Hydrogen bonding patterns in bis(pyrimethamine hydrogen sulfate) monohydrate

The crystal structure of the compound bis [2,4-diamino-5-(p-chlorophenyl)-6-ethyl pyrimidinium hydrogen sulfate] monohydrate was studied by X-ray diffraction methods. The compound crystallises in orthorhombic system, space group P2₁2₁2₁, a=18.531(2) ?, b=16.190(2) ?, c=10.777(2) ?, V=3233.3(8), Z=4. The asymmetric unit shows the presence of two crystallographically independent pyrimethamine molecules, two hydrogen sulfate anions, and a water molecule. The hydrogen sulfate anions form a cyclic hydrogen bonded motif R₂ ²(8) with the 2-amino pyrimidine of the respective protonated pyrimethamine cations, through N–H···O hydrogen bonds. Thus the sulfate anions mimic the role of carboxylate anions observed in many aminopyrimidine-carboxylate interactions. This motif self assembles through DDAA array of quadruple hydrogen bonds, N–H···Cl, O–H···O and C–H···O hydrogen bonds.Supplementary material CCDC-293607 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 IEZ, UK; fax: C44 (0) 1223-336033; e-mail: deposit@ccdc.cam.ac.uk].     

5-Pyridine 4-yl-3H-(1,3,4) Oxadiazole-2 Thione Hydrochloride Monohydrate, (I), and 4 [5-Ethylsulfanyl)-(1,3,4) Thiadiazole-2-yl]-Pyridinium Perchlorate, (II)

Abstract  

The title compounds C₇H₈ClN₃O₂S, (I), and C₉H₁₀ClN₃O₄S_2, (II), both crystallize in monoclinic space group P2₁ /c with unit cell parameters (I) a = 7.9402(7), b = 10.6312(9), c = 11.7626(10), ?, β = 99.271(5)°, Z = 4 and (II) a = 5.1439(2), b = 9.0636(4), c = 27.1814 (7), ?, β = 95.116(2)°, Z = 4. In (I) the molecule consists of a 5-pyridine-4-yl group bonded to the carbon atom at the 5 position of (1, 3, 4) oxadiazole-2 thione hydrochloride monohydrate. The angle between the mean planes of the oxadiazole and pyridine rings is 9.6(6)°. Crystal packing in (I) is stabilized by strong N–H···O hydrogen bonds in concert with a solvent water molecule and weak O–H···Cl, O–H···S, N–H···Cl intermolecular interactions. The crystal structure of compound (II) consists of 4 [5-ethylsulfanyl)-(1, 3, 4) thiadiazole-2-yl]-pyridinium perchlorate, (C₉H₁₀N₃S₂)⁺(ClO₄)⁻, cation–anion pairs, containing strong intermolecular N–H···O hydrogen bonds and weak C–H···O and N–H···O intermolecular interactions operating between the ionic species that form a cooperative hydrogen-bonded, infinite chain O–H···O–H···O–H network which generates a sheet motif structure in the unit cell. It is also supported by weak intermolecular Cg···Cg π–π and Cl–O···Cg π-ring interactions which gives additional support to molecular packing stability in the unit cell. Geometry optimized MOPAC AM1 computational calculations on each compound provides support to the structural features in their respective crystal structures.     

Structures of two N-methylated tricyclic quinolones with antimalarial activity

The crystal structures of two N-methylated tricyclic quinolones were determined. 3-amino-6-methoxy-9-methyl-(1H)pyrazolo[3,4-b]-4-quinolone hydrate, C₁₂H₁₂N₄O₂ · H₂O (1) crystallizes in P-1 with a=11.5078(18) ?, b=13.0614(19) ?, c=9.0860(15) ?, α=106.229(4)°, β=108.378(3)°, γ=71.118(3)° and Z=4, while 2,4-diamino-10-methyl-9-methoxypyrimido[4,5-b]-5-quinolone, C₁₃H₁₃N₅O₂ (2) crystallizes in P2₁/n with a=10.6643(17) ?, b=10.1114(17) ?, c=11.3185(18) ?, β=99.351(4)° and Z=4. Both molecules are essentially planar, including the exocyclic groups. 1 and 2 have moderate antimalarial activity which seems to be related to the formation of intramolecular N – H · · · O=C hydrogen bonds; 1 does not form these bonds and has approximately twice the activity of 2. In both crystal structures there are extensive networks of N–H · · · O and N–H · · · N hydrogen bonds, and in 1 the water molecules of solvation form N–H · · · Ow, Ow–H · · · O=C and Ow–H · · · Ow bonds.     

