Crystal structure of a salt of the pyridinium-pyridine ion by X-ray and neutron diffraction

The crystal structure of [(C₅H₅N)₂H]⁺[ZnBr_3/2Cl_3/2(C₅H₅N)]^– has been determined and refined by full-matrix least-squares methods using X-ray (R, on ¦F _o¦, = 0.045 with 2291 reflections) and neutron (¯R, on ¦F _o¦, = 0.035 with 2030 reflections) diffraction data. The crystals of the compound are monoclinic, space groupP2₁/c witha = 12.728(1),b = 11.600(1),c = 13.354(1) Å, = 107.38(1) °,Z = 4,D _x = 1.68, andD _m(flotation) = 1.69 g cm^–3. The X-ray and neutron intensities were measured by the counter -2 scan technique with CuK X-rays ( = 1.5418 Å) and neutrons with = 1.109 Å, respectively. An intramolecular N--H hydrogen bond holds pairs of pyridine molecules together in the lattice [N N, 2.737(3) Å]. The hydrogen atom is very asymmetrically disposed with N-H distances of 1.086(7) Å and 1.658(6) Å. The coordination about the zinc atom is tetrahedral with the nitrogen atom of the pyridine molecule in one tetrahedral position and different mixtures of the two halogen atoms in the other three positions. The important average bond distances from the neutron study are Zn-N [2.073(3) Å], Zn-Cl [2.251(2) Å], Zn-Br [2.394(3) Å], N-C [1.334(5) Å], C-C [1.378(5) Å], and C-H [1.075(7) Å].     

The crystal structure of dimethyl 4-methoxy-2,3,5,6-tetrachlorophenyl phosphate

The crystal structure of dimethyl 4-methoxy-2,3,5,6-tetrachlorophenyl phosphate was determined by X-ray analysis. It crystallized in the space group P2 ₁/c (#14) with a = 9.446(2), b = 11.977(2), c = 12.306(2) Å, = 96.55(1)°, V = 1383.1(4) ų, D _calc = 1,665 5/cm³, and Z = 4.     

Crystal and molecular structure of dibenzoyl disulfide

Crystals of dibenzoyl disulfide, C₁₄H₁₀O₂S₂, are monoclinic, space group P2₁/c, with the cell dimensions (294 K), a = 12.356 (1), b = 12.071 (1), c = 9.071 (2) Å, = 107.15(1)°, V =1292 (3) ų with D _m = 1.42, D _x = 1.411 g cm^–3, and Z = 4. Complete three-dimensional data was collected on a CAD-4 diffractometer using the /2 method, the crystal structure was solved using MULTAN and refined by full-matrix least-squares methods to a final R value of 0.036 for 2738 observed reflections. The S–S bond distance is 2.021(1) Å and has a partial double-bond character. The dihedral angle around the disulfide bond is 80.8°. The two S–C distances are 1.805(2) and 1.823(2) Å. The central part of the molecule (C–S–S–C) adopts a skewed nonplanar configuration and the planes of the two benzene rings are inclined at an angle of 93.7°. The S–S bond direction from the X-ray could be compared with the directions of g _min for (S–S) anion and g _max for (S–S) cation deduced from electron spin resonance spectroscopy. The former makes an angle of 4.6° and the latter makes an angle of 18.1° with the S–S bond direction.     

Formation and crystal structure of 1-methyl-2-phenylindolizine-3-acetonitrile

1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, ¹H NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C₁₇H₁₄N₂ crystallize in the space group C2/c with cell dimensions a = 12.956(3) Å, b =10.516(2) Å, c = 20.429(4) Å, and = 90°, = 104.98(3)°, = 90°, V =2688.7(9) ų, D _calc =1.217 Mg/m³, and Z = 8.     

Molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene(phenylsulfonylimino)-σ3λ5-phosphorane

The crystal and molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene (phenylsulfonylimino)-³⁵-phosphorane, 2,4,6-Bu^t ₃-C₆H₂-P(=CHPh)(=N--SO₂Ph), has been determined. Crystal data: triclinic, , a = 9.472(5), b = 11.427(5), c = 13.684(5) Å, = 90.61(3), = 101.21(4), = 97.02(4)°, V = 1441.1 ų, Z = 2, D _c = 1.20 g cm^–3. The observed in 1 noticeable elongation of the P=N bond 1.563(3) Å and shortening of the P=C bond 1.617(3)Å have been discussed in terms of the electron withdrawing ability of substituents on the basis of ab initio (HF/6–31+G**) calculations of the model systems.     

Dalspinin, an isoflavone from Dalbergia spinosa roots

The X-ray crystal structure of the plant isoflavone dalspinin from Dalbergia spinosa is determined. The compound, C₁₇H₁₂O₇, is monoclinic in P2₁/n with a = 3.970(1), b = 23.607(5), c = 14.633(3) Å, = 94.46(3)°, V = 1367.2(5) ų, D _calc = 1.595 g cm^–1 and Z = 4. The molecular structure is characterized by a short intramolecular O–H···O=C hydrogen bond, and a large tilt angle of the two rigid ring systems with respect to each other. The intermolecular interactions in the crystal are discussed.     

Conversion of 2,4-dihydroxybenzaldehyde to 2-benzoyloxy-4-hydroxybenzaldehyde and structural characterization of both precursor and product

2,4-Dihydroxybenzaldehyde can be acylated at the 2 position if the more reactive 4 position is first protected as the methylmethoxy ether. Deprotection permits isolation of 2-benzoyloxy-4-hydroxybenzaldehyde. 2,4-Dihydroxybenzaldehyde, C₇H₆O₃, crystallizes in P2₁/c, with a = 7.3762(6), b = 11.7455(9), c = 7.3149(6) Å, = 90.533(2)°, Z = 4, and D _X = 1.448 g cm^–3. The individual molecules are characterized by an intramolecular hydrogen bond. The molecules form sheets with additional intermolecular hydrogen bonds. 2-Benzoyloxy-4-hydroxybenzaldehyde, C₁₄H₁₀O₂, crystallizes in Pca2₁, with a = 24.2629(14), b = 3.8445(2), c = 12.3727(8) Å, Z = 4, and D _X = 1.394 g cm^–3. The molecules consist of two planar halves twisted by 51.63(5)° about the ester linkage. Intermolecular hydrogen bonding joins the molecules into ribbons approximately parallel to c.     

Crystal structure of 1-chloroanthraquinone

The X-ray crystal structure of 1-chloroanthraquinone is determined. The compound C₁₄H₇O₂Cl, is monoclinic in P2₁(#4) with a = 7.763(1), b = 3.973(2), c = 16.947(1) Å, = 95.13(1)°, V = 520.6(3) ų, D _calc = 1.548 g/cm³, and Z = 2. In the molecular structure, the Cl atom is obviously repelled by O(1). The major force of crystal formation comes from aromatic ring stacking and C–H-aromatic interaction.     

Crystal and molecular structure of calcium 2,4,6,8-cyclooctatetraene-1, 2-dicarboxylate dihydrate

Calcium 2,4,6,8-cyclooctatetraene-1,2-dicarboxylate dihydrate, CaC₈H₆(COO)₂. 2H₂O, crystallizes in the triclinic space groupP¯1 (C _i ¹) with unit cell dimensions:a = 6·270(3),b = 7·767(4),c = 12·141(7) Å, = 91·10(2), = 100·21(2), = 99·76(2) °;V _c = 572·64 ų,Z = 2,D _m = 1·520(9),D _c = 1·544 g cm^–3. The anion has an approximate 2-fold axis of symmetry to which bond lengths, angles and dihedral angles conform within experimental error. The cyclooctatetraene ring has a tub shape, similar to that found in other cyclooctatetraene structures, with its average bond lengths of 1·46 Å and 1·34 Å for single and double bonds respectively in good agreement with earlier values for similar molecules. The Ca²⁺ cation is coordinated by eight oxygen atoms (six carboxylate, two water) in a distorted tetragonal antiprism with distances ranging from 2·30 to 3·07 Å. All hydrogen atoms were located; the water hydrogens form a layer-like network of hydrogen bonds linking the water and carboxylate oxygens approximately perpendicular to the z axis. The distances range from 2·74 to 2·96 Å.     

