Structures of divalent transition metal salts of 4-aminonaphthalene-1-sulfonate: unexpected variations in layering pattern

Salts of 4-aminonaphthalene-1-sulfonate with divalent Mg, Mn, Co, and Ni cations have been crystallized and their structures determined by single crystal X-ray methods. The Mg and Mn salts are isostructural. Crystal data for hexa-aquamagnesium(II) 4-aminonaphthalene-1-sulfonate dihydrate, [Mg(H₂O)₆](H₂NC₁₀H₆SO₃)₂ 2H ₂O: monoclinic, P2₁/c, Z = 2, a = 8.622(3), b = 7.043(3), c = 23.178(3) Å, =93.78(2)°, V = 1404.3(7) ų; hexa-aquamanganese(II) 4-aminonaphthalene-1-sulfonate dihydrate, [Mn(H₂O)₆](H₂NC₁₀H₆SO₃)₂ 2H ₂O: monoclinic, P2₁/c, Z = 2, a = 8.652(3), b = 7.031(4), c = 23.402(2) Å, =93.09(2)°, V = 1421.5(9) ų. The structures are composed of alternating layers of octahedral metal–aqua complexes and sulfonate anions linked by an extensive network of hydrogen bonds. The extra water molecules of crystallization are located in the hexa-aquametal cation layers. The repeat unit along the c axis is a double layer. The Co and Ni compounds are isostructural with each other, but compared to the Mg and Mn compounds, have a strikingly different structure. Crystal data for hexa-aquacobalt(II) 4-aminonaphthalene-1-sulfonate trihydrate, [Co(H₂O)₆](H₂NC₁₀H₆SO₃)₂ 3H ₂O: orthorhombic, Pbca, Z = 8, a = 8.518(1), b = 14.327(2), c = 45.367(6) Å, V = 5536(1) ų; hexa-aquanickel(II) 4-aminonaphthalene-1-sulfonate trihydrate, [Ni(H₂O)₆](H₂NC₁₀H₆SO₃)₂ 3H ₂O: orthorhombic, Pbca, Z = 8, a = 8.4976(6), b = 14.288(1), c = 45.076(3) Å, V = 5472.9(7) ų. These structures also contain layers of octahedral hexa-aquametal complexes and additional water molecules of crystallization sandwiched by layers of sulfonate anions, however the stacking pattern is more complex with a quadruple layer repeat unit and two different types of anion layers.     

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.     

A new class of flexible energetic salts, part 3: The crystal structures of the 3,3-dinitroazetidinium dinitramide and 1-i-propyl-3,3-dinitroazetidinium dinitramide salts

The crystal structures of 3,3-dinitroazetidinium, 1, and 1-i-propyl-3,3-dinitroazetidinium dinitramide, 2, have been determined. 1 crystallizes in the orthorhombic space group Cmc2₁ with cell dimensions a = 9.932(1), b = 8.545(1), c = 11.107(1) Å, while 2 crystallizes in the orthorhombic space group Pbca with cell dimensions a = 11.464(2), b = 11.657(2), c = 17.916(4) Å. Compound 2 formed spontaneously from 1 by reacting with the solvent, acetone, during attempts to recrystallize it. The conformations adopted by the dinitramide ions are quite different with the bend, twist, and torsion angles for the dinitramide ion in 1 being much smaller than those in 2. Possible reasons for the dramatic differences in conformations observed in 1 and 2 are the different local symmetries for this ion found in the two structures as well as the absence of hydrogen bonding interactions in 2.     

