Synthesis and X-ray structural analysis of (2<Emphasis Type="Italic">Z</Emphasis>)-3(4-hydroxyphenyl)-2-pyridin-4-ylacrylonitrile and (2<Emphasis Type="Italic">Z</Emphasis>)-3-(3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-hydroxyphenyl)2-pyridin-4-ylacrylonitrile

Synthesis and X-ray structural investigations have been carried out for the two title compounds C₁₄H₁₀N₂O (3a) and C₂₂H₂₆N₂O (3b). Compound 3a crystallizes in the monoclinic space group P2₁/c, with a = 3.843(1) Å, b = 24.618(5) Å, c = 11.318(2) Å, = 92.61(3), V = 1069.7(4) Å,³ and Z = 4. Compound 3b crystallizes in the triclinic space group P-1, with a = 9.004(2) Å, b = 9.447(2) Å, c = 11.713(2) Å, = 76.70(3), = 83.12(3), = 82.16(3), V = 956.5(3) Å,³ and Z = 2. Both stilbazole derivatives have Z-geometry about the ethylene bridge which links the heterocyclic and aromatic rings. The molecular skeleton of 3a is slightly non-planar: the dihedral angles between the acrylonitrile linkage and the pyridine ring, and between this linkage and the p-hydroxyphenyl ring are 7.2(2) and 4.1(2), respectively. The molecular skeleton of 3b is less planar: the values of similar dihedral angles are 17.0(2) and 20.8(2), respectively. In the crystal of 3a, the molecules are packed in stacks along the a axis with head-to-head orientation. Intermolecular hydrogen bonds O=H s N and C=H s N link molecules into sheets parallel to (100) plane. In the crystals of 3b, the molecules have a head-to-tail orientation and intermolecular hydrogen bonds O=H s N link the molecules into infinite chains along [01-1] direction.     

Crystal structure analysis of (<Emphasis Type="Italic">N</Emphasis>-methyl piperazino) (phenyl) (dicyclohexylamino) phosphiniminocyclotrithiazene

The title compound (NC₄H₈NCH₃)(C₆H₅)[N(C₆H₁₁)₂]P{—N–S₃N₃ crystallizes in the triclinic crystal system with unit cell dimensions: a = 9.7572(2), b = 10.6845(1), c = 16.9381(3) Å, = 71.75(1), = 80.65(2), = 65.93(1), and Z = 2. The tricoordinated sulfur atom (S1) in the cyclotrithiazene deviates from the mean plane of the other five atoms by 0.716(6) Å, which is the highest among the known phosphiniminocyclotrithiazene structures. In the exocyclic P{—N4–S1 moiety, the two bond distances are short: 1.585(6) and 1.527(6) Å; but the bond angle is large 135.3(4). The S1 displacement is highly correlated with the endocyclic angle at the nitrogen atom (diagonally opposite to S1), but the nature of correlation is bimodal (R = 1.0 + or –1.0) for the cyclic and acyclic substituents (R) in the (R)(C₆H₅)[N(C₆H₁₁)₂]P{—N–S₃N₃ series. On the other hand, the S1–N4 bond distances are negatively correlated (R = –0.94) with the P{—N4–S1 bond angle in the above series.     

4-(<Emphasis Type="Italic">E</Emphasis>)-2-[3-(3-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-cyanophenyl)-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydro-1-pyrimidinyl]-1diazenylbenzonitrile: X-ray crystal structure

4-(E)-2-[3-(3-[(E)-2-(4-cyanophenyl)-1-diazenyl]hexahydro-1-pyrimidinylmethyl)hexahydro-1-pyrimidinyl]-1-diazenylbenzonitrile (1) has been synthesized by reaction of p-cyanobenzene diazonium chloride with a mixture of formaldehyde and 1,3-propanediamine. The crystal structure has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) adopts a folded conformation, similar to previously studied ethylenediamine analogues, and there is evidence of -stacking in the crystal packing. The two planar phenyltriazenyl groups are almost parallel, forming an angle of 6.6(1), and display weak intermolecular s interactions between molecules. This result establishes the structure of the product of this diazonium coupling reaction as the 1-(1-hexahydropyimidinylmethyl)hexahydropyrimidine derivative and not the alternate tetraazabicyclo[5.5.1]tridecane derivative. Crystal data: 1C₂₃H₂₆N₁₀, monoclinic, space group P2₁/c, a = 10.717(1) Å, b = 7.749(1) Å, c = 28.252(2) Å, = 97.223(2), V = 2327.5(5) ų, for Z = 4.     

