Wyniki wyszukiwania - BazTech

1

Theoretical studies of interactions in cyprodinil-α-cyclodextrin and cyprodinil-β-cyclodextrin systems

Hołaj-Krzak Jakub T.

Journal of Water and Land Development

|

2023

|

no. 57

9--20

EN

The paper presents the results of theoretical calculations in terms of the G4MP2 composite method for cyprodinil-α-cyclodextrin (C0@α-CD) and cyprodinil-β-cyclodextrin (C0@β-CD) systems. Studies also covered analogous systems consisting of the anion (C-) and the cation (C+) of cyprodinil. The geometries of the cyprodinil molecule and ions were optimized on the basis of the DFT theory, using hybrid (B3LYP, PBE0), pure (B97-D) and “meta” (M06-2X) GGA functionals for selected Pople basis sets [6-311++G(d,p), 6-311++G(2d,p), 6-311++G(2d,2p)] and Dunning basis set (aug-cc-pVDZ). The research results suggest that the affinity of “guest” molecules for “hosts” is relatively low. Theoretical studies of the “guest-host” systems allow to predict the properties of the designed preparations.

2

Analysis of Structural Changes in Starch- Aluminosilicate Binder and Molding Sand with its Participation after Physical Curing

Kaczmarska K., Grabowska B., Cukrowicz S., Bobrowski A., Żymankowska-Kumon S.

Archives of Foundry Engineering

|

2018

|

Vol. 18, iss. 3

138--143

EN

The organo-inorganic commercial binder Albertine F/1 (Hüttenes-Albertus) constituting the starch-aluminosilicate mixture was directed to structural studies. The paper presents a detailed structural analysis of the binder before and after exposure to physical curing agents (microwaves, high temperature) based on the results of infrared spectroscopy studies (FTIR). An analysis of structural changes taking place in the binder system with the quartz matrix was also carried out. Based on the course of the obtained IR spectra, it was found that during the exposure on physical agents there are structural changes within the hydroxyl groups in the polymeric starch chains and silanol groups derived from aluminosilicate as well as in the quartz matrix (SiO2). The curing of the molding sand takes place due to the evaporation of the solvent water and the formation of intramolecular and intermolecular cross-linking hydrogen bonds. Type and amount of hydrogen bonds presence in cured molding sand have an impact on selected properties of molding sand. Results indicates that for molding sand with Albertine F/1 during conventional heating a more extensive network of hydrogen bonds is created.

3

Struktura a nieelastyczne rozpraszanie neutronów przez kryształy molekularne z wiązaniami wodorowymi

Rok M., Bator G., Sobczyk L.

Wiadomości Chemiczne

|

2017

|

[Z] 71, 7-8

533--557

EN

The molecular crystals, which are built of organic or organic-inorganic molecules, are characterized by the weak intermolecular interactions. From the viewpoint of the potential applications in electronics or optoelectronics the electric properties of the crystals are essential. In turn these properties are related to their crystal structure as well as the dynamics of the molecules in the solid state. The existence of the hydrogen bonds in the crystal structures, conventional and unconventional, is crucial from the viewpoint of the electric properties of the crystals. The dynamics of methyl groups present in the structure can be a measure of the molecular interactions in the crystals. In this work the dynamical properties, first of all taking into account the research results concerning the neutron scattering, will be discussed. The neutron technique is very effective as regards the methyl group dynamics investigations. The relationship between a formation of the conventional and unconventional hydrogen bonds and a tunneling of the methyl groups at low temperature will be discussed. The method of the interpretation of the INS spectra will be described taking into account the theoretical model, the parameters of which are fitted to the experimental data. The examples will regard the following molecular crystals: p-N,N’-1,10-tetraacethyldiaminodurene (TADD) (Figs. 2 and 4), 2,3,5,6-tetramethylpyrazine with chloranilic acid (TMP·CLA) (Figs. 5, 6 and 7), 2,3,5,6- tetramethylpyrazine with bromanilic acid (TMP·BRA) (Figs. 5 and 6) and the crystal of 3,4,7,8-tetramethylphenantroline (Me4phen) and its complex with picric acid (Me4phen·PIC) (Figs. 8 and 9). In this paper we have shown that the surrounding of the methyl group and its interactions with the adjacent molecules has a stronger effect than the changes in the electronic charge density in the molecule.

