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1

Hydrogen-bonding network in the organic salts of 4-nitrobenzoic acid

100%

Chumakov Y., Simonov Y., Grozav M., Crisan M., Bocelli G., Yakovenko A., Lyubetsky D.

Open Chemistry

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2006

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vol. 4

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issue 3

458-475

EN

The crystal structures of six novel salts of 4-nitrobenzoic acid - namely, 2-hydroxyethylammonium 4-nitrobenzoate (I), 2-hydroxypropylammonium 4-nitrobenzoate (II), 1-(hydroxymethyl)propylammonium 4-nitrobenzoate (III), 3-hydroxypropylammonium 4-nitrobenzoate (IV), bis-(2-hydroxyethylammonium) 4-nitrobenzoate (V), morpholinium 4-nitrobenzoate (VI) - containing the same anion but different cations have been studied. The ionic forms of I-VI serve as building blocks of the supramolecular architecture, and in crystals they are held together via ionic N-H···O and O-H···O hydrogen bonds. In the crystal packing the building blocks of I-III are self-assembled via N-H...O, O-H···O and C-H...O hydrogen bonds to form the chains which are further consolidated into two-dimensional layers by the same type of interactions. In IV-VI the chain-like structures have been generated by building blocks.

2

The intermolecular interactions in the aminonitromethylbenzenes

100%

Kruszynski R., Sieranski T.

Open Chemistry

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2011

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vol. 9

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issue 1

94-105

EN

The intermolecular non-covalent interactions in aminonitromethylbenzenes namely 2-methyl-4-nitroaniline, 4-methyl-3-nitroaniline, 2-methyl-6-nitroaniline, 4-amino-2,6-dinitrotoluene, 2-methyl-5-nitroaniline, 4-methyl-2-nitroaniline, 2,3-dimethyl-6-nitroaniline, 4,5-dimethyl-2-nitroaniline and 2-methyl-3,5-dinitroaniline were studied by quantum mechanical calculations at RHF/311++G(3df,2p) and B3LYP/311++G(3df,2p) level of theory. The calculations prove that solely geometrical study of hydrogen bonding can be very misleading because not all short distances (classified as hydrogen bonds on the basis of interaction geometry) are bonding in character. For studied compounds interaction energy ranges from 0.23 kcal mol−1 to 5.59 kcal mol−1. The creation of intermolecular hydrogen bonds leads to charge redistribution in donors and acceptors. The Natural Bonding Orbitals analysis shows that hydrogen bonds are created by transfer of electron density from the lone pair orbitals of the H-bond acceptor to the antibonding molecular orbitals of the H-bond donor and Rydberg orbitals of the hydrogen atom. The stacking interactions are the interactions of delocalized molecular π-orbitals of the one molecule with delocalized antibonding molecular π-orbitals and the antibonding molecular σ-orbital created between the carbon atoms of the second aromatic ring and vice versa. [...]

3

Hydrogen bonding-based 3D supramolecular architecture of [Cu(CHA)2][TCM]·11H2O

100%

Vlassa M., Borodi G., Silvestru C., Vlassa M.

Open Chemistry

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2014

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vol. 12

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issue 1

14-24

EN

Reaction of Na4TCM (1) (H4TCM = tetra[4-(carboxyphenyl)oxamethyl]methane) with [Cu(CHA)](ClO4)2 (2)(CHA = 1,3,6,8,11,14-hexaaz atricyclo[12.2.1.1.8,11] octadecane) in a DMF-water mixture yields [Cu(CHA)]2[TCM] (3). Structural analysis of [Cu(CHA)]2[TCM]·11H2O (3·11H2O) by single crystal X-ray diffraction reveals strong copper-oxygen bonds between two complex cations and the tetraanion leading to a 3D coordination network (zwitterionic structure), consolidated through additional NH...O=C hydrogen bonding within the cation/anion association. The resulting coordination geometry around a copper atom is a distorted square pyramidal with an oxygen atom of the anionic ligand in the apical position. A 3D supramolecular network is developed in the crystal based only on NH...OC hydrogen bonds between the macrocyclic metallic tecton and the carboxylate groups of neighboring 3D coordinated (zwitterionic) moieties. The pseudotetrahedral TCM4− tetraanionic ligand induces a diamondoid architecture formed of large distorted adamantanoid cages. [...]