Synthesis and crystal structure of the <Emphasis Type="Italic">N</Emphasis>-8-(diphenyl-hydroxy-2-aminomethylpyridine)borane

Reaction of 2-aminomethylpyridine with diphenylborinic acid in a mixture of CHCl₃-diethyl ether gives diphenyl-(2-aminomethylpyridine-N,N)borane, a cyclic adduct that in presence of environmental moisture yields the N-8-(diphenyl-hydroxy-2-aminomethylpyridine)borane. The two compounds were characterized by NMR and infrared spectroscopy. The structure of N-8-(diphenyl-hydroxy-2-aminomethylpyridine)borane was confirmed by X-ray diffraction. This adduct crystallizes in monoclinic P2₁/n space group with unit cell dimensions: a = 13.193(2) (Å), b = 5.913(7) (Å), c = 19.604(2) (Å), = 90.295(3), V = 1529.3(3) ų, Z = 4. The BN distance is 1.645(3) Å and lies in the range of a dative bond. The NH and OH groups are involved in intermolecular hydrogen bonds formation and they add to the stabilization of the acyclic adduct in the solid state.     

The structure of 2-amino-3-cyano-4-(4-methylphenyl)-6-methoxyl-1,4,9,10-tetrahydrobenzo[<Emphasis Type="Italic">f</Emphasis>]chromene

The X-ray crystal structure of 2-amino-3-cyano-4-(4-methylphenyl)-6-methoxyl-1,4,9,10-tetrahydrobenzo [f]chromene 1, C₂₂H₂₀N₂O₂, is determined. The crystals of compound 1 are triclinic, space group P-1, a = 10.120(1), b = 13.127(1), c = 15.203(2) Å, = 67.841(9), = 80.81(1), = 77.58(1), Z = 4, V = 1819.7(4) ų. It is interesting that all the atoms of the pyran ring are coplanar, which is different from other similar compounds. The structure is stabilized by intermolecular hydrogen bonds.     

Synthesis and crystal structure of N-<Emphasis Type="Italic">tert-</Emphasis>butyl-N′-thio [O-(1-methylthioethylimino)-N″-methylcarbamic acid]-N,N′-dibenzoylhydrazine

The novel compound N-tert-butyl-N-thio[O-(1-methylthioethylimino)-N-methyl carbamic acid]- N,N-dibenzoylhydrazine has been synthesized by the reaction of N-tert-butyl-N,N-dibenzoylhydrazine with N-sulfenyl chloride of O-(1-methylthio ethylimino) -N-methylcarbamic acid. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic, space group P2₍₁₎/n with the following crystallographic parameters: a = 7.569(3) Å, b = 20.585(7) Å, c = 16.347(5) Å, = 90, = 92.606(6), = 90, V = 2544.4(14) ų, z = 4, Dx = 1.276 mg/m³, F(000) = 1032, T = 293(2) K, 2.34 25.01, the final R factor: R₁ = 0.0475, wR₂ = 0.0907. The N–N bond adopts a gauche conformation with a dihedral angle() of 98.8 for C(17)=N(1)=N(2)=C(7), whereas its parent compound N-tert-butyl-N,N-dibenzoyl hydrazine has the dihedral angle of –71.8.     