A new class of flexible energetic salts, part 2: The crystal structures of the cubane-1,4-diammonium dinitramide and cubane-1,2,4,7-tetraammonium dinitramide salts

The crystal structures of cubane-1,4-diammonium dinitramide, 1, and cubane-1,2,4,7-tetraammonium dinitramide, 2, have been determined. 1 crystallizes in the space group P2₁/c with cell dimensions a = 6.018(2), b = 11.642(3), c = 9.754(3) Å, = 107.24(2), while 2 crystallizes in the space group P2₁/c with cell dimensions a = 9.401(4), b = 9.603(3), c = 12.603(4) Å, 111.08(3). In these structures the ammonium substituents are symmetrically attached with respect to the cubane skeleton and have neither low lying empty orbitals nor available lone pairs of electrons thus they have a minimal effect on the metrical parameters of the cubane skeleton. All C–C bond lengths are close to the overall average C–C bond length for all reported cubanes of 1.559 Å. The conformations adopted by the dinitramide ions in both structures are quite different, with the bend, twist, and torsion angles for the dinitramide ion in 1 being significantly larger than those found for the dinitramide ions in 2, due to the different types of hydrogen bonding found in the two structures. In 2, the conformation adopted by the adjacent ammonium ions allows two of the three protons from each ammonium cation to form hydrogen bonds in such a manner that they span either the syn or the anti oxygen atoms of a single dinitramide anion. The dinitramide anion is thus constrained by these interactions and is less free to twist and bend. These results provide further confirmation that the metrical parameters of both the cubane and dinitramide moieties are flexible and reflect their local environment.     

Synthesis,crystal structure and characterization of new transition metal compounds of bromophenols: Bis(2,4,6‐tribromophenolato) di(N‐methylimidazole)M(II) (M=Co,Cu)

Bis(2,4,6‐tribromophenolato)di(N‐methyl imidazole)M(II), where M stands for cobalt and copper metals, was synthesized via reaction of the corresponding metal sulphate and 2,4,6‐tribromophenolate in aqueous media in the presence of N‐methyl imidazole and sodium hydroxide. Although various crystallization procedures were applied only cobalt complex was obtained as single crystals. The Co(II) ion has a distorted octahedral enviroment involving two O atoms and two N atoms of the Bis(2,4,6‐tribromophenolato)di(N‐methyl imidazole) ligand. Powder x‐ray diffraction pattern of copper compound was used for cooper complex. For characterizations of complexes carbon, hydrogen and nitrogen elemental analysis, FTIR and UV spectroscopy, DSC thermal analysis and magnetic susceptibility measurements at room temperature were performed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Low Temperature X-ray Crystallographic Structures of Two Lamotrigine Analogues: (I) 2-Methyl,3-amino, 5-imino-6-(2,3-dichlorophenyl)-1,2,4-triazine Water Solvate and (II) 2-Methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine Isethionate,Hemi-hydrate

Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 2-methyl, 3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1,2,4-triazine, C₁₀H₉Cl₂N₅, as the hemi hydrate and (II) 2-methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, C₁₀H₁₀Cl₂N₅, as the isethionate-water solvate, have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are monoclinic and centrosymmetric, with (I) in space group C2/c, and (II) in space group P2₁/n. For (I) the unit cell dimensions are a = 19.5466(10), b = 7.5483(4), c = 15.7861(8) ?, β = 91.458(3)°, volume = 2328.4(2) ?³, Z = 8, density = 1.590 Mg/m³; for (II). For (II) the unit cell dimensions are a = 6.0566(2), b = 11.0084(4) c = 23.9973(9) ?, β = 92.587(3)°, volume = 1598.35(10) ?³, Z = 4, density = 1.597 Mg/m³. For (I) final R indices [I > 2sigma(I)] are R1 = 0.0356, wR2 = 0.0782 and R indices (all data) are R1 = 0.0424, wR2 = 0.0817. For (II) final R indices [I > 2sigma(I)] are R1 = 0.0380, wR2 = 0.0871 and R indices (all data) R1 = 0.0558, wR2 = 0.0949. Both structures have a molecule of water of crystallization and (II) also includes a solvated CH₃SO₃. Comparisons are made between the two structures. Structure (I) is very unusual in having a = NH group at position C5′ on the triazine ring. No other examples of this particular substitution, which is usually −NH₂, have been reported. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry The crystal structures of (I) 2-methyl,3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine, water solvate and (II) 2-methyl,3, 5-diamino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine isethionate water solvate are presented. The relative orientation of the two rings is shown to vary. Lamotrigine and analogues have been investigated for some time for their effects on the central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW 1003C87) are voltage-gated sodium channel blockers as well as blocking the release of the neurotransmitter glutamate [D. R. Riddall, M. J. Leach, J. Garthwaite, Mol. Pharmacol. 2006, 69 (1), 278.3], BW10003C87 (like lamotrigine) has been shown to exhibit excitatory amino acid antagonist activity similar to that of three conventional antiepileptic drugs phenytoin, carbamazepine and phenobarbital [R. Lingamaneni, H. C. Hemmings Jr., Epilepsy Res. 1993, 15, 101.]. BW 1003C87 has also been shown [B. S. Meldrum, J. H. Swan, M. J. Leach, M. H. Millan, R. Gwinn, K. Kadota, S. H Graham, J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.] to reduce the release of glutamate evoked by veratrine in brain tissue, providing a therapeutic approach in both cerebral ischemia and epilepsy. This is one of a series of papers on the structures of lamotrigine analogues.      

