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Wyniki wyszukiwania dla: HALOGEN BONDS
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Novel DNA-binding protein from Nanoarchaeum equitans Kin4-M binds all kinds of nucleic acids
PublikacjaNanoarchaeum equitans is the only known representative of Archaea phylum Nanoarchaeota and stands out as one of the tiniest known living organism. What is more it has smallest genome, which is only 490.885 base pairs long. It is also one of the most compact genomes. According to predictions about 95% of the DNA encodes proteins or stable RNA. Nanoarchaeum equitans lacks genes for most vital metabolic pathways including lipid, cofactor,...
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Decomposition of halogenated nucleobases by surface plasmon resonance excitation of gold nanoparticles
PublikacjaHalogenated uracil derivatives are of great interest in modern cancer therapy, either as chemotherapeutics or radiosensitisers depending on their halogen atom. This work applies UV-Vis spectroscopy to study the radiation damage of uracil, 5-bromouracil and 5- uorouracil dissolved in water in the presence of gold nanoparticles upon irradiation with an Nd:YAG ns-pulsed laser operating at 532nm at dierent uences. Gold nanoparticles...
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Low-energy (0.1 eV) electron attachment S?S bond cleavage assisted by Coulomb stabilization
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Perceived neighborhood disorder and quality of life: The role of the human-place bond, social interactions, and out-group blaming.
PublikacjaFour studies were carried out to examine how neighborhood disorder, human-place bonds, relationships among neighbors, and urban quality of life are related and what role blaming nonresidents plays in these relationships. In the first study, local identity was a significant mediator of the relationship between neighborhood disorder and quality of life. In the second study, we found that participants exposed to vignettes describing...
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Cis/trans conformational equilibrium across the N-methylphenylalanine2- N-methylphenylalanine3 peptide bond of arginine vasopressin analogs
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Anab initiostudy of (H3B←NH3)−—a dipole-bound anion supported by the dative charge-transfer bond in the neutral host
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Understanding the interactions between protein stabilizers and the peptide bond through the analysis of the volumetric and compressibility properties for the model systems
PublikacjaThis work confirms our earlier supposition, that volumetric and acoustic parameters for simple model proposed by us are directly related to stabilizing/destabilizing effect of osmolytes on proteins structure. The apparent molar volumes, V and the apparent molar isentropic compressions, KS,, of glycine and N,N,N –trimethylglycine (betaine) were determined from densities and speed of sound measurements in aqueous solution of N-methylacetamide...
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Synthesis of compounds with C-P-P and C=P-P bond systems based on the phospha-Wittig reaction
PublikacjaA reactivity study of a β-diketiminate titanium(III) phosphanylphosphido complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] (1) towards ketones such as benzophenone, 9-fluorenone, acetophenone, cyclopentanone, cyclohexanone and cycloheptanone is reported. The reactions of 1 with aromatic ketones (without α-protons) directly lead to the Ti(III) complex [MeNacNacTi(μ2-Cl)(OSiMe3)] (5) as well as Ti(IV) complexes with the pinacol condensation...
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Chiral and achiral crystals, charge-assisted hydrogen-bond patterns and self-organization of selected solid diaminium thiosulfates
PublikacjaAbstract A series of diaminium thiosulfates, derivatives of diamines: NH2CH2CH(CH3)NH2 (1) and NH2(CH2)nNH2, n = 3-6 (2-5 respectively)and thiosulfuric acid were prepared and their structures determined by crystal X-ray diffraction analysis. Compounds 1, 2 and 4 turned out to be hydrates. The crystal structure of 1,2-proylenediaminium thiosulfate is chiral and exhibits spontaneous resolution. Crystals for both enantiomers...