Synthesis and structure of 7-methyl-5-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazolo[4,3-<Emphasis Type="Italic">e</Emphasis>]tetrazolo[4,5-<Emphasis Type="Italic">b</Emphasis>][1,2,4]triazine<Superscript>(1)</Superscript>

The synthesis of 5-azido-3-methyl-1-phenyl-1H-pyrazolo[4,3-e][1,2,4]triazine 2 and 7-methyl-5-phenyl-1H-pyrazolo[4,3-e]tetrazolo[4,5-b][1,2,4]triazine 3 is described and the crystal and molecular structure of the latter is reported. This compound crystallizes in the monoclinic system, space group P2₁/n, with cell constants a = 11.607(2) Å, b = 7.982(1) Å, c = 13.147(2) Å, = 110.60(1), Z = 4, T = 293 K and D_cal = 1.470 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0368 for 1906 reflections. The X-ray analysis revealed that the linear form of the tetrazolo-fused ring system of 3 exists in the crystal. The molecule as a whole has an almost planar conformation stabilized by the short intramolecular NsH interaction. The molecular packing in the crystal is determined by the van der Waals forces only.Part 26 in 1,2,4-triazines in organic synthesis. For part 25 see Mojzych et al.¹     

Synthesis and crystal structure of [ReOCl<Subscript>2</Subscript>(L)] (HL = 2-(1-ethanolaminomethyl)-1-methylimidazole)

The title compound was prepared from the reaction of (n-Bu₄N)[ReOCl₄] with the ligand HL in acetonitrile. The chelate L is coordinated as a terdentate uninegative N, N,O^–-donor ligand in a distorted octahedral coordination geometry around the rhenium(V) ion. The structure has a triclinic space group P-1 with a = 6.9796(3), b = 7.1530(3), c = 12.0416(6) Å, = 73.742(2), = 86.458(2), = 73.928(3), V = 554.50(4) ų, and Z = 2.     

Synthesis and structures of two chiral bis(pyrazolyl)borate complexes, [{H<Subscript>2</Subscript>B(4-Mepz)(3,5-Me<Subscript>2</Subscript>pz)}<Subscript>2</Subscript>M], M = Co,Zn

The title compounds are chiral and have similar molecular geometries. The Co complex crystallizes in space group P2₁/c with a = 8.475(4) Å, b = 7.706(8) Å, c = 35.778(9) Å, = 95.779(18) and Z = 4, while the Zn complex crystallizes in space group P2₁/n with a = 8.353(3) Å, b = 20.768(4) Å, c = 13.818(3) Å, = 100.96(2) and Z = 4. The metal atoms are tetrahedrally coordinated to two bidentate ligands with M–N distances in the ranges 1.985(2)–2.018(2) Å (Co) and 1.985(2)–2.008(2) Å (Zn), and N–M–N angles in the ranges 96.07(7)–128.23(7) (Co) and 98.50(8)–125.63(8) (Zn). No agostic bonds are formed. The molecules display C₁ symmetry; geometric considerations indicate that the formation of the other two possible conformers, with C₂ symmetry, is sterically less favorable.     

Syntheses and structures of N-phenylmaleimidetriazoles and by-products

The syntheses, properties, and structures of N-phenylmaleimidetriazole derivatives are described. Intermediates and by-products are also discussed. 1b. a = 43.997(7) Å, 5.7610(9) Å, 8.245(1) Å, = 99.339(4), C₂/c; 2a. a = 13.646(4) Å, b = 7.744(2) Å, c = 10.612(3) Å, = 91.979(6), P2₁/c. 3a. a = 22.245(1) Å, b = 22.245(1) Å, 10.010(1) Å, P42/n. 3a. a = 11.727(2) Å, b = 14.075(3) Å, c = 16.080(3) Å, = 105.859(3), = 105.331(3), = 98.187(3), P-1. 3b. a = 8.561(3) Å, b = 14.755(5) Å, c = 22.771(7) Å, = 97.006(5), P2₁/c. 3c. a = 10.500(2) Å, b = 12.189(2) Å, c = 13.040(2) Å, = 109.091(3), = 106.089(3), = 101.022(3), P-1. 8a. a = 16.389(8) Å, b = 5.749(3) Å, c = 19.316(3) Å, = 97.467(9), P2₁/n. 8b. a = 5.822(2) Å, b = 10.114(3) Å, c = 16.705(4) Å, = 84.681(5), = 82.840(5), = 75.769(4), P-1. 9b. a = 11.251(1) Å, 13.335(3) Å, 13.376(3) Å, = 102.456(4), P2₁/n. 9c. a = 15.836(3) Å, b = 8.236(2) Å, c = 5.447(3) Å, = 92.551(3), P2₁/c. 10a. a = 13.177(2) Å, b = 14.597(2) Å, c = 5.5505(8) Å, = 110.979(2), Cc. 11a. a = 14.720(2) Å, b = 13.995(2) Å, c = 38.245(6) Å, = 94.430(3), P2₁/n. 12b. a = 15.067(5) Å, b = 20.378(6) Å, c = 8.669(5) Å, = 99.16(4), = 99.32(3), = 105.23(3), P-1. 13b. a = 8.2824(6) Å, b = 10.5245(7) Å, c = 15.518(1) Å, = 92.305(1), = 100.473(1), = 100.124(1), P-1. 15a. a = 15.357(3) Å, b = 7.778(2) Å, c = 22.957(2) Å, Pbca. 16b. a = 18.0384(4) Å, b = 12.474(3) Å, c = 20.078(5) Å, Pbca.     