4

Molowa entropia orientacyjna i struktura cieczy zasocjowanych

Jadżyn J., Świergiel J.

Wiadomości Chemiczne

|

2017

|

[Z] 71, 7-8

517--532

EN

Research on the structural effects of intermolecular interactions not only brings us closer to a better understanding the macroscopic properties of liquids, but also allows one to modify these properties. Intermolecular dipolar couplings and hydrogen bonds are the most common interactions in liquids leading to formation of multimolecular entities with various structures. The natural rival of these interactions is the thermal agitation of molecules (kT), which aims to destroy the emerging structures. In this paper we present an experimental method to estimate the way of molecular self-assembly resulting from the simultaneous action of kT and intermolecular interactions. The method is based on the study of dipolar orientation effects induced by an applied electric field. As an experimental source of the information on these effects is temperature derivative of the static permittivity of tested liquid. That derivative is proportional to the liquid entropy change due to the ordering action of the electric field on the molecular dipoles. Here, we present the experimental results on temperature dependence of the static permittivity and increment of the orientation entropy of liquids where the self-association process realizes with two ways: dipolar couplings and hydrogen-bonds.

5

Azopolimery supramolekularne powstałe na bazie wiązań wodorowych

Konieczkowska J., Schab-Balcerzak E.

Polimery

|

2015

|

T. 60, nr 7-8

425--434

PL

Artykuł stanowi przegląd literatury dotyczącej fotoaktywnych polimerów supramolekularnych, wktórych tworzeniu wykorzystano niekowalencyjne oddziaływania — wiązania wodorowe — między cząsteczkami azochromoforu ałańcuchami makrocząsteczek. Wpracy przedstawiono poszczególne rodzaje tego typu polimerów oraz wyniki badań ich fotoindukowanej anizotropii optycznej. Porównano azopolimery supramolekularne bazujące na wiązaniach wodorowych z: (i) układami zawierającymi chromofory zdyspergowane w matrycy polimerowej, (ii) układami otrzymanymi w wyniku oddziaływań jonowych oraz (iii) azopolimerami funkcjonalizowanymi. Omówiono także sposoby identyfikacji wiązań wodorowych w azopolimerach supramolekularnych.

EN

The paper is a literature review on photoactive supramolecular polymers formed through noncovalent interactions, i.e. hydrogen bonds between azo chromophore molecules and macromolecule chains. The individual kinds of such polymers as well as the results of photoinduced optical anisotropy investigations related to them have been presented. The supramolecular azopolymers based on hydrogen bonds have been compared with (i) systems containing chromophores dispersed in polymer matrix, (ii) supramolecular systems based on ionic interactions and (iii) functionalized azopolymers. Additionally, the methods used for the identification of hydrogen bonds in supramolecular azopolymers were discussed.

6

Removal of Cr(III) ions from water and wastewater by sorption onto peats and clays occurring in an overburden of lignite beds in central Poland

Kyzioł-Komosińska J., Rosik-Dulewska Cz., Dzieniszewska A., Pająk M., Krzyżewska I.

Environment Protection Engineering

|

2014

|

Vol. 40, nr 1

5--22

EN

Sorption capacities of low-moor peats and Neogene clays from the overburden of lignite beds in Central Poland for Cr(III) ions as chloride and metalorganic complex ions have been investigated. The binding mechanisms and sorption parameters were determined based on the Freundlich and Langmuir nonlinear sorption isotherms. The sorption capacities of studied materials for Cr(III) ions depended on their properties (porosity, average pore diameters, specific surface area and content of Fe hydroxyoxides) as well as charge of Cr(III) ions, functional groups and their diagonal lengths. Cr(III) ions from chlorides were bound onto sorbents via Coulomb attraction and by Fe hydroxy-oxides. However the complex Cr(III) ions were bound to the sorbent surface via hydrogen bonds between the dye -OH groups and =O of the sorbent functional groups. The equation parameters of sorption isotherms indicate cooperative heterogeneous adsorption at low Cr(III) concentrations and chemisorption at high Cr(III) concentrations

7

Complexation of poly(ethylene glycol) with poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) gel based on hydrogen bonds

Liu G., Xie D., Guan Ch.