Crystal structure of vanadocene (η5-C5H5)2V

The crystal structure of vanadocene has been determined from counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/n witha = 9.269(3),b = 8.020(3),c = 5.892(2) Å, = 91.21(3)°, andD _x = 1.37 gcm^-3 for Z = 2. The finalR value for 583 observed reflections is 0.031. The vanadium atom resides on a crystallographic center of inversion. The cyclopentadienyl groups are statistically disordered 70–30%. The average vanadium-carbon (⁵) bond distance is 2.26(2) Å.     

Crystal and molecular structure of 17-β-methyl-α-isolupanine perchlorate

The formula of the title compound is C₁₆H₂₇ClN₂O₅,P2₁/a = 8.348(1),b = 10.127(1),c = 11.264(2) Å, = 116.42(1) °,Z = 2,D _x = 1.41 g cm^–3,V _c = 852.8(2) ų,MW = 362.9, (CuK) = 2.25 mm^–1. The structure was solved by direct methods and refined by full-matrix least squares to anR value of 0.055 for 1197 reflections. The cation consists of twotrans quinolizidine systems. RingA is a distorted half-chair, and the remaining rings are chairs. The CH₃ group attached to C(17) is in the axial position. There is a weak hydrogen bond between N(16) and O(2) of the ClO ₄ ^– group with N(16) ... O(2) distance 2.968(7) Å.     

Copper(II) complexes 1-phenylpropane-1,2-dione- and benzil bis(3-piperidylthiosemicarbazone): A structural study

The crystal and molecular structure of copper(II) complexes of benzil bis(3-piperidylthiosemicarbazone), [Cu(Bnzpip)] and 1-phenylpropane-1,2-dione bis(3-piperidylthiosemicarbazone), [Cu(Pmpip)] have been determined. [Cu(Bnzpip)] is monoclinic, space group P2₁/n with a = 13.9375(10) Å, b = 11.6621(4) Å, c = 16.4710(10) Å, = 100.667(2)°, and V = 2630.9(3) ų with Z = 4, for d _calc = 1.399 g/cm³. [Cu(Pmpip)] is also monoclinic, space group P2₁/n with a = 11.292(6) Å, b = 10.219(5) Å, c = 20.292(6) Å, = 101.50(3)°, and V = 2295(2) ų with Z = 4, for d _calc = 1.525 g/cm³. Both complexes involve N₂S₂ coordination, are relatively planar except for the phenyl rings and have similar bond distances and angles to copper(II) complexes of other 3-piperidylthiosemicarbazones.     

Keto–enol tautomerism, conformations, and structure of 1-[N-(4-chlorophenyl)]aminomethylidene-2(1H)naphthalenone

1-[N-(4-chlorophenyl)]aminomethylidene-2(1H)naphthalenone (C₁₇H₁₂NOCl) (1) was synthesized and the crystal structure was determined. Compound 1 crystallizes in the monoclinic space group P2₁/n with a = 4.761(3) Å, b = 20.347(1) Å, c = 13.773(2) Å, = 92.89(3)°, V = 1332.4(3) ų, Z = 4, D _c = 1.404 g cm^–3, (Mo K) = 0.28 mm^–1, and R = 0.036 for 2680 reflections [I > 2(I)]. Molecule 1 is not planar, and the dihedral angle between the naphthaldeyde plane A [C1–C11, 01] and the 4-chloroaniline plane B [C12–C17, C11, N1] is 20.1(3)°. An intramolecular hydrogen bond occurs between the hydroxyl oxygen and imine nitrogen atoms [2.528(3) Å]. IR, ¹H NMR, and UV measurements and AM1 semiempirical quantum mechanical calculations support the keto form found in the X-ray structure.     

