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Wyniki wyszukiwania dla: DFT
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Electronic structure calculations in electrolyte solutions: Methods for neutralization of extended charged interfaces
PublikacjaDensity functional theory (DFT) is often used for simulating extended materials such as infinite crystals or surfaces, under periodic boundary conditions (PBCs). In such calculations, when the simulation cell has non-zero charge, electrical neutrality has to be imposed, and this is often done via a uniform background charge of opposite sign (“jellium”). This artificial neutralization does not occur in reality, where a different...
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Exploring thiophene-2-acetate and thiophene-3-acetate binding modes towards the molecular and supramolecular structures and photoluminescence properties of Pb(ii) polymers
PublikacjaTo evaluate the impact of the flexible positional isomeric ligands thiophene-2-acetate (2tpacCOO) andthiophene-3-acetate (3tpacCOO) on the construction and self-assembly process of Pb(II) polymers, twonovel compounds, [Pb(2tpacCOO)2(H2O)]n(1) and [Pb(3tpacCOO)2]n(2), were preparedviaanonhydro-thermal method with respect to green chemistry rules. The obtained polymers were fully characterized byelemental analysis, TG/DTG and PXRD,...
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Linear-scaling calculation of Hartree-Fock exchange energy with Non-orthogonal Generalised Wannier Functions
PublikacjaWe present a method for the calculation of four-centre two-electron repulsion integrals in terms of localised non-orthogonal generalised Wannier functions (NGWFs). Our method has been imple- mented in the ONETEP program and is used to compute the Hartree-Fock exchange energy component of Hartree-Fock and Density Functional Theory (DFT) calculations with hybrid exchange-correlation functionals. As the NGWFs are optimised in situ...
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A comparison of structural and luminescence properties of lead(II) coordination polymers with isomeric thiophenecarboxylate ligands
PublikacjaTwo new lead(II) coordination polymers with isomeric thiophenecarboxylates, namely [Pb(2tpCOO)2]n (1) and [Pb(3tpCOO)2(H2O)]n (2) (2tpCOO− = thiophene-2-carboxylate, 3tpCOO− = thiophene-3-carboxylate), were synthesized and characterized. Single crystal X-ray crystallography revealed a distorted pentagonal pyramidal geometry {PbO6} around Pb in 1 and a distorted dodecahedral geometry {PbO8} in 2. The distortion derived from the...
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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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In situ transformation boosts the pseudocapacitance of CuNi-MOF via cooperative orientational and electronic governing
PublikacjaThe disordered arrangement and thereof inferior conductivity of 2D MOF sheets seriously hinder their practical application. Herein, we propose in situ transformation strategy to architect vertically oriented bimetallic CuNi-MOF as a self-supporting electrode, leading to a decuple high specific capacitance of 1262 C g-1 in comparison with the pristine Ni-MOF powder of 114 C g-1 at 2 A g-1. DFT calculations reveal that introduction...
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Unraveling Energy Transfer and Fluorescence Quenching Dynamics in Biomolecular Complexes: A Comprehensive Study of Imiquimod-Rifampicin Interaction.
PublikacjaIn nature, numerous biomolecules are implicated in charge transfer (CT) and energy transfer (ET) mechanisms crucial for fundamental processes such as photosynthesis. Unveiling these mechanisms is pertinent to multiple disciplines including chemistry, engineering and biochemistry. This letter presents a study involving two molecules forming a model system with efficient ET properties. Specifically, their complex exhibits dark quenching...
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Structural properties of hypothetical CeBa2Cu3O7 compound from LSDA+DMFT calculations
PublikacjaThe hypothetical stoichiometric CeBa2Cu3O7 (Ce123) compound, which has not been synthesized as a single phase yet, was studied by the density functional theory (DFT). We utilized a method which merges the local spin density approximation (LSDA) with the dynamical mean-field theory (DMFT) to account for the electronic correlations. The LSDA+DMFT calculations were performed in the high-temperature range. The particular emphasis was...
