Anna Kaczmarek-Kedziera

Acetate platinum(II) compound with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine that overcomes cisplatin resistance: structural characterization, in vitro cytotoxicity, and kinetic studies

The reaction of silver acetate with cis-[PtI2(dbtp)2], where dbtp = 5,7-ditertbutyl-1,2,4-triazolo-[1,5-a]pyrimidine, yielded cis-[Pt(OOCCH3)2(dbtp)2]·dmf (1). The complex has been analyzed by multinuclear magnetic resonance (1H, 13C, 15N), IR, and Raman. The compound formed two rotamers in CDCl3 and its spatial structures have been optimized using computational calculation. It was found that head-to-tail rotamer (1a) is more stable than its head-to-head counterpart (1b). In vitro antiproliferative activity against four tumor cell lines (A549, T47D, FaDu, and A2780cis) revealed in all cases significant cytotoxicity (IC50 = 0.26–1.80 μM), possessing IC50 values at least fivefold lower than cisplatin, carboplatin, and oxaliplatin (except A2780cis). The remarkable in vitro activity against T47D and A2780cis suggested the ability to overcome cisplatin resistance in these types of tumor cells. In addition, in vitro toxicity was evaluated against BALB/3T3 and has shown that the lipophilic platinum(II) complex (1) inhibits cell proliferation weaker than cisplatin and oxaliplatin. Additionally, cis-[Pt(OOCCH3)2(dbtp)2]·dmf exhibited selective activity, in contrast to cisplatin or oxaliplatin. Graphical abstract

Molecular aspects of squaraine dyes aggregation and its influence on spectroscopic properties

Molecular aggregates of two squaraine dyes of different ability for hydrogen-bond formation are investigated with computational chemistry tools. Oligomers up to hexamers are included into the present analysis. Potential energy surface scan for dimers and small oligomers indicates a preference for regular staircase and zig-zag structures. A decomposition of interaction energy of the dimers with SAPT0 procedure allows to notice a clear predominance of dispersion-bound structures in the case of 2,4-bis(4-dimethylaminophenyl)squaraine and susceptibility of the 2,4-bis(aminophenyl)squaraine for hydrogen-bond formation, what is consistent with predictions based on molecular structure. An influence of aggregation on spectroscopic properties is analyzed. An elongation of the squaraine oligomer leads to a shift on the maximum absorption wavelength and an increase of the intensity of the signal. Moreover, in the case of the 2,4-bis(aminophenyl)squaraine, the new interaction-induced signals appear in the long-wavelength part of the UV–Vis spectrum.

Structural stability of diclofenac vs. inhibition activity from ab initio molecular dynamics simulations. Comparative study with ibuprofen and ketoprofen

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 confirmed during the X-ray analysis. In the present research we use static DFT calculations, the Quantum Theory of Atoms in Molecules and non-covalent interactions (NCI) index to confirm the additional intramolecular interactions, which influence the drug molecular structure. We focus on the structural stability of diclofenac as the result of the hydrogen bonds breaking/formation at finite temperature utilizing ab initio molecular dynamics simulations. The lifetime of different intramolecular hydrogen bonds is estimated. We perform also the comparative analysis of the structural stability of ibuprofen and ketoprofen molecules in the gas phase at 300 K with respect to diclofenac in terms of the NSAID inhibition activity. Due to the detailed description of diclofenac intramolecular interactions, possible drug modifications for its enhanced water solubility can be suggested.

Simple and efficient synthesis with theoretical calculations of novel N-halamine monomers

Hydantoins represent a group of compounds which over the past few years has attracted great attention because of their diverse biological activities. The synthetic methods for 5,5-dimetyhyl hydantoin (well-known biocidal material) available in literature are particularly difficult, and the yield of the synthesis after purification does not exceed 40%. On the other hand, styrene-type monomers containing spirohydantoin moieties were successfully synthesized by N-alkylation reaction. A simple and efficient preparation of N-chlorinated (N-halamine) monomers is presented, and the experimental data are supported by DFT calculations.

Influence of intermolecular interactions on the properties of carbon nanotubes

This study is aiming at theoretical and experimental confirmations of the deposition of oligothiophene dyes (OT) on structurally and chemically diverse surfaces of carbon materials, especially carbon nanotubes (CNTs). This study is a contribution to the wide search and design of novel hybrid materials for light-sensitive (dye solar cells) and light-emitting (LEDs) structures. The obtained materials containing OTs embedded in the pores of a carbon matrix were analysed by means of microscopic and spectroscopic techniques as well as low-temperature adsorption of nitrogen, together with an investigation of the surface area by the BET method. Confocal microscopy was employed to confirm the immobilization of oligomers on the surface of CNTs. Raman spectra, XRD and HTEM microscopies allowed to judge the quality of the carbonaceous material and to compare the test material before and after the introduction of OT. Additionally, the elemental content and elemental surface species were determined by means of XPS and combustion elemental analyses. The explanation of thiophene; 2,2

On the potential application of DFT methods in predicting the interaction-induced electric properties of molecular complexes. Molecular H-bonded chains as a case of study

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Assessment of DFT functionals for the calculation of interaction-induced electric properties of molecular complexes

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