X-ray crystallography of methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4<Emphasis Type="Italic">H</Emphasis>-pyran)-3-carboxylate

The organic carbonitrile namely methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4H-pyran)- 3-carboxylate is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst and its crystal structure is determined by X-ray technique. The crystals are monoclinic, sp. gr. C2/c, a = 12.3069(8) Å, b = 9.7023(7) Å, c = 24.812(2) Å, β = 94.862(6)°, Z = 8. The dihedral angle between pyran and phenyl rings is 87.8(1)°; the pyran ring is almost planar The dihedral angle between the mean planes of phenyl ring and nitro group is 44.4(2)°. The crystal structure is stabilized by N?H···N and N?H···O hydrogen bonds. In addition, C?H···π interactions are also observed in the crystal structure.     

Crystal structure of (<Emphasis Type="Italic">E</Emphasis>)-3-fluoro-N-((5-nitrothiophen-2-yl)methylene)aniline

The structure of the title compound C₁₁H₇FN₂O₂S was characterized by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with Z = 12, i.e. with three molecules in asymmetric unit. The molecules are not planar: the dihedral angles between the planes of thiophene and the benzene rings are 42.3(3)°, 42.0(3)°, and 48.9(2)°. In the crystal, intermolecular C–H···F interactions link the molecules through R₂² (14) ring motif. The crystal packing is also stabilized by π···π interactions.     

Crystal Structure of Ethyl 6-Amino-5-cyano-4-(4-fluorophenyl)- 2,4-dihydropyrano[2,3-<Emphasis Type="Italic">c</Emphasis>]pyrazole-3-carboxylate

Ethyl 6-amino-5-cyano-4-(4-fluorophenyl)-2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylate was synthesized based on a commercially available trisodium citrate dihydrate as an inexpensive and eco-friendly catalyst for the first-time via one-pot tandem Knoevenagel-cyclocondensation of malononitrile, 4-f luorobenzaldehyde and in situ generated ethyl 5-oxo-2,5-dihydro-1H-pyrazole-3-carboxylate in aqueous ethanol at room temperature and its crystal structure is determined by X-ray structure analysis. The crystals are triclinic, sp. gr. \(P\bar 1\), a = 8.7914(7) Å, b = 11.3632(8) Å, c = 11.4005(9) Å, α = 62.278(7)°, β = 71.099(7)°, γ = 80.856(6)°, Z = 2, R = 0.0544 for 2491 observed ref lections. Pyran and pyrazole rings are almost coplanar and phenyl ring is almost perpendicular to these two rings. Pyran ring adopts boat conformation. The crystal structure is stabilized by N–H···N, N–H···O, C–H···F, and C–H···π hydrogen interactions. In addition, a number of weak π···π interactions also contribute to stabilize the crystal structure.     

Synthesis,Spectroscopic and Crystal Structure Analysis of <Emphasis Type="Italic">N</Emphasis>-[imidazolidin-2-ylidene]-5-(thien-2-yl)[1,3,4]thiadiazole-2-amine

The crystal structure of the title compound has been determined. The compound crystallizes in the monoclinic space group P2₁/c with a = 5.9885(2) Å, b = 14.7345(4) Å, c = 12.3719(4) Å, β = 96.655(5)°, V = 1084.31(8) Å³, z = 4. An intramolecular N–H···N hydrogen bond forms a pseudo-six-membered ring with graph set S ¹ ₁(6). The crystal structure is stabilized by intermolecular interactions of the type N–H···N and C–H···N. The packing motifs in accordance with Etter’s analysis are R ² ₂(8) corresponding to N–H···N dimer and that generated by the chain is C(7).     

