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Synthesis, structure and biological activity of four new picolinohydrazonamide derivatives

Four new picolinohydrazonamide derivatives, namely, 6-methyl-N'-(morpholine-4-carbonothioyl)picolinohydrazonamide, C₁₂H₁₇N₅OS, 6-chloro-N'-(morpholine-4-carbonothioyl)picolinohydrazonamide methanol monosolvate, C₁₁H₁₄ClN₅OS·CH₃OH, 6-chloro-N'-(4-phenylpiperazine-1-carbonothioyl)picolinohydrazonamide, C₁₇H₁₉ClN₆S, and 6-chloropicolinohydrazonamide, C₆H₇ClN₄, have been synthesized and characterized by NMR spectroscopy and single-crystal low-temperature X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The first three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules in the structure. They also adopt the same symmetry, i.e. P2₁/c (P2₁/n), unlike the fourth structure which is chiral and has the space group P2₁2₁2₁. For all the studied cases, intermolecular N-H...O and N-H...N hydrogen bonds play an essential role in the formation of the structures.

Crystal structure, Hirshfeld surface analysis and DFT studies of (E)-4-methyl-2-{[(4-methyl-phen-yl)imino]-meth-yl}phenol

In the title compound, C15H15NO, the configuration of the C=N bond of the Schiff base is E, and an intra-molecular O-H⋯N hydrogen bond is observed, forming an intra-molecular S(6) ring motif. The phenol ring is inclined by 45.73 (2)° from the plane of the aniline ring. In the crystal, mol-ecules are linked along the b axis by O-H⋯N and C-H⋯O hydrogen bonds, forming polymeric chains. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the packing arrangement are from H⋯H (56.9%) and H⋯C/C⋯H (31.2%) inter-actions. The density functional theory (DFT) optimized structure at the B3LYP/ 6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure, and the HOMO-LUMO energy gap is provided. The crystal studied was refined as an inversion twin.

The crystal structures, Hirshfeld surface analyses and energy frameworks of two hexa-thia-pyrazino-phane regioisomers; 2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane and 2,5,8,11,14,17-hexa-thia-[9.9](2,5,3,6)-pyrazino-phane

The title thia-pyrazino-phanes, 2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane, C16H24N2S6, (I), and 2,5,8,11,14,17-hexa-thia-[9.9](2,5,3,6)-pyrazino-phane, C16H24N2S6, (II), are regioisomers; m-bis L1 and p-bis L1, respectively. Both compounds have a central tetra-2,3,5,6-methyl-ene-pyrazine unit with two -S-CH2-CH2-S-CH2-CH2-S- chains, linking the methyl-ene C atoms at positions 2 and 6 and 3 and 5 on the pyrazine ring of I, but linking the methyl-ene C atoms at positions 2 and 5 and 3 and 6 on the pyrazine ring of II. Both compounds crystallize with half a mol-ecule in the asymmetric unit. The whole mol-ecule of I is generated by inversion symmetry, with the pyrazine ring being located about a center of symmetry. The whole mol-ecule of II is generated by twofold rotation symmetry, with the pyrazine N atoms being located on the twofold rotation axis. In compound I, there are pairs of intra-molecular C-H⋯S contacts present, but none in compound II. In the crystal of I, there are no significant inter-molecular inter-actions present, while in the crystal of II, mol-ecules are linked by pairs of C-H⋯S hydrogen bonds, forming corrugated layers lying parallel the ac plane. The Hirshfeld surfaces and the energy frameworks of the two regioisomers indicate little difference in the inter-atomic contacts, which are dominated by dispersion forces.

Selective synthesis and crystal structures of manganese(I) complexes with a bi- or tridentate terpyridine ligand

The crystal structures of two manganese(I) complexes with a different coordination mode of the supporting ligand are reported: fac-bromido-tricarbon-yl(4'-phenyl-2,2':6',2''-terpyridine-κ2 N,N')manganese(I), [MnBr(C21H15N3)(CO)3], I, and cis-bromido-dicarbon-yl(4'-phenyl-2,2':6',2''-terpyridine-κ3 N,N',N'')manganese(I), [MnBr(C21H15N3)(CO)2], II. In both complexes, the manganese(I) atom is coordinated by terminal carbonyl ligands, a bromide ion, and a 4'-phenyl-2,2':6',2''-terpyridine ligand within a distorted octa-hedral environment. In I, the metal ion is facially coordinated by three carbonyl ligands and the terpyridine ligand binds in a bidentate fashion. The non-coordinating nitro-gen atom in the terpyridine ligand is positioned on the side opposite to the bromido ligand. In II, the metal ion is coordinated by two carbonyl ligands in a cis configuration and the terpyridine ligand binds in a tridentate fashion; notably, one carbonyl and the trans bromido ligand are mutually disordered over two positions. In I, the complex mol-ecules are linked by C-H⋯Br hydrogen bonds. In II, aromatic π-π contacts are present, as well as pairs of C-H⋯Br and C-H⋯O hydrogen bonds.

Crystal structure of posnjakite formed in the first crystal water-cooling line of the ANSTO Melbourne Australian Synchrotron MX1 Double Crystal Monochromator

Exceptionally large crystals of posnjakite, Cu4SO4(OH)6(H2O), formed during corrosion of a Swagelock(tm) Snubber copper gasket within the MX1 beamline at the ANSTO-Melbourne, Australian Synchrotron. The crystal structure was solved using synchrotron radiation to R 1 = 0.029 and revealed a structure based upon [Cu4(OH)6(H2O)O] sheets, which contain Jahn-Teller-distorted Cu octa-hedra. The sulfate tetra-hedra are bonded to one side of the sheet via corner sharing and linked to successive sheets via extensive hydrogen bonds. The sulfate tetra-hedra are split and rotated, which enables additional hydrogen bonds.

Crystal structures of [(μ2-L1)di-bromidodicopper(II)] dibromide and poly[[(μ2-L1)diiodido-dicopper(I)]-di-μ-iodido-dicopper(I)], where L1 is 2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane

The reaction of the hexa-thia-pyrazino-phane ligand, 2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane (L1), with copper(II) dibromide led to the formation of a binuclear complex, [μ2-2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane]bis-[bromi-docopper(II)] dibromide, [Cu2Br2(C16H24N2S6)]Br2, (I). The complex possesses inversion symmetry with the pyrazine ring being situated about a center of symmetry. The ligand coordinates to the copper(II) atom in a bis-tetra-dentate manner and the copper atom has a fivefold NS3Br coordination environment with a distorted shape. The reaction of ligand L1 with copper(I) iodide also gave a binuclear complex, which is bridged by a Cu2I2 unit to form a two-dimensional coordination polymer, poly[[μ2-2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane]tetra-μ-iodido-tetra-copper(I)], [Cu4I4(C16H24N2S6)] n , (II). The binuclear unit possesses inversion symmetry with the pyrazine ring being located about a center of symmetry. The Cu2I2 unit is also located about an inversion center. The two independent copper(I) atoms are both fourfold coordinate. That coordinating to the ligand L1 in a bis-tridentate manner has an NS2I coordination environment and an irregular shape, while the second copper(I) atom, where L1 coordinates in a bis-monodentate manner, has an SI3 coordination environment with an almost perfect tetra-hedral geometry. In the crystal of I, the cations and Br- anions are linked by a number of C-H⋯S and C-H⋯Br hydrogen bonds, forming a supra-molecular network. In the crystal of II, the two-dimensional coordination polymers lie parallel to the ab plane and there are no significant inter-layer contacts present.