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Reactive imines: Addition of 2-aminopyrimidine to the imine bond and isolation of the aminal from the equilibrium mixture aminal/imine
PublikacjaThe reaction between o-vanillin and 2-aminopyrimidine leads to the formation of a single crystalline product: aminal, 1, which results from the reaction of the initially formed imine with 2-aminopyrimidine. The reaction was followed by the NMR spectroscopy. VT NMR studies prove that in solution two major species are observed: aminal and imine and their ratio depends on the time or/and temperature with the imine content increasing...
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ortho-Fluorobenzanilides and ortho-fluorothiobenzanilides: Molecular conformations and crystal packing
PublikacjaSeries of 2-fluoro and 2,6-difluorobenzanilides and their thiobenzanilide analogs have been synthesized to investigate the influence of the fluorine atom on their crystal structures and self-assembly in the crystal lattice. The X-ray analysis of the single crystal revealed that the synthesized molecules adopt a geometry being deflected from planarity. The deflection was investigated by analysis of dihedral angles between mean planes...
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<i>N,N</i>'-diphenylthiourea acetone monosolvate
PublikacjaIn the title compound, C13H12N2S·C3H6O, the phenyl rings of the thiourea molecule are in syn and anti positions in relation to the C=S bond. Two molecules are connected by N-HS=C hydrogen bonds into a centrosymmetric dimer. An additional N-HO=C hydrogen bond to the acetone solvent molecule and some weak C-H interactions reinforce the crystal structure.
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Model silnika spalinowego w formie grafów wiązań (GW).A model of the IC engine in the form of the bond graph (BG).
PublikacjaPrzedstawiono uzasadnienie użycia metody grafów wiązań do do modelowania silnika spalinowego jako źródła energii w systemach energetycznych składających się z elementów o różnej naturze fizycznej, na przykład w pojazdach hybrydowych. Przedstawiono propozycję formalizacji charakterystyki silników spalinowych wynikającą z przyjętej metody modelowania. Analityczną formę charakterystyki przedstawiono jako wielowymiarową funkcję wektorową....
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Peptide bond modification. I. Simple and efficient method of Boc-Gly[CH(OH)CH2]Gly-OH synthesis.
PublikacjaZaprezentowano prostą i efektywną metodę syntezy obu enancjomerów t-butoksykarbonylo chronionego pseudo dipeptydu (R) oraz (S)-Boc-Gly[CH(OH)CH2]Gly-OH.
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Multiple intermodal-vectorial four-wave mixing bands generated by selective excitation of orthogonally polarized LP01 and LP11 modes in a birefringent fiber
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Analiza oddziaływań w kryształach związków zawierających w strukturze pierścień pirydynowy
PublikacjaMożliwość tworzenia się wiązań wodorowych jest kluczowym parametrem z punktu widzenia inżynierii kryształu, ponieważ wiązania wodorowe mają bezpośredni wpływ na strukturę oraz trwałość sieci krystalicznej. Głównym celem niniejszej rozprawy doktorskiej była analiza porównawcza wiązań wodorowych występujących w układach, zawierających w strukturze pierścień pirydynowy. Badane układy podzielono na: (1) układy ze związkami krzemosiarkowymi...
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Thioamides and selenoamides with chirality solely due to hindered rotation about the C-N bond: enantioselective complexation with optically active hosts
PublikacjaBariera rotacji wokół wiązania C-N w tioamidach jest średnio o 3-5 kcal/mol wyższa niż w odpowiednich amidach, a w analogicznych selenoamidach wzrasta jeszcze o 1 kcal/mol. Dzięki temu związki te występują w dwu enancjomerycznych formach, których wzajemna przemiana zachodzi w wyniku rotacji wokół wiązań C-N. Bariera rotacji jest wystarczająco wysoka, aby można było podjąć próbę ich rozdziału na enancjomery w temperaturze pokojowej....