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Synthesis and characterization of mononuclear Zn(II), Co(II) and Ni(II) complexes containing a sterically demanding silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol
PublikacjaFour heteroleptic complexes of zinc(II), cobalt(II) and nickel(II) containing a monodentate silanethiolate ligand derived from tris(2,6-diisopropylphenoxy)silanethiol (TDST), were prepared and characterized. The geometries of ligands in the complexes are typical: distorted tetrahedral in zinc and cobalt(II) complexes and square planar in nickel(II) compound. Magnetic studies performed for Ni(II) and Co(II) compounds confirm the...
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Compressible gas density measurement by means of Fourier analysis of interferograms
PublikacjaThis paper describes a method for nonintrusive compressible gas density measurement by means of automated analysis of interferograms using FFT (Fast Fourier Transform), and its implementation using DFT (Discrete Fourier Transform), that does make this measurement technique a fairly valuable and accessible experimental method. The presented approach makes it possible to use the finite fringe setting of the interferometer, thus reducing...
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Stability and phase transition investigation of olanzapine polymorphs
PublikacjaWe use electrical embedded-fragment QM method with both DFT/ωB97XD/6-31G* and MP2/6-31G* to investigate the phase transformations of olanzapine. Gibbs free energy calculations predict that form I is always the most stable structure and form II is the least stable one, while form IV is more stable than form III below about 200 K but less stable above this temperature, implying a polymorphic phase transformation. This may account...
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Optimization of Hydrogen - Evolving Photochemical Molecular Devices
PublikacjaA molecular photocatalyst consisting of a RuII photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light-driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy...
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Relationship between electronic structure and geometry of silanethiols and their derivatives. Elucidation of copper group silanethiolates
PublikacjaWyznaczono strukturę elektronową wybranych silanotioli X3SiSH (dla X=H, C2H5, OCH3, F, Cl i Br) oraz powstalych z nich anionów. Geometrię i funkcje falowe wyznaczono przy użyciu teorii funcjonałów gęstości elektronowej DFT. Przeanalizowano wpływ efektów anomerycznych oraz wielkości calki nakładania sigma(Si-S) na obserwowane skrócenie wiązania Si-S przy deprotonowaniu silanotioli. Podano nowe wyjaśnienie wyjątkowo niskiej kwasowości...
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Unassisted formation of hemiaminal ether from 4-aminopyridine and o-vanillin - experimental and theoretical study
PublikacjaThe reactions between o-vanillin and three isomeric aminopyridines lead to imines of diverse spatial conformation and reactivity. The direct products of these simple reactions carried out in methanol are either imine compounds formed in the reactions of 2- amino- and 3-aminopyridine with o-vanillin or the α-aminoether formed in the reaction of o-vanillin with 4-aminopyridine. The Schiff-type derivative of 4-aminopyridine and o-vanillin,...
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Protein thermal stabilization in aqueous solutions of osmolytes
PublikacjaProteins’ thermal stabilization is a significant problem in various biomedical, biotechnological, and technological applications. We investigated thermal stability of hen egg white lysozyme in aqueous solutions of the following stabilizing osmolytes: Glycine (GLY), N-methylglycine (NMG), N,N-dimethylglycine (DMG), N,N,N-trimethylglycine (TMG), and trimethyl-N-oxide (TMAO). Results of CD-UV spectroscopic investigation were compared...
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Do positrons measure atomic and molecular diameters?
PublikacjaWe report on density functional calculations (DFT) of elastic integral scattering cross-sections for positron collisions with argon, krypton, nitrogen and methane. The long-range asymptotic polarization potential is described using higher-order terms going much beyond an induced dipole potential (−α / r 4) while the short-range interaction is modeled by two different forms of electron – positron correlation potential (Boroński-Nieminen...
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Li nucleation on the graphite anode under potential control in Li-ion batteries
PublikacjaApplication of Li-ion batteries in electric vehicles requires improved safety, increased lifetime and high charging rates. One of the most commonly used intercalation anode material for Li-ion batteries, graphite, is vulnerable to Li nucleation, a side reaction which competes with the intercalation process and leads to loss of reversible capacity of the battery, ageing and short-circuits. In this study, we deploy a combined grand...
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Prediction of Overall In Vitro Microsomal Stability of Drug Candidates Based on Molecular Modeling and Support Vector Machines. Case Study of Novel Arylpiperazines Derivatives
PublikacjaOther than efficacy of interaction with the molecular target, metabolic stability is the primary factor responsible for the failure or success of a compound in the drug development pipeline. The ideal drug candidate should be stable enough to reach its therapeutic site of action. Despite many recent excellent achievements in the field of computational methods supporting drug metabolism studies, a well-recognized procedure to model...