Crystal structure and Hirshfeld surface analysis of 4-{[(E)-4-(hept-yloxy)benzyl-idene]amino}-N-(naphthalen-2-yl)-1,3-thia-zol-2-amine

In the title compound, C27H28N2OS, the naphthalene unit is planar to within 0.015 (2) Å and makes a dihedral angle of 14.24 (16)° with the thia-zole ring. The anisole ring is inclined to the thia-zole ring by a dihedral angle of 13.18 (23)°. The torsion angle between the heptyl chain and the anisole ring is 61.1 (4)°. These dihedral and torsion angles render the mol-ecule non-planar. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming zigzag chains that propagate parallel to the b axis. The roles of the various inter-molecular inter-actions in the crystal packing were clarified by Hirshfeld surface analysis; the most important contributions are from H⋯H (51.5%) and C⋯H/H⋯C (31.8%) contacts.

Crystal structure and Hirshfeld surface analysis of 1-(2-fluoro-phen-yl)-1H-tetra-zole-5(4H)-thione

In the crystal of the title compound, C7H5FN4S, the mol-ecules are non-planar, with dihedral angle formed by least-squares planes of tetra-zole and benzene rings of 59.94 (8) °. The crystal packing is formed by N-H⋯S hydrogen bonds, which link the mol-ecules into centrosymmetric dimers with an R 2 2(8) ring motif, and by the offset face-to-face π-π stacking inter-actions between the benzene rings, which join the dimers into layers parallel to (100). The Hirshfeld surface analysis shows that the most important contributions to the surface contacts are from N⋯H/H⋯N (21.9%), S⋯H/H⋯S (21.1%), H⋯H (14.6%), F⋯H/H⋯F (11.8%) and C⋯H/H⋯C (9.5%) inter-actions.

Crystal structure and Hirshfeld surface analysis of 1-methyl-4-(2-methyl-10H-benzo[b]thieno[2,3-e][1,4]diazepin-4-yl)piperazin-1-ium 2,5-di-hydroxy-benzoate propan-2-ol monosolvate

The asymmetric unit of the title salt, C17H21N4S+·C7H5O4 -·C3H7OH, consists of an olanzapinium cation, an independent 2,5-di-hydroxy-benzoate anion and a solvent isopropyl alcohol mol-ecule. The central seven-membered heterocycle is in a boat conformation, while the piperazine ring displays a distorted chair conformation. The dihedral angle between the benzene and thiene rings flanking the diazepine ring is 52.58 (19)°. In the crystal, the anions and cations are connected by N-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional network.

Two N-{[4-(3-aryl-4-sydnonyl-idene-amino)-5-sulfan-yl-idene-1H-1,2,4-triazol-3-yl]meth-yl}benzamides as disordered ethanol monosolvates

Two new N-{[4-(3-aryl-4-sydnonyl-idene-amino)-5-sulfanyl-idene-1H-1,2,4-triazol-3-yl]meth-yl}benzamides have been prepared by acid-promoted condensation reactions between 3-aryl-4-formyl-sydnones and N-[(4-amino-5-sulfanyl-idene-1H-1,2,4-triazol-3-yl)meth-yl]benzamide, and both have been crystallized as ethanol monosolvates. N-{[4-(3-Phenyl-4-sydnonyl-idene-amino)-5-sulfanyl-idene-1H-1,2,4-triazol-3-yl]meth-yl}benzamide ethanol monosolvate, C19H15N7O3S·C2H6O (I), and N-({4-[3-(4-methyl-phen-yl)-4-sydnonyl-idene-amino]-5-sulfanyl-idene-1H-1,2,4-triazol-3-yl}meth-yl)benzamide ethanol monosolvate, C20H17N7O3S·C2H6O (II), differ only in the presence of a methyl group for (II) instead of a hydrogen atom for (I), and in both of them the ethanol component is disordered over two sets of atomic sites having occupancies of 0.836 (6) and 0.164 (6) in (I), and 0.906 (6) and 0.094 (6) in (II). Combinations of O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules into cyclic, centrosymmetric four-mol-ecule aggregates. Comparisons are made with the structures of some related compounds.

Crystal structures and Hirshfeld surface analyses of 6,8-dimeth-oxy-3-methyl-1H-isochromen-1-one and 5-bromo-6,8-dimeth-oxy-3-methyl-1H-isochromen-1-one chloro-form monosolvate

In the mol-ecule of 6,8-dimeth-oxy-3-methyl-1H-isochromen-1-one, C12H12O4, (I), the two meth-oxy groups are directed anti with respect to each other. In the mol-ecule of the brom-inated derivative, 5-bromo-6,8-dimeth-oxy-3-methyl-1H-isochromen-1-one, that crystallized as a chloro-form monosolvate, C12H11BrO4·CHCl3, (II·CHCl3 ), the meth-oxy groups are directed syn to each other. In the crystal of I, mol-ecules are linked by bifurcated C-H⋯O hydrogen bonds, forming chains along the c-axis direction. The chains are linked by C-H⋯π inter-actions, forming a supra-molecular framework. In the crystal of II·CHCl3 , mol-ecules are linked by C-H⋯O hydrogen bonds forming 21 helices parallel to the b-axis direction. The chloro-form solvate mol-ecules are linked to the helices by C-H⋯O(carbon-yl) hydrogen bonds. The helices stack up the c-axis direction and are linked by offset π-π inter-actions [inter-centroid distance = 3.517 (3) Å], forming layers parallel to the (100) plane. Compound II·CHCl3 was refined as a two-component twin. Two chlorine atoms of the chloro-form solvate are disordered over two positions and were refined with a fixed occupancy ratio of 0.5:0.5.

The crystal structure, Hirshfeld surface analysis and energy frameworks of 2-[2-(meth-oxy-carbon-yl)-3,6-bis-(meth-oxy-meth-oxy)phen-yl]acetic acid

In the title compound, C14H18O8, (I), the meth-oxy-carbonyl [-C(=O)OCH3] and the acetic acid [-CH2C(=O)OH] groups are inclined to the benzene ring by 79.24 (11) and 76.71 (13)°, respectively, and are normal to each other with a dihedral angle of 90.00 (13)°. In the crystal, mol-ecules are linked by a pair of O-H⋯O hydrogen bonds forming the familiar acetic acid inversion dimer. The dimers are linked by two C-H⋯O hydrogen bonds and an offset π-π inter-action [inter-centroid distance = 3.6405 (14) Å], forming layers lying parallel to the (10) plane. The layers are linked by a third C-H⋯O hydrogen bond and a C-H⋯π inter-action to form a supra-molecular framework.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-2-(4-methyl-phen-yl)diazen-1-yl]ethen-yl}-N,N-di-methyl-aniline

In the tile compound, C17H17Cl2N3, the dihedral angle between the benzene rings is 62.73 (9)°. In the crystal, there are no classical hydrogen bonds. Mol-ecules are linked by a pair of C-Cl⋯π inter-actions, forming an inversion dimer. A short inter-molecular HL⋯HL contact [Cl⋯Cl = 3.2555 (9) Å] links the dimers, forming a ribbon along the c-axis direction. The Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that the most important contributions for the crystal packing are from H⋯H (45.4%), Cl⋯H/H⋯Cl (21.0%) and C⋯H/H⋯C (19.0%) contacts.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-(4-chloro-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline

The title compound, C16H14Cl3N3, comprises three mol-ecules of similar shape in the asymmetric unit. The crystal cohesion is ensured by inter-molecular C-H⋯N and C-H⋯Cl hydrogen bonds in addition to C-Cl⋯π inter-actions. Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that Cl⋯H/H⋯Cl (33.6%), H⋯H (27.9%) and C⋯H/H⋯C (17.6%) are the most important contributors towards the crystal packing.