Persistence of layer motifs in the crystal structures of [1,4-bis-(2-methoxy-2-carbonylethyl)piperazinium (2’)] chloride and [1,4-bis-(2-amidoethyl)piperazinium (2’)] perchlorate

Two structures of the closely related piperazinium salts, [1,4-bis-(2-methoxy-2-carbonylethyl)piperazinium (2+)] chloride (1) and [1,4-bis-(2-amidoethyl)piperazinium (2+)] perchlorate (2) reveal the persistence of a layer structure, interspersed with anions, held in place by N–H···Cl, C–H···O and C–H···Cl interactions in the case of 1, and N–H···O and C–H···O interactions in the case of 2. Compound 1 crystallizes in the triclinic space group P-1 with a=6.7667(6) ?, b = 6.9467(6) ?, c=9.3880(18) ?, α=105.845(9)°, β=99.896(16)°, γ=103.600(9)°, and Z=1. Compound 2 crystallizes in the monoclinic space group P2₁/c with a = 9.0930(8) ?, b=10.0525(11) ? c=10.2104(13) ?, β=114.279(9)°, and Z=2.     

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.     

Inter- and Intra-Molecular Hydrogen Bonding in Bis(2-amino-5-fluoro-3-methylphenyl)disulfide

Abstract  Bis(2-amino-5-fluoro-3-methylphenyl)disulfide was obtained by oxidation of 2-amino-5-fluoro-3-methylbenzenethiol and was characterized by elemental analysis, IR and ¹H-NMR spectroscopy. The X-ray structure was determined. Crystal data: C₁₄H₁₄N₂F₂S₂: Monoclinic, P2₁ /n, a = 11.8268(3), b = 9.5770(3), c = 12.3977(3) ?, β = 98.079(2)°, V = 1390.29(7) ?, Z = 4. The supramolecular structure arises because the NH₂ groups form three center S···H···F hydrogen bonds and two center N–H···F and N–H···S hydrogen bonds. Index Abstract  Inter- and Intra-Molecular Hydrogen Bonding in Bis(2-amino-5-fluoro-3-methylphenyl)disulfide J. E. Drake¹, M. B. Hursthouse², M. E. Light², R. Maheshwari³, K.G. Ojha³, R. Ratnani^3* Bis(2-amino-5-fluoro-3-methylphenyl)disulfide is linked into a three-dimensional frame work by a combination of intermolecular N–H···F and N–H···N and intramolecular N–H···S hydrogen bonds. The supramolecular structure arises because the NH₂ groups form three center S···H···F hydrogen bonds and two center N–H···F and N–H···S hydrogen bonds.      

Synthesis and Crystal Structure of <Emphasis Type="Italic">N</Emphasis>′-(6-Chloropyridin-3-formyl)-<Emphasis Type="Italic">N</Emphasis>-<Emphasis Type="Italic">t</Emphasis>-Butyl Urea

Abstract The crystal structure of N′-(6-chloropyridin-3-formyl)-N-t-butyl urea, C₁₁H₁₄ClN₃O₂, has been established, and which belongs to monoclinic crystal system, space group Pn with unit cell dimensions a = 9.335(3) ?, b = 12.715(3) ?, c = 21.813(6) ?, β = 95.417(6)°, V = 2577.6(12) ?³ and Z = 8. An intramolecular N–H···O hydrogen bond forms a six-membered ring in the central part of the molecule. Both two N–H atoms of single unit participate in intermolecular hydrogen bonds and an intramolecular hydrogen bond, respectively. Index Abstract The crystal structure ofN′-(6-chloropyridin-3-formyl)-N-t-butyl urea, C₁₁H₁₄ClN₃O₂, has been established, and which belongs to monoclinic crystal system withZ = 8, space group Pn.      