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Theoretical study of the structure, energetics and vibrational frequencies of water-acetone and water-2-butanone complexes
PublikacjaKompleksy acetonu i 2-butanonu z 0-2 cząsteczkami wody połączonymi wiązaniem wodorowym z tlenem karbonylowym zbadano z wykorzystaniem teorii funkcjonału gęstości (DFT) na poziomie B3LYP/6-311++G(d,p). Obliczenia w fazie gazowej uzupełniono o optymalizacje w otoczeniu rozpuszczalnika, symulowanego za pomocą modelu polaryzowalnego kontinuum (PCM). Częstości drgań oscylacyjnych otrzymane na podstawie zależności empirycznej sa zgodne...
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Mixed-ligand complexes of zinc(II), cobalt(II) and cadmium(II) with sulfur, nitrogen and oxygen ligands. Analysis of the solid state structure and solution behavior. Implications for metal ion substitution in alcohol dehydrogenase
PublikacjaScharakteryzowano strukturę heteroleptycznych kompleksów cynku(II), kobaltu(II) i kadmu(II) z 2-(2'-hydroksyetylopirydyną), tri-tert-butoksysilanotiolem i metanolem. Przy pomocy widm UV-Vis i NMR stwierdzono szybką wymianę N-liganda w roztworach tych kompleksów. Wyznaczono przesunięcia 15N NMR 2-(2'-hydroksyetylopirydyny) w kompleksach cynku(II) i kadmu(II). Na podstawie widm w podczerwieni i obliczeń DFT oszacowano względną moc...
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Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
PublikacjaWe report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies....
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Reactivity of bulky aminophosphanes towards small molecules: Activation of dihydrogen and carbon dioxide by aminophosphane/borane frustrated Lewis pairs
PublikacjaA series of mono- and bisaminophosphanes with formulas R2NPR’R’’ and (R2N)2PR’ (R = iPr, Cy; R’ = Ph, Cy; R’’ = iPr) were characterized by X-ray analysis, NMR spectroscopy and computational methods. The common structural futures of these species are short and polarized PAN bonds, a pyramidal geometry at the P atom and an almost planar geometry at the N atoms. According to DFT calculations, these...
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Crystal structure and electronic structure of CePt2In7
PublikacjaWe report a corrected crystal structure for the CePt2In7 superconductor, refined from single crystal x-ray diffraction data. The corrected crystal structure shows a different Pt–In stacking along the c-direction in this layered material than was previously reported. In addition, all of the atomic sites are fully occupied with no evidence of atom site mixing, resolving a discrepancy between the observed high resistivity ratio of...
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Comparison of the coordination geometries of Zn(II) and Cd(II) ions in complexes with water, methanol and bulky aryloxysilanethiolate ligands
PublikacjaZinc and cadmium complexes containing silanethiolate anions and methanol or water were synthesized and characterized by X-ray diffraction, FT-IR and NMR spectroscopy, and DFT calculations. Contrary to zinc, the cadmium ion utilizes very weak donors to complete its coordination sphere; it forms contacts to phenyl rings of the silanethiolate ligand. Two zinc analogs of the general formula [Zn{SSi(OAr)3}2(L)2] where L = CH3OH (2)...
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A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
PublikacjaIn this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations...
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Theoretical pKa prediction of O-phosphoserine in aqueous solution
PublikacjaSprawdzono zdolność modelu polaryzowalnego kontinuum (PCM) do przewidywania wartości pKa w roztworze wodnym dla O-fosfoseryny (P-Ser). Obliczenia przeprowadzono w ramach teorii funkcjonału gęstości (DFT) przy użyciu funkcjonałów B3LYP i M06-2X oraz baz 6-31+G(d) and 6-31+G(d,p). Obliczenia na poziomie B3LYP/6-31+G(d,p) przy użyciu modelu solwatacji SMD zapewniają doskonałą zgodność z doświadczeniem, pod warunkiem uwzględnienia...