Two Beta-Phosphorylamide Compounds as Ligands for Sm3+, Eu3+, and Tb3+: X-ray Crystallography and Luminescence Properties

This paper describes the synthesis of two beta-phosphorylamide ligands and their coordination chemistry with the Ln ions Tb³⁺, Eu³⁺, and Sm³⁺. Both the ligands and Ln complexes were characterized by IR, NMR, MS, and X-ray crystallography. The luminescence properties of the Tb³⁺ and Eu³⁺ complexes were also characterized, including the acquisition of lifetime decay curves. In the solid state, the Tb³⁺ and Sm³⁺ ligand complexes were found to have a 2:2 stoichiometry when analyzed by X-ray diffraction. In these structures, the Ln ion was bound by both oxygen atoms of each beta-phosphorylamide moiety of the ligands. The Tb³⁺ and Eu³⁺ complexes were modestly emissive as solutions in acetonitrile, with lifetime values that fell within typical ranges.

Crystal structure of bromido-triphenyl-(triphenylarsine oxide-κO)tin(IV), C36H30AsBrOSn

C36H30AsBrOSn, triclinic, P1̄ (no. 2), a = 9.8316(1) Å, b = 10.8781(2) Å, c = 14.9388(2) Å, α = 102.367(1)°, β = 93.369(1)°, γ = 103.134(1)°, V = 1510.07(4) Å3, Z = 2, R gt(F) = 0.0175, wR ref(F 2) = 0.0469, T = 100 K.

Reactivity trends of cobalt(III) complexes towards various amino acids based on the properties of the amino acid alkyl chains

The reactivity of the cobalt(III) complexes dichlorido[tris(2-aminoethyl)amine]cobalt(III) chloride, [CoCl₂(tren)]Cl, and dichlorido(triethylenetetramine)cobalt(III) chloride, [CoCl₂(trien)]Cl, towards different amino acids (L-proline, L-asparagine, L-histidine and L-aspartic acid) was explored in detail. This study presents the crystal structures of three amino acidate cobalt(III) complexes, namely, (L-prolinato-κ²N,O)[tris(2-aminoethyl)amine-κ⁴N,N',N'',N''']cobalt(III) diiodide monohydrate, [Co(C₅H₈NO₂)(C₆H₁₈N₄)]I₂·H₂O, I, (L-asparaginato-κ²N,O)[tris(2-aminoethyl)amine-κ⁴N,N',N'',N''']cobalt(III) chloride perchlorate, [Co(C₄H₇N₂O₃)(C₆H₁₈N₄)](Cl)(ClO₄), II, and (L-prolinato-κ²N,O)(triethylenetetramine-κ⁴N,N',N'',N''')cobalt(III) chloride perchlorate, [Co(C₄H₇N₂O₃)(C₆H₁₈N₄)](Cl)(ClO₄), V. The syntheses of the complexes were followed by characterization using UV-Vis spectroscopy of the reaction mixtures and the initial rates of reaction were obtained by calculating the slopes of absorbance versus time plots. The initial rates suggest a stronger reactivity and hence greater affinity of the cobalt(III) complexes towards basic amino acids. The biocompatibility of the complexes was also assessed by evaluating the cytotoxicity of the complexes on cultured normal human fibroblast cells (WS1) in vitro. The compounds were found to be nontoxic after 24 h of incubation at concentrations up to 25 mM.

Halobismuth(III) salts with substituted aminopyridinium cations

The crystal structures of six halobismuth(III) salts of variously substituted aminopyridinium cations display discrete mononuclear [BiCl₆]^3- and dinuclear [Bi₂X₁₀]^4- anions (X = Cl or Br), and polymeric cis-double-halo-bridged [Bi_nX_4n]^n- anionic chains (X = Br or I). Bis(2-amino-3-ammoniopyridinium) hexachloridobismuth(III) chloride monohydrate, (C₅H₉N₃)₂[BiCl₆]Cl·H₂O, (1), contains discrete mononuclear [BiCl₆]^3- and chloride anions. Tetrakis(2-amino-3-methylpyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)], (C₆H₉N₂)₄[Bi₂Cl₁₀], (2), tetrakis(2-amino-3-methylpyridinium) di-μ-bromido-bis[tetrabromidobismuth(III)], (C₆H₉N₂)₄[Bi₂Br₁₀], (3), and bis(4-amino-3-ammoniopyridinium) di-μ-chlorido-bis[tetrachloridobismuth(III)] dihydrate, (C₅H₉N₃)₂[Bi₂Cl₁₀]·2H₂O, (4), incorporate discrete [Bi₂X₁₀]^4- anions (X = Cl or Br), while catena-poly[2,6-diaminopyridinium [[cis-diiodidobismuth(III)]-di-μ-iodido]], {(C₅H₈N₃)[BiI₄]}_n, (5), and catena-poly[2,6-diaminopyridinium [[cis-dibromidobismuth(III)]-di-μ-bromido]], {(C₅H₇N₂)[BiBr₄]}_n, (6), include [Bi_nX_4n]^n- anionic chains (X = Br or I). Structures (2) and (3) are isostructural, while that of (5) is a pseudomerohedral twin. There is no discernible correlation between the type of anionic species obtained and the cation or halide ligand used. The Bi^III centres always have a slightly distorted octahedral geometry and there is a correlation between the Bi-X bond lengths and the number of classic N-H...X hydrogen bonds that the X ligand accepts, with a greater number of interactions corresponding with slightly longer Bi-X distances. The supramolecular networks formed by classic N-H...X hydrogen bonds include ladders, bilayers and three-dimensional frameworks.

Stereochemistry of the methyl-idene-bridged quinazoline-iso-quinoline alkaloid 3-{[6,7-dimeth-oxy-1-(4-nitro-phen-yl)-1,2,3,4-tetra-hydro-isoquinolin-2-yl]methyl-idene}-1,2,3,9-tetra-hydro-pyrrolo-[2,1-b]quinazolin-9-one methanol monosolvate

Two potentially bioactive fragments, namely a tricyclic quinazoline derivative with an exocyclic alkene moiety and a substituted iso-quinoline, are coupled to give 3-{[6,7-dimeth-oxy-1-(4-nitro-phen-yl)-1,2,3,4-tetra-hydro-isoquinolin-2-yl]methyl-idene}-1,2,3,9-tetra-hydro-pyrrolo-[2,1-b]quinazolin-9-one. The target product crystallizes as a methanol solvate, C29H26N4O5·CH4O, and is E configured. The alternative Z isomer would necessarily imply either considerable twist about the central double bond or very unfavourable intra-molecular contacts between sterically more demanding substituents. The main residue and the co-crystallized solvent mol-ecule aggregate to discrete pairs via a classical O-H⋯O hydrogen bond with a distance of 2.8581 (7) Å between the methanol OH donor and the quinazolinone O=C acceptor.