Molecular structure of ThBr4(DME)2 (DME = 1,2-dimethoxyethane)

The molecular structure of ThBr₄(DME)₂ (DME = 1,2-dimethoxyethane), the first structurally characterized thorium complex containing a simple bidentate ether ligand, is described. The eight-coordinate complex presents a distorted dodecahedral geometry, with Th—Br and Th—O bond lengths in the ranges 2.8516(13)–2.8712(13) Å and 2.564(8)–2.620(8) Å, respectively. ThBr₄(DME)₂ is monoclinic, space group P2₁/n, a = 7.672(1), b = 14.581(1), c = 15.847(2) Å, = 102.24(1)°, V = 1732.4(3) ų, and Z = 4.     

Crystal and molecular structure of chlorotris(monomethylthiourea)silver(I)

The crystal and molecular structure of chlorotris(monomethylthiourea)silver(I) has been solved and refined by full-matrix least-squares methods to a finalR of 0·039 from 1150 reflections measured by counter techniques at ambient room temperature. The crystals are orthorhombic:Pmcn, a = 14·824(2),b = 8·524(1),c = 12·671(1) Å,Z = 4,D _m = 1·68,D _c = 1·72 gcm^–3. The structure consists of independent, distorted tetrahedral Ag(I) moieties with only weak hydrogen bonds and/or van der Waals interactions between molecules. These molecules are packed in such a way that Ag, Cl and one entire monomethylthiourea ligand all lie in a crystallographic mirror plane, and the other two ligands are related by this mirror. This arrangement, plus the alternation of the Ag-Cl bond direction, leads to a non-polar sheet of Ag, Cl and monomethylthiourea groups with other monomethylthiourea groups protruding from either side of the sheet. Only N-HCl hydrogen bonds and van der Waals interactions exist between sheets. The Ag-S distance is somewhat long at 2·649(3) Å, as is one of the Ag-S distances at 2·665(3) Å. The other two Ag-S distances are 2·520(2) Å. The geometry of the complex makes it clear that the Ag-S bond is formed by donation of an electron pair from a sulfur sp² orbital.     

Study on the crystal and molecular structure of triphenyl tin methacrylate: (C6H5)3SnOCOCCH2CH3

The crystal and molecular structure of (C₆H₅)₃SnOCOCCH₂CH₃ has been determined by a single crystal X-ray diffraction study. The crystal is monoclinic with space group P2₁/c,a=11.902(3),b=10.104(4),c=16.721(2) Å,=97.56(1)°,V=1930.4 ų,Z=4 andD _c =1.495 g/ cm³,F(0,0,0)=872,(CuK)=1.5418 Å. The structure was solved by the heavy-atom method and refined by full-matrix least-squares procedures to anR factor of 0.060 based on 2157 independent reflections. The results showed that the Sn-O bond distance is 2.064(4) Å. The average Sn-C bond distance is 2.126 Å. There is a weak coordination through the O of the CO group of the methacrylate residue (Sn-O(2) 2.774(5) Å) except for four normal coordinations. The coordination number at the Sn⁴⁺ is 5.     

Crystal structure and conformation of the antimalarial drug 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin

The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin, C₁₆H₁₈O₅, M _r = 290.3 Da, has been determined from X-ray diffraction data. The material crystallizes in the monoclinic space group P2₁/c with 4 molecules per unit cell of dimensions a = 8.9044(9), b = 17.623(1), c = 10.175(1) Å, = 113.97(1)°, crystal density D _c = 1.322 g/cm³. The structure was determined using direct methods and refined by full-matrix least squares to a conventional R index of 0.066 for 2416 measured reflections and 206 parameters.The coumarin ring system is almost planar with the methoxy C atoms rotated slightly out of the coumarin mean plane. Apart from the terminal CH₃ groups C(12) and C(13), which are 1.184(3) Å above and –1.315(3) Å below the plane, the 3-methyl-1-buten-3-ol substituent is planar (rms deviation 0.009 Å) making an angle of 6.31(7)° with the phenyl ring. One intermolecular hydrogen bond is present in the crystal structure between O(5)–HO(5) and the symmetry related O(2) oxygen, generated by the symmetry operation (x, 1/2 – y, –1/2 + z).     