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Diphosphinoboranes as Intramolecular Frustrated Lewis Pairs: P–B–P Bond Systems for the Activation of Dihydrogen, Carbon Dioxide, and Phenyl Isocyanate
PublikacjaHerein, we present the first example of the activation of small molecules by P-B-P bond systems. The reactivity study involves reactions of two selected diphosphinoboranes, (tBu2P)2BPh (1’) and (Cy2P)2BNiPr2 (2), that differ in terms of their structural and electronic properties for the activation of dihydrogen, carbon dioxide, and phenyl isocyanate. Diphosphinoborane 1’ activates H2 under very mild conditions in the absence of...
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Unusual and Conventional Dative Bond Formation by s2 Lone Pair Donation from Alkaline Earth Metal Atoms to BH3, AlH3, and GaH3
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Activation of N2O and SO2 by the P–B Bond System. Reversible Binding of SO2 by the P–O–B Geminal Frustrated Lewis Pair
PublikacjaHerein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P−B bond and formation of a P−O−B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively.
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Intermolecular Hydrogen Bonding Directed by Aryl–Perfluoroaryl π–π Stacking Interactions
PublikacjaThe crystal structures of five compounds capable of forming self-complementary hydrogen bonds but crystallizing as catemers or creating more complex crystal structures were compared with their complexes prepared by cocrystallization with perfluoroaryl compounds. The results of X-ray diffraction revealed that in all the cases the π–π stacking interactions caused reorganization of hydrogen bonds and induced creation of the expected...
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Molecular Structures of the Phospha-Wittig Reaction Intermediate: Initial Step in the Synthesis of Compounds with a C═P–P Bond as Products in the Phospha-Wittig Reaction
PublikacjaThe phospha-Wittig reactivity ofβ-diketiminate titanium(III) complexes with phosphanylphosphido ligands was investigated. The reactions of [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] and [MeNacNacTi(Cl){η2-P(SiMe3)-P(Ph)tBu}] with acetone conducted in toluene solution under mild conditions led to the phospha-Wittig intermediates [{(ArN=C(Me)CHC(Me)=NAr)(C(Me)2O}Ti(Cl){PtBu2-P(SiMe3)C(Me)2O}] (1) and [{(ArN=C(Me)CHC(Me)=NAr) (C-(Me)2O}Ti(Cl){P(Ph)tBu-P(SiMe3)C(Me)2O}]...
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Hydration of Oxometallate Ions in Aqueous Solution
PublikacjaThe strength of hydrogen bonding to and structure of hydrated oxometallate ions in aqueous solution have been studied by double difference infrared (DDIR) spectroscopy and large-angle X-ray scattering (LAXS), respectively. Anions are hydrated by accepting hydrogen bonds from the hydrating water molecules. The oxygen atom of the permanganate and perrhenate ions form weaker and longer hydrogen bonds to water than the hydrogen bonds...
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1,3-Di-<i>n</i>-butylthiourea
PublikacjaIn the title compound, C9H20N2S, the n-butyl groups are in syn and anti positions in relation to the C=S bond. In the crystal, two molecules are connected by two N-H···S=C hydrogen bonds into a centrosymmetric dimer. Another N-H···S=C hydrogen bond links the dimers, forming layers with a hydrophilic interior and a hydrophobic exterior, which spread across the (100) plane. Interlacing of the...
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Bonding in Phosphanylphosphinidene Complexes of Transition Metals and their Correlation with Structures, 31 P NMR Spectra, and Reactivities
PublikacjaTheoretical studies of the bonding interactions and most important properties are carried out for isolable phosphanylphosphinidene complexes of transition metals. Three main types of phosphanylphosphinidene complexes are distinguished, based on the way in which the phosphanylphosphinidene ligand bonds to the metal center: (i) side-on complexes of platinum, where the R2Pβ–Pα ligand mimics structural features of free singlet phosphanylphosphinidenes...