Synthesis,antityrosinase activity of curcumin analogues,and crystal structure of (1<Emphasis Type="Italic">E</Emphasis>,4<Emphasis Type="Italic">E</Emphasis>)-1,5-bis(4-ethoxyphenyl)penta-1,4-dien-3-one

Five derivatives of curcumin analogue (R = OCH₂CH₃ (1), R = N(CH₃)₂ (2), R = 2,4,5-OCH₃ (3), R = 2,4,6-OCH₃ (4), and R = 3,4,5-OCH₃ (5)) were synthesized and characterized by ¹H NMR, FT-IR and UV–Vis spectroscopy. The synthesized derivatives were screened for antityrosinase activity, and found that 4 and 5 possess such activity. The crystal structure of 1 was determined by single crystal X-ray diffraction: monoclinic, sp. gr. P2₁/c, a = 17.5728(15) Å, b = 5.9121(5) Å, c = 19.8269(13) Å, β = 121.155(5)°, Z = 4. The molecule 1 is twisted with the dihedral angle between two phenyl rings being 15.68(10)°. In the crystal packing, the molecules 1 are linked into chains by C?H···π interactions and further stacked by π···π interactions with the centroid–centroid distance of 3.9311(13) Å.     

Structure of (2<Emphasis Type="Italic">E</Emphasis>)-Ethyl 2-((4-(cyanomethoxy)benzylidene)hydrazono)-3,4-dimethyl-2,3-dihydrothiazole-5-carboxylate Studied by X-ray and DFT Calculations

The molecular structure of (2E)-ethyl 2-((4-(cyanomethoxy)benzylidene)hydrazono)-3,4-dimethyl-2,3-dihydrothiazole-5-carboxylate was determined using X-ray diffraction. The crystals are triclinic: sp. gr. P1; Z = 2; the unit cell parameters a = 8.4747(7) Å, b = 8.9382(8) Å, c = 11.9913(10) Å. The title compound has two C–H···O type intramolecular hydrogen bonds, one C–H···O and one C–H···N type intermolecular hydrogen bonds. For theoretical calculations, the molecular structure was investigated by DFT/B3LYP method with 6-311G(d) and 6-311G(d, p) basis sets. The calculated and experumental results (bond lenghts, bond angles, and dihedral angles) were compared with each other. Total energy, dipole moment, and mulliken atomic charges were calculated using two different basis sets.     

Crystal structure of the molecular complex of 3-[1-(4-nitrophenyl)-3-oxobutyl]-4-hydroxychromen-2-one with ethanol

The crystal structure of 2,3H-2-methyl-4-(4-nitrophenyl)-5-oxobenzopyrano[3,4-e]dihydropyran-2-ol is investigated using X-ray diffraction. The unit cell contains an ethanol molecule that forms hydrogen bonds with O-H and C-O groups of two molecules of the main compound and acts as a proton donor and a proton acceptor in these hydrogen bonds. Owing to these interactions, infinite chains are formed in the crystal. The crystallographic data for the structure of C₁₉H₁₅NO₆·C₂H₅OH (M = 399.39) are as follows: the crystals are triclinic, space group P1, a = 5.5340(3) Å, b = 8.0109(4) Å, c = 11.0112(5) Å, α = 88.773(2)°, β = 84.788(2)°, γ = 79.958(2)°, and Z = 1.     

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.     

Molecular and Crystal Structure of 2-{(<Emphasis Type="Italic">E</Emphasis>)-[(5-Chloro-2-methoxyphenyl)imino]methyl}-4-nitrophenol

The molecular structure of the title compound, C₁₄H₁₁ClN₂O₄, was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic sp. gr. P2₁/c with Z = 4. The title compound, C₁₄H₁₁ClN₂O₄, is a Schiff base which adopts the phenol-imine tautomeric form in the solid state.The molecule is almost planar and the dihedral angle between the planes of two aromatic ring is 2.2(1)°. The molecular structure is stabilized by intramolecular O–H···N hydrogen bond which generates a six-membered ring. In the crystal structure, the molecules are linked together by intermolecular C–H···O interactions.     