Crystal and molecular structure ofE-mesityl(phenylsulphinyl)sulphine

E-mesityl(phenylsulphinyl)sulphine, C₁₆H₁₆O₂S₂, crystallizes in the monoclinic system: space groupP2₁/c,a = 8.310(2),b = 14.141(3),c = 14.873(4)Å, = 116.67(4) ° andz = 4.The structure has been determined by direct methods and refined by full-matrix least squares toR = 0.060 for 1834 non-zero reflections. The sulphine moiety has bond lengths 1.628(5)Å for C-S, 1.470(5)Å for S-O and a C-S-O angle of 113.8(2) °, values which are consistent with a cumulated double-bond system and sp² hybridization on the sulphur atom. All other bond distances and angles are close to those usually found for such functional groups.     

Synthesis and crystal structure of two vanadium(V) hydroxylamido complexes with amino acid ligands

Two vanadium(V) hydroxylamido complexes with amino acid ligands including Alanine, [VO(NH₂O)₂(Ala)]·2H₂O, and Threonine, VO(NH₂O)₂(Thr), were synthesized and characterized by elemental analyses, IR spectrum, and single crystal X-ray diffraction. The two complexes are seven-coordinated with four nitrogen atoms and three oxygen atoms in pentagonal bipyramidal geometry. The different hydrogen bonds (N–H···O, O–H···O) observed in the two complexes result in the two-dimensional network structure. [VO(NH₂O)₂(Ala)]·2H₂O belongs to monoclinic: space group P2(1)/c, with a = 21.874(13) Å, b = 8.874(5) Å, c = 15.865(9) Å, = 100.423(8)°, V = 3029(3) ų, Z = 12, D _c = 1.678 g/cm³, (MoK) = 1.002 mm^–1, F (000) = 1584, and final R ₁ = 0.0375, wR ₂ = 0.0886 for observed reflections 1189 (IT > I> 2(I)). VO(NH₂O)₂(Thr) is rhombohedral: space group R-3, with a = 21.460(16) Å, b = 21.460(16) Å, c = 11.184(12) Å, = 120°, V = 4461(7) ų, Z = 18, D _c = 1.669 g/cm³, (MoK) = 1.012 mm^–1, F(000) = 2304, and final R ₁ = 0.0356, wR ₂ = 0.0924 for observed reflections 1306 (I > 2(I)).     

Schiff bases and their complexes with metal ions. Part II. Structures of N-n-butyl-2-hydroxy-1-naphthaldimine and bis[N-n-pentyl-2-hydroxy-1-naphthaldiminato]nickel(II)

The Schiff base ligand (1), [C₁₅H₁₇NO] crystallizes in the monoclinic space group P2₁/c witha=10.054(3),b=10.313(3), c=13.173(4)Å, =107.42(4)°,V=1303.2(7)ų,Z=4,Dx=1.159 g cm^–3, and (MoK)=0.674 cm^–1. The C2-O[1.23(1)Å] and C3–C4 [1.33(2)Å] bond lengths are short, due to its quinoidal structure. In the Schiff base nickel complex (2), [Ni(C₁₆H₁₈NO)₂] the asymmetric unit is comprised of two half-complexes. It crystallizes in the triclinic space group witha=5.124(3),b=16.227(3),c=16.886(4)Å, =95.47(8), =96.00(1), =90.71(4)°,V=1389.6(9) ų,Z=2,Dx=1.289 g cm^–3, and (MoK) =12.1 cm^–1. The coordination of the Ni(II) ions are square planar with bond angles between 87.9(1) and 92.1(1)°. The Ni–O and Ni–N distances are 1.819(2), 1.922(2) and 1.823(2), 1.914(3)Å in these two complexes.