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Method using square-pulse excitation for high-impedance spectroscopy of anticorrosion coatings
PublikacjaArtykuł prezentuje metodę spektroskopii impedancyjnej przeznaczonej do diagnostyki powłok antykorozyjnych na obiektach bezpośrednio w terenie. Aby skrócić czas uzyskania widma impedancji (w zakresie od 1 mHz do 1 MHz) do kilku minut, wykorzystano sygnały harmoniczne do pomiaru widma powyżej 10 Hz a impuls prostokątny w dolnym zakresie częstotliwości. Do wyznaczania widma użyto algorytmów DSP odpowiednich do sygnału pobudzenia....
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Experimental and theoretical studies on the photodegradation of 2-ethylhexyl 4-methoxycinnamate in the presence of reactive oxygen and chlorine species
Publikacja2-Ethylhexyl 4-methoxycinnamate (EHMC) is one of the most commonly used sunscreen ingredient. In this study we investigated photodegradation of EHMC in the presence of such common oxidizing and chlorinating systems as H2O2, H2O2/HCl, H2O2/UV, and H2O2/HCl/UV. Reaction products were detected by gas chromatography with a mass spectrometric detector (GC-MS). As a result of experimental studies chloro-substituted 4-methoxycinnamic...
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Analizator do spektroskopii wysokoimpedancyjnej obiektów technicznych modelowanych obwodami elektrycznymi.
PublikacjaW pracy przedstawiono prototyp analizatora do spektroskopii wysokoimpedancyjnej przeznaczonego do diagnostyki powłok antykorozyjnych w warunkach laboratoryjnych oraz terenowych. Obiekt mierzony o module impedancji do 100Gohm jest dołączany do analizatora za pomocą sondy pomiarowej dwuzaciskowej dla obiektów uziemionych lub trzyzaciskowej w przypadku obiektów nieuziemionych. W sondzie są wydzielane dwa sygnały proporcjonalne do...
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Hydration of Simple Carboxylic Acids from Infrared Spectra of HDOand Theoretical Calculations
PublikacjaBadanie hydratacji kwasów karboksylowych w rozcieńczonych roztworach wodnych ma duże znaczenie dla zrozumienia ich funkcji biologicznych. Metodą stosowaną w badaniach była spektroskopia oscylacyjna FTIR z zastosowaniem techniki rozcieńczenia izotopowego wody półciężkiej HDO w roztworze wody zwykłej. Do analizy danych widmowych wykorzystano ''metodę widm różnicowych''. Widma HDO zaburzonej przez kwasy: mrówkowy, octowy i propionowy...
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Local Conformation and Cocrystallization Phenomena in Renewable Diaminoisoidide-Based Polyamides Studied by FT-IR, Solid State NMR, and WAXD
PublikacjaBiobased polyamides synthesized from diaminoisoidide (DAII), 1,4-diaminobutane, and sebacic acid are investigated by FT-IR, 13C{1H} magic-angle spinning/cross-polarization (CP/MAS) NMR spectroscopy, and WAXD. Their molecular conformation and mobility undergo distinct changes as a function of temperature and diaminoisoidide content in the compositions. The presence of randomly distributed diaminoisoidide (DAII) in the polyamides...
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Current harmonic controller in multiple reference frames for series active power filter integrated with 18-pulse diode rectifier
PublikacjaThe paper presents the control system and selected results of experimental tests of the AC/DC power converter consisting of an 18-pulse diode rectifier based on coupled reactors and a serial active power filter. Proportional integral controllers with decoupling components are implemented in multiple reference frames for selective line current harmonic suppression. The regulator is provided with a backtracking anti-windup mechanism...
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Proton transfer and hydrogen bonds in supramolecular, self-assembled structures of imidazolium silanethiolates. X-ray, spectroscopic and theoretical studies
PublikacjaThe reaction of 1-methylimidazole, 2-ethyl-4-methylimidazole and 2-ethylimidazole with tris(2,6- diisopropylphenoxy)silanethiol (TDST) leads to the formation of three new salts, which have been characterized by elemental analyses, thermogravimetric analyses, FTIR spectroscopy, and their structures were determined by single-crystal X-ray diffraction. Structural analyses indicate that in all three compounds a proton transfer has...
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Theoretical studies of fragmentation processes of neutral and ionized furan molecule
PublikacjaThis PhD thesis focuses on the fragmentation mechanism of the furan molecule in the gas phase. The approach taken in this work comprised of three theoretical methodologies considering the dynamical, energetical and entropic aspects of the studied process. First, molecular dynamics simulations were performed. Next, the potential energy surfaces were explored at the DFT/B3LYP level of theory. Finally, a new statistical Microcanonical...
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Mechanism of Li nucleation at graphite anodes and mitigation strategies
PublikacjaLithium metal plating is a critical safety issue in Li-ion cells with graphite anodes, and contributes significantly to ageing, drastically limiting the lifetime and inducing capacity loss. Nonetheless, the nucleation mechanism of metallic Li on graphite anodes is still poorly understood. But in-depth understanding is needed to rationally design mitigation measures. In this work, we conducted FirstPrinciples studies to elucidate...
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Hydration of simple amides. FTIR spectra of HDO and theoretical studies
PublikacjaZastosowano metodę ważonych widm różnicowych do opisu hydratacji amidów w roztworach wodnych: formamidu, N-metyloformamidu, N,N-dimetyloformaidu, acetamidu, N-metyloacetamidu, N,N-dimetyloacetamidu. Narzędziem wspomagającym interpretację wyników eksperymentalnych są struktury agregatów solwatacyjnych wokół cząsteczki substancji rozpuszczonej uzyskane na podstawie obliczeń teoretycznych metodą ab initio z korelacją elektronową...
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Comparison of effectiveness of musical sound separation algorithms employing neural networks.
PublikacjaNiniejszy referat przedstawia kilka algorytmów służących do separacji dźwięków instrumentów muzycznych. Zaproponowane podejście do dekompozycji miksów dźwiękowych opiera się na założeniu, że wysokość dźwięków w miksie jest znana, tzn. wejściem dla algorytmów jest przebieg zmian wysokości dźwięków składowych miksu. Proces estymacji fazy i amplitudy składowych harmonicznych wykorzystuje dopasowywanie zespolonych przebiegów harmonicznych...
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Electronic structure of TbBa2Cu3O7
PublikacjaW pracy wykonano obliczenia kwantowomechaniczne struktury elektronowej hipotetycznego materiału TbBa2Cu3O7 (Dy123) metodą FP-LAPW (full potential - linearized augmented plane wave) w ramach formalizmu DFT (density functional theory) stosując przybliżenie GGA (generalized gradient approximation). Ze względu na silne oddziaływania korelacyjne elektronów 4f w atomie Tb zastosowano dodatkowo poprawkę kulombowską U w ramach modelu...
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Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents
PublikacjaThe paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate have been...
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Theoretical and Experimental Studies on the Visible Light Activity of TiO2 Modified with Halide-Based Ionic Liquids
PublikacjaFormation of a surface complex between organic molecules and TiO2 is one of the possible strategies for the development of visible light-induced TiO2 photoactivity. Herein, three ionic liquids (ILs) with the same cation and dierent anions (1-butylpirydynium chloride/bromide/iodide) have been applied for the surface modification of TiO2 and to understand the role of anions in visible light-induced activity of ILs-TiO2 systems. Photocatalytic...
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Density functional LCAO calculations of vibrational modes and phonon density of states in the strained single-layer phosphorene
PublikacjaThe paper presents an investigation of phosphorene under axial strain on the phonon density of states and vibrational modes. The studies were performed by means of density functional theory (DFT) within the linear combination of atomic orbitals (LCAO). The strained models were constructed using optimised supercell techniques. The vibrational mode spectra were estimated for strains applied for both the zigzag and armchair directions...
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Tuning the work function of graphite nanoparticles via edge termination
PublikacjaGraphite nanoparticles are important in energy materials applications such as lithium-ion batteries (LIBs), supercapacitors and as catalyst supports. Tuning the work function of the nanoparticles allows local control of lithiation behaviour in LIBs, and the potential of zero charge of electrocatalysts and supercapacitors. Using large scale density functional theory (DFT) calculations, we find that the surface termination of multilayer...
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Mechanochemically synthesized Mn3O4@β-cyclodextrin mediates efficient electron transfer process for peroxymonosulfate activation
PublikacjaThe rational surface engineering of heterogeneous catalysts is of great significance in advanced oxidation processes (AOPs) for eliminating refractory contaminants but remains challenging. In this study, β-cyclodextrin modified Mn3O4 (Mn3O4@β-CD) was prepared through a mechanochemical approach for peroxymonosulfate (PMS) activation, which achieved efficient bisphenol A (BPA) removal via electron transfer process (ETP). The reactive...
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Symmetrical and unsymmetrical diphosphanes with diversified alkyl, aryl and amino substituents
PublikacjaWe present the comprehensive study of diphosphanes with diversified substituents regarding their syntheses, structures, and properties. To this end, we have synthesized a series of novel unsymmetrical alkyl, aryl and amino-substituted diphosphanes of the general formula R1R2P-PR3R4 (where R1, R2, R3, R4 = tBu, Ph, Et2N or iPr2N) via salt metathesis reactionof halophosphanes with metal phosphides in high yield. We vastly expanded...
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Photoinduced electron transfer in 5-bromouracil labeled DNA. A contrathermodynamic mechanism revisited by electron transfer theories
PublikacjaThe understanding of the 5-bromouracil (BrU) based photosensitization mechanism of DNA damage is of large interest due to the potential applications in photodynamic therapy. Photoinduced electron transfer (ET) in BrU labeled duplexes comprising the 50 -GBrU or 50 -ABrU sequence showed that a much lower reactivity was found for the 50 -GBrU pattern. Since the ionization potential of G is lower than that of A, this sequence selectivity...
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Synthetic, Structural, and Spectroscopic Characterization of a Novel Family of High-Spin Iron(II) [(β-Diketiminate)(phosphanylphosphido)] Complexes
PublikacjaThis work describes a series of iron(II) phosphanylphosphido complexes. These compounds were obtained by reacting lithiated diphosphanes R2PP(SiMe3)Li (R = t-Bu, i-Pr) with an iron(II) β-diketiminate complex, [LFe(μ2-Cl)2Li(DME)2] (1), where DME = 1,2-dimethoxyethane and L = Dippnacnac (β-diketiminate). While the reaction of 1 with t-Bu2PP(SiMe3)Li yields [LFe(η1-Me3SiPPt- Bu2)] (2), that of 1 with equimolar amounts of i-Pr2PP(SiMe3)Li,...
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Unexpected Z/E isomerism of N-methyl-O-phosphothioyl benzohydroxamic acids, their oxyphilic reactivity and inertness to amines
PublikacjaThiophosphinoylation of N-methyl p-substituted benzohydroxamic acids using disulfanes (method A) or diphenylphosphinothioyl chloride (method B) provides only one conformer of the respective O-phosphothioyl derivative (Xray and NMR analysis). Undergoing the P-transamidoxylation reaction is an evidence of the reversibility of thiophosphinoylation. Only those products containing strong EWG substituents in the aroyl residue or bulky...
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The electronic structure of p-xylylene and its reactivity with vinyl molecules
PublikacjaThe electronic states of p-xylylene molecule were described at the multi-configurational CASSCF/MRMP2 level of theory. The closed-shell singlet state representing the quinoidal p-xylylene molecule was pre-dicted to be the ground electronic state whereas the triplet (benzoidal) and the singlet open-shell states were found to be much higher in energy (by 159 and 423 kJ/mol, respectively, as found at the CASSCF(8,8)/6-31+G(d) level)....
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Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study
PublikacjaA series of Er-, Yb-, Ho-, Tb-, Gd-, Pr-TiO2 nanotubes (RE-NTs) was prepared via an electrochemical method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis absorption, scanning electron microscopy (SEM) and luminescent spectroscopy. The experiments demonstrated that toluene in the gas phase was successfully degraded under visible light (LEDs λmax = 465...
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Towards sugar-derived polyamides as environmentally friendly materials
PublikacjaAs part of our ongoing study investigating isohexide-based polyamides, we have synthesized isosorbide(bis(propan-1-amine)) (DAPIS) and studied its reactivity in the polymerization towards fully biobased polyamides. Polycondensation of nylon salts with various contributions of DAPIS afforded a family of homo- and copolyamides, which were characterized using complementary spectroscopic techniques. The chemical structure of the materials...