Synthesis,characterization, and crystal structure of 5,5″-Difluoro-1<Emphasis Type="Italic">H</Emphasis>,1″<Emphasis Type="Italic">H</Emphasis>-[3,3′:3′,3″-terindol]-2′(1′<Emphasis Type="Italic">H</Emphasis>)-one

The new indole derivative, 5,5′′-Difluoro-1H,1′′H-[3,3′:3′,3′′-terindol]-2′(1′H)-one C₂₄H₁₅F₂N₃O, is synthesized in 87% yield, and its crystal structure is determined by X-ray structure analysis. The crystals are monoclinic, sp. gr. P2₁/n, a = 15.4563(7), b = 10.8340(6), c = 16.4718(6) Å, β = 102.403(4)°, Z = 4. Bicyclic indole moieties form dihedral angle of 61.92(5)° with each other; the oxindole ring is twisted with respect to them at angles of 85.70(5)° and 75.62(5)°. The crystal structure is stabilized by N–H···O and C–H···O hydrogen bonds involving both the DMSO solvent molecules. In addition, one C–H···π interaction is observed.     

Crystal structure analysis of 4-phenylquinolin-2-(1<Emphasis Type="Italic">H</Emphasis>)-one

The crystal structure of 4-phenylquinolin-2-(1H)-one (C₁₅H₁₁NO) is determined by X-ray diffraction. The compound crystallizes in the orthorhombic crystal system (space group Pbca) with the unit cell parameters a = 7.382(2) Å, b = 21.795(3) Å, c = 14.066(5) Å, and Z = 8. The structure is solved by direct methods and refined to an R-value of 0.0398 for 1360 observed reflections [F₀ > 4σ (F₀)]. The quinoline moiety and the substituted phenyl ring are nearly planar. The dihedral angle between these two moieties is 64.65(6)°. The crystal structure is stabilized by two intermolecular N-H?O and C-H?O interactions.     

Crystal and molecular structure of 2-[(4-nitrophenyl)carbonyl]cyclohex-1-ene-1-yl 4-nitrobenzoate

The crystal structure of 2-[(4-nitrophenyl)carbonyl]cyclohex-1-ene-1-yl 4-nitrobenzoate is studied (T = 173 K, R1 = 0.0354 for 2713 observed reflections). This crystal is orthorhombic, a = 7.8367(8) Å, b = 9.6082(10) Å, c = 23.856(3) Å, V = 1796.3(3) ų, space group P2₁2₁2₁, and Z = 4. The molecule has a folded configuration, which is stabilized by π-π interactions between its two parts. A system of intermolecular C-H...O hydrogen bonds (H...O, 2.44–2.67 Å; CHO angles 122°–169°) and intramolecular C-H...O contacts closing five-membered cycles (H...O, 2.42–2.59 Å; CHO angles 96°–102°) are formed in the structure.     

Crystal structure of the supramolecular system of indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal and its thiosemicarbazone

The crystal structure of a supramolecular system consisting of indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal (I) and indole-2,3-dione 1-(2-oxopropyl)-3-ethylene ketal thiosemicarbazone (II) molecules that are linked together by hydrogen bonds is determined using X-ray diffraction. The crystal is monoclinic, and the unit cell parameters are as follows: a = 12.8360(3) Å, b = 10.7330(3) Å, c = 19.4610(3) Å, β = 99.566(1)°, space group P2₁/c, and Z = 4 (C₂₇H₂₉N₅O₇S). In molecules I and II, the indole-2,3-dione 3-ethylene ketal fragments have a virtually identical structure. The pyrrole and dioxolane fragments are spiro-linked through the carbon atom with a dihedral angle close to 90°. The adjacent pyrrole and benzene rings are coplanar to within 4.4°. In molecule II, the oxygen atom of the dioxolane fragment and the terminal nitrogen atom of the thiosemicarbazide fragment are involved in the N-HïO intramolecular hydrogen bond [3.294(2) Å]. The key role in the formation of the crystal structure is played by intermolecular hydrogen bonds of the N-H?dO, C-H?O, C-H?N, and N-H?S types.     