Polish Journal of Chemical Technology

|

2013

|

Vol. 15, nr 3

85-90

EN

The complexes of poly(ethyl methacrylate-co-N-vinyl-2-pyrrolidone) (P(EMA-co-VP)) gel with poly- (ethylene glycol) (PEG) stabilized by the hydrogen bonds were prepared. It was found that both the concentration and the molecular weight of PEG have a strong effect on the P(EMA-co-VP) gel. When PEG was introduced into the P(EMA-co-VP) gel, the glass transition temperatures (Tg) of the complexes decreases with the decreasing of PEG molecular weight. In such a system, the maximum molecular weight of PEG required for the complex formation is no more than 2000, and P(EMA-co-VP)/PEG complexes are a homogeneous amorphous phase, which was studied by FTIR, XRD, TEM, and DSC.

8

Modification of the hydrogen bonding network at the reversed micelles interface by near infrared radiation

Walski T., Gałecka T., Grzeszczuk-Kuć K., Komorowska M.

Nukleonika

|

2013

|

Vol. 58, No. 3

435--438

EN

The purpose of this paper is to prove that near infrared radiation (NIR) modifies hydrogen bonds localized in the interface of reversed micelles. The degree of modification of the hydrogen bonds was monitored by TEMPO-palmitate spin probe introduced into the structure of reverse micelles formed by cetyltrimethylammonium bromide (CTAB) (TCAB/phosphate buffer/isooctane/hexanol and TCAB/NaCl/isooctane/hexanol (W = 15)). Electron paramagnetic resonance (EPR) spectra were performed on the argonated samples. The isotropic tumbling correlation time (τc) and the hyperfine coupling constant A+ = h0 – h+1 (h+1, and h0 correspond to the low-, and centre-field lines, respectively) were determined from the EPR spectra as a quantitative measure for monitoring the action of NIR radiation. A+ values depend on the composition of the water pool (1.640 mT for phosphate buffer and 1.630 mT for NaCl). NIR irradiation led to decrease in A+. This parameter reached the same value for both solutions (1.625 ± 0.003 and 1.626 ± 0.003 mT) after exposition to NIR. The tumbling correlation time after exposure to NIR decreased for TCAB/phosphate buffer/ isooctane/hexanol reversed micelles from 2.10 × 10–10 s to 1.44 × 10–10 s but did not change for TCAB/NaCl/isooctane/ hexanol). The results obtained confirm the possibility of modification of the hydrogen bonds by NIR radiation.

9

Hydrogen bonds in camphorsulfonic acid doped polyaniline

Łużny W., Piwowarczyk K.

Polimery

|

2011

|

T. 56, nr 9

652-656

EN

We conducted a set of computer simulations to explore in details the way polyaniline (PANI) interacts with its dopant molecules like camphorsulfonic acid (CSA) and with solvent like chloroform, m-cresol or a mixture of m-cresol and water. The simulated system was built of a single layer of polyaniline chains in protonated state with attached camphorsulfonic acid ions as dopants. The system of the size above 50 A* was subject to the periodic boundary conditions. All atoms in simulated molecules were assigned to atom types from OPLS-AA force field. However the inter-ring torsion profile for polyaniline in protonated emeraldine state was modified according to the density functional theory simulations. Prepared systems were simulated for 1 ns under the constant temperature (293 K) and constant pressure (1000 hPa) conditions. The results of molecular dynamics simulation exhibit a broad variety of hydrogen bond patterns between PANI-CSA as well as solvent molecules. We observed high probability (36 %) of configurations where single CSA molecule is attached to a PANI chain via a single hydrogen bond. However, the high probability (44 %) of a configuration where single CSA molecule bridges two or more PANI chains via hydrogen bonds was quite unexpected. Our simulations show also that in the presence of solvent, PANI-CSA interaction slightly weakens. Nevertheless, in the case of solvents being able to form hydrogen bonds in which CSA molecule is involved.