Crystal structure of a 1:1 co-crystal of the anti-cancer drug gefitinib with azelaic acid

In the title co-crystal, C22H24ClFN4O3·C9H16O4, gefitinib (GTB; systematic name: quinazolin-4-amine) co-crystallizes with azelaic acid (AA; systematic name: nona-nedioic acid). The co-crystal has the monoclinic P21/n centrosymmetric space group, containing one mol-ecule each of GTB and AA in the asymmetric unit. A structure overlay of the GTB mol-ecule in the co-crystal with that of its most stable polymorph revealed a significant difference in the conformation of the morpholine moiety. The significant deviation in the conformation of one of the acidic groups of azelaic acid from its usual linear chain structure could be due to the encapsulation of one acidic group in the pocket formed between the two pincers of GTB namely, the morpholine and phenyl moieties. Both GTB and AA mol-ecules form N-H⋯O, O-H⋯N, C-H⋯O hydrogen bonds with C-H⋯F close contacts along with off-stacked aromatic π-π inter-actions between the GTB mol-ecules.

1-Ethyl 2-methyl 3,4-bis-(acet-yloxy)pyrrolidine-1,2-di-carboxyl-ate: crystal structure, Hirshfeld surface analysis and computational chemistry

The title compound, C13H19NO8, is based on a tetra-substituted pyrrolidine ring, which has a twisted conformation about the central C-C bond; the Cm-Ca-Ca-Cme torsion angle is 38.26 (15)° [m = methyl-carboxyl-ate, a = acet-yloxy and me = methyl-ene]. While the N-bound ethyl-carboxyl-ate group occupies an equatorial position, the remaining substituents occupy axial positions. In the crystal, supra-molecular double-layers are formed by weak methyl- and methyl-ene-C-H⋯O(carbon-yl) inter-actions involving all four carbonyl-O atoms. The two-dimensional arrays stack along the c axis without directional inter-actions between them. The Hirshfeld surface is dominated by H⋯H (55.7%) and H⋯C/C⋯H (37.0%) contacts; H⋯H contacts are noted in the inter-double-layer region. The inter-action energy calculations point to the importance of the dispersion energy term in the stabilization of the crystal.

In situ synthesis, crystal structures, topology and photoluminescent properties of poly[di-μ-aqua-di-aqua-[μ3-4-(1H-tetra-zol-1-id-5-yl)benzoato-κ4 O:O,O':O'']barium(II)] and poly[μ-aqua-di-aqua-[μ3-4-(1H-tetra-zol-1-id-5-yl)benzoato-κ4 O:O,O':O']strontium(II)]

Two alkaline-earth coordination compounds, [Ba(C8H4N4O2)(H2O)4] n , (I), and [Sr(C8H4N4O2)(H2O)3] n , (II), from the one-pot hydrolysis transformation of benzoyl chloride and the in situ self-assembled [2 + 3] cyclo-addition of nitrile are presented. These coordination compounds are prepared by reacting 4-cyano-benzoyl chloride with divalent alkaline-earth salts (BaCl2 and SrCl2) in aqueous solution under hydro-thermal conditions. The mononuclear coordination compounds (I) and (II) show the same mode of coordination of the organic ligands. The cohesion of the crystalline structures is provided by hydrogen bonds and π-stacking inter-actions, thus forming three-dimensional supra-molecular networks. The two compounds have a three-dimensional (3,6)-connected topology, and the structural differences between them is in the number of water mol-ecules around the alkaline earth metals. Having the same emission frequencies, the compounds exhibit photoluminescence properties with a downward absorption value from (I) to (II).

2-[Carbamo-thio-yl(2-hy-droxy-eth-yl)amino]-ethyl benzoate: crystal structure, Hirshfeld surface analysis and computational study

The title di-substituted thio-urea, C12H16N2O3S, has the hy-droxy-lethyl and ethyl benzoate substituents bound to the same amine-N atom, and is twisted, having a (+)syn-clinal conformation with the Namine-C-C-O(hydroxyl, carbon-yl) torsion angles of 49.39 (13) and 59.09 (12)°, respectively; the dihedral angle between the almost planar CN2S core and the pendent benzene ring is 69.26 (4)°. In the crystal, supra-molecular layers propagating in the ac plane are formed via a combination of hydroxyl-O-H⋯S(thione), amine-N-H⋯O(hydroxyl, carbon-yl) hydrogen-bonds. The layers stack along the b axis with inter-digitation of the benzene rings allowing the formation of π-π stacking [inter-centroid separation = 3.8722 (7) Å] and parallel C=O⋯π inter-actions. A computational chemistry study shows the conventional hydrogen bonding in the crystal leads to significant electrostatic stabilization but dispersion terms are also apparent, notably through the inter-actions involving the benzene residue.

TAAM: a reliable and user friendly tool for hydrogen-atom location using routine X-ray diffraction data

Hydrogen is present in almost all of the molecules in living things. It is very reactive and forms bonds with most of the elements, terminating their valences and enhancing their chemistry. X-ray diffraction is the most common method for structure determination. It depends on scattering of X-rays from electron density, which means the single electron of hydrogen is difficult to detect. Generally, neutron diffraction data are used to determine the accurate position of hydrogen atoms. However, the requirement for good quality single crystals, costly maintenance and the limited number of neutron diffraction facilities means that these kind of results are rarely available. Here it is shown that the use of Transferable Aspherical Atom Model (TAAM) instead of Independent Atom Model (IAM) in routine structure refinement with X-ray data is another possible solution which largely improves the precision and accuracy of X-H bond lengths and makes them comparable to averaged neutron bond lengths. TAAM, built from a pseudoatom databank, was used to determine the X-H bond lengths on 75 data sets for organic molecule crystals. TAAM parametrizations available in the modified University of Buffalo Databank (UBDB) of pseudoatoms applied through the DiSCaMB software library were used. The averaged bond lengths determined by TAAM refinements with X-ray diffraction data of atomic resolution (d_min ≤ 0.83 Å) showed very good agreement with neutron data, mostly within one single sample standard deviation, much like Hirshfeld atom refinement (HAR). Atomic displacements for both hydrogen and non-hydrogen atoms obtained from the refinements systematically differed from IAM results. Overall TAAM gave better fits to experimental data of standard resolution compared to IAM. The research was accompanied with development of software aimed at providing user-friendly tools to use aspherical atom models in refinement of organic molecules at speeds comparable to routine refinements based on spherical atom model.