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SPECYFIKA OBLIGACJI ZAMIENNYCH EMITOWANYCH PRZEZ SPÓŁKI PUBLICZNE
PublikacjaUpublicznienie rynku instrumentów dłużnych przedsiębiorstw w Polsce umożliwiło spółkom bardziej efektywne pozyskiwanie środków finansowych poprzez zaciąganie długu u wierzycieli detalicznych, równolegle z istniejącą już możliwością pozyskiwania kapitałów własnych. Rynek ten otworzył także spółkom publicznym drogę do emisji obligacji zamiennych, które z kolei bez obecności instrumentów udziałowych emitenta na rynku publicznym, stają...
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N-phosphonomethylglycine utilization by the psychrotolerant yeast Solicoccozyma terricola M 3.1.4.
PublikacjaSolicoccozymaterricolaM 3.1.4., the yeast strain isolated from soil sample from blueberry cultivation in MiedzyrzecPodlaski in Poland, is capable to split of phosphorus to nitrogen and nitrogen to carbon bonds inN-phosphono-methylglycine (PMG, glyphosate). The biodegradation process proceeds in the phosphate-independent manner. Itis the first example of a psychrotolerant yeast strain able to degrade PMGviaCeN bond cleavage accompanied...
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Investigation of tetrabutylammonium bromide-glycerol-based deep eutectic solvents and their mixtures with water by spectroscopic techniques
PublikacjaDeep eutectic solvents (DES) are formed by an acceptor and a donor of hydrogen bonds. They are generally considered as a possible alternative to hazardous organic solvents in various fields. Very recently they have also appeared in analytical chemistry, used mainly for the separation of analytes before instrumental quantification. For the development of new extraction procedures, it is important, among other things, to understand...
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Impact of selected amino acids of HP0377 (Helicobacter pylori thiol oxidoreductase) on its functioning as a CcmG (cytochrome c maturation) protein and Dsb (disulfide bond) isomerase
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Bond graph modeling of the new generation engine cooling systems = Zastosowanie metody grafów wiązań do modelowania nowej generacji układów chłodzenia silników spalinowych
PublikacjaW referacie szczegółowo opisano modele wymiany ciepła i przepływów w układzie chłodzenia. Metoda grafów wiązań okazała się szczególnie użyteczną dla modelowania skomplikowanych systemów energetycznych o różnych postaciach energii. Jako przykładu użyto obiegu chłodzenia silnika badawczego na hamowni silnikowej.
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Closer look into the structures of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water
PublikacjaIn recent years, deep eutectic solvents (DES) and it’s mixture with water have become more and more attention as green solvents used in chemistry. However, there are only a few theoretical studies on the mechanisms of pure DES and DES-water complex formation. Therefore, the structural properties of tetrabutylammonium bromide–glycerol-based deep eutectic solvents and their mixtures with water have been investigated by means of Molecular...
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The structure of novel polyurethanes containing synthetic poly[(R,S)-3-hydroxybutyrate]
PublikacjaThe aim of this study was to estimate the structure of new polyurethanes with the potential to be used in medicine. Atactic poly[(R,S)-3-hydroxybutyrate], obtained via a ring-opening polymerization, and polycaprolactonediol or polyoxytetramethylenediol were used to built the soft segments. 4,4'-methylene dicyclohexyl diisocyanate and 1,4-butanediol were the components to form hard segments. Polyurethanes with low-molecular weight...
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Syntheses and Structures of Transition Metal Complexes with Phosphanylphosphinidene Chalcogenide Ligands
PublikacjaThe reactivity of the phosphanylphosphinidene complex [(DippN)2W(Cl)(η2-P-PtBu2)]− (1) toward chalcogens (Ch = Se, S) was studied. Reactions of stoichiometric amounts of 1 with chalcogens in DME yielded monomeric tungsten complexes with phosphanylphosphinidene chalcogenide ligands of the formula tBu2P−P−Ch (Ch = Se (in 2) and S (in 5)), which can be regarded as products of the addition of a chalcogen atom to a P=W bond in starting...