PL

W celu lepszego zrozumienia wpływu wiązań wodorowych na strukturę polianiliny (PANI) domieszkowanej kwasem kamforosulfonowym (CSA), przeprowadziliśmy symulacje tego systemu metodą dynamiki molekularnej uwzględniając także cząsteczki rozpuszczalnika, tj. chloroform, m-krezol oraz m-krezol z dodatkiem wody. Symulowany układ był złożony z warstwy polianiliny, którą tworzyło 12 łańcuchów polimeru otoczonych 96 jonami CSA. Cały układ o wymiarach rzędu 50 A* podlegał periodycznym warunkom brzegowym, tak że łańcuchy polianiliny mogły być efektywnie traktowane jak nieskończony polimer. Parametry oddziaływań międzyatomowych zostały dobrane w ramach pola siłowego OPLS-AA, przy czym parametry profilu torsyjnego dla łańcucha polianiliny w stanie sprotonowanym zostały obliczone na podstawie symulacji kwantowych metodą DFT/B3LYP/6-31G*. Tak spreparowane systemy były symulowane w temp. 293 K i ciśnieniu 1000 hPa przez 1 ns. Wyniki symulacji pokazują dużą różnorodność konfiguracji wiązań wodorowych. Zaobserwowaliśmy znaczny procent (36 %) oczekiwanych konfiguracji, w których jedna cząsteczka CSA łączy wiązaniem wodorowym jeden łańcuch PANI. Niespodziewanym wynikiem było duże prawdopodobieństwo (44 %, tabela 2) konfiguracji, w których cząsteczka CSA łączy za pomocą wiązań wodorowych dwa lub trzy łańcuchy PANI [wzór (III)—(V)]. W przypadku dodania rozpuszczalnika, symulacje odkryły dwa typy zachowań. Cząsteczki rozpuszczalnika zdolne do formowania wiązań wodorowych (m-krezol, woda) wbudowują się między CSA i PANI tworząc rodzaj mostków [wzór (I)] i nie wpływając w sposób istotny na całkowitą liczbę wiązań wodorowych, w których uczestniczy polianilina. To zachowanie powoduje znaczny wzrost liczby wiązań wodorowych między CSA i rozpuszczalnikiem, co usztywnia strukturę takiego układu i powoduje, że jest on mniej podatny na zmiany. Z drugiej strony, cząsteczki dowolnego rozpuszczalnika osłaniają cząsteczki CSA [wzór (VII)] i redukują liczbę wiązań wodorowych PANI-CSA (tabela 3).

10

Two Supramolecular Complexes with Hydrogen-bonds of N-H ··· O and C-H ··· O between Dicarboxylic Acids and Bis-imidazoles

Jin S. W., Wang D. Q., Jin Z. J., Wang L. Q.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 11

1937-1944

EN

Two imidazole derived supra molecular complexes (N,N'-butylenebis(imidazole) : (tere - phthalic acid)2 (1), and N,N'-butylenebis(imidazole) : sebacic acid (2)) were synthesized and structurally characterized by X-ray crystallography. Compounds 1 and 2 both crystallize in the triclinic P-1 space group. In compound 1, one-dimensional grid structure is formed through imidazolium moieties hydrogen bonded to mono-ion carboxylate groups of two par al lel terephthalate chains. Ad ja cent grids packed along the b axis through C-H ··· O hydrogen bonds form 3D network. For compound 2, with strong O-H ···N hydrogen bonds, the bis(imidazole) and the sebacic acid are arranged alternatively to form 1D in finite chain, which is further stacked into a 3D net work structure through additional C-H ··· O hydrogen bonds.