Structure and characterization of hexakis(imidazole) cobalt(II) complexes: [Co(Im)6(OBz)2] and [Co(Im)6(mB)2] (Im = imidazole, OBz = benzoate, mB = p-methoxybenzoate)

The crystal and molecular structures of the complexes of [Co(Im)₆(OBz)₂] and [Co(Im)₆(mB)₂] (Im = imidazole, OBz = benzoate, mB = p-methoxybenzoate) have been determined by X-ray crystallography. The crystal structures are very similar and consist of discrete molecules of [Co(Im)₆(OBz)₂] and [Co(Im)₆(mB)₂], respectively. They both crystallize in the triclinic system, space group the former with lattice parameters a = 7.6934(3), b = 10.4518(5), c = 11.6088(5) Å, = 73.920(1), = 79.023(1), = 73.681(1)°, and Z = 1; the latter with a = 9.8336(3), b = 10.5509(2), c = 10.8889(3) Å, = 61.450(1), = 76.832(1), = 71.157(1)°, and Z = 1. The cobalt(II) ions have octahedral geometry with a CoN₆ chromophore. In the solid state, the complexes all form a three-dimensional network through N—H···O hydrogen bonds. The electronic spectra and IR spectra data are in agreement with the structural data.     

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.     

Synthesis,Characterization, and Crystal Structure of 5'-Amino-4,4'-Dichloro-2'-Nitro-2',3'-Dihydro-[1,1':3',1'-Terphenyl]-4',4',6'(1'H)-Tricarbonitrile-Dimethyl Sulfoxide

Crystallography Reports - The cyclohexene derivative...     

Synthesis, crystal structure, and molecular modeling (AM1) of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1, 4-dihydropyridine-3-carboxylate

The synthesis and structural characterization of Methyl 6-chloro-4-(2-chlorophenyl)-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate is described. The structure was refined to R₁ = 0.0470 for 2665 reflections (with I > 2(I)). Crystal data: C₁₅H₁₃C₁₂NO₃, monoclinic,space group P2₁/c, a = 11.163(9), b = 14.484(8), c = 9.422(7) Å, V = 1512.9(19) ų, Z = 4. The results of crystallographic and molecular modeling (AM1) were compared. The Cl atom attached to the phenyl group has two possible orientations, having 75% (sp) and 25% (ap) occupancy, respectively. The molecules in the crystal are held together by means of intermolecular hydrogen bonds of the type N=H...O and by C=H...O interactions.     

Ligand Substitution Chemistry of the Diphosphine Ligand endo,endo-2,3-Bis(diphenylphosphinomethyl)-5-norbornene (dpmn): Syntheses and X-ray Diffraction Structures of PtCl2(dmn) and PtMe2(dpmn)

