di[(<Emphasis Type="Italic">E</Emphasis>)-2-(2-nitrophenyl)-1-diazenyl]piperazine and Methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate

Abstract The crystal structures of methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate (2a) and 1,4-di[(E)-2-(2-nitrophenyl)-1-diazenyl]piperazine (3a) have been determined by single crystal X-ray diffraction analysis. The bis-triazene (3a) adopts an unusual pseudo-boat conformation in the piperazine ring, with a dihedral angle of 52.20(0.06)° between the two planes defined within the piperazine ring. The crystal structures of 2a and 3a are compared with the structure of the triazene (4) and the closely related bis-triazene (5). The piperazine ring of 2a adopts a typical chair conformation, whereas the piperazine ring of 3a adopts an unusual boat conformation. Crystal data: 2a C₁₃H₁₈N₄O₂, monoclinic, space group P2₁ /n, a = 13.849(3) ?, b = 6.577(1) ?, c = 14.904(3) ?, α = 90°, β = 96.098(3)°, γ = 90° and V = 1,349.8(4) ?³, for Z = 4. 3a C₁₆H₁₆N₈O₄, triclinic, space group P-1, a = 7.6066(6) ?, b = 8.3741(7) ?, c = 14.507(1) ?, α = 78.673(1)°, β = 81.877(1)°, γ = 73.445(1)° and V = 865.0(1) ?³, for Z = 2. Index abstract The crystal structures of methyl 4-{(E)-2-(4-methylpiperazino)-1-diazenyl}benzoate (2a) and 1,4-di[(E)-2-(2-nitrophenyl)-1-diazenyl]piperazine (3a) have been determined by single crystal X-ray diffraction analysis.     

Two new CrIII(bpb)(H2O)X complexes derived from [Cr(bpb)(N3)2]− or [Cr(bpb)(CN)2]− (bpb2− = 1,2-bis(pyridine-2-carboxamido)benzenate, X− = hydroxo or azide)

Two new Cr(III) complexes, [Cr(bpb)(H₂O)(OH)]·3H₂O (1) and [Cr(bpb)(H₂O)(N₃)]·H₂O (2) have been synthesized and structurally characterized. Both complexes were unexpectedly obtained as single crystals during the reactions of [Cr(bpb)(CN)₂]⁻ or [Cr(bpb)(N₃)₂]⁻ with [Ni(L)](ClO₄)₂ (L = 3,10-dimethyl-1,3,6,8,10,12-hexaazacyclotetradecane) or MX₂·nH₂O (M = Cu, Ni and Mn, X = Cl⁻ and ClO₄ ⁻). Complex 1 crystallizes in the triclinic system, space group P-1, formula CrC₁₈H₂₁N₄O₇ with a = 7.1543(17) ?, b = 12.420(3) ?, c = 12.955(3) ?, α = 115.021(5)°, β = 95.544(5)°, and γ = 101.575(5)°. Complex 2 crystallizes in the monoclinic system, space group P2₁/c, formula CrC₁₈H₁₆N₇O₄ with a = 11.7171(9) ?, b = 9.4999(7) ?, c = 16.8799(13) ?, and β = 97.449(2)°. Both complexes exhibit distorted octahedral coordination environment with four nitrogen atoms of bpb²⁻ situated at the equatorial plane (Cr–N bond distances range from 1.961(3) to 2.1088(15) ?), and the remaining two trans-positions occupied by terminal ligands H₂O/HO and H₂O/N₃ in 1 and 2, respectively. It is noteworthy that a hydrogen-bonded folded ladder-like structure involving twelve O atoms in 1 and a chair-like hexagonal hydrogen-bonded cluster containing six O atoms are formed.     

Structural and spectroscopic study of tetrakis(N,N-diethyldithiocarbamato)molybdenum(V) triiodide,Mo[S2CN(C2H5)2]4 I3

Oxidation of Mo₂[S₂CN(C₂H₅)₂]₆ with iodine in a 12 molar ratio yielded the complex MO[S₂CN(C₂H₅)₂]₄ I₃, for which magnetic susceptibility, NMR, IR, UV/visible spectra, and single crystal X-ray structure are reported. Crystals of Mo[S₂CN(C₂H₅)₂]₄ I₃ are monoclinic, space groupC2/c (No. 15),a=26.242(7),b=7.003(1),c=20.447(3) Å,D _o =1.97,Z=4,D _c =1.890 g cm^–3. The structure was determined from 1909 observed reflections and refined by blocked cascade least squares to anR factor of 0.042. The core of the cation, Mo[S₂CN(C₂H₅)₂] ₄ ⁺ , is dodecahedral with approximate point symmetryD _2d (¯42m). The eight S atoms coordinated to the Mo center can be divided into two sets, each forming a distorted tetrahedron. The set constituting a flattened tetrahedron has a mean Mo-S distance of 2.545(2) Å, whereas the set that forms an elongated one has a mean value of 2.500(2) Å. The oxidation state of +5 for the molybdenum atom is supported by the thioureide band [v(RNC)] at 1507 cm^–1, which lies between those of similar Mo(IV) and Mo(VI) complexes.     

