Comparative study of two oxalate isomers with different dimensionalities

2014 ◽  
Vol 70 (a1) ◽  
pp. C656-C656
Author(s):  
Hamza Kherfi ◽  
Malika Hamadène ◽  
Achoura Guehria-Laidoudi ◽  
Slimane Dahaoui ◽  
Claude Lecomte

We report here two bimetallic oxalate isomers with the same chemical formula [RbCr(C2O4)2(H2O)2], which have been synthesized respectively by a slow evaporation method at room temperature (compound I) [1], and under hydrothermal conditions (compound II) [2] with the same starting salts. Their structures show a several discrepancies, due probably to the synthetic conditions. Indeed, the compound I crystallizes in space group C2/m with the Cr, Rb atoms and one oxygen from water molecule lying on special positions. Moreover, the unique oxalate ligand forms a bridge between metal centers. The Cr atom is coordinated to 2 bidentate-chelating oxalates and 2 aqua ligands in a trans-conformation and any water molecule has been found around the 8-coordinated Rb atom, leading to a layered structure consists of alternating Rb and Cr polyhedra connected via the unique organic ligand. Whereas, the compound II crystallizes in space group P21/n, with all atoms located on general positions. Furthermore, two independent oxalato ligands exhibit different configurations, which one is pentadentate and the other is hexadentate with two different chelating modes. The very slightly distorted Cr octahedra consists of 2 bidentate-chelating oxalato ligands and 2 water molecules in a cis-conformation, while the alkali metal is surrounded by seven O atoms from oxalate groups, completed with two H2O molecules which are bridging the Cr and Rb polyhedra by one common edge. This results in the formation of three different chains of alternating edge- and vertex-shared polyhedra through oxalates groups and aqua ligands, running along the three space directions to build a three dimensional framework. These two compounds can be considered as supramolecular isomers [3].

2013 ◽  
Vol 69 (10) ◽  
pp. 1186-1191
Author(s):  
Balasubramanian Sridhar ◽  
Krishnan Ravikumar ◽  
Venkatasubramanian Hariharakrishnan

Zolmitriptan hydrogen oxalate [(S)-dimethyl(2-{5-[(2-oxo-1,3-oxazolidin-4-yl)methyl]-1H-indol-3-yl}ethyl)azanium hydrogen oxalate], C16H22N3O2+·C2HO4−, (I), and zolmitriptan camphorsulfonate [(S)-dimethyl(2-{5-[(2-oxo-1,3-oxazolidin-4-yl)methyl]-1H-indol-3-yl}ethyl)azanium (S,R)-{2-hydroxy-7,7-dimethylbicyclo[2.2.1]heptan-1-yl}methanesulfonate], C16H22N3O2+·C10H15O4S−, (II), are the first reported salt complexes of the antimigraine drug zolmitriptan. Compound (I) crystallizes in the space groupP21with two molecules of protonated zolmitriptan and two oxalate monoanions in the asymmetric unit, while compound (II) crystallizes in the space groupP212121with one protonated zolmitriptan molecule and one camphorsulfonate anion in the asymmetric unit. The orientations of the ethylamine side chain and the oxazolidinone ring with respect to the indole ring of the zolmitriptan cation are different for (I) and (II). In (I), they are oriented in opposite directions and the molecule adopts a step-like appearance, while in (II) the corresponding side chains are folded in the same direction, giving the molecule a cup-like appearance. The zolmitriptan molecules of (I) form anR22(8) dimer, while in (II) they form a helical chain with aC(11) motif. The oxalate monoanions of (I) interact with the zolmitriptan cations and extend the dimer into a three-dimensional hydrogen-bonded network. In (II), the camphorsulfonate anion forms anR22(15) ring motif with the zolmitriptan cation.


2014 ◽  
Vol 70 (4) ◽  
pp. 408-415 ◽  
Author(s):  
Sergio A. Guerrero ◽  
Carlos M. Sanabría ◽  
Alirio Palma ◽  
Justo Cobo ◽  
Christopher Glidewell