Abstract  The reaction of phosphine ligand endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene (dpmn) with PtCl₂(cod) and PtMe₂(cod) yields PtCl₂(dpmn) (2) and PtMe₂(dpmn) (4), respectively. Treatment of 2 with excess MeLi or MeMgCl also furnishes 4 in good yield. Both new platinum compounds have been isolated and characterized by NMR spectroscopy (¹H and ³¹P), elemental analyses, and X-ray crystallography. 2 Crystallizes, as the CH₂Cl₂ solvate, in the orthorhombic space group Pnma, a = 18.062(3) ?, b = 16.602(3) ?, c = 11.088(2) ?, V = 3,324.7(9) ?³, Z = 4, D _cacl = 1.681 mg/m³; R = 0.0432, R _w = 0.0759 for 3,755 observed reflections with I > 2σ(I). 4 Crystallizes, as the CH₂Cl₂ solvate, in the orthorhombic space group Pnma, a = 17.969(3) ?, b = 16.689(3) ?, c = 11.237(2) ?, V = 3,370(1) ?³, Z = 4, D _cacl = 1.610 mg/m³; R = 0.0268, R _w = 0.0665 for 4,098 observed reflections with I > 2σ(I). The solid-state structures of 2 and 4 confirm the coordination of the platinum(II) center by the seven-membered chelating dpmn ligand; 2 and 4 represent the first structurally characterized examples of organometallic compounds based on the endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene ligand. Graphical Abstract  The new platinum(II) compounds PtCl₂(dpmn) (2) and PtMe₂(dpmn) (4) have been synthesized, and their structures established by NMR spectroscopy (¹H and ³¹P) and X-ray crystallography. Compounds 2 and 4 are the first structurally characterized examples of organometallic compounds containing the endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene (dpmn) ligand.

Central Nervous System Drugs: Low Temperature X-ray Structures of (I) the Base 5-(2,3-Dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine (4030W92) and (II) 5-(2,6-Dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine methanesulphonic acid salt (227C89)

Abstract  The X-ray crystal structures of (I), the base 4030W92, 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine, C₁₁H₉Cl₂FN₄, and (II) 227C89, the methanesulphonic acid salt of 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine, C₁₁H₁₁Cl₂N₄ · CH₃O₃S, have been carried out at low temperature. A detailed comparison of the two structures is given. Structure (I) is non-centrosymmetric, crystallizing in space group P2₁ with unit cell a = 10.821(3), b = 8.290(3), c = 13.819(4) ?, β = 105.980(6)°, V = 1191.8(6) ?³, Z = 4 (two molecules per asymmetric unit) and density (calculated) = 1.600 mg/m³. Structure (II) crystallizes in the triclinic space group with unit cell a = 7.686(2), b = 8.233(2), c = 12.234(2) ?, α = 78.379(4), β = 87.195(4), γ = 86.811(4)°, V = 756.6(2) ?³, Z = 2, density (calculated) = 1.603 mg/m³. Final R indices [I > 2sigma(I)] are R1 = 0.0572, wR2 = 0.1003 for (I) and R1 = 0.0558, wR2 = 0.0982 for (II). R indices (all data) are R1 = 0.0983, wR2 = 0.1116 for (I) and R1 = 0.1009, wR2 = 0.1117 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this structural series and their biological activities. Index Abstract  Low temperature X-ray structures of (I): the base 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine (4030W92); and (II): 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine methanesulphonic acid salt (227C89) are presented. Both drugs act on the central nervous system. (I) crystallizes in non-centrosymmetric space group P2₁ with two molecules A and B per asymmetric unit cell and (II) is triclinic in space group . The absolute configuration of (I) is determined.      

Reactions of triosmium clusters with indole: X-ray structures of [Os3(CO)10(μ-OH)(μ-OMeCO)] and [Os3(μ-H)(CO)10(μ-1, 2-η2-NC8H6)]