Stereoselective Synthesis and X-Ray Structure Determination of Labeled [1, 2, 3-<Superscript>13</Superscript>C<Subscript>3</Subscript>]-1-(Phenylsulfinyl)-3-Benzyloxyacetone

[1,2,3-¹³C₃]-1-(Phenylsulfinyl)-3-benzyloxyacetone, C₁₆H₁₆O₃S, (3) has been synthesized and its crystal structure has been determined by a single-crystal X-ray diffraction analysis. The X-ray diffraction study revealed that compound 3 crystallizes in the monoclinic crystal system in the acentric space group Pc, with cell constants at T = 100 K: a = 16.073(5), b = 5.5079(16), c = 7.949(2) Å, β = 100.221(4)^°, V = 692.6(3) ų, Z = 2, d _calc = 1.383 g/cm³. Compound 3 contains the chiral tetravalent three-coordinated sulfur atom, which has a distorted tetrahedral configuration with a lone electron pair occupying one of the tetrahedron vertices. In the crystal, the molecules are packed in stacks along the b axis; the stacks consist of the molecules of the same chirality. Furthermore, the stacks of the molecules of the opposite chirality alternate along the c axis. The molecules in neighboring stacks are arranged by head-to-tail orientations. There are no short intermolecular contacts in the crystal of 3.     

Crystal structure of <Emphasis Type="Italic">p</Emphasis>-carboxyphenylhydrazone benzoylacetone

The crystal structure of p-carboxyphenylhydrazone benzoylacetone is determined. The crystals are monoclinic, a = 13.614(4) Å, b = 11.388(2) Å, c = 20.029(6) Å, β = 104.82(2)°, V = 2339(9) ų, Z = 8, space group C2/c, and R = 0.038 for 1622 reflections with I > 2σ(I). The crystal is built of C₁₇H₁₄N₂O₄ neutral molecules that are linked by O-H?O hydrogen bonds between the carboxyl groups into centrosymmetric pseudodimers. The effect of carboxylation of the phenylhydrazone fragment and the position of the carboxyl group on the molecular packing in the crystal is determined. The N(1)-H(1N)?O(1) intramolecular hydrogen bond (N-H, 0.94 Å; H?O, 1.87 Å; N?O, 2.59 Å; and the N-H?O angle, 133°) is formed in the molecule.     

Synthesis and Crystal Structure of a Four-coordinated Cobalt Complex with 1-Methylbenzimidazole

A four-coordinated complex, L₂Co(NCO)₂, (L = 1-methylbenzimidazole) has been synthesized and characterized by IR spectroscopy, elemental analyses, and single crystal X-ray diffraction. The crystal is monoclinic, a = 14.522(2) Å, b = 14.610(2) Å, c = 8.6850(13) Å, β = 92.037(3)°, Z = 4, sp. gr. P2₁/c. Bond lengths Co–N(L) are equal to 2.0165(16) and 2.0174(15) Å, Co–O(NCO) are 1.944(2) and 1.945(2) Å. Intermolecular C–H···O, C–H···N, and C–H···π interactions link the molecules into three-dimensional networks in the crystal.     

X-ray and Theoretical Studies of 2-((5-Amino-1,3,4-thiadiazol-2-yl)thio)-1-phenylethanone

The crystal structure of 2-((5-amino-1,3,4-thiadiazol-2-yl)thio)-1-phenylethanone was determined by X-ray diffraction method. The compound crystallizes in orthorhombic crystal system, sp. gr. Pbca. The atoms that constitute thiadiazole and phenyl rings do not form any significant deviation from the ring planes. Compound has two intermolecular N–H···N hydrogen bonds and one C–H···π interaction. Using DFT/B3LYP method with 6-31G(d), 6-311G(d), 6-311G(d, p), and 6-311++G(d, p) basis sets, the molecular geometry of the compound was optimised. Bond lenghts, bond angles, torsion angles, dihedral angles, and HOMO–LUMO were calculated from the optimised geometry of the compound. The results obtained by X-ray diffraction method were compared with the results obtained through four different basis sets. Total energy of the molecule was calculated for four different basis sets.     

