Darwin and mass-velocity relativistic corrections in non-Born-Oppenheimer variational calculations

The Pauli approach to account for the mass-velocity and Darwin relativistic corrections has been applied to the formalism for quantum mechanical molecular calculations that does not assume the Born-Oppenheimer (BO) approximation regarding separability of the electronic and nuclear motions in molecular systems. The corrections are determined using the first order perturbation theory and are derived for the non-BO wave function of a diatomic system expressed in terms of explicitly correlated Gaussian functions with premultipliers in the form of even powers of the internuclear distance. As a numerical example we used calculations of the transition energies for pure vibrational states of the HD(+) ion.     

Synthesis of 2,3-trans disubstituted tetrahydrofurans through sequential xanthate radical addition-substitution reactions

A two-step preparation of 2,3-trans disubstituted tetrahydrofuran derivatives is reported from S-alkyl dithiocarbonates. The study of the group transfer reaction from xanthates and alkenes afforded intermediate S-alkyl dithiocarbonates. From 2,3-dihydrofuran derivatives, the displacement of the resulting anomeric xanthates with various nucleophiles in the presence of Lewis acid allowed the formation of new carbon-carbon and carbon-heteroatom bonds. This strategy was illustrated by a two-step synthesis of a precursor of modified 2'-beta-C-branched nucleoside analogues.     

The question of aromaticity in open-shell cations and anions as ion-radical offsprings of polycyclic aromatic and antiaromatic hydrocarbons

Arene cation-radicals and anion-radicals result directly from the one-electron oxidation and reduction of many aromatic hydrocarbons, yet virtually nothing is known of their intrinsic (thermodynamic) stability and hence "aromatic character". Since such paramagnetic ion radicals lie intermediate between aromatic (Hückel) hydrocarbons with 4n + 2-electrons and antiaromatic analogues with 4n-electrons, we can now address the question of pi-delocalization in these odd-electron counterparts. Application of the structure-based "harmonic oscillator model of aromaticity" or the HOMA method leads to the surprising conclusion that the aromaticity of these rather reactive, kinetically unstable arene cation and anion radicals (as measured by the HOMA index) is actually higher than that of their (diamagnetic) parent-contrary to conventional expectations.     

Formation of Polymer Nanolayers with Special Properties at Polymer Surfaces

A principal possibility of the utilization of polymer peroxides for the modification of polymer surfaces that provides an immobilization of the tailored quantity of peroxide groups at them has been established. The processes of polymer surface activation with following “grafting from” or “grafting to” utilizing immobilized peroxide groups has been studied using a FTIR-ATR spectroscopy, ellipsometry and measurements of contact angles. The proposed technique of polymer surface activation is based on the universal ability of carbon chain polymer to participate the free radical reactions.     

Chiral Monolithic Silica-Based HPLC Columns for Enantiomeric Separation and Determination: Functionalization of Chiral Selector and Recognition of Selector-Selectand Interaction

This review draws attention to the use of chiral monolithic silica HPLC columns for the enantiomeric separation and determination of chiral compounds. Properties and advantages of monolithic silica HPLC columns are also highlighted in comparison to conventional particle-packed, fused-core, and sub-2-µm HPLC columns. Nano-LC capillary monolithic silica columns as well as polymeric-based and hybrid-based monolithic columns are also demonstrated to show good enantioresolution abilities. Methods for introducing the chiral selector into the monolithic silica column in the form of mobile phase additive, by encapsulation and surface coating, or by covalent functionalization are described. The application of molecular modeling methods to elucidate the selector–selectand interaction is discussed. An application for enantiomeric impurity determination is also considered.     