(2R*,4S*)-Methyl 2,3,4,5-tetrahydro-1,4-epoxy-1H-benz[b]azepine-2-carboxylate, C12H13NO3, (I), and its reduction product (2R*,4S*)-methyl 4-hydroxy-2,3,4,5-tetrahydro-1H-benz[b]azepine-2-carboxylate, C12H15NO3, (II), both crystallize as single enantiomers in the space groupP212121, while the hydrolysis product (2RS,4SR)-4-hydroxy-2,3,4,5-tetrahydro-1H-benz[b]azepine-2-carboxylic acid, C11H13NO3, (III), and the lactone (2RS,5SR)-8-(trifluoromethoxy)-5,6-dihydro-1H-2,5-methanobenz[e][1,4]oxazocin-3(2H)-one, C12H10F3NO3, (IV), both crystallize as racemic mixtures in the space groupP21/c. The molecules of compound (IV) are linked into centrosymmetricR22(10) dimers by N—H...O hydrogen bonds, and those of compound (I) are linked into chains by C—H...π(arene) hydrogen bonds. A combination of O—H...O and O—H...N hydrogen bonds links the molecules of compound (III) into sheets containing equal numbers ofR44(14) andR44(26) rings, and a combination of C—H...π(arene) hydrogen bonds and three-centre O—H...(N,O) hydrogen bonds links the molecules of compound (II) into a three-dimensional framework structure. Comparisons are made with some related compounds.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 603
Author(s):  
Prashanth Sandineni ◽  
Hooman Yaghoobnejad Asl ◽  
Weiguo Zhang ◽  
P. Shiv Halasyamani ◽  
Kartik Ghosh ◽  
...  

Herein, we report the syntheses of two lithium-vanadium oxide-fluoride compounds crystallized from the same reaction mixture through a time variation experiment. A low temperature hydrothermal route employing a viscous paste of V2O5, oxalic acid, LiF, and HF allowed the crystallization of one metastable phase initially, Li2VO0.55(H2O)0.45F5⋅2H2O (I), which on prolonged heating transforms to a chemically similar yet structurally different phase, Li3VOF5 (II). Compound I crystallizes in centrosymmetric space group, I2/a with a = 6.052(3), b = 7.928(4), c = 12.461(6) Å, and β = 103.99(2)°, while compound II crystallizes in a non-centrosymmetric (NCS) space group, Pna21 with a = 5.1173(2), b = 8.612(3), c = 9.346(3) Å. Synthesis of NCS crystals are highly sought after in solid-state chemistry for their second-harmonic-generation (SHG) response and compound II exhibits SHG activity albeit non-phase-matchable. In this article, we also describe their magnetic properties which helped in unambiguous assignment of mixed valency of V (+4/+5) for Li2VO0.55(H2O)0.45F5⋅2H2O (I) and +4 valency of V for Li3VOF5 (II).


Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title compounds,catena-poly[[[bis[(R)-propane-1,2-diamine-κ2N,N′]copper(II)]-μ-cyanido-κ2N:C-[tris(cyanido-κC)(nitroso-κN)iron(III)]-μ-cyanido-κ2C:N] monohydrate], {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O}n, (I), and poly[[hexa-μ-cyanido-κ12C:N-hexacyanido-κ6C-hexakis[(R)-propane-1,2-diamine-κ2N,N′]dichromium(III)tricopper(II)] pentahydrate], {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O}n, (II) [where Lpn = (R)-propane-1,2-diamine, C3H10N2], are new chiral cyanide-bridged bimetallic coordination polymers. The asymmetric unit of compound (I) is composed of two independent cation–anion units of {[Cu(Lpn)2][Fe(CN)5)(NO)]} and two water molecules. The FeIIIatoms have distorted octahedral geometries, while the CuIIatoms can be considered to be pentacoordinate. In the crystal, however, the units align to form zigzag cyanide-bridged chains propagating along [101]. Hence, the CuIIatoms have distorted octahedral coordination spheres with extremely long semicoordination Cu—N(cyanido) bridging bonds. The chains are linked by O—H...N and N—H...N hydrogen bonds, forming two-dimensional networks parallel to (010), and the networks are linkedviaN—H...O and N—H...N hydrogen bonds, forming a three-dimensional framework. Compound (II) is a two-dimensional cyanide-bridged coordination polymer. The asymmetric unit is composed of two chiral {[Cu(Lpn)2][Cr(CN)6]}−anions bridged by a chiral [Cu(Lpn)2]2+cation and five water molecules of crystallization. Both the CrIIIatoms and the central CuIIatom have distorted octahedral geometries. The coordination spheres of the outer CuIIatoms of the asymmetric unit can be considered to be pentacoordinate. In the crystal, these units are bridged by long semicoordination Cu—N(cyanide) bridging bonds forming a two-dimensional network, hence these CuIIatoms now have distorted octahedral geometries. The networks, which lie parallel to (10-1), are linkedviaO—H...O, O—H...N, N—H...O and N—H...N hydrogen bonds involving all five non-coordinating water molecules, the cyanide N atoms and the NH2groups of the Lpn ligands, forming a three-dimensional framework.


Author(s):  
Mouhamadou Birame Diop ◽  
Libasse Diop ◽  
Laurent Plasseraud ◽  
Thierry Maris

The tin(IV) atom in the complex anion of the title salt, (C4H7N2)[Sn(C2O4)Cl3(H2O)], is in a distorted octahedral coordination environment defined by three chlorido ligands, an oxygen atom from a water molecule and two oxygen atoms from a chelating oxalate anion. The organic cation is linked through a bifurcated N—H...O hydrogen bond to the free oxygen atoms of the oxalate ligand of the complex [Sn(H2O)Cl3(C2O4)]−anion. Neighbouring stannate(IV) anions are linked through O—H...O hydrogen bonds involving the water molecule and the two non-coordinating oxalate oxygen atoms. In combination with additional N—H...Cl hydrogen bonds between cations and anions, a three-dimensional network is spanned.


2015 ◽  
Vol 71 (3) ◽  
pp. 222-228 ◽  
Author(s):  
Mohamed Abdellatif Bensegueni ◽  
Aouatef Cherouana ◽  
Slimane Dahaoui

Two alkaline earth–tetrazole compounds, namelycatena-poly[[[triaquamagnesium(II)]-μ-5,5′-(azanediyl)ditetrazolato-κ3N1,N1′:N5] hemi{bis[μ-5,5′-(azanediyl)ditetrazolato-κ3N1,N1′:N2]bis[triaquamagnesium(II)]} monohydrate], {[Mg(C2HN9)(H2O)3][Mg2(C2HN9)2(H2O)6]0.5·H2O}n, (I), and bis[5-(pyrazin-2-yl)tetrazolate] hexaaquamagnesium(II), (C5H3N6)[Mg(H2O)6], (II), have been prepared under hydrothermal conditions. Compound (I) is a mixed dimer–polymer based on magnesium ion centres and can be regarded as the first example of a magnesium–tetrazolate polymer in the crystalline form. The structure shows a complex three-dimensional hydrogen-bonded network that involves magnesium–tetrazolate dimers, solvent water molecules and one-dimensional magnesium–tetrazolate polymeric chains. The intrinsic cohesion in the polymer chains is ensured by N—H...N hydrogen bonds, which formR22(7) rings, thus reinforcing the propagation of the polymer chain along theaaxis. The crystal structure of magnesium tetrazole salt (II) reveals a mixed ribbon of hydrogen-bonded rings, of typesR22(7),R22(9) andR24(10), running along thecaxis, which are linked byR24(16) rings, generating a 4,8-cflunet.


2015 ◽  
Vol 71 (11) ◽  
pp. 1379-1383 ◽  
Author(s):  
Chen Liu ◽  
Khalil A. Abboud

The title compounds, μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl)-1H-imidazole-κ2N3,N4](azido-κN1)copper(II)], [Cu2(C2O4)(N3)2(C5H9N3)2], (I), and μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl)-1H-imidazole-κ2N3,N4](dicyanamido-κN1)copper(II)], [Cu2(C2O4)(C2N3)2(C5H9N3)2], (II), are two oxalate-bridged dinuclear copper complexes. Each CuIIion adopts a five-coordinate square-pyramidal coordination sphere where the basal N2O2plane is formed by two O atoms of the oxalate ligand and two N atoms of a bidentate chelating histamine molecule. The apical coordination site in compound (I) is occupied by a monodentate azide anion through one of its terminal N atoms. The apical coordination site in compound (II) is occupied by a monodentate dicyanamide anion through one of its terminal N atoms. The molecules in both structures are centrosymmetric. In the crystals of compounds (I) and (II), the dinuclear complexes are linked through N—H...Xand C—H...X(X= N, O) hydrogen bonds where the donors are provided by the histamine ligand and the acceptor atoms are provided by the azide, dicyanamide, and oxalate ligands. In compound (I), the coordinatively unsaturated copper ions interact with the histamine ligandviaa C—H...Cu interaction. The coordinatively unsaturated copper ions in compound (II) interactviaa weak N...Cu interaction with the dicyanamide ligand of a neighboring molecule. The side chain of the histamine ligand is disordered over three sets of sites in (II).