The Crystal Structure of 1-[2-(furan-2-yl)-6-methyl-1,2,3,4-tetrahydroquinolin-4-yl]Pyrrolidin-2-one

Abstract  

The title compound, C₁₈H₂₀N₂O₂, a potential pharmaceutical agent, crystallizes in the monoclinic P2₁/n space group with unit cell parameters a = 11.157 (7) ?, b = 8.776 (6) ?, c = 16.460 (11) ?, β = 103.08 (3)°. The tetrahydroquinoline ring system formed by the fusion of the benzene ring and the piperidine ring via two carbon atoms is coplanar, with the later adopting a sofa conformation. The pyrrolidine group in position 4 adopts an envelope conformation. Dimers related by inversion centers and linked by hydrogen bonds of the type N–H···O form cycles described by the graph set R₂²(16). Additionally, the dimers connect through weak hydrogen bonds of the type C–H···O with graph set C(10) to form chains extending along [001].     

Synthesis, characterization, and structural analysis of ethyl (2Z)-3-(4-chlorophenyl)-2-cyano-3-(methoxyamino)prop-2-enoate

Ethyl (2Z)-3-(4-chlorophenyl)-2-cyano-3-(methoxyamino)prop-2-enoate was prepared by reacting the lithium salt of ethyl cyanoacetate with (Z)-O-methyl-4-chloroben-zohydroximoyl fluoride. This compound crystallizes in space group Pbca,with lattice constants a=7.5740(15) ?, b=11.337(2) ?, and c=30.424(5) ? at 110 K. Characterizations include spectrometric identifications employing IR, UV, and ¹H and ¹³C NMR. The compound exists in the solid as the enamine tautomer, with the cyano group cis to the 4-chlorophenyl group (the Z configuration). The C=C and C–N bond distances are 1.3930(16) ? and 1.3278(16) ?, respectively. The N–H group forms a bifurcated hydrogen bond with acceptors C=O (intramolecular) and C≡N (intermolecular).Supplementary material CCDC-289444 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, by e-mailing data_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44(0)1223-336033.     

Br···HN, N···HC, Br···HC, and Br···Br intermolecular interactions as supramolecular synthons: Synthesis and crystal structure of bis(2-amino-5-methylpyridinium) tetrabromomercurate(II)

The bis(2-amino-5-methylpyridinium) tetrabromomercurate(II) (C₆H₉N₂)₂[HgBr₄] salt is triclinic, P1, with the following cell parameters: a=8.060(8) ?, b=9.035(9) ?, c=14.964(10) ?, α=96.032(19)°, β=90.317(15)°, γ=113.32(2)°, V=993.8(15) ?³, with Z=2 formula units. The crystal structure consists of alternating stacks of inorganic HgBr₄ ²⁻ anions and organic layers of 2-amino-5-methylpyridinium cations parallel to c-axis. The cohesion forces that connect molecules in the organic layers are N···HC hydrogen bonding and π–π stacking. The HgBr₄ ²⁻ units in the inorganic stacks are attracted via Br···Br intermolecular interactions.Supplementary material CCDC 270395 contains the supplementary crystallographic data. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by e-mailing at data_request@ccdc.cam.ac.uk, or by contacting the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: + 44(0)1223-336033.     

Molecular Association of Almotriptan with Oxalate and Terephthalate Anions

Abstract  

Crystal structures of anti-migraine drug almotriptan were crystallized with oxalic acid (I) and with terephthalic acid (II) and their crystal structures and molecular associations were determined using X-ray diffraction methods. Crystals of both (I) and (II) are monoclinic, space group P2₁/c, with a = 5.6270(4) ?, b = 27.6419(19) ?, c = 13.6228(9) ?, β = 93.057(1)°, V = 2115.9(3) ?³, Z = 4 (I) and a = 13.3756(15) ?, b = 15.6065(17) ?, c = 10.7238(12) ?, β = 98.017(2)°, V = 2216.7(4) ?³, Z = 4 (II). In almotriptan oxalate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium semioxalate}, C₁₇H₂₆N₃O₂S⁺, C₂HO₄ ⁻, (I) and in almotriptan hemi terephthalate hydrate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium hemi terephthalate monohydrate}, C₁₇H₂₆N₃O₂S⁺, 0.5(C₈H₄O₄ ²⁻), H₂O, (II), both the almotriptan cations form a trimer with the corresponding anions via N–H···O hydrogen bonds. In (I), the oxalate salt is monoprotonated and in (II), the terephthalic acid is located across the inversion centre and exists as doubly protonated anion. In (I), the cation and anion are interlinked by the N–H···O and O–H···O hydrogen bonds into continuous two-dimensional layers generate an R₆⁶(34) hydrogen-bonded motif tetramers running parallel to the (0 0 1) plane. In (II), the cation and water form a centrosymmetric tetramer of R₄⁴(22) hydrogen-bonded motif via N–H···O and O–H···O hydrogen bonds and further cross-linked by centrosymmetric anions to form an infinite three-dimensional supramolecular hydrogen-bonded networks.     