11

Structural and Vibrational Investigation of 2-Amino-5-nitropyridine. A Combined Experimental and Theoretical Studies

Oszust J., Baran J., Pietraszko A., Drozd M.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 5

835-855

EN

The crystal structure of 2-amino-5-nitropyridine at low temperature was previously determined by other authors [1]. In this paper, the complementary X-ray study at ambient temperature is reported. The small differences in lattice parameters measurement in both experiments were found. The differential scanning calorimetric (DSC) measurements were performed. No phase transition was found in the temperature range 100–300 K. Additionally, the detailed vibrational spectroscopic analysis of 2-amino- 5-nitropyridine are reported. Powder infrared and Raman spectra of the title compound were measured at room temperature. The molecular structure of 2-amino-5-nitro pyridine has been calculated with the aid of density functional (B3LYP) method with the extended 6-311++G(d,p) basis set. The calculated geometrical parameters of investigated molecule in gas phase were compared with experimental X-ray data. The harmonic frequencies, potential energy distribution (PED) and IR intensities of 2-amino-5-nitro pyridine were calculated with B3LYP method. The assignment of the experimental spectra has been made as suming the calculated PED.

12

Intermolecular Interactions in o-Tolidinium Dichloride Dihydrate: X-ray Structural and Quantum Mechanical Study

Kruszynski R.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 4

615-623

EN

The title compound, C14H22Cl2N2O2, (I), was determined by X-ray crystallography, and the intermolecular interactions energy was calculated in terms of Natural Bond Orbital analysis. The (I) is composed from 3,3'-dimethyl-(1,1'-biphenyl)-4,4'-diammonium cation two chloride anions and two water molecules. The mid point of the linking aromatic rings C—C bond is located on two fold rotation axis, and thus asymmetric unit is occupied by half of cation, one anion and one water molecule. All the interatomic distances and angles in (I) are normal. The almost planar aromatic rings are inclined at 38.82(4) graduate. In the structure exists intermolecular N—HźźźO, N—HźźźCl, O—HźźźCl hydrogen bonds with bonding energy ranging from 4 to 26 kcal/mol. All hydrogen bonds of (I) in terms of first level graphs create D motifs. No face-to-face stacking interactions are observed.

13

Hydrogen Bonding of Anilines: Experimental and Theoretical Studies of Complexes of Various Compositions

Borisenko V. E.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 5

1025-1059

EN

Review of works on studies of the influence of the position, numberand a kind of substituents in phenylring of aniline on proton do or ability in hydrogen bond, spectral, geometric, electrooptic and force characteristics of amino group in complexes with different proton acceptors of 1:1 and 1:2 composition in intra- and intermolecular hydrogen bonds is presented. The influence of proton donors and proton acceptors on the kind of correlation between spectral, geometric, force and electrooptic characteristics of the amino group is analyzed. Obtained results demonstrate the possibility of quantitative description of the changes of dynamic, geometric, force and electrooptic properties of amino group in substituted anilines on passing from free molecules to bonded ones and extend the under standing of the role of various factors in the process of molecular agreegation.

14

Crystal Structure and Third-Order Non-Linear Optical Property of a Novel Three-Dimensional Supramolecular Network Compound of Co(II)

Li Y., Zhang Z. X., Wu Z. X., Li K. C., Li Q. S.

Polish Journal of Chemistry

|

2009

|

Vol. 83, nr 3

373-381

EN

A new metal-organic complex formulated as [Co(ISOIN)2(H2O)4] 1 (H2ISOIN) = isonicotinic acid) has been synthesized by low-temperature solid-state reaction and characterized by single-crystal X-ray diffraction, elemental analyses, IR and UV-visible spectra. The strong intermolecular O-Hź ź źO hydrogen-bonds interactions are the most significant factors controlling the novel supramolecular sheet fashion packing of the title compound in the crystal state. The third-order non-linear optical (NLO) properties of 1 were also investigated and they exhibit the reverse saturable absorption and self-defocusing performance with modulus of the hyperpolarizability gamma 8.75×10-31 esu for 1 in a 1.56×10-4 molźdm-3 DMF solution.