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The CON−H…+NH2 Blue-Shifting H-Bond Stabilizing Effect on Z Secondary Amides and Cyclic System Conformational Rearrangement through an Alkylamine-Chain Migration Pathway
PublikacjaThe paper is focusing on the amide linkage exceptional properties and usage of chemistry (conformational rearrangement, geometrical stereoisomers, spectroscopic blue shift phenomenon, protonation and deprotonation reactions, synthetic scope, and mechanistic implications). Hydrogen-bond-stabilized acylation reactions of a diamine with thioamides or nitriles reveal how substituents influence both the outcome of stereoselectivity...
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Investor confidence and high financial literacy jointly shape investments in risky assets
PublikacjaHouseholds consistently invest less in equities and bonds than predicted by economic theory. We explain this from a behavioral economics perspective and distributional analysis using rich US survey microdata. We find that higher investor self-confidence in her financial abilities and financial literacy jointly increase the probability of investing in equities. Conditional on participation, confidence in the macroeconomy additionally...
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Interactions of fish gelatin and chitosan in uncrosslinked and crosslinked with EDC films: FT-IR study
PublikacjaFilms based on fish gelatin, chitosan and blend of fish gelatin and chitosan before and after cross-linking with EDC have been characterized by FT-IR spectroscopy. The FT-IR spectrum of fish gelatin film showed the characteristic amide I, amide II and amide III bands, and the FT-IR spectrum of chitosan film confirmed that the polymer was only a partially deacetylated product, and included CH3-C=O and NH2 groups, the latter both...
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Hydration of amino acids: FTIR spectra and molecular dynamics studies
PublikacjaThe hydration of selected amino acids, alanine, glycine, proline, valine, isoleucine and phenylalanine, has been studied in aqueous solutions by means of FTIR spectra of HDO isotopically diluted in H2O. The difference spectra procedure and the chemometric method have been applied to remove the contribution of bulk water and thus to separate the spectra of solute-affected HDO. To support interpretation of obtained spectral results,...
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Photoelectrochemical activity of visible light-responsive BiVO4@La1-xSrxFeO3-δ (x = 0, 0.2, 0.4) heterojunction architectures – Optimizing activity by tuning Fe O bond in perovskites
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Investor confidence and high financial literacy jointly shape investments in risky assets
PublikacjaHouseholds consistently invest less in equities and bonds than predicted by economic theory. We explain this from a behavioral economics perspective and distributional analysis using rich US survey microdata. We find that higher investor self-confidence in her financial abilities and financial literacy jointly increase the probability of investing in equities. Conditional on participation, confidence in the macroeconomy additionally...
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Crystallographic study of self-organization in the solid state including quasi-aromatic pseudo-ring stacking interactions in 1-benzoyl-3-(3,4-dimethoxyphenyl)thiourea and 1-benzoyl-3-(2-hydroxypropyl)thiourea
Publikacja1-Benzoylthioureas contain both carbonyl and thiocarbonyl functional groups and are of interest for their biological activity, metal coordination ability and involvement in hydrogen-bond formation. Two novel 1-benzoylthiourea derivatives, namely 1-benzoyl-3-(3,4-dimethoxyphenyl)thiourea, C₁₆H₁₆N₂O₃S, (I), and 1-benzoyl-3-(2-hydroxypropyl)thiourea, C₁₁H₁₄N₂O₂S, (II), have been synthesized and characterized. Compound (I) crystallizes...
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A competition between two- and three-body dissociation channels in photo-double-ionization of tetrahydro-2H-pyran and 3,4-dihydro-2H-pyran molecules
PublikacjaVarious molecules possess structures consisting of the heterocyclic rings containing oxygen atoms. These substances often play a significant role in many different fields of chemistry, medicine, and biology. Due to a specific atomic composition and bond arrangement, many of these molecules retain unique electronic properties, which may be probed by diverse spectroscopic techniques, including those utilizing synchrotron radiation....