Synthesis,Anticancer, and QSAR Studies of 2‐Alkyl(aryl,hetaryl)quinazolin‐4(3H)‐thione's and [1,2,4]Triazolo[1,5‐c]quinazoline‐2‐thione's Thioderivatives

Considering the frightening high level of mortality from cancer, studies of anticancer agents are vital nowadays. The 24 thioderivatives of 2‐alkyl(aryl)‐quinazolin‐4(3H)‐thiones and 20 thioderivatives of [1,2,4]triazolo[1,5‐c]quinazoline‐2‐thiones were synthesized and evaluated for preliminary in vitro anticancer activity with subsequent in silico QSAR analysis. The substance 18 had the best results inhibiting growth of eight cancer cell lines: CCRF‐CEM of leukemia; SF‐539, SNB‐75, and U251 of CNS cancer; 786, RXF393, and UO‐31 of renal cancer; and MDA‐MB‐231/ATCC of breast cancer (?31.50 – 47.41% of cell growth) with low procancer effect. Calculated QSAR‐models for CCRF‐CEM of leukemia, T‐47D and HS 578T of breast cancer, and mean cell growth demonstrated good rate of anticancer activity prediction (r² = 0.7 – 0.8,  = 0.5 – 0.7).     

A simple and cost-effective molecular diagnostic system and DNA probes synthesized by light emitting diode photolithography

This work introduces a novel chip to be used in the future as a simple and cost-effective method for creating DNA arrays using light emission diode (LED) photolithography. The DNA chip platform contains 24 independent reaction sites, which allows for the testing of a corresponding amount of patients’ samples in hospital. An array of commercial UV LEDs and lens systems was combined with a microfluidic flow system to provide patterning of 24 individual reaction sites, each with 64 independent probes. Using the LED array instead of conventional laser exposure systems or micro-mirror systems significantly reduces the cost of equipment. The microfluidic system together with microfluidic flow cells drastically reduces the amount of used reagents, which is important due to the high cost of commercial reagents. The DNA synthesis efficiency was verified by fluorescence labeling and conventional hybridization.     

Binary volume phase masks in photo-thermo-refractive glass

Permanent binary phase masks with planar surfaces and high tolerance to laser radiation are recorded in the volume of photo-thermo-refractive glass using the contact copying technique and binary amplitude master masks. Conversion of a Gaussian beam to higher order modes is shown.     

Generation of diversiform gold nanostructures inspired by honey's components: Growth mechanism, characterization, and shape separation by the centrifugation-assisted sedimentation

The green synthesis of irregular-shaped nanomaterials used for various applications in nanoplasmonics, medicine, and biotechnology creates an economical and environmental challenge. We describe the rapid wet-chemical approach to synthesis of stable and water-soluble gold nanostructues at room temperature. In addition to spherical and road-like nanoparticles, gold decahedra and triangular plates were grown using the one-step synthesis process of HAuCl(4) in the presence of honey, in which main components act as reducing (glucose) and stabilizing (fructose) agents; the mechanism of the process is discussed in details. The requirements for anisotropic phase boundaries for generation of polyhedral gold nanocrystals in solutions are highlighted. The synthesis, morphology, and separation procedure of gold nanoparticles are examined using the techniques of optical spectroscopy, transmission electron microscopy, and atomic force microscopy. We demonstrate that centrifugation can be used for efficient separation of nanoparticles with different shapes from a mixture. It was found that while centrifuging, the spheres sediment at the bottom of the tube, segregating from rods that form a deposit on the side wall, whereas polygons remain in the solution.     

Synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]‐pyrimidine‐6‐carboxamides

Possible approaches to synthesis of 5‐methyl‐4‐oxo‐2‐(coumarin‐3‐yl)‐N‐aryl‐3,4‐dihydrothieno[2,3‐d]pyrimidine‐6‐carboxamides 4 have been discussed. It is shown that the preferable approach is cyclization of 2‐iminocoumarin‐3‐carboxamides 1 , utilizing 5‐amino‐3‐methyl‐N²‐arylthiophene‐2,4‐dicarboxamides 2 as binucleophilic reagents. The proposed procedure allowed us to easily obtain 4 in two stages, using common reagents. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:341–346, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20303