Syntheses and structures of two novel fluorescent metal-organic frameworks generated from a tridentate donor-acceptor motif ligand

The tridentate organic ligand 4,4',4''-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6,10-triyl)tribenzoic acid (H₃L) has been synthesized (as the methanol 1.25-solvate, C₄₈H₃₉NO₆·1.25CH₃OH). As a donor-acceptor motif molecule, H₃L possess strong intramolecular charge transfer (ICT) fluorescence. Through hydrogen bonds, H₃L molecules construct a two-dimensional (2D) network, which pack together into three-dimensional (3D) networks with an ABC stacking pattern in the crystalline state. Based on H₃L and M(NO₃)₂ salts (M = Cd and Zn) under solvothermal conditions, two metal-organic frameworks (MOFs), namely, catena-poly[[triaquacadmium(II)]-μ-10-(4-carboxyphenyl)-4,4'-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6-diyl)dibenzoato], [Cd(C₄₈H₃₇NO₆)(H₂O)₃]_n, I, and poly[[μ₃-4,4',4''-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6,10-triyl)tribenzoato](μ₃-hydroxido)zinc(II)], [Zn₂(C₄₈H₃₆NO₆)(OH)]_n, II, were synthesized. Single-crystal analysis revealed that both MOFs adopt a 3D structure. In I, partly deprotonated HL^2- behaves as a bidentate ligand to link a Cd^II ion to form a one-dimensional chain. In the solid state of I, the existence of weak interactions, such as O-H...O hydrogen bonds and π-π interactions, plays an essential role in aligning 2D nets and 3D networks with AB packing patterns for I. The deprotonated ligand L^3- in II is utilized as a tridentate building block to bind Zn^II ions to construct 3D networks, where unusual Zn₄O₁₄ clusters act as connection nodes. As a donor-acceptor molecule, H₃L exhibits fluorescence with a photoluminescence quantum yield (PLQY) of 70% in the solid state. In comparison, the PL of both MOFs is red-shifted with even higher PLQYs of 79 and 85% for I and II, respectively.

Febuxostat ethanol monosolvate

The title compound, 2-(3-cyano-4-iso-but-oxyphen-yl)-4-methyl-1,3-thia-zole-5-car-b-oxy-lic acid ethanol monosolvate, C16H16N2O3S·C2H6O, (I), displays inter-molecular O-H⋯O and O-H⋯N bonds in which the carboxyl group of the febuxostat mol-ecule and the hydroxyl group of the ethanol mol-ecule serve as hydrogen-bond donor sites. These inter-actions result in a helical hydrogen-bonded chain structure. The title structure is isostructural with a previously reported methanol analogue.

Crystal structure and Hirshfeld surface analysis of 4-(naphthalen-2-yl)-N-[(Z)-4-propoxybenzyl-idene]-1,3-thia-zol-2-amine

The asymmetric unit of the title compound, C23H20N2OS, contains one slightly bent mol-ecule. The naphthalene ring system and the thia-zole ring are twisted with respect to each other, making a dihedral angle of 13.69 (10)°; the anisole ring is inclined to the plane of the naphthalene ring system, the dihedral angle being 14.22 (12)°. In the crystal structure, mol-ecules are linked by C-H⋯π inter-actions, resulting in the formation of sheets parallel to (100). Within the sheets, very weak π-π stacking inter-actions lead to additional stabilization. Hirshfeld surface analysis and fingerprint plots reveal that the cohesion in the crystal structure is dominated by H⋯H (42.5%) and C⋯H/H⋯C (37.2%) contacts.

Obtaining the best results: aspects of data collection, model finalization and inter-pretation of results in small-mol-ecule crystal-structure determination

In small-mol-ecule single-crystal structure determination, we now have at our disposal an inspiring range of fantastic diffractometers with better, brighter sources, and faster, more sensitive detectors. Faster and more powerful computers provide integrated tools and software with impressive graphical user inter-faces. Yet these tools can lead to the temptation not to check the work thoroughly and one can too easily overlook tell-tale signs that something might be amiss in a structure determination; validation with checkCIF is not always revealing. This article aims to encourage practitioners, young and seasoned, by enhancing their structure-determination toolboxes with a selection of tips and tricks on recognizing and handling aspects that one should constantly be aware of. Topics include a pitfall when setting up data collections, the usefulness of reciprocal lattice layer images, processing twinned data, tips for disorder modelling and the use of restraints, ensuring hydrogen atoms are added to a model correctly, validation beyond checkCIF, and the derivation and inter-pretation of the final results.

Three 4-(4-fluoro-phen-yl)piperazin-1-ium salts containing organic anions: supra-molecular assembly in one, two and three dimensions

Three salts containing the 4-(4-fluoro-phen-yl)piperazin-1-ium cation have been prepared and structurally characterized. In 4-(4-fluoro-phen-yl)piperazin-1-ium 2-hy-droxy-3,5-di-nitro-benzoate, C10H14FN2 +·C7H3N2O7 -, (I), the anion contains an intra-molecular O-H⋯O hydrogen bond, and it has a structure similar to that of the picrate ion. The cations and anions are linked into [001] chains of rings by a combination of two three-centre N-H⋯(O)2 hydrogen bonds. The anion in 4-(4-fluoro-phen-yl)piperazin-1-ium hydrogen oxalate, C10H14FN2 +·C2HO4 -, (II), is planar, and the cations and anions are linked into (100) sheets by multiple hydrogen bonds including two-centre N-H⋯O, three-centre N-H⋯(O)2, O-H⋯O, C-H⋯O and C-H⋯π(arene) types. In 4-(4-fluoro-phen-yl)piperazin-1-ium hydrogen (2R,3R)-tartrate monohydrate, C10H14FN2 +·C4H5O6 -·H2O, (III), the anion exhibits an approximate non-crystallographic twofold rotation symmetry with anti-periplanar carboxyl groups. A combination of eight hydrogen bonds, encompassing two- and three-centre N-H⋯O systems, O-H⋯O and C-H⋯π(arene) types, link the independent components into a three-dimensional framework. Comparisons are made with some related structures.

Two ZnII-based MOFs constructed with biphenyl-2,2',5,5'-tetracarboxylic acid and flexible N-donor ligands: syntheses, structures and properties

Two new Zn²⁺-based metal-organic frameworks (MOFs) based on biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. H₄(o,m-bpta), and N-donor ligands, namely, poly[[(μ₄-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,3-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·C₃H₇NO·2H₂O}_n or {[Zn₂(o,m-bpta)(1,3-bimb)₂]·C₃H₇NO·2H₂O}_n (1) {1,3-bimb = [1,3-phenylenebis(methylene)]bis(1H-imidazole)}, and poly[[(μ₄-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,4-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] monohydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·H₂O}_n or {[Zn₂(o,m-bpta)(1,4-bimb)₂]·H₂O}_n (2) {1,4-bimb = [1,4-phenylenebis(methylene)]bis(1H-imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. Structurally, the (o,m-bpta)^4- ligands are fully deprotonated and combine with Zn²⁺ ions in μ₄-coordination modes. Complex 1 is a (3,4)-connected porous network with honeycomb-like [Zn₂(o,m-bpta)]_n sheets formed by 4-connected (o,m-bpta)^4- ligands. Complex 2 exhibits a (2,4)-connected network formed by 4-connected (o,m-bpta)^4- ligands linking Zn²⁺ ions in left-handed helical chains. The cis-configured 1,3-bimb and 1,4-bimb ligands bridge Zn²⁺ ions to form multi-membered [Zn₂(bimb)₂] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H₄(o,m-bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C_2v polar point group.

The crystal structure and Hirshfeld surface analysis of 1-(2,5-di-meth-oxy-phen-yl)-2,2,6,6-tetra-methyl-piperidine

In the title compound, C17H27NO2, the piperidine ring has a chair conformation and is positioned normal to the benzene ring. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains propagating along the c-axis direction.