Syntheses and crystal structures of an organometallic thiosemicarbazone and an organometallic enehydrazide

Reactions of ferrocenoylacetone with thiosemicarbazide and isonicotinic acid hydrazide generate an organometallic thiosemicarbazone 1 and enehydrazide 2, respectively. The complexes 1 and 2, which can be formulated as [C₅H₅FeC₅H₄C(O)CH₂C(=NNHCSNH₂)CH₃] and [C₅H₅FeC₅H₄C(O)CH=C(NHNHCOC₅H₄N-4)CH₃], have been characterized by elemental analyses, IR, NMR, UV and were structurally characterized by single-crystal X-ray crystallography. Complex 1 (C₁₅H₁₇FeN₃OS) crystallizes in the monoclinic space group P2₁/c, with lattice constants: a = 13.939(3) ?, b = 8.2600(17) ?, c = 13.176(3) ?, β = 94.83(3)°, V = 1511.7(6) ?³, Z = 4, D _c = 1.508 g cm⁻³, F(000) = 712, R ₁ = 0.0602, wR ₂ = 0.1526. Two intermolecular hydrogen bonds N–H···S (N···S = 3.356(8) and 3.499(7) ?, N–H···S = 168 and 170°) form a chain in the [010] direction. The intermolecular hydrogen bond C–H···O (C···O = 3.432(10) ?, C–H···O = 151°) leads to a [010] double-chain through each unit cell. The intermolecular hydrogen bond C–H···O (C···O = 3.359(10) ?, C–H···O = 173°) makes the [010] double-chain pack along the c axis to result in a two-dimensional network. Complex 2 (C₂₀H₁₉FeN₃O₂) crystallizes in the monoclinic space group P2₁/c, with lattice constants: a = 14.091(2) ?, b = 10.024(2) ?, c = 13.806(2) ?, β = 112.41(2)°, V = 1802.8(6) ?³, Z = 4, D _c = 1.434 g cm⁻³, F(000) = 808, R ₁ = 0.0576, wR ₂ = 0.1593. The strong intramolecular hydrogen bond N–H···O from the enamine N atom and carbonyl O atom stabilizes the enehydrazide. The intermolecular hydrogen bonds N–H···O and C–H···O (N···O = 2.906(6) ?, N–H···O = 155° C···O = 3.364(6) ?, C–H···O = 153°) generate a [010] chain. The intermolecular hydrogen bond N–H···O (N···O = 2.989(6) ?, N–H···O = 128°) forms a [010] double-chain through each unit cell. The π···π stacking interation involving the pyridyl groups makes the [010] double-chain pack along the c axis to lead to a two-dimensional network.     

Structures of two N-{2-([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-halophenyl}acetamides

Abstract  

The compounds, N-{2-[(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-chlorophenyl}acetamide (1: X = Cl) and N-{2([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-bromo-phenyl}acetamide (1: X = Br), are isostructural. The molecules are near ‘‘V’’ shaped with the angles between the two aromatic planes ca. 84° in each case. The various intermolecular interactions, namely N–H···O, N–H···N, N–H···F, and C–H···N hydrogen bonds and C–H···π, C–Cl···π and C–O···π interactions, generate 3-D arrays. Compound (1: X = Cl) crystallizes in the monoclinic space group P21/c with a = 16.9032(7) ?, 10.2193(4) ?, c = 7.5227(4) ?, β = 100.179(3)° and Z = 4. Compound (1: X = Br) crystallizes in the monoclinic space group P21/c with a = 17.2119(4) ?, 10.2167(2) ?, c = 7.5677(2) ?, β = 100.326(2)° and Z = 4.     

