Theoretical studies of the structure of nitrimines. I. Structure of 2-nitroguanidine and its alkyl derivatives

The molecular structure of 2-nitroguanidine and its 1-methyl, 1-ethyl, and 1,1,3,3-tetramethyl derivatives was studied by quantum-chemical methods. The results were compared with X-ray data. Using a basis larger than 6-31G and polarization functions and including electron correlation in calculations did not improve agreement with experiment. The major reason for this is the considerable effect of the crystal field on the geometrical parameters of the molecules.     

Crystal and molecular structure of nitraminotetrazoles and nitramino-1,2,4-triazoles. V. 5-nitraminotetrazole methylammonium salt

An X-ray study was performed to investigate the structure of 5-nitraminotetrazole methylammonium salt. Monoclinic crystals, space group P2₁/n; a = 6.541(2) Å, b = 19.157(4) Å, c = 10.726(2) Å; β = 96.24(2)°; V = 1336.07(1) ų; Z = 8, ρ_calc = 1.602 g/cm³. The crystal structure has anions and cations of two independent types with close geometrical parameters. The anions are planar and have a nitrimine structure with an intramolecular hydrogen bond. All hydrogen atoms of the cationic amino groups form hydrogen bonds to the oxygen and nitrogen atoms of the anions. The negative charge is delocalized to different extents in the anions.     

Crystal and molecular structure of nitraminotetrazole and nitramino-1,2,4-triazole. IV. 5-nitraminotetrazole sodium salt sesquihydrate

The structure of 5-nitraminotetrazole sodium salt sesquihydrate was determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/c;a = 3.551(1) Å, b = 21.834(4) Å, c = 9.075(2) Å; = 110.68(3)°; V = 658.3(2) ų; Z = 4; _calc = 1.807 g/cm³. The anion is planar and has an intramolecular hydrogen bond. The negative charge of the anion is localized on one of the oxygens of the nitro group. The sodium cation (c.n.6) is coordinated by three oxygen atoms of different anions and three oxygens of crystallization water. One of the crystallization water molecules is disordered in the unit cell. The anions are hydrogen-bonded with each other and with crystallization water molecules.Original Russian Text Copyright © 2004 by A. M. Astakhov, A. D. Vasiliev, M. S. Molokeev, L. A. Kruglyakova, A. M. Sirotinin, and R. S. StepanovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 562–565, May–June 2004.     

Crystal and molecular structure of 1-(trimethylsilylmethyl)benzotriazole

The crystal and molecular structure of 1-(trimethylsilylmethyl)benzotriazole has been established by X-ray diffraction (XRD) analysis. The coordination polyhedron of the silicon atom in this molecule is a tetrahedron. The bond lengths and angles of the 1-(trimethylsilylmethyl)benzotriazole molecule were compared with those of related crystal structures.     

Crystal and molecular structure of N-(1-silatranylmethyl)benzimidazole

The crystal and molecular structure of N-(1-silatranylmethyl)benzimidazole was established by X-ray diffraction. The coordination polyhedron of the silicon atom in this molecule is a trigonal bipyramid. The bond lengths and angles of the N-(1-silatranylmethyl)benzimidazole (SMBI) molecule are compared with the corresponding values for other derivatives of this heterocycle. The silatranylmethyl group, having a high electron-donor inductive effect, does not increase the total aromaticity of the SMBI molecule.     

Crystal and molecular structure of 1-chloromethyl-1-oxo-1,3-dihydro-2,1-benzoxaphosphole

The crystal and molecular structure of 1-chloromethyl-1-oxo-1,3-dihydro-2,1-benzoxaphosphole was determined by x-ray diffraction structural analysis. This compound has an almost planar bicyclic unit with extruding phosphorus atoms and atrans Cl-C-P=O fragment.Institute of Physiologically Active Compounds, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1670–1673, July, 1992.     