Crystal structure and Hirshfeld surface analysis of 4-{2,2-di-chloro-1-[(E)-(4-fluoro-phen-yl)diazen-yl]ethen-yl}-N,N-di-methyl-aniline

In the title compound, C16H14Cl2FN3, the dihedral angle between the two aromatic rings is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C-Cl⋯π and van der Waals inter-actions. The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H⋯H (33.3%), Cl⋯H/H⋯Cl (22.9%) and C⋯H/H⋯C (15.5%) inter-actions are the most important contributors towards the crystal packing.

Synthesis and crystal structure of (1,10-phenanthroline-κ2 N,N')[2-(1H-pyrazol-1-yl)phenyl-κ2 N 2,C 1]iridium(III) hexa-fluorido-phosphate with an unknown number of solvent mol-ecules

The cationic complex in the title compound, [Ir(C9H7N2)2(C12H8N2)]PF6, comprises two phenyl-pyrazole (ppz) cyclo-metallating ligands and one 1,10-phenanthroline (phen) ancillary ligand. The asymmetric unit consists of one [Ir(ppz)2(phen)]+ cation and one [PF6]- counter-ion. The central IrIII ion is six-coordinated by two N atoms and two C atoms from the two ppz ligands as well as by two N atoms from the phen ligand within a distorted octa-hedral C2N4 coordination set. In the crystal structure, the [Ir(ppz)2(phen)]+ cations and PF6 - counter-ions are connected with each other through weak inter-molecular C-H⋯F hydrogen bonds. Additional C-H⋯π inter-actions between the rings of neighbouring cations consolidate the three-dimensional network. Electron density associated with additional disordered solvent mol-ecules inside cavities of the structure was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unknown solvent mol-ecule(s). The title compound has a different space-group symmetry (C2/c) from its solvatomorph (P21/c) comprising 1.5CH2Cl2 solvent mol-ecules per ion pair.

Bulk polarity of 3,5,7-trinitro-1-azaadamantane mediated by asymmetric NO2(lone pair)...NO2(π-hole) supramolecular bonding

Molecular crystals exhibiting polar symmetry are important paradigms for developing new electrooptical materials. Though accessing bulk polarity still presents a significant challenge, in some cases it may be rationalized as being associated with the specific molecular shapes and symmetries and subtle features of supramolecular interactions. In the crystal structure of 3,5,7-trinitro-1-azaadamantane, C₉H₁₂N₄O₆, the polar symmetry of the molecular arrangement is a result of complementary prerequisites, namely the C_3v symmetry of the molecules is suited to the generation of polar stacks and the inherent asymmetry of the principal supramolecular bonding, as is provided by NO₂(lone pair)...NO₂(π-hole) interactions. These bonds arrange the molecules into a trigonal network. In spite of the apparent simplicity, the structure comprises three unique molecules (Z' = 1/3 + 1/3 + 1/3), two of which are donors and acceptors of three N...O interactions and the third being primarily important for weak C-H...O hydrogen bonding. These distinct structural roles agree with the results of Hirshfeld surface analysis. A set of weak C-H...O and C-H...N hydrogen bonds yields three kinds of stacks. The orientation of the stacks is identical and therefore the polarity of each molecule contributes additively to the net dipole moment of the crystal. This suggests a special potential of asymmetric NO₂(lone pair)...NO₂(π-hole) interactions for the supramolecular synthesis of acentric materials.

Self-assembly of a cobalt(II)-based metal-organic framework as an effective water-splitting heterogeneous catalyst for light-driven hydrogen production

The solar photocatalysis of water splitting represents a significant branch of enzymatic simulation by efficient chemical conversion and the generation of hydrogen as green energy provides a feasible way for the replacement of fossil fuels to solve energy and environmental issues. We report herein the self-assembly of a Co^II-based metal-organic framework (MOF) constructed from 4,4',4'',4'''-(ethene-1,1,2,2-tetrayl)tetrabenzoic acid [or tetrakis(4-carboxyphenyl)ethylene, H₄TCPE] and 4,4'-bipyridyl (bpy) as four-point- and two-point-connected nodes, respectively. This material, namely, poly[(μ-4,4'-bipyridyl)[μ₈-4,4',4'',4'''-(ethene-1,1,2,2-tetrayl)tetrabenzoato]cobalt(II)], [Co(C₃₀H₁₆O₈)(C₁₀H₈N₂)]_n, crystallized as dark-red block-shaped crystals with high crystallinity and was fully characterized by single-crystal X-ray diffraction, PXRD, IR, solid-state UV-Vis and cyclic voltammetry (CV) measurements. The redox-active Co^II atoms in the structure could be used as the catalytic sites for hydrogen production via water splitting. The application of this new MOF as a heterogeneous catalyst for light-driven H₂ production has been explored in a three-component system with fluorescein as photosensitizer and trimethylamine as the sacrificial electron donor, and the initial volume of H₂ production is about 360 µmol after 12 h irradiation.

Crystal structure and Hirshfeld surface analysis of 4-bromo-anilinium nitrate

The title compound C4H7BrN+·NO3 - crystallizes in the monoclinic crystal system with space group P21/c. In the crystal, π-π stacking inter-actions and strong N-H⋯O and C-H⋯O hydrogen bonds link the cations and anions into layers parallel to the bc plane. The O⋯H/H⋯O inter-actions between the cation and anion are the major factor determining the crystal packing.

Crystal structure, Hirshfeld surface analysis and computational study of the 1:2 co-crystal formed between N,N'-bis-[(pyridin-4-yl)meth-yl]ethanedi-amide and 3-chloro-benzoic acid

The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises a half-mol-ecule of oxalamide (4 LH2), being located about a centre of inversion, and a mol-ecule of3-chloro-benzoic acid (3-ClBA) in a general position. From symmetry, the 4 LH2 mol-ecule has a (+)anti-periplanar conformation with the 4-pyridyl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angle between the core and pyridyl ring being 74.69 (11)°; intra-molecular amide-N-H⋯O(amide) hydrogen bonds are noted. The 3-ClBA mol-ecule exhibits a small twist as seen in the C6/CO2 dihedral angle of 8.731 (12)°. In the mol-ecular packing, three-mol-ecule aggregates are formed via carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonding. These are connected into a supra-molecular tape along [111] through amide-N-H⋯O(carbon-yl) hydrogen bonding. Additional points of contact between mol-ecules include pyridyl and benzoic acid-C-H⋯O(amide), methyl-ene-C-H⋯O(carbon-yl) and C-Cl⋯π(pyrid-yl) inter-actions so a three-dimensional architecture results. The contributions to the calculated Hirshfeld surface are dominated by H⋯H (28.5%), H⋯O/O⋯H (23.2%), H⋯C/C⋯H (23.3%), H⋯Cl/Cl⋯H (10.0%) and C⋯Cl/C⋯Cl (6.2%) contacts. Computational chemistry confirms the C-Cl⋯π inter-action is weak, and the importance of both electrostatic and dispersion terms in sustaining the mol-ecular packing despite the strong electrostatic term provided by the carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonds.

