X-ray diffraction and spectral study of products of reaction between 2,7-dinitro and 2,4,7-trinitrophenanthrenequinone and nitromethane

The molecular and crystalline structures of three products of the reaction between 2,7-dinitro- and 2,4,7-trinitrophenanthrenequinone with nitromethane in an HMPTA solution were studied by x-ray diffraction. Two of these products are H-bonded 1:1 solvates.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Patrice Lumumba People's Friendship University, 117198 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1575–1584, July, 1992.     

Syntheses,structures, and properties of four coordination polymers based on 2,7-di(pyridin-4-yl)-9H-fluoren-9-one

Four coordination polymers (CPs), [Cd(2,7-dpfo)₂(NO₃)₂(CH₃OH)]_n (1) , [Zn(2,7-dpfo)(NO₃)(CH₃COO)]_n (2) , [Co(2,7-dpfo)₂(H₂L)]_n (3) , and [Ni(2,7-dpfo)₂(H₂L)]_n (4) (where 2,7-dpfo is 2,7-di(pyridin-4-yl)-9H-fluoren-9-one and H₄L is 1,1′:4′,1′′-terphenyl-4,2′,5′,4′′-tetracarboxylic acid), were synthesized and structurally characterized. Compounds 1 – 4 were determined by elemental analyses, single crystal X-ray diffraction analyses, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analyses. Compound 1 displays a one-dimensional (1D) zigzag chain structure, while compound 2 possesses a 1D ladder chain structure. Compounds 3 and 4 are isostructural and consist of 1D chains. The solid-state luminescent properties of 1 and 2 and the magnetic properties of 3 and 4 were also investigated.     

A study of the reaction of Se(IV) with 3,4-diaminobenzoic acid and 4-bromo-1, 2-phenylenediamine

The condensation reactions of Se(IV) with 3,4-diaminobenzoic acid and 4-bromo-1,2-phenylenediamine have been studied by means of UV spectra and kinetic investigations. A mechanism for the formation of 2,1,3-benzoselenadiazole in acidic medium is proposed. The influence of substitution at C(4) in 1,2-phenylenediamine on the reactivity of the system is discussed.     

Hydrogen bond in 3-acetyl-4-hydroxycoumarin: X-ray diffraction study and quantum-chemical calculations

The proton transfer and the character of the strong intramolecular O--H...O hydrogen bond (O...O 2.442 ) in 3-acetyl-4-hydroxycoumarin were analyzed based on the results of X-ray diffraction study in the temperature range from 100 to 353 K and quantum-chemical B3LYP/6-31G(d,p) calculations. The barrier to proton transfer along the H-bond line is low (2 kcal mol^–1). However, no proton transfer was observed in the crystal at 100 K. Bader's topological analysis of the electron density distribution both in the crystal and in the isolated molecule demonstrated that the hydrogen bond corresponds to an intermediate type of interatomic interactions (E(r) < 0, ²(r) > 0 at the critical point (3, –1)).     

Vibrational assignment, structure and intramolecular hydrogen bond of 4-methylamino-3-penten-2-one

The molecular structure, intramolecular hydrogen and vibrational frequencies of 4-methylamino-3-penten-2-one were investigated by a series of density functional theoretical (DFT) calculations and ab initio calculation at the post-Hartree-Fock (MP2) level. Fourier transform infrared and Fourier transform Raman spectra of this compound and its deuterated analogue were clearly assigned. The calculated geometrical parameters show a strong intramolecular hydrogen bond with a N...O distance of 2.622-2.670 A. This bond length is about 0.02 A shorter than that in its parent, 4-amino-3- penten-2-one which is in agreement with spectroscopic results. Furthermore, the conformations of methyl groups with respect to the plane of the molecule and with respect to each other were investigated.     

Two Directions of the Reaction of 4-Bromobenzaldehyde with Substituted Acetophenones and Urea. Synthesis of Aryl-substituted Pyrimidin-2-one and Hexahydropyrimido[4,5-d]pyrimidin-2,7-dione

Condensation of 4-bromobenzaldehyde, urea, and 4-alkyl-substituted acetophenones gave substituted hexahydro-1H,8H-pyrimido[4,5-d]pyrimidin-2,7-diones or 1H-pyrimidin-2-ones, depending on the substituent on the acetophenone ring and the nature of the solvent (i-PrOH, BuOH, AcOH). The corresponding 5-bromopyrimidin-2-ones were formed on bromination of these compounds. The structures of these compounds were confirmed by IR, UV, and ¹H NMR spectroscopy.     