Nitration of 2,2＇-Dinitro-4,4＇-biphenyldicarboxylic Acid at High Concentration of Sulfuric and Nitric Acids

Nitration of 4,4'-biphenyldicarboxylic acid(BPDC) was studied and an aromatic carboxylic acid containing four nitro groups was synthesized and characterized through elemental analysis and IR spectra.Crystal structure of TNBPDC(TNBPDC = 2,2',6,6'-tetranitro-4,4'-biphenyl dicarboxylic acid) was determined by X-ray single-crystal diffraction.The title compound(C20H20N6O14,Mr = 600.42) crystallizes in tetragonal,space group I41/a with a = 9.8774(1),b = 9.8774(1),c = 25.335(7) ,V = 2471.7(8) 3,Z = 4,Dc = 1.613 g/cm3,F(000) = 1240,μ(MoKα) = 0.142 mm-1,T = 294(2) K,the final R = 0.0797 and wR = 0.2177 for 554 observed reflections with I > 2σ(I).In this crystal,there exist a number of H-bonds which link the molecules to form a three-dimensional infinite network structure.The thermal decomposition of the title compound has been carried out through DSC and TG-DTG analyses at a heating rate of 10 ℃/min.The results indicate that the compound has high heat-resistant stability.     

Crystal structure of 4-n-nonylbenzoic acid

The title compound, 4-n-nonylbenzoic acid, CH₃(CH₂)₈C₆H₄COOH (NBA), has been characterized thus: triclinic, P1, a = 13.514(4)Å, b = 23.4672(5)Å, c = 7.658(3)Å, alpha = 90.914(3)°, beta = 100.403(3)°, gamma = 77.781(2)°, V = 2334(2)ų, Z = 2, and F.W = 745.06, D_m = 1.161 g cm^-3, D_c = 1.061 g cm^-3, F₀₀₀ = 816.00, lambda = 0.71069Å, mu = 0.6 cm^-1, goodness-of-fit is 1.029, final R1 = 0.063 and wR2 = 0.16.     

The structure of a new copper(II) complex with 3-methyl-5-carboxylatopyrazole

Molecular and crystal structures of a new complex compound of copper(II) with 3-methyl-5-carboxylatopyrazole (CH₃PzCOO^?) with the composition Cu(CH₃PzCOO)₂·H₂O have been determined by single crystal XRD. It has been demonstrated that the carboxylate ion performs the bridging tridentate function. In the equatorial plane coordination occurs through the pyridine N atom of the pyrazole and one of O atoms of the carboxylate group yielding a five-membered metallocycle CuNOC₂. The second O atom of one of the ligands is bound to the neighboring copper(II) ion affording an infinite linear chain. The coordination polyhedron of the copper atom is a square pyramid, coordination core CuN₂O₃.     

Crystal and Molecular Structure of Nitramino Derivatives of Tetrazole and 1,2,4-Triazole. II. 5-Nitraminotetrazole Diammonium Salt

The structure of the diammonium salt of 5-nitraminotetrazole wasestablished bysinglecrystalX-ray diffraction. The crystals are monoclinic, space group P2/c; a=7.272(1), b=8.643(1), c=10.427(1) ; =93.20(1)°; V=654.33(39) ³; Z=4;_calc=1.666 g/cm³. The dianion is nonplanar, but contains two practically planar fragments -- the tetrazole cycle and the nitramine group. The ammonium cations form an extended net of hydrogen bonds with the dianions, involving all hydrogen atoms. The negative charges of the dianion are located on the nitro oxygen atoms and the nitrogens of the tetrazole cycle. The difference between the geometrical parameters of the compound and those of other 5-nitraminotetrazole salts is examined.     

Crystal and molecular structure of two new Schiff bases: Paeonol-ethylenediamine and paeonol-1,3-propylenediamine

Two new Schiff bases were prepared by the condensation reaction of paeonol with ethylenediamine (for compound 1) and 1,3-propylenediamine (for compound 2). The compounds were studied with single crystal X-ray diffraction method. Compound 1 is monoclinic, space group P2₁/c, a = 10.956(15) Å, b = 6.767(10) Å, c = 12.494(18) Å; β = 104.66(2)°, V = 896(2) ų, Z = 2. Compound 2 is triclinic, space group P-1, a = 6.878(2) Å, b = 12.141(4) Å, c = 12.414(4) Å; α = 101.023(6)°, β = 103.415(6)°, γ = 102.337(6)°, V = 952.8(6) ų, Z = 2. The molecular structures of 1 and 2 are similar; the molecule being centrosymmetric in 1 but asymmetric in 2.     