Crystal Structure,Conformation and Vibrational Analysis of a Mannich Base: 2-[(phenylamino) methyl]-isoindole-1,3-dione

Abstract  

The crystal structure of 2-[(phenylamino) methyl]-isoindole-1,3-dione, C₁₅H₁₂N₂O₂, crystallizes in the triclinic space group Pī with cell parameters of a = 7.1176 (2) ?, b = 8.5533 (3) ?, c = 10.9163 (4) ?, α = 95.937 (2)°, β = 102.975 (2)°, γ = 108.474 (2)°, V = 603.18 (4) ?³ and Z = 2. This indole derivative is a Mannich base in which a methyl group bridges the molecules of phthalimide and aniline molecules. The dihedral angle between the phthalimide and aniline is 75.47 (3)°. The molecules of the title compound forms a centrosymmetric hydrogen-bonded dimer through a pair of N–H···O hydrogen bonds. C–H···π and an extensive π···π interactions, in addition, stabilize the molecular structure. The compound presented here is V-shaped, the angle at the methyl bridge [N–C–N] being 115.04 (12)°. Present study reports the conformation and hydrogen bonding interactions which play an important role in biological functions. Vibration analysis complement the structure analysed.     

Supramolecular Network via Hydrogen Bonding and π–π Stacking in 4,4′-Bipyridin-1-ium Perchlorate Dihydrate

Abstract The crystal structure of 4,4′-bipyridin-1-ium perchlorate dihydrate, [C₁₀H₉N₂](ClO₄) · 2H₂O, is determined by room temperature X-ray diffraction. The compound crystallizes in the triclinic space group P-1 with a = 8.122(3) ?, b = 9.726(3) ?, c = 17.648(6) ?, α = 78.181(4)°, β = 82.797(5)°, γ = 67.439(4)°, Z = 2, V = 1258.4(7) ?³. In the compound, monoprotonated 4,4′-bipyridin-1-ium cations are self-assembled into supramolecular chains along the a-axis through N–H···N hydrogen bonds in a head-to-tail fashion. The chains are stacked via π–π stacking interactions to create two-dimensional sheets. The interlayer space is occupied by the hydrogen-bonded water chains that are linked to the organic sheets via C–H···O interactions and the perchlorate anions that are linked to the water chains and the organic sheets via O–H···O and C–H···O hydrogen bonds, respectively, thus generating a three-dimensional supramolecular architecture. Index Abstract Supramolecular Network via Hydrogen Bonding and π–π Stacking in 4,4′-Bipyridin-1-ium perchlorate dihydrate Jian-Yong Zhang, Ai-Ling Cheng and En-Qing Gao* Monoprotonated 4,4′-bipyridin-1-ium cations are self-assembled into supramolecular chains along the a-axis through N–H···N hydrogen bonds, and these chains are stacked via π–π stacking and hydrogen bond interactions involving water molecules and perchlorate anions.      

Spectral and X-ray Diffraction Studies of <Emphasis Type="Italic">N</Emphasis>-(2-Nitrophenyl)-5-Phenyl-1,3,4-Oxadiazole-2-Amine

Abstract  

Thiosemicarbazides and their derivatives are well known for their use in biological activity and many applications in pharmaceutical and industrial fields. The cyclization of 1-benzoyl-4-(2-nitrophenyl)-3-thiosemicarbazide (BNPTSC) in dimethylformamide (DMF) medium furnished N-(2-nitrophenyl)-5-phenyl-1,3,4-oxadiazole-2-amine (NPPOA). The chemical structure of the above substituted 1,3,4-oxadiazole has been assigned by IR, mass and X-ray diffraction studies. The XRD studies reveal the presence of four types of hydrogen bonds (N–H···O, N–H···N, C–H···O, C–H···N) in the crystal packing. The crystal system was found to be orthorhombic with a space group Pca2(1) and the unit cell dimensions are: a = 26.873(3) ?, b = 6.0827(7) ?, c = 7.8502(10) ?, α = 90°, β = 90°, γ = 90° and Z = 4.     

Crystal and Molecular Structure of 4-Aminobenzohydrazide

Abstract  

The molecule of 4-aminobenzohydrazide is essentially planar and geometric parameters conform to literature precedents. Supramolecular N–H···O and N–H···N interactions combine to link molecules of 4-aminobenzohydrazide into a three-dimensional network. Weaker N–H···N and N–H···π interactions consolidate the structure. The compound crystallizes in the monoclinic space group P2₁/n with a = 5.411(2) ?, b = 14.000(6) ?, c = 9.894(4) ?, β = 103.917(7)o, and Z = 4.     