Reaction of Ru3(CO)12 with 1,3-diferrocenylprop-2-ene-1-one. Crystal and molecular structures of the complexes Ru3(CO)8(FcC=CHCOFc)2 and [Ru(CO)2Cl(FcC=CHCOFc)]2

The reaction of Ru₃(CO)₁₂ with 1,3-diferrocenylprop-2-en-1-one,trans-FcCH=CHCOFc (where Fc is ferrocenyl), in boiling hexane afforded the complex (2c), which was converted into (3c) upon further heating. These complexes gave the complex (4) containing two Cl-bridged oxaruthenacycles upon dissolution in CHCl₃ or CH₂Cl₂. The structures of complexes 3 and 4 were established by X-ray diffraction analysis. According to the data of¹H NMR spectroscopy, the Cl-bridged complex exists in solutions as a mixture of isomers along with the monomeric form resulting from the cleavage of the halide bridges. All interconversions of the isomers occur with the participation of the monomeric form. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1616–1623, September, 2000.     

Structure of 1:1 and 1:2 complexes formed by aromatic NH and OH proton donors with aliphatic amines. Possibility of homoconjugated NHN cation formation

Structure of the complexes with NHN hydrogen bond formed by bis(2,3,5,6-tetrafluoro-4-trifluoromethyl-phenyl)-amine ((4-CF₃C₆F₄)₂NH, FA) as proton donor with aliphatic amines (dibutyl-, tributyl- and trimethylamines) as proton acceptors in aprotic solvents (isooctane and methylene chloride) in a wide range of concentrations and temperatures have been studied by IR and UV spectra. Quantitative treatment of the spectra by a computer program based on factor analysis reveals the equilibrium between free molecules and FA–aliphatic amine complexes of 1:1 and 1:2 composition, the latter having an ionic structure with proton transferred from FA to the aliphatic amine. Thermodynamic characteristics of the 1:1 and 1:2 complexes for FA+dibutylamine system have been measured. Appearance of IR bands indicating formation of NHN⁺ homoconjugated cation has been detected in FA+trimethylamine solution in methylene chloride at temperatures 190–150 K. Spectral manifestations of the complexes containing the (trimethylamine-H-trimethylamine)⁺ cation, formed by FA and OH proton donor (pentachlorophenol) are compared.     

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- （naphthalen- 1-yl）- 1-tosyl- 1H-pyrrol-2（5H）- one

The title compound 4-bromo-5-ethoxy-3-methyl-5-(naphthalen-1-yl)-1-tosyl-1H- pyrrol-2(5H)-one 1 (C24H22BrNO4S, Mr = 500.40) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562(15), b = 18.118(3), c = 14.055(2) , β = 99.855(3)o, V = 2221.9(6) 3, Z = 4, Dc = 1.496 g/cm3, μ = 1.975 mm-1, λ = 0.71073 , F(000) = 1024, R = 0.0607 and wR = 0.1371.     

On the structural and spectroscopic properties of the thienyl chalcone derivative: 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one

In this study, we investigate the structural and spectroscopic properties of the thienyl chalcone derivative 3-(5-Bromo-2-thienyl)-1-(4-nitrophenyl)-prop-2-en-1-one, C₁₃H₈BrNO₃S, using nuclear magnetic resonance (¹H and ¹³C NMR), UV–vis and Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy at room conditions combined with density functional theory (DFT) and time-dependent DFT (TD-DFT) augmented with B3LYP/6-311G(d,p) and CAM-B3LYP/6-311G(d,p) basis sets, yielding valuable information on the molecular conformational preferences, vibrational assignments, optical properties and electronic transitions. The vibrational mode assignments of the most stable conformer of C₁₃H₈BrNO₃S are discussed based on potential energy distribution (PED) analysis and establishing a comparison with a similar chemical structure. The temperature dependence on the Raman spectra of the C₁₃H₈BrNO₃S shows a reversible phase transition in the range 443–443 K pointed out by the discontinuity in the dω/dT of bands in the external and internal modes region. The UV–vis spectrum of the C₁₃H₈BrNO₃S indicates a semiconductor behavior with an optical band gap of 2.6 eV, corresponding to the predicted value of 3.42 eV assigned as the electronic transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). TD-DFT calculations reveal that the electron donor and acceptor group substitution on the 1-phenyl-3-(thiophen-2-yl)prop-2-en-1-one affects its absorption and nonlinear activity.     

