Reaction-path calculations and crystal structures of 1,1′-(ethylene-1,2-diyl)dipyridinium dichloride dihydrate and 1,1′-(ethylene-1,2-diyl)dipyridinium dibromide

2016 ◽  
Vol 72 (2) ◽  
pp. 112-118
Author(s):  
Mwaffak Rukiah ◽  
Mahmoud M. Al-Ktaifani ◽  
Mohammad K. Sabra

The design of new organic–inorganic hybrid ionic materials is of interest for various applications, particularly in the areas of crystal engineering, supramolecular chemistry and materials science. The monohalogenated intermediates 1-(2-chloroethyl)pyridinium chloride, C5H5NCH2CH2Cl+·Cl−, (I′), and 1-(2-bromoethyl)pyridinium bromide, C5H5NCH2CH2Br+·Br−, (II′), and the ionic disubstituted products 1,1′-(ethylene-1,2-diyl)dipyridinium dichloride dihydrate, C12H14N22+·2Cl−·2H2O, (I), and 1,1′-(ethylene-1,2-diyl)dipyridinium dibromide, C12H14N22+·2Br−, (II), have been isolated as powders from the reactions of pyridine with the appropriate 1,2-dihaloethanes. The monohalogenated intermediates (I′) and (II′) were characterized by multinuclear NMR spectroscopy, while (I) and (II) were structurally characterized using powder X-ray diffraction. Both (I) and (II) crystallize with half the empirical formula in the asymmetric unit in the triclinic space groupP\overline{1}. The organic 1,1′-(ethylene-1,2-diyl)dipyridinium dications, which display approximateC2hsymmetry in both structures, are situated on inversion centres. The components in (I) are linkedviaintermolecular O—H...Cl, C—H...Cl and C—H...O hydrogen bonds into a three-dimensional framework, while for (II), they are connectedviaweak intermolecular C—H...Br hydrogen bonds into one-dimensional chains in the [110] direction. The nucleophilic substitution reactions of 1,2-dichloroethane and 1,2-dibromoethane with pyridine have been investigated byab initioquantum chemical calculations using the 6–31G** basis. In both cases, the reactions occur in two exothermic stages involving consecutive SN2 nucleophilic substitutions. The isolation of the monosubstituted intermediate in each case is strong evidence that the second step is not fast relative to the first.

2008 ◽  
Vol 63 (2) ◽  
pp. 134-138 ◽  
Author(s):  
Fatih Yilmaz ◽  
Veysel T. Yilmaz ◽  
Haydar Karakaya ◽  
Orhan Büyükgüngör

Two silver 5,5-diethylbarbiturate (barb) complexes with 2,2'-bipyridine (bpy) and 3-(2-pyridyl) propanol (pypr), [Ag(barb)(bpy)] (1) and [Ag(barb)(pypr)] (2), have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single crystal X-ray diffraction. Both complexes crystallize in the triclinic space group P1 with Z = 2. The barb ligand in 1 is N-coordinated and the bpy ligand acts as a bichelating ligand leading to an AgN3 tricoordination. Crystals of 1 feature a three-dimensional network based on N-H···O hydrogen bonding, π(bpy)···π(bpy), C-H···π(bpy) and π(bpy)-Ag interactions. In 2, the pypr and barb ligands behave as monodentate ligands through their N atoms, forming a distorted linear AgN2 coordination. Molecules of 2 are doubly bridged by N-H···O hydrogen bonds and further connected via O-H···O hydrogen bonds and aromatic π(pypr)···π(pypr) stacking interactions into a supramolecular network. Both complexes exhibit similar thermal decomposition behavior in air. The first stage corresponds to removal of the co-ligands such as bpy or pypr while the degradation of the barb moiety occurs at higher temperatures to give Ag2O. Like the barb, bpy and pypr ligands, 2 does not show any significant antimicrobial activity, but 1 is active against bacteria and fungi


2018 ◽  
Vol 74 (2) ◽  
pp. 240-247 ◽  
Author(s):  
Nassima Bendjellal ◽  
Chahrazed Trifa ◽  
Sofiane Bouacida ◽  
Chaouki Boudaren ◽  
Mhamed Boudraa ◽  
...  