3-[4-Bromo-α(<Emphasis Type="Italic">R</Emphasis>*)-methoxybenzyl]-6-chloro-3(<Emphasis Type="Italic">S</Emphasis>*),4(<Emphasis Type="Italic">S</Emphasis>*)-dihydroxychroman: X-ray and DFT Studies

Sodium borohydride reduction of E-3-benzylidenechromanone epoxides in dry methanol has afforded 3(S*), 4(S*)-dihydroxy-3-[α(R*)-methoxybenzyl]chromans as an interesting class of products, the structures of which have been assigned mainly from spectral data and consideration of the mechanistic aspects. X-ray diffraction study of one of them, 3-[4-bromo-α(R*)-methoxybenzyl]-6-chloro-3(S*),4(S*)- dihydroxychroman, is performed. The title compound crystallizes in the monoclinic sp. gr. P2₁/n, with a = 13.336(6) Å, b = 10.866(5) Å, c = 27.166(11) Å, β = 95.193(6)°, V = 3920(3) ų, and Z = 8. Supramolecular construction of the compound involves O–H···O intermolecular hydrogen bonds as well as three other types of non-covalent interactions which are responsible for crystal packing. Density functional theory was applied for geometry optimization, molecular orbital calculations, and prediction of UV spectral features. The geometric parameters (bond lengths, bond angles, and dihedral angles) for the representative compound obtained from density functional theory with B3LY6-31G basis set were in good agreement with experimental values.     

Crystal Structure of Two <Emphasis Type="Italic">V</Emphasis>-shaped Ligands with <Emphasis Type="Italic">N</Emphasis>-Heterocycles

Two V-shaped ligands with N-heterocycles, bis(4-(1H-imidazol-1-yl) phenyl)methanone (1), and bis(4-(1H-benzo[d]imidazol-1-yl)phenyl)methanone (2) have been synthesized and characterized by elemental analyses, IR and 1H NMR spectroscopy. Crystal structures of 1 and 2 have been determined by X-ray diffraction. The crystal of 1 is monoclinic, sp. gr. P2₁/c, Z = 4. The crystal of 2 is orthorhombic, sp. gr. Fdd2, Z = 8. X-ray diffraction analyses show that the V-shaped angles of 1 and 2 are 122.72(15)° and 120.7(4)°, respectively. Intermolecular C–H···O, C–H···N, C–H···π, and π···π interactions link the components into three-dimensional networks in the crystal structures.     

Crystal structures of complexes of the <Emphasis Type="Italic">cys-syn-cys</Emphasis> isomer of dicyclohexano-18-crown-6 with oxonium hexafluorotantalate and oxonium hexafluoroniobate

The crystal structures of [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][TaF₆] and [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][NbF₆] complex compounds are determined using X-ray diffraction analysis. The tantalum complex has two polymorphic modifications, namely, the monoclinic (I) and triclinic (II) modifications. The unit cell parameters of these compounds are as follows: a = 8.507(4) Å, b = 11.947(5) Å, c = 27.392(12) Å, β = 93.11(1)°, Z = 4, and space group P2₁/n for modification I; and a = 10.828(1) Å, b = 11.204(1) Å, c = 12.378(1) Å, α = 72.12(1)°, β = 79.40(1)°, γ = 73.70(1)°, Z = 2, and space group P-1 for modification II. The triclinic niobium complex [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][NbF₆] (III) with the unit cell parameters a = 10.796(3) Å, b = 11.183(3) Å, c = 12.352(3) Å, α = 72.364(5)°, β = 79.577(5)°, γ = 73.773(4)°, Z = 2, and space group P-1 is isostructural with tantalum complex II. The structures of all three complexes are ionic in character. The oxonium cation in complexes I–III is encapsulated by the crown ether and thus forms one ordinary and two bifurcated hydrogen bonds with the oxygen atoms of the crown ether. This macrocyclic cation is bound to the anions through the C-H...F contacts (H...F, 2.48–2.58 Å). The conformation of the macrocycle in complex I differs substantially from that in complex II (III).