Structures of Two (<Emphasis Type="Italic">E</Emphasis>)-3-Substituted Cinnamoylbenzotriazole 1-Oxides

Abstract  

The molecule of (E)-3-(3-MeOC₆H₄CH=CHCO)-benzotriazole 1-oxide, 2, has a very near planar structure, while the 2-nitrophenyl ring is rotated out of the plane of the remaining atoms in (E)-3-(2-O₂NC₆H₄CH=CHCO)-benzotriazole 1-oxide, 1. The nitrogen oxide bond lengths in 1 and 2 are 1.258 (6) and 1.2683 (15) ?, respectively, and are in the region found for related compounds. There are no strong intermolecular hydrogen-bonds in either compound, instead there are weak C–H···O intermolecular hydrogen-bonds and π···π stacking interactions in 1, and C–H···O, C–H···π, and π···π stacking interactions in 2. Different three-dimensional arrays are generated in each case. Compound 1 crystallises in the orthorhombic space group Pna2₁, with a = 25.061 (2) ?, b = 3.6997 (2) ?, c = 14.2623 (12) ? and Z = 4. Compound 2 crystallises in the triclinic space group P-1, with a = 5.7297 (3) ?, b = 10.8440 (6) ?, c = 11.4965 (6) ?, α = 89.689 (3)°, β = 76.019 (3)°, γ = 75.047 (3)°, Z = 2.     

Crystal structures of substituted imidazolidine derivatives

The crystal structures of isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]methyl-5-phenyl-,N-oxide] (C₁₃H₁₃N₅O₃) (I), isoxazole,3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(4-methylphenyl)-,N-oxide] (C₁₄H₁₅N₅O₃) (II) and isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(2-methoxyphenyl)-,N-oxide] (C₁₄H₁₅N₅O₄) (III) have been determined by X-ray diffraction studies. The compound I, crystallized in triclinic space group with unit cell dimensions a = 7.2405(7) ?, b = 7.9936(8) ?, c = 11.6573(11) ?, α = 97.801(2)°, β = 90.884(2)°, γ = 96.250(2)° and Z = 2. Compound II crystallized in orthorhombic space group Pna2₁ with unit cell dimensions a = 10.1778(10) ?, b = 28.228(3) ?, c = 5.1206(5) ?, and Z = 4. Compound III crystallized in monoclinic space group P2₁/n with unit cell dimensions a = 7.8439(9) ?, b = 7.8544(9) ?, c = 23.534(3) ?, β = 99.464(2)° and Z = 4. For all three compounds, the five-membered imidazolidine ring adopts an envelope conformation. The crystal structures are stabilized by both the intramolecular N–H···O and intermolecular N–H···N hydrogen bonding.     

Three Dimensional Network Polymeric Structure of (4,4′-bipyridinium)[CdBr<Subscript>4</Subscript>]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>: Supramolecular Motifs and Crystal Supramolecularity

Abstract A single crystal structure determination of the complex (4,4′-bipyridinium)[CdBr₄] _n , [henceforth (I)], has been carried out. It crystallizes in the monoclinic space group C2/c, with the following cell parameters: a = 16.119(3) ?, b = 13.206(3) ?, c = 7.2601(15) ?, β = 115.62°, V = 1393.5(6) ?³, with Z = 4 formula units. The polymeric anion forms an infinite zig-zag chain of edge-sharing octahedra along c, with a distorted octahedral stereochemistry around Cd. There are N–H···Br [Br2···N1 of 3.386(13) ? and Br1···N1 of 3.363(13) ?] and C–H···Br [Br2···C5 of 3.552(16) ?] hydrogen bonding interactions, tying the CdBr chains to the cations to form 2D-network. The resulting 2D-networks are further linked by aryl···aryl (π···π) interactions within the cationic chains leading to a 3D-network. Index Abstract Three dimensional network polymeric structure of (4,4′-bipyridinium)[CdBr₄] _n : Supramolecular motifs and crystal supramolecularity. Rawhi Al-Far and Basem F. Ali The polymeric anion consists of a zig–zag chain of distorted edge shared octahedra run along c axis. The protonated cation bridges the anion chains through N–H···Br and C–H···Br into a supramolecular array.