2004 ◽  
Vol 59 (9) ◽  
pp. 992-998 ◽  
Author(s):  
Christian Näther ◽  
Andreas Beck

Reaction of silver(I) bromide with ethylenediamine (en) leads to the formation of the 1:1 compound poly[AgBr(μ2-en-N,N’)] (I). In the crystal structure the silver atoms of AgBr dimers are connected to two bridging bromine atoms and two nitrogen atoms of different en ligands. The dimers are thus connected by the ligands into layers via μ-N,N’ coordination. In the 2:1 coordination polymer poly[(AgBr)2(μ2-en-N,N’)] (II) a three-dimensional AgBr substructure occur which consists of helical AgBr chains that are connected via peripheral Ag-Br contacts into a three-dimensional network that contains large channels. The en ligands are situated in these channels bridging the Ag atoms. From solution this compound cannot be obtained as a pure phase, since compound I is always formed as the major phase. On heating the 1:1 compound I in a thermobalance the sample mass decreases slowly and several mass steps are observed, which are not fully resolved. If the reaction is stopped at 230°C, pure AgBr has formed. At 115°C only traces of compound II are found. The major phase consists of an as yet unidentified ligand poor compound.


Author(s):  
Dilovan S. Cati ◽  
Helen Stoeckli-Evans

The title compounds, C32H28N10O4· unknown solvent, (I), and C32H28N10O4, (II), are pyrazine-2,3,5,6-tetracarboxamide derivatives. In (I), the substituents are (pyridin-2-ylmethyl)carboxamide, while in (II), the substituents are (pyridin-4-ylmethyl)carboxamide. Both compounds crystallize in the monoclinic space groupP21/n, withZ′ = 1 for (I), andZ′ = 0.5 for (II). The whole molecule of (II) is generated by inversion symmetry, the pyrazine ring being situated about a center of inversion. In (I), the four pyridine rings are inclined to the pyrazine ring by 83.9 (2), 82.16 (18), 82.73 (19) and 17.65 (19)°. This last dihedral angle involves a pyridine ring that is linked to the adjacent carboxamide O atom by an intramolecular C—H...O hydrogen bond. In compound (II), the unique pyridine rings are inclined to the pyrazine ring by 33.3 (3) and 81.71 (10)°. There are two symmetrical intramolecular C—H...O hydrogen bonds present in (II). In the crystal of (I), molecules are linked by N—H...O and N—H...N hydrogen bonds, forming layers parallel to (10-1). The layers are linked by C—H...O and C—H...N hydrogen bonds, forming a three-dimensional framework. In the crystal of (II), molecules are linked by N—H...N hydrogen bonds, forming chains propagating along the [010] direction. The chains are linked by a weaker N—H...N hydrogen bond, forming layers parallel to the (101) plane, which are in turn linked by C—H...O hydrogen bonds, forming a three-dimensional structure. In the crystal of compound (I), a region of disordered electron density was treated with the SQUEEZE routine inPLATON[Spek (2015).Acta Cryst. C71, 9–18]. Their contribution was not taken into account during refinement. In compound (II), one of the pyridine rings is positionally disordered, and the refined occupancy ratio for the disordered Car—Car—Npyatoms is 0.58 (3):0.42 (3).


Author(s):  
Július Sivý ◽  
Dušan Bortňák ◽  
Daniel Végh ◽  
Erik Rakovský

The crystals, C11H4BrF5N2S, (I), 1-((4-bromothiophen-2-yl)methylene)-2-(perfluorophenyl)hydrazine and C12H6BrF5N2S, (II), 1-((4-bromo-5-methylthiophen-2-yl)methylene)-2-(perfluorophenyl)hydrazine are molecules with two rings and hydrazone part like a centre of the molecule. The compounds have been synthesized and characterized by elemental, spectroscopic (1H-NMR) analysis. The crystal structures of the solid phase were determined by single crystal X-ray diffraction method. They crystallize in the monoclinic space group with Z = 4 and Z = 2 molecules per unit-cell. The compound (I) crystallizes as a racemate in the centrosymmetric space group and the compound (II) crystallizes as a non-racemate in the non-centrosymmetric space group. The “absolute configuration and conformation for bond values” were derived from the anomalous dispersion (ad) for (II). The crystal structures are revealed diverse non-covalent interactions such as intra- and interhydrogen bonding, π-ring···π-ring, C-H···π-ring and they were investigated. The expected stereochemistry of hydrazones atoms C7, N2 and N1 were confirmed for (I) and (II). The hole molecule of the (I), and (II) possesses “a boat conformation” like a 6-membered ring. The results of the single crystal studies are reproduced with the help of Hirshfeld surface study and Gaussian software.


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