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. The diverse coordination modes of N-donor ligands have been employed to assemble metal–organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds; they are thus good candidates for the construction of supramolecular architectures. We synthesized under reflux or hydrothermal conditions two new alkaline earth(II) complexes, namely poly[(1,10-phenanthroline-κ2N,N′)bis(μ-3-phenylprop-2-enoato-κ3O,O′:O)calcium(II)], [Ca(C10H7O2)2(C10H8N2)]n, (1), and poly[(1,10-phenanthroline-κ2N,N′)(μ3-3-phenylprop-2-enoato-κ4O:O,O′:O′)(μ-3-phenylprop-2-enoato-κ3O,O′:O)barium(II)], [Ba(C10H7O2)2(C10H8N2)]n, (2), and characterized them by FT–IR and UV–Vis spectroscopies, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction analysis, as well as by powder X-ray diffraction (PXRD) analysis. Complex (1) features a chain topology of type 2,4 C4, where the Ca atoms are connected by O and N atoms, forming a distorted bicapped trigonal prismatic geometry. Complex (2) displays chains of topology type 2,3,5 C4, where the Ba atom is nine-coordinated by seven O atoms of bridging/chelating carboxylate groups from two cinnamate ligands and by two N atoms from one phenanthroline ligand, forming a distorted tricapped prismatic arrangement. Weak C—H...O hydrogen bonds and π–π stacking interactions between phenanthroline ligands are responsible to the formation of a supramolecular three-dimensional network. The thermal decompositions of (1) and (2) in the temperature range 297–1173 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.


2019 ◽  
Vol 75 (3) ◽  
pp. 277-282 ◽  
Author(s):  
Xi Liu ◽  
Bo Fu ◽  
Lin Li ◽  
Yun-Fei Jian ◽  
Si Shu

The assembly of metal–organic frameworks (MOFs) with metal ions and organic ligands is currently attracting considerable attention in crystal engineering and materials science due to their intriguing architectures and potential applications. A new three-dimensional MOF, namely poly[[diaqua(μ8-para-terphenyl-3,3′,5,5′-tetracarboxylato)dizinc(II)] dimethylformamide disolvate monohydrate], {[Zn2(C22H10O8)(H2O)2]·2C3H7NO·H2O} n , was synthesized by the self-assembly of Zn(NO3)2·6H2O and para-terphenyl-3,3′,5,5′-tetracarboxylic acid (H4TPTC) under solvothermal conditions. The compound was structurally characterized by FT–IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analysis. Each ZnII ion is located in a square-pyramidal geometry and is coordinated by four carboxylate O atoms from four different TPTC4− ligands. Pairs of adjacent equivalent ZnII ions are bridged by four carboxylate groups, forming [Zn2(O2CR)4] (R = terphenyl) paddle-wheel units. One aqua ligand binds to each ZnII centre along the paddle-wheel axis. Each [Zn2(O2CR)4] paddle wheel is further linked to four terphenyl connectors to give a three-dimensional framework with NBO-type topology. The thermal stability and solid-state photoluminescence properties of the title compound have also been investigated.


2006 ◽  
Vol 61 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Veysel T. Yilmaz ◽  
Sevim Hamamci ◽  
Orhan Büyükgüngör

AbstractTwo new silver(I) saccharinate (sac) complexes, [Ag(sac)(pz)(H2O)]n (1) and [Ag(sac)(im)]·2H2O (2) (pz = pyrazole and im = imidazole), have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̅, respectively. The sac, pz and im ligands all are N-coordinated. In 1, the [Ag(sac)(pz)] units are bridged by aqua ligands to generate a one-dimensional helical chain, in which the silver(I) ions exhibit a distorted square-planar AgN2O2 coordination geometry. The polymeric chains are connected by N-H· · ·O hydrogen bonds into sheets, which are further linked by aromatic π(pz) · · ·π(sac) stacking interactions into a three-dimensional supramolecular network. Complex 2 consists of individual molecules containing linearly coordinated silver(I) ions with a slightly distorted coordination of AgN2. The molecules interact with each other through hydrogen bonds and π· · ·π interactions to form a three-dimensional supramolecular network.


Author(s):  
Monsumi Gogoi ◽  
Birinchi Kumar Das

A nickel(II) terephthalate complex, viz. [Ni(C6H4N2)2(H2O)4](O2CC6H4CO2)·4H2O, has been synthesized and studied by single-crystal X-ray diffraction. It crystallizes in the triclinic space group P\overline{1}. The crystal structure shows an approximately octahedral coordination environment of the complex with the [Ni(H2O)4(3-NCpy)2]2+ (3-NCpy is pyridine-3-carbonitrile) cation associated with four free water molecules and hydrogen bonded to a terephthalate dianion [graph set R 2 2(8)]. The supramolecular structure of the compound is stabilized by a three-dimensional array of O—H...O and O—H...N hydrogen bonds, along with π–π stacked pyridine-3-carbonitrile rings and C—H...O interactions.