Synthesis,characterization and crystal structure of oxovanadium(IV) complex with tridentate o-van-gly and bidentate phenanthroline

A novel oxovanadium(IV) complex with tridentate schiff base and bidentate phenanthroline ligands, VO(o-van)(phen) 2H₂O[o-van-gly: o-vanillin-glycine; phen: phenanthroline], was synthesized and characterized by elemental analysis, IR and UV-vis spectra. The crystal structure was determined by X-ray single crystal diffraction analysis. The crystal of title complex (C₂₂H₂₁N₃O₇V, M_w = 490.36) belongs to triclinic, space group P-1 with the following crystallographic parameters: a = 9.247(3) Å, b = 10.125(4) Å, c = 13.100(5) Å, = 106.343(6), = 96.042(7), = 101.726(7), V = 1135.0(7) ų, Z = 2, D_c = 1.435 Mg m^–3, (MoK = 0.485 mm^–1, F(000) = 506, and final R₁ = 0.0779, wR₂ = 0.1598 for observed reflections 1606 (I > 2(I)). V(IV) is six-coordinate with three oxygen atoms and three nitrogen atoms in a distorted octahedral geometry. The complex forms a 3-D network via – stacking and hydrogen bonds.     

[Cd<Subscript>5</Subscript>(OH)(H<Subscript>2</Subscript>O)<Subscript>3</Subscript>][CH<Subscript>3</Subscript>CO<Subscript>2</Subscript>]<Subscript>9</Subscript>, a cadmium hydroxy-acetate compound with a layered network

[Cd₅(OH)(H₂O)₃][CH₃CO₂]₉ crystallizes in the triclinic system, with the space group P , a = 10.897(3) Å, b = 11.035(5) Å, c = 16.061(12) Å, = 96.83(7), = 95.31(8), = 118.22(6) and z = 2. Its structure has been determined using 9497 unique single crystal data. The final refinements let the agreement factors R₁ and wR₂(F²) converge to reach the respective values of 0.0548 and 0.0986. R₁ = 0.0338 for the 7264 unique data with I > 2(I). [Cd₅(OH)(H₂O)₃][CH₃CO₂]₉ is a cadmium hydroxide acetate compound with a bi-dimensional structure in which hydrogen bonds insure cohesion between layers stacked along the [1 10] direction. The inorganic network is built up of layers constituted of CdO₆ octahedra and CdO₇ pentagonal bi-pyramids sharing edge or corner.     

Synthesis and crystal structure of 2-anilino-6<Emphasis Type="Italic">H</Emphasis>-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine

A novel pyrazolone derivative 2-anilino-6H-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine (PMCP-PTSC) containing NNS hexa-atomic heterocycle has been obtained and characterized by means of single crystal X-ray diffraction, IR and ¹H NMR spectroscopies. It is interesting that when grown from two different solvents, two different crystalline structures are formed. The monoclinic crystal A belongs to a P2₁/c space group. The unit cell parameters are a = 16.414(4) Å, b = 12.530(3) Å, c = 8.432(1) Å, = 91.75(2) Å, and Z = 4. The triclinic crystal B belongs to a P space group. The unit cell parameters are a = 11.386(2) Å, b = 12.326(2) Å, c = 12.411(3) Å, = 83.07(1)°, = 87.76(2)°, = 86.52(2)°, and Z = 4. The structure analyses show the title compound is the keto-form. Dimers in crystal packing of A and supramolecular one-dimensional (B) concatenate structures were assembled by the intermolecular hydrogen bonds.     