The missing crystal structure in the series of N,N',N''-tris-(pyridinyl)benzene-1,3,5-tricarbox-amides: the 2-pyridinyl derivative

In the first reported crystal structure involving the potential ligand N,N',N''-tris-(pyridin-2--yl)benzene-1,3,5--tricarboxamide, C24H18N6O3, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules via their amide groups into slanted ladder-like chains, in which the uprights of the ladder are formed by the hydrogen-bonding inter-actions and the benzene ring cores of the mol-ecules act as the rungs of the ladder. Only two of the three amide groups in the mol-ecule are involved in hydrogen bonding and this influences the degree of out-of-plane twisting at each amide group, with the twist being more significant for those amide groups participating in hydrogen bonds.

Crystal structures, packing features, Hirshfeld surface analyses and DFT calculations of hydrogen-bond energy of two homologous 8a-aryl-2,3,4,7,8,8a-hexahydropyrrolo[1,2-a]pyrimidin-6(1H)-ones

The crystal structures and packing features of two homologous Meyer's bicyclic lactams with fused pyrrolidone and medium-sized perhydropyrimidine rings, namely, 8a-phenyl-2,3,4,7,8,8a-hexahydropyrrolo[1,2-a]pyrimidin-6(1H)-one, C₁₃H₁₆N₂O (1), and 8a-(4-methylphenyl)-2,3,4,7,8,8a-hexahydropyrrolo[1,2-a]pyrimidin-6(1H)-one, C₁₄H₁₈N₂O (2), were elucidated, and Hirshfeld surface plots were calculated and drawn for visualization and a deeper analysis of the intermolecular noncovalent interactions. Molecules of 1 and 2 are weakly linked by intermolecular C=O...H-N hydrogen bonds into chains, which are in turn weakly linked by other C=O...H-C_ar interactions. The steric volume of the substituent significantly affects the crystal packing pattern.

Ditopic halogen bonding with bipyrimidines and activated pyrimidines

The potential of pyrimidines to serve as ditopic halogen-bond acceptors is explored. The halogen-bonded cocrystals formed from solutions of either 5,5'-bipyrimidine (C₈H₆N₄) or 1,2-bis(pyrimidin-5-yl)ethyne (C₁₀H₆N₄) and 2 molar equivalents of 1,3-diiodotetrafluorobenzene (C₆F₄I₂) have a 1:1 composition. Each pyrimidine moiety acts as a single halogen-bond acceptor and the bipyrimidines act as ditopic halogen-bond acceptors. In contrast, the activated pyrimidines 2- and 5-{[4-(dimethylamino)phenyl]ethynyl}pyrimidine (C₁₄H₁₃N₃) are ditopic halogen-bond acceptors, and 1:1 halogen-bonded cocrystals are formed from 1:1 mixtures of each of the activated pyrimidines and either 1,2- or 1,3-diiodotetrafluorobenzene. A 1:1 cocrystal was also formed between 2-{[4-(dimethylamino)phenyl]ethynyl}pyrimidine and 1,4-diiodotetrafluorobenzene, while a 2:1 cocrystal was formed between 5-{[4-(dimethylamino)phenyl]ethynyl}pyrimidine and 1,4-diiodotetrafluorobenzene.

Crystal structures of (η4-cyclo-octa-1,5-diene)bis(1,3-di-methyl-imidazol-2-yl-idene)iridium(I) iodide and (η4-cyclo-octa-1,5-diene)bis-(1,3-di-ethyl-imidazol-2-yl-idene)iridium(I) iodide

The title complexes, (η4-cyclo-octa-1,5-diene)bis-(1,3-di-methyl-imidazol-2-yl-idene)iridium(I) iodide, [Ir(C5H8N2)2(C8H12)]I, (1) and (η4-cyclo-octa-1,5-di-ene)bis-(1,3-di-ethyl-imidazol-2-yl-idene)iridium(I) iodide, [Ir(C7H12N2)2(C8H12)]I, (2), were prepared using a modified literature method. After carrying out the oxidative addition of the amino acid l-proline to [Ir(COD)(IMe)2]I in water and slowly cooling the reaction to room temperature, a suitable crystal of 1 was obtained and analyzed by single-crystal X-ray diffraction at 100 K. Although this crystal structure has previously been reported in the Pbam space group, it was highly disordered and precise atomic coordinates were not calculated. A single crystal of 2 was also obtained by heating the complex in water and letting it slowly cool to room temperature. Complex 1 was found to crystallize in the monoclinic space group C2/m, while 2 crystallizes in the ortho-rhom-bic space group Pccn, both with Z = 4.

Di-propyl-ammonium 4-amino-benzene-sulfonate

In the title mol-ecular salt, NH2(C3H7)2 +·[NH2C6H4SO3]-, the cation displays an extended conformation. In the crystal, anion-to-anion N-H⋯O and N-H⋯(O,O) hydrogen bonds generate (101) layers. Cation-to-anion N-H⋯O hydrogen bonds connect the layers into a three-dimensional network.

Two new zinc(II) and mercury(II) complexes based on N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide): synthesis, crystal structures and antibacterial activities

Reaction of N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide), C₂₀H₁₈F₂N₄O₂, (L^F), with zinc chloride and mercury(II) chloride produced different types and shapes of neutral coordination complexes, namely, dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ²N,O]zinc(II), [ZnCl₂(C₂₀H₁₈F₂N₄O₂)], (1), and dichlorido[N,N'-(cyclohexane-1,2-diylidene)bis(4-fluorobenzohydrazide)-κ⁴O,N,N',O']mercury(II), [HgCl₂(C₂₀H₁₈F₂N₄O₂)], (2). The organic ligand and its metal complexes are characterized using various techniques: IR, UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, in addition to powder X-ray diffraction (PXRD), single-crystal X-ray crystallography and microelemental analysis. Depending upon the data from these analyses and measurements, a typical tetrahedral geometry was confirmed for zinc complex (1), in which the Zn^II atom is located outside the bis(benzhydrazone) core. The Hg^II atom in (2) is found within the core and has a common octahedral structure. The in vitro antibacterial activities of the prepared compounds were evaluated against two different bacterial strains, i.e. gram positive Bacillus subtilis and gram negative Pseudomonas aeruginosa bacteria. The prepared compounds exhibited differentiated growth-inhibitory activities against these two bacterial strains based on the difference in their lipophilic nature and structural features.

Synthesis, crystal structure and Hirshfeld and thermal analysis of bis[benzyl 2-(heptan-4-yl-idene)hydrazine-1-carboxyl-ate-κ2 N 2,O]bis(thio-cyanato)-nickel(II)

The title centrosymmetric NiII complex, [Ni(NCS)2(C15H22N2O2)2], crystallizes with one half mol-ecule in the asymmetric unit of the monoclinic unit cell. The complex adopts an octa-hedral coordination geometry with two mutually trans benzyl-2-(heptan-4-yl-idene)hydrazine-1-carboxyl-ate ligands in the equatorial plane with the axial positions occupied by N-bound thio-cyanato ligands. The overall conformation of the mol-ecule is also affected by two, inversion-related, intra-molecular C-H⋯O hydrogen bonds. The crystal structure features N-H⋯S, C-H⋯S and C-H⋯N hydrogen bonds together with C-H⋯π contacts that stack the complexes along the b-axis direction. The packing was further explored by Hirshfeld surface analysis. The thermal properties of the complex were also investigated by simultaneous TGA-DTA analyses.