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The hydrogen bond network structure within the hydration shell around simple osmolytes: Urea, tetramethylurea, and trimethylamine-N-oxide, investigated using both a fixed charge and a polarizable water model
PublikacjaDespite numerous experimental and computer simulation studies, a controversy still exists regarding the effect of osmolytes on the structure of surrounding water. There is a question, to what extent some of the contradictory results may arise from differences in potential models used to simulate the system or parameters employed to describe physical properties of the mixture and interpretation of the results. Bearing this in mind,...
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The hydrogen bond network structure within the hydration shell around simple osmolytes: Urea, tetramethylurea, and trimethylamine-N-oxide, investigated using both a fixed charge and a polarizable water model
PublikacjaDespite numerous experimental and computer simulation studies, a controversy still exists regarding the effect of osmolytes on the structure of surrounding water. There is a question, to what extent some of the contradictory results may arise from differences in potential models used to simulate the system or parameters employed to describe physical properties of the mixture and interpretation of the results. Bearing this in mind,...
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Structural and dynamic changes adopted by EmrE, multidrug transporter protein—Studies by molecular dynamics simulation
PublikacjaEmrE protein transports positively charged aromatic drugs (xenobiotics) in exchange for two protons and thus provides bacteria resistance to variety of drugs. In order to understand how this protein may recognize ligands, the monomer and asymmetric apo-form of the EmrE dimer embedded in a heterogeneous phospholipid (POPE + POPG) membrane were studied by molecular dynamics simulations. Dimer is regarded as a functional form of the...
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Morphology, surface properties and photocatalytic activity of the bismuth oxyhalides semiconductors prepared by ionic liquid assisted solvothermal method
PublikacjaThis is the first report of the effect of the ILs cation type (imidazolium, pyridinium and pyrrolidinium) on the morphology, surface properties and photoactivity of BiOX semiconductors type obtained by solvothermal method in glycerol. The various ionic liquids (IL) cation type as a halogen source and templating agent for the synthesis of the bismuth oxyhalides nanoparticles has been systematically investigated. The role of ILs...
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DFT study of low-energy electron interaction with pyridine, pyrazine and their halo derivatives
PublikacjaIn this work, the density functional theory with B3LYP hybrid functional was employed to calculate quantities useful for estimating the behavior of pyridine, pyrazine and their derivatives monosubstituted with Cl or Br atom, when exposed to low-energy electron impact. Vertical electron affinities obtained in several Pople basis sets and in aug-cc-pVTZ basis set are reported. Although some of the investigated molecules do not form...
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On thio‐substituted N‐heterocyclic arsines
PublikacjaMetathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic...
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Dissociative photo-double-ionization of the isoxazole molecules
PublikacjaThe five-membered heterocyclic rings are incorporated into a wide variety of structures that play a vital role in many biochemical processes. In particular, the isoxazole molecule appears in many bioactive compounds due to its unique ring structure that consists of one oxygen atom and one nitrogen atom at adjacent positions. The unique atomic composition and bond arrangement of isoxazole imply its specific electronic properties...
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Correlation between the Reactivity and Spectroscopic Properties of N-Substituted Secondary Thioamides. New Intramolecular N• •H+• •N Binding Approach and Proton Complexes Based on Thioamide Ligation
PublikacjaFrom a comparison of chem. shifts and wavenumbers of several secondary thioamides and amides having monocationic substituents attached to thiocarbamoyl or carbamoyl groups by a polymethylene chain, new intramol. unconventional N···H+···N H bonding effects were discovered. It is argued that the CH2-N rotation is hindered and two +H···NHMe nonequiv. protons occur in a proton spectrum of hydrochloride RCH2C(S)NH(CH2)3NHMe-HCl...
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Structural properties of hydration shell around various conformations of simple polypeptides
PublikacjaIn this paper we investigate structural properties of water within the solvation shell around the peptide core created by a well-defined conformation of polypeptide chain. The following secondary structures are investigated: linear (straight chain), and three helices PII (polyproline-like), 310, and α. We propose using the two-particle contribution to entropy as a rational measure of the water structural ordering within the solvation...