2017 ◽  
Vol 73 (8) ◽  
pp. 1208-1212
Author(s):  
Anatoliy S. Burlov ◽  
Valery G. Vlasenko ◽  
Pavel V. Dorovatovskii ◽  
Yan V. Zubavichus ◽  
Victor N. Khrustalev

The title compound, [Zn(C20H15N4O)2]·2.5CH3OH, I, was synthesized via the reaction of zinc acetate with the respective ligand and isolated as a methanol solvate, i.e., as I·2.5CH3OH. The crystal structure is triclinic (space group P-1), with two complex molecules ( A and B ) and five methanol solvent molecules in the asymmetric unit. One of the five methanol solvent molecules is disordered over two sets of sites, with an occupancy ratio of 0.75:0.25. Molecules A and B are conformers and distinguished by the conformations of the bidentate 1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl]-1H-pyrazol-5-olate ligands. In both molecules, the zinc cations have distorted tetrahedral coordination spheres, binding the monoanionic ligands through the pyrazololate O and imine N atoms. The two ligands adopt slightly different conformations in terms of the orientation of the terminal phenyl and quinoline substituents with respect to the central pyrazololate moiety. The molecular geometries of A and B are supported by intramolecular C—H...O and C—H...N hydrogen bonds. In the crystal of I, molecules form dimers both by secondary intermolecular Zn...O [3.140 (2)–3.553 (3) Å] and π–π stacking interactions. The dimers are linked by intermolecular hydrogen bonds through the solvent methanol molecules into a three-dimensional network.


IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Palash Sanphui ◽  
Geetha Bolla ◽  
Ashwini Nangia ◽  
Vladimir Chernyshev

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR),p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.


2005 ◽  
Vol 60 (9) ◽  
pp. 978-983 ◽  
Author(s):  
Sevim Hamamci ◽  
Veysel T. Yilmaz ◽  
William T. A. Harrison

Two new saccharinato-silver(I) (sac) complexes, [Ag(sac)(ampy)] (1), and [Ag2(sac)2(μ-aepy)2] (2), [ampy = 2-(aminomethyl)pyridine, aepy = 2-(2-aminoethyl)pyridine], have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̄, respectively. The silver(I) ions in both complexes 1 and 2 exhibit a distorted T-shaped AgN3 coordination geometry. 1 consists of individual molecules connected into chains by N-H···O hydrogen bonds. There are two crystallographically distinct dimers in the unit cell of 2 and in each dimer, the aepy ligands act as a bridge between two silver(I) centers, resulting in short argentophilic contacts [Ag1···Ag1 = 3.0199(4) Å and Ag2···Ag2 = 2.9894(4) Å ]. Symmetry equivalent dimers of 2 are connected by N-H···O hydrogen bonds into chains, which are further linked by aromatic π(py)···π(py) stacking interactions into sheets.


2000 ◽  
Vol 55 (3-4) ◽  
pp. 299-316 ◽  
Author(s):  
Dagmar Henschel ◽  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones

Abstract In a study aim ed at the „deconstruction“ of the supramolecular aggregate 3(18C6) · 2HN( SO2Me)2 (1,18C6 = 18-crown-6), which is known to display a ladder structure with two isotactic [18C6 - Me SO2N(H)SO2Me···)∞ polymers forming the uprights and symmetrically N - H···O bonded 18C6 rings providing the rungs, the following crystalline complexes were isolated and (except for 2b) characterized by low-temperature X-ray diffraction: 18C6-ClN (SO2Me)2 (2a, triclinic, space group P1̅, Z = 2), 18C6-PhN (SO2Me)2 (2b), 18C6 -MeN(SO2Me)2 (3, monoclinic, P21/c, Z = 8), Bz18C6-HN(SO2Me)2 (4, Bz18C6 = benzo-18-crown-6, monoclinic, P21/n, Z = 4), 18C6-2 MeN (SO2Me)2 (5, triclinic, P1̅, Z = 1), 18C6-Me2SO- HN( SO2Me) (SO2Ph) (13, triclinic, P1̅, Z = 2), and 18C6-H2OMe2SO·2HN(SO2Me)2 (14, triclinic, P1̅, Z = 2). Each of the one-dimensional polymers 2a (syndiotactic), 3 (disyndiotactic) and 4 (isotactic) mimics a single upright of 1; in contrast to 1 and 2a, where the intra-catemer connectivity solely relies on S - Me ··· crow n and crown ··· O = S hydrogen bonds, this bonding system is reinforced in 3 by N -Me ··· crown and in 4 by N - H ··· crown hydrogen bonds. Complex 5 is monomeric and matches a fragment formally extruded from the catemer 3; moreover, 3 and 5 represent a rare case of two structurally characterized 18C6 complexes containing the same uncharged guest species in distinct molecular ratios. The surprising structure of the quaternary adduct 14 exhibits an [18C6 ··· MeSO2N(H)SO2Me ··· ]∞ chain, which can be regarded both as an isolated, though unmodified upright from the ladder 1 and, being syndiotactic, as a stereochemical analogue of 2a; the potentially rung-forming *NH functions in the chain are blocked by hydrogenbonded side chains of the type * N - H ··· water ··· sulfoxide ··· H - N (SO2Me)2. The ternary complex 13 consists of chains [18C6 ··· Me2SO ··· H - N (SO2Ph)SO2Me···]∞ and is not closely related to the other structures


2004 ◽  
Vol 19 (2) ◽  
pp. 197-197
Author(s):  
L. Margulies ◽  
S. Schmidt ◽  
E. M. Lauridsen ◽  
H. F. Poulsen ◽  
D. Juul Jensen ◽  
...  

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