Synthesis, Structure and Spectroscopy of Clathrate Inclusion Compounds of Cobalt(II), Cadmium(II) and Zinc(II) trans-4-styrylpyridine nitrates as Host with trans-4-styrylpyridine as Guest (2 : 1)

New clathrate inclusion compounds with the general formula,MA₃X₂ 1/2G (M = Co(II)(1),Cd(II)(2), and Zn(II)(3), X = NO₃ ^- andA and G = trans-4-styrylpyridine), differing from the usualWerner clathrates, MA₄X₂ 2G, have been prepared and characterized by elemental and thermal analyses,IR and electronic spectroscopy and X-ray crystallography. Tworepresentative compounds [Co(stpy)₃(NO₃)₂] 1/2stpy (1) and [Cd(stpy)₃(NO₃)₂] 1/2 stpy (2)are investigated by single crystal X-ray diffraction. Compound (1)crystallizes in the triclinic space group P¯1 with a = 10.966(2),b = 12.802(4), c = 16.063(5) Å = 83.38(3), = 71.30(2), = 76.88(3) °,Z = 2. The structure is made up of discretemolecules of [Co(stpy)₃(NO₃)₂]. The central Co(II) issurrounded by three stpy nitrogen atoms and four oxygen atoms of twoasymmetrically coordinated bidentate nitrate ligands. One of the oxygensis semicoordinated leading to a distorted octahedral geometry for Co(II).Compound (2) crystallizes in the monoclinic space group P2₁/nwith a = 15.597(3), b = 18.313(5), c = 16.188(3) Å = 115.998(14)° and Z = 4. The structure consists of neutralmolecules of [Cd(stpy)₃(NO₃)₂]. The geometry aroundCd(II) is best described as pentagonal bipyramid with four oxygen atomsfrom symmetrical bidentate nitrate groups and one stpy nitrogen atom inthe equatorial positions. Two other nitrogen atoms from stpy ligands occupythe axial positions. The guest stpy molecules are trapped in the centrosymmetricalcavities in lattices of both 1 and 2. Compound 3is found to beisomorphous with 2. A large splitting of the symmetric and asymmetricNO₂ stretching vibrations reveals the presence of bidentate nitrate ligands.Thermogravimetric and DTA studies on the Cd(II) compound, show it to be athermally stable inclusion compound.     

Structures and properties of (H2GaN3)n (n = 1–4) clusters: A DFT study

Computations on the systems of (H₂GaN₃)_n (n = 1–4) are performed using the density functional theory (DFT)/B3LYP method with different basis sets. (H₂GaN₃)₂ possessing D_2h symmetry is found to exhibit the planar Ga₂N₂ ring structure. (H₂GaN₃)₃ involving a six‐membered Ga₃N₃ ring is found to exhibit two minima with very similar binding energies (ca. −235 ∼ −231 kJ · mol⁻¹). One minimum is the newly found boat‐like conformation possessing C_s symmetry. Another minimum possessing C_3v symmetry is the chair‐like conformation. (H₂GaN₃)₄ occurs in several structures with Ga₄N₄ eight‐membered ring structures that correspond to minima with slight energy differences among them. The structural changes of the clusters are large compared with the monomer. Frequency calculations are carried out on each optimized structure, and their infrared (IR) spectra are discussed. Thermodynamic properties demonstrate that the systems of H₂GaN₃ occur at dimer–trimer–tetramer equilibrium, and the trimer is the main component. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

Synthesis of 5H-thiazolo[3,2-a]pyrimidine derivatives from 6-methyl-2-thiouracil and 1-acyl-2-bromoacetylenes. X-ray structural study of 3-benzoyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one

3-Acyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-ones were synthesized by the reaction of 1-acyl-2-bromoacetylenes with 6-methyl-2-thiouracil, carried out with heating in DMF, dioxane, or acetonitrile in the presence of triethylamine. The structure of 3-benzoyl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one was established by X-ray structural analysis.Deceased in 1995.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2306–2308, September, 1996.     

Small-ring inclusion hosts. 4. X-ray crystal structures oftrans-3,3-Bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid and of its inclusion complex with Dimethyl Sulphoxide (1:2)