Crystal and Molecular Structure of the Nitramino Derivatives of Tetrazole and 1,2,4-Triazole. III. 5-Nitraminotetrazole Lithium Salt Monohydrate

The structure of 5-nitraminotetrazole lithium salt monohydrate was determined by X-ray diffraction analysis. Crystals are monoclinic, space group P2₁/c; a = 8.3789(5), b = 10.1872(6), c = 6.6709(5) ; = 106.63(1)°; V = 545.60(98) ³; Z = 4; _calc = 1.875 g/cm³. The anion has a planar nitrimine structure with a delocalized negative charge. Each lithium cation (c.n. 5) is bound to three anions and two hydration water molecules. Both oxygen atoms of the nitro groups and the N(3) atom of the tetrazole ring are involved in cation coordination. The geometrical characteristics of the anion are similar to those found for other monosalts of 5-nitraminotetrazole.     

Crystal and molecular structure of 1:1 molecular complexes of triphenyl-N-(4-methylpyridyl-2)phosphinimine and triphenyl-N-(3-methylpyridyl-2)phosphinimine with perchloric acid

X-ray diffraction analysis has been used to determine the crystal structures of the 1:1-composition products of protonation by perchloric acid of isomeric triphenyl-N-(4-methylpyridyl-2)phosphinimine (1) and triphenyl-N-(3-methylpyridyl-2)phosphinimine (2). The structures were refined toR=0.048 andR=0.052, respectively, using 2274 (1) and 2647 (2) reflections. The protonation centers are located at the sites of N atoms of the pyridine ring (1) and the phosphinimino group (2). The distribution of the bond lengths in the cations suggests that a significant contribution is made by a phosphonic structure with positive charges localized on the P atoms. N-H...O hydrogen bonds, with lengths of 2.890(4) and 3.020(3) Å, connect cations and anions in both structures.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 629–635, March, 1992.     

Crystal and molecular structure of 2-chloro-1-methyl-4-phenyl-α-carboline hydrochloride

A compound with the composition C₁₈H₁₆Cl₂ON₂ was subjected to an x-ray diffraction study. All of the rings in themolecule are planar. Both of the six-membered rings of the carboline system are inclined slightly and identically with respect to the central pyrrole ring, forming angles of 3 ° with it and 6 ° with one another. The phenyl ring is turned at an angle of 52.7 ° relative to the average plane of the carboline system.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp, 779–782, June, 1984.     

Crystal and molecular structure of N,N,N′,N′-tetra(2-nitrilethyl) ethane-1,2-diamine and N-(2-nitrilethyl)benzylamine hydrobromide

N,N,N′,N′-tetra(2-nitrilethyl) ethane-1,2-diamine and N-(2-nitrilethyl)benzylamine hydrobromide were prepared by the addition reaction of acrylonitrile with corresponding amines, and the two structures were determined by X-ray single crystal diffraction. The two compounds crystallize in monoclinic system, and almost no classical hydrogen bond exists in the two crystal structures.     

Synthesis and molecular structure of 6-aryl-3-ethoxycarbonyl-4-hydroxypyridazines

EthylZ-5-aryl-2-diazo-5-hydroxy-3-oxopent-4-enoates interact with triphenylphosphine to give 6-aryl-3-ethoxycarbonyl-4-hydroxypyridazines (Ar=Ph, 4-MeC₆H₄, 4-ClC₆H₄). Quantum-chemical calculations (MNDO) were performed to estimate the tautomeric equilibrium in the latter using a 6-phenyl-substituted derivative as an example. Acetylation of the 4-hydroxypyridazines led to 4-acetoxy-6-aryl-3-ethoxycarbonylpyridazines. The structure of the latter was confirmed by an X-ray diffraction analysis of 4-acetoxy-3-ethoxycarbonyl-6-(p-tolyl)pyridazine. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2260–2263, December, 1997.