X-Ray Diffraction Studies of 4-n-Decyl(oxy)phenyl-4'-n'-butyl(oxy)benzoate and 4-n-Decyl(oxy)phenyl-4'-n'-hexyl(oxy)benzoate

Liquid crystal aromatic esters of compositions C₁₀H₂₁OC₆H₄C(O)OC₆H₄OC₄H₉ (1) and C₁₀H₂₁OC₆H₄C(O)OC₆H₄OC₆H₁₃ (2) have been investigated by X-ray structural analysis. On temperature rise, these compounds undergo phase transitions crystal-smectic (S_A)-nematic-isotropic (1) and crystal-smectic (S_C)-smectic(S_A)-nematic-isotropic (2) at temperatures 64.5, 80.7, 89.1°C and 62.0, 77.0, 82.5, 88.5°C, respectively. Crystal packing of the compounds consists of alternating loosely packed aliphatic and closely packed aromatic regions. The number of types of weak directional interactions in aromatic regions in both crystal packings was found to be equal to a number of phase transitions in crystal-mesophase-isotropic systems.     

Synthesis and physicochemical characterization of a porous coordination polymer of Sn-Cu xylarate: The structure of [Sn4Cu8.5(HL)2(L)4O2(OH)(H2O)12.5] · 17.2H2O

A porous coordination polymer of Sn-Cu xylarate [Sn₄Cu_8.5(HL)₂(L)₄O₂(OH)(H₂O)_12.5] · 17.2H₂O (H₅ L is xylaric acid) is synthesized for the first time and characterized by chemical analysis, IR spectroscopy, and X-ray diffraction. Centrosymmetric heterometallic fragments [Sn₄Cu₆(HL)₂(L)₄O₂(H₂O)₆] (A) including copper Cu1–3 and tin Sn1,2 atoms are distinguished in the structure. The Cu4(OH)_0.5(H₂O)_2.5 bridges connect A units into chains running along the c axis, and the Cu5(OH)(H₂O) bridges connect A fragments into layers perpendicular to the c axis. The Cu4,5 atoms form a framework whose voids accommodate the crystallization water molecules.     

1-[2-(p-Tolyl)-1-diazenyl]-3-({3-[2-(p-tolyl)-1-diazenyl] perhydrobenzo[d]imidazol-1-yl}methyl)perhydrobenzo[d]imidazole: synthesis,characterization and X-ray crystal structure

1-[2-(p-Tolyl)-1-diazenyl]-3-({3-[2-(p-tolyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-yl}methyl)perhydrobenzo[d]imidazole(1) has been synthesized by reactionof a mixture of 1,2-diaminocyclohexane and formaldehyde withp-toluene diazonium chloride inaqueous solution. The product has been characterized by IR and NMRspectroscopy and elemental analysis. A crystal grown from solution ina mixed solvent system of ethyl acetate and hexanes was analyzed byX-ray crystallography. The solution of the crystal structure of(1) is important in establishing theconnectivity of this molecule and other compounds of similarstructure. The crystal structure of (1) is compared with the previously reportedstructure of the p-cyano analogue(2). Compounds (1) and (2)differ principally in the relative orientation of the heterocyclicrings; in (1), the molecule has adistinct V-shape, whereas compound (2) adopts a more extended conformation.Significant conjugation within the triazene moieties is evident inboth (1) and (2), as manifested in the N465=N andN–N bond lengths. The conjugation is greater in (2) due to the extended conjugation through tothe nitrile group. The title compound (1){C₂₉H₄₀N₈}crystallizes in the monoclinic, space group C2/c, with lattice constants: a = 30.532(6) ?,b =5.9050(12) ?, c= 15.463(3) ?, α = 90°,β = 99.94(3)°, γ = 90°,V =2746.0(10) ?³, Z = 4, D _c =1.209 mg m⁻³,F(000) = 1076, R ₁ = 0.0785,wR ₂= 0.1877.