Treatment of [Os₃(CO)₁₂] with indole in presence of a methanolic solution of Me₃NO⋅2H₂O at 60^∘C afforded the previously reported compounds [(μ-H)Os₃(CO)₁₀(μ-OMe)] 2, [(μ-H)Os₃(CO)₁₀(μ-OH)] 3 and [Os₃(CO)₁₀(μ-OH)(μ-OMeCO)] 4 in 10, 5 and 20% yields, respectively. The reaction of [Os₃(CO)₁₀(MeCN)₂] with indole at room temperature gave [(μ-H)Os₃(CO)₁₀(μ-1,2-η²-NC₈H₆)] 5 in 40% yield. Compounds 4 and 5 have been characterized by single crystal X-ray diffraction studies. Compound 4 crystallizes in the monoclinic space group P2(1)/c with a = 23.1239(3), b = 9.8087(4), c = 16.9017(6) ?, β = 92.6998(14)^∘, Z = 8 and V = 3829.3(2) ?³ and 5 crystallizes in the monoclinic space group P2(1)/c with a = 9.009(3), b = 9.764(4), c = 24.906(6) ?, β = 93.452(14)^∘, Z = 4 and V = 2186.9(13) ?³. Compound 4 consists of an open cluster of three osmium atoms with the hydroxy and methoxycarbonyl ligands bridging the open Os–Os edge. Compound 5 consists of an isosceles triangle of osmium atoms with one elongated Os–Os edge which is bridged by the hydride and the indolyl ligands.     

Synthesis, thermal and magnetic properties of new metal iodate: (LiFe1/3)(IO3)2

This paper reports the detail synthesis of a new kind of metal iodate, anhydrous (LiFe_1/3)(IO₃)₂, from aqueous solutions. The synthesized compound shows spinal morphology and is chemical stable up to 400°C. The iodate shows paramagnetic behavior from room temperature down to 4.2 K. At room temperature, the new compound has a hexagonal structure with the lattice parameters a=5.4632(2) Å, c=5.0895(6) Å, Z=1, space group of P6₃.     

Synthesis,characterization and impedance spectroscopy of the new material [(CH3) (C6H5) 3P] 2CoBr4: a member of the A2BX4 family

The crystal structure of bis‐(methyltriphenylphosphonium) tetrabromocobaltate (II), [(C₁₉H₁₈P)₂ CoBr₄] is determined: M_r = 933.203, monoclinic, P2₁, a = 9. 6977 (3) Å, b = 12.5547 (4)Å, c = 16.4503 (6)Å, β = 105.603 (2)°, V = 1929.04 (11)ų, Z = 2, D_x = 1.607 Mg m^‐3, T = 298 K. Differential thermal analysis at high temperatures shows three endothermic peaks characterizing four phases, with onset temperatures at T₁= 313±2 K, T₂ = 320±4 K and T₃= 360±1 K. The structural instability detected via the temperature dependence of permittivity at T₁ is ascribed to order‐disorder transition associated with cation dipole reorientation. Permittivity and ac conductivity studies as a function of temperature (295 K‐375 K) and frequency (0.11 kHz < f <100 kHz) are presented. The results indicate the importance of the cation size and shape on the phase transitions in the system. Bulk conductivity behavior is thermally activated. The associated activation energies are in the range 2.9 to 1.0 eV depending on the temperature regime. Two contributions to the ac conductivity, one dominating at low temperatures and high frequencies which are characterized by superlinear frequency exponent and the second dominates at high temperatures characterized by a sublinear frequency exponent. The behavior is interpreted in terms of the jump relaxation model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and crystal structures of two potential gem-di(pyrazolyl)cycloalkane ligands, 1,1-di(pyrazol-1-yl)cyclohexane [C6H10(C3N2H3)2] and 1,1-di(pyrazol-1-yl)cyclopentane [C5H8(C3N2H3)2]

The species 1,1-di(pyrazol-1-yl)cyclohexane, C₁₂H₁₆N₄, crystallizes in the monoclinic space group P2₁/c with a = 8.340(2), b = 14.281(5), c = 10.153(3) Å, = 106.86(2)°, and Z = 4. The cyclohexane moiety has the chair conformation. The congener, 1,1-di(pyrazol-1-yl)cyclopentane, C₁₁H₁₄N₄, while not isomorphous, also crystallizes in space group P2₁/c with a = 14.350(2), b = 6.776(1), c = 11.043(2) Å, = 100.68(1)°, and Z = 4. The cyclopentane ring has a conformation in which four carbon atoms are essentially coplanar, while the fifth (that with the two pyrazolyl substituents) lies 0.63 Å from this plane, resulting in a bend of 41.3° across the C(2)···C(5) vector. The hydrogen atoms in each structure were located directly and their coordinates refined.     