15

Magnetyczne oddziaływania nadwymienne przez wiązania wodorowe

Korabik M.

Wiadomości Chemiczne

|

2008

|

[Z] 62, 5-6

449-478

EN

Hydrogen bonds play a key role in interactions in biological structures, supramolecular chemistry, and crystal engineering [28, 29]. The development of supramolecular structure created by hydrogen bonds is a new challenge for the synthesis of materials, in order to study their magnetic behaviour [59, 62]. A role played by hydrogen bonds in the transmission of magnetic interactions is still not fully understood, but the number of magnetically coupled hydrogen-bonded systems is growing. The present paper describes magnetic properties of copper(II) complexes [33] with nitrobenzoate and salicylate ligands where the system of hydrogen bonds O-HźźźO is the only path of magnetic interaction. Magnetic measurements in the temperature range 1.8-300 K show magnetic phase-transition at 6 K to antiferromagnetically coupled CuII dimers with singlet-tryplet energy gap 2J = -6.26 cm-1. A variety of different supramolecular hydrogen bond structures [27, 33-52, 57-62] and significant changes in their magnetic properties were analyzed to show the role of hydrogen bonds in magnetic interactions. Magnetostructural correlation has been made taking into account both covalently bridging ligand and the existence of intermolecular hydrogen bonds. An evidence for hydrogen-bond-mediated exchange coupling has been observed in magnetic study as well as in DFT calculations [40, 48]. Intermolecular interaction has been generally treated as a nuance, but today, it has established itself as an important functional tool, tunable at will [59] in the design of nanosized magnetic materials and their dimensionally-expanded compounds [57-62]. Intermolecular magnetic exchange interactions through hydrogen bonds, can have a large influence on the quantum properties of single molecular magnets SMMs [59]. Hydrogen bonding leads to coupling of the magnetic effects of individual SMMs units and to different quantum behaviour. Even very weak hydrogen bond inter-molecular interactions demonstrate a possibility of switching from an original nanosized magnetic system to a correlated system, for example, from single molecule magnet SMM to single chain magnet SCM or from such nanosized magnets to a bulk magnet [59].

16

Different Complexation Behavior of a Proton Transfer Compound Obtained from Pyridine-2,6-dicarboxylic Acid and Creatinine with Tl(I), Cu(II), Fe(III) and Bi(III): Synthesis, Characterization, Crystal Structures and Solution Studies

Aghabozorg H., Ramezanipour F., Soleimannejad J., Sharif M. A., Shokrollahi A., Shamsipur M., Moghimi A., Attar Gharamaleki J., Lippolis V., Blake A. J.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 3

487-507

EN

The different complexation methods of a proton transfer compound, (creatH)(pydcH)źH2O (pydcH2 = pyridine-2,6-di carboxylic acid; creat = creatinine) with metal ions have been studied and formation of [(Tl(pydcH)]n (1), [(Fe(pydc)(H2O)2)2ox]ź6H2O (2), [Cu(pydc)(pydcH2)]ź2H2O (3) and (creatH)2[Bi(pydc)2]2ź4H2O (4) are re ported. The characterization was performed using IR spectroscopy and single crystal X-ray diffraction analysis. The Tl(I) complex [(Tl(pydcH)]n (1) obtained from (creatH)(pydcH)źH2O is a polymeric system, showing only the contribution of the anionic species of (creatH)(pydcH)źH2O to the complexation. The Fe(III) and the Cu(II) complexes [(Fe(pydc)(H2O)2)2ox]ź6H2O (2) (ox = ox a late) and [Cu(pydc)(pydcH2)]ź2H2O (3) were also obtained from (creatH)(pydcH)źH2O. The Bi(III) complex (creatH)2[Bi(pydc)2]2ź4H2O (4) is a dimeric system, showing both contribution of the cationic and anionic fragments. The complexes 1-4 show a variety of structural features including mononuclear, binuclear, polymeric structures and unusual ligand formation. In compounds (1), (2), (3) and (4), a large number of hydrogen bonds are observed. These interactions as well as p-p stacking play an important role in the formation and stabilization of supra molecular systems in the crystal lattices. The stoichiometry and stability of the Cu(II), Tl(I) and Bi(III) complexes with (pydc)(creat) and Fe(III) with pydc-ox mixture in aqueous solution were investigated by potentiometric pH titration.

