Dariusz C. Bieńko

Bio: Dariusz C. Bieńko is an academic researcher from Wrocław University of Technology. The author has contributed to research in topics: Hydrogen bond & Infrared spectroscopy. The author has an hindex of 16, co-authored 38 publications receiving 890 citations.

Density Functional, Hartree−Fock, and MP2 Studies on the Vibrational Spectrum of Phenol

Abstract: Vibrational spectra of phenol are calculated with ab initio Hartree−Fock and MP2 methods as well as with density functional theory (DFT) using the 6-31G(d,p) basis set. A clear-cut assignment of th...

Theoretical infrared spectrum and revised assignment for para-nitrophenol. Density functional theory studies

Abstract: The harmonic vibrational frequencies and infrared intensities of p-nitrophenol as well as geometries of ortho- and para-nitrophenol, are calculated with density functional theory (DFT), using BLYP functional and 6-31G(d,p) basis set. The calculated (unscaled) spectra are in very good agreement with the gas phase and solid IR spectra of p-nitrophenol. A detailed interpretation of the infrared spectra of p-nitrophenol is reported on the basis of the calculated potential energy distribution (PED). Several reassignments have been made.

``Troublesome'' Vibrations of Aromatic Molecules in Second-Order Möller-Plesset and Density Functional Theory Calculations: Infrared Spectra of Phenol and Phenol-OD Revisited

Abstract: The infrared spectra of phenol and phenol-OD are thoroughly reinvestigated, to resolve the contradictory assignment of some vibrations. The harmonic frequencies, integrated IR intensities, and potential energy distribution (PED) have been calculated by the B3LYP method with the 6-311++G(df,pd) basis set. The Fourier transform infrared (FT-IR) spectra of phenol and phenol-OD have been measured in carbon tetrachloride and cyclohexane solutions, in the frequency range 3700−400 cm-1, and the experimental integrated infrared intensities are reported. On the basis of the results obtained, the detailed assignment of all the fundamental modes of Ph-OH and Ph-OD are presented. The study demonstrates that density functional B3LYP is clearly superior to the ab initio Hartree−Fock (HF) and second-order Moller−Plesset (MP2) methods in reliable prediction of the vibrational spectra of phenol. In particular, it is shown that scaling of the B3LYP-calculated frequencies of the CH and OH(OD) stretching vibrations by the sc...

Infrared matrix isolation and theoretical studies on glutarimide

Abstract: Infrared spectra of glutarimide isolated in low-temperature Ar and N2 matrixes are reported. The molecular structure, vibrational frequencies, and infrared intensities of glutarimide are calculated with ab initio Hartree−Fock and second-order Moller−Plesset perturbation (MP2) methods as well as with density functional theory (DFT) using the nonlocal gradient corrected functional (BP86). The best overall agreement between the calculated and experimental spectra has been obtained at the MP2/D95V** level. Unequivocal assignment of the experimental infrared bands is performed on the basis of the potential energy distribution (PED). A striking similarity is noted for frequencies of the corresponding CO and NH vibrations in glutarimide and in uracil, thymine, and their methyl derivatives. Furthermore, the significant flattening of the glutarimide ring, predicted by calculations, indicates its structural resemblance to pyrimidine bases. It is suggested that some glutarimide drugs are able to intercalate between ...

A Chemist's Guide to Density Functional Theory

Abstract: "Chemists familiar with conventional quantum mechanics will applaud and benefit greatly from this particularly instructive, thorough and clearly written exposition of density functional theory: its basis, concepts, terms, implementation, and performance in diverse applications. Users of DFT for structure, energy, and molecular property computations, as well as reaction mechanism studies, are guided to the optimum choices of the most effective methods. Well done!" Paul von RaguE Schleyer "A conspicuous hole in the computational chemist's library is nicely filled by this book, which provides a wide-ranging and pragmatic view of the subject.[...It] should justifiably become the favorite text on the subject for practioneers who aim to use DFT to solve chemical problems." J. F. Stanton, J. Am. Chem. Soc. "The authors' aim is to guide the chemist through basic theoretical and related technical aspects of DFT at an easy-to-understand theoretical level. They succeed admirably." P. C. H. Mitchell, Appl. Organomet. Chem. "The authors have done an excellent service to the chemical community. [...] A Chemist's Guide to Density Functional Theory is exactly what the title suggests. It should be an invaluable source of insight and knowledge for many chemists using DFT approaches to solve chemical problems." M. Kaupp, Angew. Chem.

Carrier-mediated cellular uptake of pharmaceutical drugs: an exception or the rule?

Abstract: It is generally thought that many drug molecules are transported across biological membranes via passive diffusion at a rate related to their lipophilicity. However, the types of biophysical forces involved in the interaction of drugs with lipid membranes are no different from those involved in their interaction with proteins, and so arguments based on lipophilicity could also be applied to drug uptake by membrane transporters or carriers. In this article, we discuss the evidence supporting the idea that rather than being an exception, carrier-mediated and active uptake of drugs may be more common than is usually assumed - including a summary of specific cases in which drugs are known to be taken up into cells via defined carriers - and consider the implications for drug discovery and development.

Some Aspects of the Properties and Degradation of Polyacrylamides

Abstract: This review summarizes the literature concerning the degradation of polyacrylamides via a number of pathways. Thermal, photo-, biological, chemical, and mechanical degradation are discussed in relation to both linear and cross-linked polyacrylamides. The chemistry of polyacrylamide degradation is described, focusing on two categories: side chain substituent reactivity and polymer backbone reactivity.