Single-crystal structure determination of a new polymorph (ε-Alq<Subscript>3</Subscript>) of the electroluminescence OLED (organic light-emitting diode) material,tris(8-hydroxyquinoline)aluminum (Alq<Subscript>3</Subscript>)

Tris(8-hydroxyquinoline) aluminum, Alq₃, is the most widely used electroluminescent material in organic light-emitting diode (OLED), chemistry. Single-crystal structure determination of a new polymorph of Alq₃, designated as -Alq₃, is described. There are three molecules of Alq₃ in the asymmetric unit. This octahedrally coordinated complex crystallizes in the triclinic space group P-1, lattice parameters a = 13.5190(5) Å, b = 15.8550(6)~Å, c = 18.7110(8) Å, = 95.4940(19), = 109.774(2), = 114.6270(16), Volume = 3296.8(2) ų, Z = 6, Z = 3.     

Hydrothermal synthesis and crystal structure of a new europium fumarate compound

The complex {[Eu₂F₃4H₂O]3H₂O}_n (H₂F = fumaric acid) has been synthesized and structurally characterized by single crystal X-ray diffration methods. The complex crystallizes in the monoclinic system with space group P2₁/n, lattice parameters a = 9.475(3) Å, b = 14.700(5) Å, c = 14.810(4) Å, = 90, = 91.250(5), = 90, V = 2062.1(11) ų, Z = 4, D_calc = 2.487 Mg/m³. The Eu(III) center is in distorted tricapped trigonal prism coordination environment that is coordinated by nine oxygen atoms, seven from five F^2– groups, two from two water molecules. Eu(III) ions are connected into three-dimensional coordination network structure by the oxygen atoms of the carboxyl groups and hydrogen bonds.     

Crystal and molecular structures of quinazolines: A ring conformational study

The solid state structures of two dihydropyrimidines (DHPM) viz, 2-[(4-dimethylamino)phenyl]-1-phenethyl-2,3-dihydro-1H-quinazolin-4-one (compound 1) and 1-phenethyl-2p-tolyl-2,3-dihydro-1H-quinazolin-4-one (compound 2) are reported here. The compound 1 belongs to triclinic (P-1) space group with cell parameters a = 7.4314(12) Å, b = 9.9747(16) Å, c = 14.658(2) Å, = 104.142(3), = 102.584(3), = 98.188(3). The compound 2 also belongs to triclinic (P-1) space group with cell parameters a = 9.8707(11) Å, b = 9.9225(11) Å, c = 10.7425(13) Å, = 79.227(2), = 80.568(2), = 63.649(2). The structures show that the substituent at 2-position will play a key role in defining the pyrimidine ring conformation. The central dihydropyrimidine ring in both the structures are affected by conjugation. The sum of the valence angles around all the nitrogens is very close to 360, indicating that the state of hybridization of these atoms is sp². The DHP ring is puckered in such a manner that the atoms N1, C3, C4, C5, and N2 are coplanar and the sixth atom C2 is displaced 0.605 Å (0.18 Å for compound 2) above the least squares plane. The conformation of dihydropyrimidine ring can be described as a sofa with asymmetric parameters C_s[C2] = 6.09 (compound 1) and 4.73 (compound 2), respectively. The phenethyl group has a fully extended conformation with respect to the central pyrimidine ring (N2–C16–C17–C18 174.8(2) and 179.1(6) for compounds 1 and 2, respectively). The substituents on the DHPM ring, dimethylamino-phenyl/p-tolyl groups of compound 1/2 occupy equatorial/axial positions at C2. In the crystal packing, six membered rings form through dimerization using N–HO hydrogen bonding.     