17

Synthesis and 1H-NMR Characterization of the Self-Assembly Based on Melamine – 5,5-Diethylbarbituric Acid

Pokrop A., Lipkowski P., Jurczak J.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 5-6

893-901

EN

The characterization of carbonyl–metal and maleimidato–metal bonding has been performed using the topological analysis of electron distribution function estimated for molecules of ( 5-C5H5)M(CO)3( 1-N-maleimidato) (M = W, Mo) and ( 5-C5H5)Fe(CO)2( 1-N-maleimidato). The Atoms in Molecules (AIM) approach has been applied for characterization of and -components of the metal–ligand bonds. The -electron communication between trans-placed ligands is present in Wand Mo derivatives. The ellipticity parameter is suggested to be a useful and highly sensitive parameter in the analysis of the metal–ligand bonding

18

Magnetic Interactions in Cu(pyridine-2-carboxylate)2

Żurowska B., Mroziński J., Ciunik Z.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 3

403-410

EN

The magnetic properties of the compound of the formula Cu(2-pca)2, (2-pca = 2-picolinate ion) were studied in the light of its known X-ray structure. The crystal structure consists of a copper atom lying in the centre of symmetry, trans square-planar coordinated via two pyridine nitrogens and the carboxylate oxygen atoms of the two picolinate anions. The crystal packing is due to short pi-pi stacking interactions between pyridine rings belonging to different molecules giving rise to a one-dimensional polymeric network arrangement. Additional CH-O hydrogen bonds form a three-dimensional polymeric network. The variable-temperature (1.8-300 K) magnetic susceptibility data of the complex were interpreted with the Bonner-Fisher expression with molecular field approximation, yielding J, zJ' and g values of -0.76, -0.47 cm-1, 2.09, respectively. The magnitude of the magnetic interaction through the pi-pi stacking interaction and hydrogen bond, and the nature of the exchange coupling is discussed on the basis of the structural data results.

19

Intermolecular Interactions in Three Crystalline Acid Salts of Monocarboxylic Acids

Madej A., Oleksyn B., Śliwiński J.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 5-6

1201-1218

EN

Three new acid salts of two monocarboxylic acids were obtained and their crystal structure analysis performed using experimental data collected with KM-4 diffractometer. The crystal structures of hydrogen bis(sulfosalicylates) of sodium and potassium contain hydrogen-bonded acid-anion dimers of very similar geometry and are classified to type A and pseudo A of hydrogen bis(monocarboxylates). Crystalline sodium hydrogen bis(3,5-dinitrobenzoate) contains a trimer acid-anion-acid. Its structure, which differs from that of potassium salt determined earlier, is classified as type B. The role of cations and anions in the investigated structures is discussed.

20

Conformation, Hydrogen Bonds and Their Effects on the Packing of Phenol, 2,2'-bis-[1,3-phenylenebis(methylidynenitrilo)] and Phenol, 2,2'-bis-[2,5-thiophenediylbis(methylidynenitrilo)]

Fridman N.

Polish Journal of Chemistry

|

2007

|

Vol. 81, nr 5-6

825-832

EN

The crystal structure of phenol, 2,2-bis-[1,3-phenylenebis(methylidynenitrilo)] (1), and phenol, 2,2-bis-[2,5-thiophenediylbis(methylidynenitrilo)] (2) are described with connection to the effect of hydrogen bonding on themolecular conformation and on the packing of molecules in the unit cell. The conformation is compared to the conformation observed in similar compounds. The geometric parameters of hydrogen bonding between hydroxyl groups are analyzed from crystallographic data provided by the Cambridge Crystallographic Data Center.