1:1 Crystal Complexes of 2',6'‐Dimethoxyflavone with 3‐Bromo and 3‐Chloro‐2,6‐dimethoxybenzoic Acid

The structures of two solid inclusion compounds with the 2',6'‐dimethoxyflavone host molecule, 1, were investigated by single‐crystal X‐ray analysis. Both compounds, 1�3‐bromo‐2,6‐dimethoxybenzoic acid (1:1) and 1�3‐chloro‐2,6‐dimethoxybenzoic acid (1:1) crystallize in the centrosymmetric group P‐1. The complexation involves an intermolecular hydrogen bond between the carbonyl group of the flavone and the acidic hydrogen of the acid.     

Synthesis,spectroscopic and crystal structure analysis of a compound with pharmocophoric substituent: 2-cyclohexyl-6-(2-oxo-2H-chromen-3-yl)- imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde

Imidazo[2,1-b][1,3,4] thiadiazole derivatives are significant for their various pharmacological properties. This paper reports the synthesis and structure of one of them, 2-cyclohexyl-6-(2-oxo-2H-chromen-3-yl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde. The compound crystallizes in the monoclinic space group P2₁/c with a=17.316(3)?, b=6.5420(9)?, c =17.056(3)?, β=112.909(2)°, V=1779.7(4)?³, z=4. The, Imidazo[2,1-b][1,3,4] thiadiazole and the coumarin ring systems are each planar but inclined at an angle of 48.14(2)° towards each other. The crystal structure is stabilized by C–H … O interactions.     

Structure and conformation of a nickel complex: {2‐Hydroxo‐3‐piperidine‐1‐yl‐methyl‐N,N′(bis‐5‐bromobenzylpropylenediimine)nickel(II)perchlorate}

The title compound, a nickel complex [C₂₃H₂₆N₃O₂Br₂Ni.(ClO₄)] (CCDC 199520) crystallizes in triclinic space group P with the cell parameters a = 10.2560(4), b = 10.8231(4), c = 12.0888(5)Å, α = 99.404(1), β = 99.780(1), γ = 92.252(1)° and V = 1301.49(9)ų. The structure was solved by Patterson method and refined by full‐matrix least‐squares procedures to a final R = 0.0497 using 6287 observed reflections. In the complex, the piperidine ring takes chair conformation and the geometry around the Ni ion is slightly distorted square planar. The dihedral angle between the planes [N‐Ni‐N and O‐Ni‐O] is 9.4(1)°. The chelate ring containing both the nitrogen atoms adopts twisted boat conformation. The molecules in the crystal are stabilized by N‐H…O and C‐H…O types of hydrogen bonds in addition to a C‐H…π interaction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pincer ligand coordination at Co3 and Ru6 clusters: Syntheses, reactivity studies, and X-ray diffraction structures of [PhCCo3(CO)8]2(dppx) and [Ru6(μ6-C)(CO)16]2(dppx)

The reaction of the pincer diphosphine ligand 4,6-bis(diphenylphosphinomethyl)-m-xylene (dppx) with the metal cluster compounds PhCCo₃(CO)₉ and Ru₆(μ₆-C)(CO)₁₇ has been explored. Both clusters react with dppx to afford the simple substitution products [PhCCo₃(CO)₈]₂(dppx) and [Ru₆(μ₆-C)(CO)₁₆]₂(dppx), where two cluster units are tethered by the pincer ligand. The molecular structures of the title products and the 2:1 cluster-pincer ligand stoichiometry have been established by X-ray crystallography. The stability of [PhCCo₃(CO)₈]₂(dppx) and [Ru₆(μ₆-C)(CO)₁₆]₂(dppx) has been investigated under gentle thermolysis conditions (ca. 55–65°C). Both dppx-substituted clusters are unstable with [PhCCo₃(CO)₈]₂(dppx) decomposing and [Ru₆(μ₆-C)(CO)₁₆]₂(dppx) transforming into the diphosphine-bridged cluster Ru₆(μ₆-C)(CO)₁₅(μ-dppx) as the major observable product. The identity of the latter cluster has been ascertained by IR and NMR spectroscopies and mass spectrometry.