The crystal structures of the unsolvatedtrans-3,3-bis(4-methylphenyl)cyclopropane-1,2-dicarboxylic acid (1) and of its inclusion compound with dimethyl sulphoxide,1·DMSO (1:2), have been studied by X-ray diffraction. Crystals of1 show triclinic symmetry (P ) withZ = 4 and the unit cell dimensionsa = 7.617(2),b = 15.321(4),c = 15.297(3) Å, = 109.76(2), = 103.47(1), = 89.87(2)°. FinalR = 0.037 for 3601 reflections collected atT = 153(1) K. Crystals of1·DMSO (1: 2) are monoclinic (P2₁/n) withZ = 4 and cell dimensionsa = 10.744(1),b = 10.806(1),c = 21.302(2) Å, = 101.68(1)°. The clathrate structure was refined toR = 0.034 for 1671 reflections obtained atT = 173(1) K. In the unsolvated host compound cyclic pairs of O-H ... bonds, commonly observed in carboxylic acids, couple the carboxylic functions two by two, thus giving rise to endless chains due to the bifunctionality and thetrans position of the acid groups of1. The complex with DMSO as guest, however, consists of distinct hydrogen-bonded 1:2 host-guest associates, held together by weak intermolecular interactions.Supplementary Data relating to this article have been deposited with the British Library at Boston Spa, Wetherby, West Yorkshire, U.K., as Supplementary Publication No. SUP 82139 (32 pages).For Part 3, see Reference [1].     

Reaction of perfluoro-2-methylpent-2-en-3-yl isothiocyanate with ethyl and isopropyl alcohols

Perfluoro-2-methylpent-2-en-3-yl isothiocyanate reacts with ethyl or isopropyl alcohols in the presence of NEt₃ to give derivatives of 4,5-dihydrothiazole and ethoxy(ethylthio)methylene-(1,1,1,4,4,5,5,5-octafluoro-2-trifluoromethylpent-2-en-3-yl)amine and isopropoxy(isopropylthio)methylene-(1,1,1,4,4,5,5,5-octafluoro-2-trifluoromethylpent-2-en-3-yl)amine, respectively. Heating of ethyl or isopropylN-(perfluoro-2-methyl-2H-pentylidene-3-amino)thiocarbamate with potassium carbonate in DMF yields the same products plus 3-tetrafluoroethylidene-5,5-bis(trifluoromethyl)thiazolidin-2-one. The structure of the latter was confirmed by X-ray diffraction analysis. The IR spectroscopy data for this compound in solution (CCl₄) and in the solid state (KBr) suggest the formation of the intermolecular NH...O=C hydrogen bond between the NH group and the oxygen atom of the heterocycle. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2021–2026, October, 1998.     

Synthesis of imidazolidin-4-one and 1H-imidazo[2,1-a]isoindole-2,5(3H,9bH)-dione derivatives of primaquine: scope and limitations

The synthesis of imidazolidin-4-one derivatives of primaquine as potential antimalarial agents is described. The target compounds were synthesized in three steps: (i) condensation of (±)-primaquine with N^α-protected amino acids, (ii) removal of the N^α-protecting group, and (iii) reaction of the N-acylprimaquine with a carbonyl compound: acetone, three cyclic ketones and veratraldehyde. Using 2-formylbenzoic acid in the third step afforded 1H-imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones. All products were isolated in good to excellent yields. Whereas imidazolidin-4-ones were formed as mixtures of all possible diastereomers in equal amounts, 1H-imidazo[2,1-a]isoindole-2,5(3H,9bH)-diones were produced in a stereoselective fashion. The compounds hydrolyse very slowly (t_1/2 5-30 d) in pH 7.4 buffer to release primaquine. These primaquine derivatives are being submitted to biological assays, and preliminary results of their antimalarial activity are quite encouraging.     

Effect of p-tert-butylcalix[4]arene fitted with phosphinoyl pendant arms as synergistic agent in the solvent extraction of trivalent lanthanoids with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione and structural study of solid complexes by IR,NMR and X-ray

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [LnL₃S₂]. The values of the equilibrium constants and the separation factor have been calculated. The influence of the synergistic agent on the extraction process has been discussed.     

Synthesis and structural study of a new NASICON-type solid solution: Li1−xLax/3Zr2(PO4)3

A new complete solid solution of NASICON-type compounds between LiZr₂(PO₄)₃ and La_1/3Zr₂(PO₄)₃ was evidenced with the general formula Li_1−xLa_x/3Zr₂(PO₄)₃ (0?x?1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li⁺→1/3La³⁺+2/3□ leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li_1−xLa_x/3□_2x/3Zr₂(PO₄)₃ (0?x?1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0?x?0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3¯c), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1¯), as observed for LiZr₂(PO₄)₃ prepared above 1100 °C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6?x?0.9, the compounds crystallize in a rhombohedral cell (s.g. R3¯), while for x=1, the phase La_1/3Zr₂(PO₄)₃ is obtained (s.g. P3¯, Z=6, a=8.7378(2) Å, c=23.2156(7) Å).This paper is devoted to the structure analysis of the series Li_1−xLa_x/3Zr₂(PO₄)₃ (0?x?1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies.