Pawel Rodziewicz

Jan Kochanowski University | UJK · Institute of Chemistry

1-chloromethyl-1-fluorosilacyclopentane (1-ClM-1-FSiCP) was synthesized for the first time and investigated by means of vibrational spectroscopy and theoretical calculations. FT-IR and Raman spectroscopic methods were implemented to collect vibrational spectra of 1-ClM-1-FSiCP. The conformational analysis was performed utilizing FT-IR matrix isolat...

1-chloro-1-chloromethylsilacyclohexane (1-Cl-1-ClMSiCH) is a newly synthesized molecular compound whose conformational analysis was performed by means of vibrational spectroscopy and theoretical calculations. Conventional ATR-FTIR and Raman spectroscopic methods were used to obtain vibrational spectra of the liquid sample. Additionally, FTIR spectr...

Fulleropyrrolidine tris-acid (CPTA) has a wide scope of applications, therefore, we study its solubility in the series of organic solvents and aqueous solutions in a full pH range. Since the solubility, primarily depends on the physicochemical properties of the solute and the solvent but also varies due to the change of the external factors like te...

After World War II, based on decisions made at the Potsdam Conference in 1945, over 15 000 tons of chemical warfare agents (CWAs) were dumped in the Baltic Sea. These chemicals are still a threat to people and the maritime economy, but most of all to marine ecosystems. It is important to study the mechanisms of CWA reactions that could take place i...

Since 1-chloromethyl-1-fluorosilacyclohexane is a newly synthesized molecular compound its structural parameters and conformational stability is unknown. Raman and infrared vibrational spectroscopy methods were employed for analysis of this molecule. IR spectra were recorded for both gas phase and liquid sample, whereas the Raman experiments were p...

We investigate the adsorption of a chemical warfare agent, namely sulfur mustard (SM), on clean and water-saturated ZnO(101¯0) surfaces using density functional theory calculations to understand the first step of its efficient neutralization to less toxic chemical compounds. We determine the relative stability of various SM conformers adsorbed at d...

Tetrahydrofuran (THF) is a widely used chemical compound, in particular as a solvent in organic and inorganic synthesis. The THF molecule has also an interesting property, namely, undergoes pseudorotation, similar to the case of the cyclopentane. Low energy difference between the envelope (Cs symmetry) and twisted (C2 symmetry) conformations of the...

The molecular interactions between the commonly used solvent tetrahydrofuran (THF) and single-walled carbon nanotubes (SWCNT) are studied using density functional theory calculations and Car–Parrinello molecular dynamics simulations. The competitive interplay between THF–THF and THF–SWCNT interactions via C-H⋯O and C-H⋯π hydrogen bonds is analyzed...

Solubility–permeability relationship of active pharmaceutical ingredients determines the efficacy of their usage. Diclofenac (DCL), which is a widely used nonsteroidal anti-inflammatory drug, is characterized by extremely good membrane permeability, but low water solubility limiting drug effectiveness. The present research focuses on the fundamenta...

Diclofenac is the world known nonsteroidal anti-inflammatory drug (NSAID) predicted before its syntesis on the basis of the model COX enzyme. Due to its specific structural properties the drug possesses high reactivity and outstanding tolerability. Among the key features defining the diclofenac structure is intramolecular N-H ⋯O hydrogen bond confi...

The FTIR spectra of fluoroform trapped in argon and nitrogen matrices are studied at T~10 – 30 K. The bands of E symmetry show the splitting effect in a nitrogen matrix, which is absent in an argon matrix. The effect is the most prominent in the case of the ν4 CH bending vibration. It decreases slightly with increasing temperature. Both static and...

We used static DFT calculations to analyze in detail intramolecular hydrogen bonds formed in the low molecular weight polyethylene glycol (PEG) with two to five repeat subunits. Both conventional O-H$\cdots$O and improper C-H$\cdots$O H-bonds, which control the structural flexibility of PEG, were detected. To estimate the strength of these H-bonds...

Sulfur mustard (SM) is one of the most dangerous chemical compounds used against humans, mostly at war conditions but also in terrorist attacks. Even though the sulfur mustard has been synthesized over a hundred years ago, some of its molecular properties are not yet resolved. We investigate the structural flexibility of the SM molecule in the gas...

Because collagen is the most abundant component of connective tissue, it is an excellent biomaterial in numerous medical applications. However, the utility of collagen is limited by its low mechanical strength in aqueous solutions and its susceptibility to proteolytic degradation in vivo. To improve the physical properties of collagen and to enhanc...

Ab initio molecular dynamics simulations (AIMD) are used to investigate the influence of the vacancy- and divacancy (5-8-5) defects on the surface of single-walled carbon nanotube (SWCNT)(10,0) on the structural properties of covalently attached aromatic diisocyanate molecules, namely 4,4′-methylene diphenyl diisocyanate (MDI) and toluene-2,4-diiso...

The photocatalytic degradation of the prevalent colourful food additive, Food Yellow 13 (FY13), was examined in TiO2 and ZnO aqueous suspensions under solar irradiation. Series of physicochemical properties of the applied photocatalysts was determined. As a benchmark of the influence of the natural conditions, photocatalytic studies were performed...

Covalent sidewall functionalisation of defective zigzag single-walled carbon nanotubes [SWCNTs(10,0)] with COOH groups is investigated by using DFT. Four types of point defects are considered: vacancy (V), divacancy [V2 (5-8-5), V2 (555-777)], adatom (AA) and Stone-Wales (SW). The energetic, structural, electronic and vibrational properties of thes...

Ranitidine is a histamine H2-receptor antagonist that reduces gastric acid secretion. We studied the flexibility of the ranitidine molecule with the special focus on the network of diverse intramolecular hydrogen bonds: N-H ⋯O, N-H ⋯N, C-H ⋯O, C-H ⋯N and N-H ⋯S. We performed static density functional theory calculations of global and local minima a...

A reactant used globally in the production of polyurethane is the molecule 4,4'-methylene diphenyl diisocyanate (4,4'-MDI). The structural flexibility of 4,4'-MDI is one of the most important molecular properties influencing the polymerization process and this property was therefore modeled using density functional theory (DFT) calculations and Car...

The adsorption of fluoroform molecules on a hexagonal ice (0001) surface was studied using static density functional theory (DFT) calculations and Car-Parrinello molecular dynamics (CP-MD) simulations. Extending our previous work on isolated molecules we focus in the present study on the interplay between molecule-molecule and molecule-substrate in...

Ab initio calculations of NMR shielding constants of alkali earth metal ions in the series of water clusters are presented. The shielding constants for systems modeling the structure of the solvation layer of these ions are determined by adding to the coupled cluster singles-and-doubles (CCSD) results the calculated relativistic corrections. The re...

The asymmetric unit of the title compound, [Ru(CHN)](ClO), contains one octahedrally coordinated Ru cation of the ruthenium-phenanthroline complex and three differently occupied perchlorate anions: two, denoted and , are located on the twofold axis while another, denoted , is positioned in the proximity of the twofold screw axis. Perchlorate anions...

The asymmetric unit of the title compound, [Ru(C(15)H(11)N(3))(2)](ClO(4))(2)·0.5H(2)O, contains one ruthenium-terpiridine complex cation, two perchlorate anions and one half-mol-ecule of water. Face-to-face and face-to-edge π-stacking inter-actions between terpyridine units [centroid-centroid distances = 3.793 (2) and 3.801 (2)  Å] stabilize the c...

For isolated fluoroform (F(3)CH) molecules adsorbed on a hexagonal ice (0001) surface the properties of blue- and red-shifting hydrogen bonds were studied using static density functional theory (DFT) calculations and Car-Parrinello molecular dynamics (CP-MD) simulations. A systematic search by starting from many initial configurations was performed...

Ab initio molecular dynamics technique has been used to estimate the structural, electronic and vibrational properties of the blue-shifted hydrogen bonded CF3H center dot center dot center dot(HF)(1 <= n <= 3) complexes. Different reaction pathways and aggregation products have been studied as a function of temperature. The self-aggregation of HIF...

Dimerization of formic acid has been simulated using ab initio molecular dynamics at conditions mimicking rare gas matrix isolation experiments. Aggregation product distributions and the corresponding reaction pathways have been studied as a function of temperature. At higher temperatures, the cyclic, C(2h) symmetric, global minimum structure A wit...

Results of FTIR spectroscopic measurements in cryosolutions and ab initio calculations performed for a set of complexes stabilized by conventional and "improper" H-bonds have been presented and analyzed. The main attention is paid to the blue and red frequency shift effects on the stretching vibrations which were observed/or predicted for complexes...

Static and dynamic density functional theory calculations on CF3H dimer, trimer and tetramer are presented. All the structures analyzed present the cyclic C–H···F pattern. The energetic, geometrical and vibrational contributions resulting from cooperative ef- fects have been analyzed. The Car-Parrinello molecular dynamics technique has been used to...

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Butanone side chains at arenes and hetarenes, efficiently introduced by a Heck-type reaction, are transformed to annulated thieno[3,2-b]thiophenes in a domino redox process under Willgerodt-Kindler conditions. A nucleophilic aromatic substitution with an intermediary thioenolate is a reasonable key step of this process.

Solvent effect on the νc frequency of CH stretching vibration of the blue shifted F3CH…FCD3 complex has been studied in liquefied N2, CO, Ar, Kr and Xe. In the case of Xe, the spectroscopic measurements have also been extended to the solid state. It was found that the νc position of the complex in the solutions studied lowers with respect to the va...

The dimerization of formamide (FMA) has been investigated by matrix isolation spectroscopy, static ab initio calculations, and ab initio molecular dynamics (AIMD) simulations. Comparison of the experimental matrix IR spectra with the ab initio calculations reveals that two types of dimers A and C are predominantly formed, with two and one strong NH...

The structures and relative energies of the most stable conformers of both naked and microsolvated phenylalanine, Phe.(H(2)O)(n)(n=0-3), are calculated by density functional theory. For selected structures, coordination-constrained ab initio molecular dynamics simulations determine the proton-transfer mechanism connecting neutral and zwitterionic f...

The geometric and spectroscopic features as well as an interaction energy of Hal3CH/F2CD2 (Hal = F, Cl) and F3CH/FH heterodimers have been studied using MP2(full)/6-31+G(d,p) ab initio calculations, with a priori BSSE correction method. The decomposition of the interaction energy into physically distinct contributions has been performed in the fram...

Fluoroform, as confirmed by both experimental and theoretical studies, can participate in improper H-bond formation, which is characterized by a noticeable increase in the fundamental stretching frequency nu(C-H) (so-called blue frequency shift), an irregular change of its integral intensity, and a C-H bond contraction. A Car-Parrinello molecular d...

Fluoroform–CO interactions in the liquid phase at 100 K were studied by Car–Parrinello molecular dynamics (CPMD) calculations. The authors confirmed that this system can be characterized as a blue-shifted weak-hydrogen-bond system; their simulations show a blue-shifted fundamental stretching frequency with decreased intensity and a contraction of t...

The features of blue- and red-shifted electron acceptor-donor (ACH/B) hydrogen bonds have been compared by using quantum chemical calculations. The geometry, the interaction energy and the vibrational frequencies of both blue- (ACH=F3CH, Cl3CH with B=FCD3) and red-shifted (ACH=F3CH, Cl3CH with B=NH3 and ACH=CH3CCH with B=FCD3, NH3) complexes were o...

The FTIR spectra of F 3CH/FCD 3 and Cl 3CH/FCD 3 mixtures have been studied in liquefied Kr in the range of frequencies ˜500-10 000 cm -1. Spectroscopic evidence of a weak H-bonded complex formation in the solutions studied have been found. The blue frequency shift of the ν1C-H stretching vibration and of the majority of the combination and overton...

FTIR spectra of mixtures of fluoroform (F3CH) and ammonia (NH3), have been studied in liquid xenon between 5400 and 500 cm-1. Spectroscopic evidence for the formation of a hydrogen bonded complex has been found and the complexation enthalpy Delta(LXe)H degrees in the temperature interval between 173 and 215 K, was determined to be 14.4 (7) kJ mol-1...

The FTIR spectra of CF3H and C2H2 have been studied in liquefied Ar, N2, and CO. The frequency blue shift of the C–H stretching vibration accompanied by a decrease in the integrated intensity of the corresponding ν1 band was found for CF3H, whereas in the case of C2H2 the usual red shift and increasing integrated intensity of the C–H stretching ν3...

Weak to medium H-bonded interactions of the CH⋯B type (B=CS2 and N(CD)5) have been studied in C2H2/B mixtures. The spectral characteristics (frequency, width, and absolute integral intensity) of the CH asymmetric stretching band of acetylene were determined. Analogously to C2H2/CO2 system studied earlier, in the case of CS2 solutions, the combinati...

FTIR spectra of acetylene have been studied in liquefied Ar, Kr, N2, CO and CO2 in the range ∼1000–9000 cm−1. Width, position and absolute integral intensity of a set of fundamental and combination bands were determined. In the case of ν3 band an effect of vibrational resonance interaction of Fermi-type has been taken into account and the position...

A transition from a blue shifted frequency of the v(CH) vibrations of CF3H to a conventional red frequency shift, accompanied by unusually varying integrated intensity of the corresponding nu(1) band, have been studied in CF3H/B systems, where B = Ar, N-2, CO, CO2, O(CD3)(2), NH3, and N(CD3)(3). DFT/B3LYP and ab inito MP2 calculations, utilizing th...

The FTIR spectra of CF3H have been studied in liquefied Ar, N2, CO, and CO2. The effect of a blue shift of frequency of the C–H stretching vibration accompanied by a decrease in the integral intensity of the corresponding ν1 band was found in the studied series of solvents. The combination bands ascribed to simultaneous excitation of vibrations of...