Conversion of 3-amino-4-arylamino-1H-isochromen-1-ones to 1-arylisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones: synthesis, spectroscopic characterization and the structures of four products and one ring-opened derivative

An efficient synthesis of 1-arylisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazotization of 3-amino-4-arylamino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The molecules of 1-phenylisochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C-H...N and C-H...O hydrogen bonds, while the structures of 1-(2-methylphenyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chlorophenyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the molecules into simple chains, which are further linked into sheets by π-stacking interactions in (II) but not in (III). In the structure of 1-(4-chlorophenyl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C-H...O and C-H...π(arene) hydrogen bonds links the molecules into sheets. When compound (II) was exposed to a strong acid in methanol, quantitative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hydroxy-1-(2-methylphenyl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the molecules are linked by paired O-H...O hydrogen bonds to form centrosymmetric dimers.

Tris(ethane-1,2-di-amine-κ2 N,N')zinc(II) tetra-chlorido-zincate(II)

The title complex, [Zn(C2H8N2)3][ZnCl4], exists as discrete ions. The [Zn(C2H8N2)3]2+ cation exhibits a distorted octa-hedral shape. In the [ZnCl4]2- anion, the ZnII atom is in an almost regular tetra-hedral environment. The crystal packing is consolidated by N-H⋯Cl and C-H⋯Cl hydrogen bonds.

Synthesis of N-substituted 3-(2-aryl-2-oxoethyl)-3-hydroxyindolin-2-ones and their conversion to N-substituted (E)-3-(2-aryl-2-oxoethylidene)indolin-2-ones: synthetic sequence, spectroscopic characterization and structures of four 3-hydroxy compounds and five oxoethylidene products

An operationally simple and time-efficient approach has been developed for the synthesis of racemic N-substituted 3-(2-aryl-2-oxoethyl)-3-hydroxyindolin-2-ones by a piperidine-catalysed aldol reaction between aryl methyl ketones and N-alkylisatins. These aldol products were used successfully as strategic intermediates for the preparation of N-substituted (E)-3-(2-hetaryl-2-oxoethylidene)indolin-2-ones by a stereoselective dehydration reaction under acidic conditions. The products have all been fully characterized by 1H and 13C NMR spectroscopy, by mass spectrometry and, for a representative selection, by crystal structure analysis. In each of (RS)-1-benzyl-3-hydroxy-3-[2-(4-methoxyphenyl)-2-oxoethyl]indolin-2-one, C24H21NO4, (Ic), and (RS)-1-benzyl-3-{2-[4-(dimethylamino)phenyl]-2-oxoethyl}-3-hydroxyindolin-2-one, C25H24N2O3, (Id), inversion-related pairs of molecules are linked by O-H...O hydrogen bonds to form R22(10) rings, which are further linked into chains of rings by a combination of C-H...O and C-H...π(arene) hydrogen bonds in (Ic) and by C-H...π(arene) hydrogen bonds in (Id). The molecules of (RS)-1-benzyl-3-hydroxy-3-[2-oxo-2-(pyridin-4-yl)ethyl]indolin-2-one, C22H18N2O3, (Ie), are linked into a three-dimensional framework structure by a combination of O-H...N, C-H...O and C-H...π(arene) hydrogen bonds. (RS)-3-[2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoethyl]-1-benzyl-3-hydroxyindolin-2-one, C24H19NO5, (If), crystallizes with Z' = 2 in the space group P-1 and the molecules are linked into complex sheets by a combination of O-H...O, C-H...O and C-H...π(arene) hydrogen bonds. In each of (E)-1-benzyl-3-[2-(4-fluorophenyl)-2-oxoethylidene]indolin-2-one, C23H16FNO2, (IIa), and (E)-1-benzyl-3-[2-oxo-2-(thiophen-2-yl)ethylidene]indolin-2-one, C21H15NO2S, (IIg), the molecules are linked into simple chains by a single C-H...O hydrogen bond, while those of (E)-1-benzyl-3-[2-oxo-2-(pyridin-4-yl)ethylidene]indolin-2-one, C22H16N2O2, (IIe), are linked by three C-H...O hydrogen bonds to form sheets which are further linked into a three-dimensional structure by C-H...π(arene) hydrogen bonds. There are no hydrogen bonds in the structures of either (E)-1-benzyl-3-[2-(4-methoxyphenyl)-2-oxoethylidene]indolin-2-one, C24H19NO3, (IIc), or (E)-1-benzyl-5-chloro-3-[2-(4-chlorophenyl)-2-oxoethylidene]indolin-2-one, C23H15Cl2NO2, (IIh), but the molecules of (IIh) are linked into chains of π-stacked dimers by a combination of C-Cl...π(arene) and aromatic π-π stacking interactions.

Crystal structure and Hirshfeld surface analysis of 2-phenyl-1H-phenanthro[9,10-d]imidazol-3-ium benzoate

In the title compound, C21H15N2 +·C7H5O2 -, 2-phenyl-1H-phenanthro[9,10-d]imidazole and benzoic acid form an ion pair complex. The system is consolidated by hydrogen bonds along with π-π inter-actions and N-H⋯π inter-actions between the constituent units. For a better understanding of the crystal structure and inter-molecular inter-actions, a Hirshfeld surface analysis was performed.

A 2D coordination polymer assembled from a nickel(II) tetraazamacrocyclic cation and 4,4'-(dimethylsilanediyl)diphthalate(3-) linker

The preformed nickel(II) complex of the 14-membered macrocyclic ligand 1,4,8,11-tetraazacyclotetradecane (cyclam, L), when treated with 4,4'-(dimethylsilanediyl)diphthalic acid (H₄A) in a DMF/H₂O mixture (4:1 v/v) under heating, leads to [Ni(L)]₃(HA)₂·3DMF (I·DMF). Redissolution of this compound in a DMF/H₂O/MeOH mixture (4:1:30 v/v/v) with mild acidification under gentle heating results in the formation of a similar compound but containing water and methanol molecules of crystallization, [Ni(L)]₃(HA)₂·5H₂O·2MeOH (II·H₂O). At lower temperature and concentration of reactants and longer reaction time, single crystals of composition {[{Ni(L)}₃(HA)₂]·4CH₃OH}_n (II·MeOH) were isolated. Single-crystal X-ray diffraction analysis of this compound, which, according to PXRD is isostructural with II·H₂O but different from I·DMF, revealed its two-dimensional (2D) polymeric structure, i.e. poly[[bis{μ₃-4-[(4-carboxy-3-carboxylatophenyl)dimethylsilyl]benzene-1,2-dicarboxylato-κ³O¹:O²:O^3'}tris(1,4,8,11-tetraazacyclotetradecane-κ⁴N)trinickel(II)] methanol tetrasolvate], {[Ni₃(C₁₈H₁₃O₈Si)₂(C₁₀H₂₄N₄)₃]·4CH₃OH}_n. It is built up of the monoprotonated tricarboxylate HA^3- ligand coordinated in a monodentate manner in the axial positions of two crystallographically independent Ni^II cations, one of which is located on a crystallographic inversion centre. Both metal ions adopt a slightly tetragonally elongated trans-N₄O₂ octahedral geometry. The compound has a lamellar structure with polymeric layers oriented parallel to the (10-2) plane, which are in turn linked via hydrogen bonds involving protonated carboxylic acid groups of the ligand. Bulk compounds I·DMF and II·H₂O were characterized by FT-IR and diffuse reflectance spectroscopy and thermogravimetry, which provide evidence of their structural differences.