4

L-leucinium perchlorate: new molecular complex with nonlinear optical properties. Vibrational, calorimetric and theoretical studies

88%

Marchewka M., Drozd M.

Open Chemistry

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2013

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vol. 11

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issue 8

1264-1277

EN

On the basis of prior X-ray crystallographic results published by J. Janczak and G. Perpetuo, detailed vibrational studies were performed. The FT-IR and Raman spectra at ambient temperature were measured. The NLO properties were determined with the Kurtz-Perry experiment. Theoretical vibrational spectra were calculated. A detailed potential energy distribution (PED) analysis was performed. Assignments of observed bands were made. On the basis of these results, the behaviour of hydrogen bonds in the investigated compound was analysed and discussed. The equilibrium geometry of L-leucinium perchlorate was obtained. The results were compared with experimental X-ray data. The DFT formalism was used in theoretical studies. Detailed TDDFT study of hyperpolarizbility of first and second order for the investigated molecule was performed. Results were compared with experiments. Theoretical population analysis was used to determine the local electron density and local charges in investigated molecule. Differential scanning calorimetric study (DSC) was performed. [...]

5

1-Naphthyl-TADDOL/Emim BF4: A new catalytic system for the asymmetric addition of Chan’s diene to aromatic aldehydes

88%

Villano R., Acocella M., Sio V., Scettri A.

Open Chemistry

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2010

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vol. 8

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issue 6

1172-1178

EN

A new organocatalytic system was tested as a promoter for the asymmetric addition of Chan’s diene to aldehydes under solvent-free conditions. This new organocatalyst generated in situ by mixing 1-naphthyl-TADDOL derivative and Emim BF4 was able to give enantioenriched vinylogous aldols and hetero-Diels-Alder cycloadducts. A mechanistic investigation through the detection of nonlinear effects confirmed the involvement of the ionic liquid in the formation of a new catalytic supramolecular species.

6

Unusual potassium-oxalate coordination in the two-dimensional trimetallic [CoCl(NH3)5][KCr(C2O4)3]·0.5H2O complex

88%

Wrzeszcz G., Wojtczak A., Zawadzka M.

Open Chemistry

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2014

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vol. 12

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issue 6

652-658

EN

A new heterometallic compound, [CoCl(NH3)5][KCr(C2O4)3]·0.5H2O (1), has been synthesized and characterized by elemental analysis, IR and electronic spectra, thermal analysis, variable temperature magnetic susceptibility measurements, and single crystal X-ray diffraction. Compound 1 consists of two-dimensional [{KCr(C2O4)3}n]2n− layers, [CoCl(NH3)5]2+ ions and water molecules. Within the 2-D layer, three different types of oxalate coordination modes are present. Each K cation is coordinated by eight oxygen atoms from oxalate groups and also weakly interacts with the ninth oxygen atom. The extensive network of hydrogen bond is formed between the [KCr(C2O4)3]2− layer and the [CoCl(NH3)5]2+ ions. These interactions involve all hydrogen atoms of ammonia ligads and water molecule.

7

Excess thermodynamic quantities of D2O water calculated from its Raman O−D stretching spectra

75%

Georgiev M., Goutev N., Nickolov Z., Georgiev G.

Open Physics

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2005

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vol. 3

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issue 1

104-114

EN

Excess thermodynamic functions of D2O water have been calculated from the vibrationally decoupled O−D stretching spectra of very dilute solutions of HOD in H2O. Comparison of the results with reference calorimetric data for water showed a good correspondence for excess heat capacity above the melting point of ice. The excess enthalpy at the melting point also coincides well with latent heat of melting.

Refine search results

Hydrogen-bonding network in the organic salts of 4-nitrobenzoic acid

The intermolecular interactions in the aminonitromethylbenzenes

Hydrogen bonding-based 3D supramolecular architecture of [Cu(CHA)2][TCM]·11H2O

L-leucinium perchlorate: new molecular complex with nonlinear optical properties. Vibrational, calorimetric and theoretical studies

1-Naphthyl-TADDOL/Emim BF4: A new catalytic system for the asymmetric addition of Chan’s diene to aromatic aldehydes

Unusual potassium-oxalate coordination in the two-dimensional trimetallic [CoCl(NH3)5][KCr(C2O4)3]·0.5H2O complex

Excess thermodynamic quantities of D2O water calculated from its Raman O−D stretching spectra