Crystal and molecular structure of an ion-pair complex based on [Ni(mnt)<Subscript>2</Subscript>]<Superscript>2−</Superscript> anion and imidazolium derivative cations

A new ion-pair complex, 1-methyl-3-benzylimidazolium bis(maleonitrile-dithiolato) nickelate(II), has been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy and X-ray crystallography. The crystallographic data for the complex: triclinic , a = 8.415(1) Å, b = 9.924(1) Å, c = 11.333(2) Å, = 114.11(1), = 102.46(1), = 100.88(1), V = 801.8(2) ų, Z = 1. The molecular packing pattern showed a completely separated column stacking for cations and anions of the complex along with the b-axis. The anion is not completely planar. The five-membered nickel-containing rings are slightly puckered. The cation, [BzIm]⁺, adopts a conformation where the benzene ring and imidazole ring twisted with the reference plane C10–C11–N3.     

Synthesis and structural characterization of the bitopic ferrocene-based tris(pyrazolyl)methane ligand Fe[C5H4CH2OCH2C(pz)3]2 (pz = pyrazolyl ring)

The structure of Fe[C₅H₄CH₂OCH₂C(pz)₃]₂ (pz = pyrazolyl ring) contains 1.5 independent molecules in the asymmetric unit. One molecule has no imposed symmetry with the iron atom located on a general position while in the other the iron atom is located on an inversion center. The two independent molecules are arranged into a three-dimensional supramolecular structure by a series of C—H s N and C—H s O weak hydrogen bonding interactions and C—H s interactions. The crystals are triclinic, space group, P , with a = 8.1202(4) Å, b = 16.7209(9) Å, c = 18.6540(10) Å = 85.8270(10), = 85.4740(10), = 81.5910(10), and Z = 3     

Synthesis,thermal reactivity and structure of 1,2-bis(4-hydroxy-3-methoxyphenylethynyl)benzene

The crystal structure of the new enediyne 3 was determined by X-ray diffraction. 3 crystallizes in the orthorhombic space group Pbca (No. 61) with a = 12.7148(9) Å, b = 7.4872(8) Å, c = 38.890(4) Å, = = = 90 and Z = 8. The three-dimensional structure is characterized by an 8-membered cyclic array linking four molecules of 3 by hydrogen bonding between phenolic and methoxy groups. Furthermore, stabilization by –-stacking and CH s interactions is present. The important cd distance (between the two terminal acetylene carbons of the enediyne) which is relevant for the Bergman cyclization, was determined to 401 pm, being in good agreement with the high cyclization barrier ( G = 147.9 kJ mol^–1 at 220C) that was determined by differential scanning calorimetry (DSC).     

Crystal structure of 1,5,8-trihydroxyl-3-methoxy xanthone from Swertia chirayita

In order to study the relationship between biological and pharmacological activities with their structures, a series of tri-, tetra-oxygenated xanthones including 1-hydroxyl-2,3,4,7-tetramethoxy xanthone 1, 1-hydroxyl-2,3,4,5-tetramethoxyl xanthone 2, 1-hydroxyl-3,5-dimethoxy xanthone 3, 1,8-dihydroxyl-3,5-dimethoxyl xanthone 4, 1,5,8-trihydroxyl-3-methoxy xanthone 5 has been isolated from Swertia chirayita. Their structures were established on the basis of spectral and chemical evidence. The crystal structure of 5 was also investigated by single crystal X-ray diffraction analysis. It crystallizes in the triclinic system, space group P , with a = 7.1540(10) Å, b = 7.520(2) Å, c = 10.671(2) Å, V = 562.7(2) ų, = 86.50(3), = 80.06(3), = 85.00(3), Z = 2, D_c = 1.618 g m^–3, R_int = 0.0230, wR(F²) = 0.1028, F(000) = 284. The molecular structure is nearly plane and four substituents are much closer to the plane of the molecule. Compound 5 also shows three intermolecular hydrogen bonds. A recent study shows that phenolic hydroxyls in xanthones are the main active groups capable of scavenging OH and O₂.