Radical stabilization energies (RSEs) for a wide variety of nitrogen-centered radicals and their protonated counterparts have been calculated at G3(MP2)-RAD G3B3 level. The RSE values can be rationalized through the combined effects resonance delocalization unpaired spin, electron donation adjacent alkyl groups or lone pairs, inductive donation/electron withdrawal. influence ring strain as well synergistic combination individual substituent (captodatively stabilized N-radicals) also...

Mixed-valence (MV) binuclear ferrocenyl compounds have long been studied as models for testing theories of electron transfer and in attempts to design molecular-scale electronic devices (e.g., molecular wires). In contrary that, far less attention has paid MV ferrocenes anticancer agents. Herein, we discuss the synthesis six 1,2,3-triazole combined (spectro)electrochemical, paramagnetic resonance (EPR), computational, activity studies. Our synthetic approach was based on copper-catalyzed...

A series of six novel metallocenyl-7-ADCA (metallocenyl = ferrocenyl or ruthenocenyl; 7-ADCA 7-aminodesacetoxycephalosporanic acid) conjugates were synthesized and their antibacterial properties evaluated by biochemical microbiological assays. The ruthenocene derivatives showed a higher level inhibition DD-carboxypeptidase 64-575, Penicillin Binding Protein (PBP), than the ferrocene reference compound penicillin G. X-ray crystallographic analysis revealed covalent acyl-enzyme complex...

This study was designed to evaluate the nano–bio interactions between endogenous biothiols (cysteine and glutathione) with biomedically relevant, metallic nanoparticles (silver (AgNPs) gold (AuNPs)), in order assess biocompatibility fate of biological systems. A systematic comprehensive analysis revealed that preparation AgNPs AuNPs presence leads stabilized oxidized forms biothiols. Their safety tested by evaluation cell viability, reactive oxygen species (ROS) production, apoptosis...

The Hofmann–Löffler–Freytag (HLF) reaction is a method that employs N-chlorinated precursors in radical-mediated rearrangement cycles to synthesize pyrrolidine rings and C–H functionalized products. This study aims elucidate the mechanism of propagation cycle, identify rate-limiting step, uncover factors influencing regioselectivity HLF reaction. Combining experimental techniques─laser flash photolysis (LFP), electron paramagnetic resonance (EPR), nuclear magnetic (NMR)─with computational...

Abstract A series of 11 cymantrene and cyrhetrene nucleobase conjugates, together with the hitherto unreported N7 isomer a ferrocene–adenine conjugate were synthesised characterised. The synthetic approach involved Michael addition reaction in‐situ‐generated acryloylcymantrene, acryloylcyrhetrene acryloylferrocene canonical nucleobases thymine, uracil adenine. mechanism these reactions was investigated by means density functional theory calculations. products characterised spectroscopic...

The Hofmann–Löffler–Freytag (HLF) reaction serves as a late-stage functionalization technique for generating pyrrolidine heterocyclic ring systems. Contemporary HLF protocols utilize in situ halogenated sulfonamides precursors the radical-mediated rearrangement cycle. Despite its well-established mechanism, experiments toward detection of radical intermediates using EPR techniques have only recently been attempted. However, obtained spectra lack distinct features N-centered radicals expected...

The reactions of hypochlorous acid (HOCl) with ammonia, (di)methylamine, and heterocyclic amines have been studied computationally using double-hybrid DFT methods (B2PLYP-D BK-PLYP) a G3B3 composite scheme. In the gas phase calculated energy barriers for N- and/or C-hydroxylation are ca. 100 kJ mol(-1) lower than barrier N-chlorination amines. model solvent, however, latter process becomes kinetically more favored. explicit solvent effects crucial determination reaction mechanism. is...

Quantum chemical calculations were carried out to study the mechanism of degenerate 1,2-, 1,3-, and 1,4-hydride shifts in acyclic tertiary carbocations 2,3-dimethyl-2-butyl, 2,4-dimethyl-2-pentyl, 2,5-dimethyl-2-hexyl. Stable structures transition calculated at B3LYP MP2 levels using 6-31G(d) 6-311G(d,p) basis sets. The potential energy profile for these hydride has global minima wells that correspond two interchanging open-chain carbocation a high lying local minimum corresponding...

Summary This study was undertaken (i) to optimise and validate a suitable method for multi‐element determination in cereal products (ii) evaluate content differences commercially available conventional vs. organic wheat flours. Presented ICP‐MS is simple accurate the of eighteen elements food. Obtained results show metal between flours confirm that both types production are well within toxicological safety limits regarding contents. The significant among were obtained As, Cd, Cr, Fe, Mg, Mo,...

In the reaction of purines with ferrocenoyl chloride in dimethylformamide (DMF), a regioselective acylation occurred. The two products have been isolated and, according to detailed NMR analysis, identified as N7- and N9-ferrocenoylated isomers. more polar solvent, for example, dimethylsulfoxide (DMSO), isomers interconvert each other. N7/N9 isomerization was followed by 1H spectroscopy, until dynamic equilibrium reached. Both kinetics thermodynamics transacylation process are governed...

Chlorination of amides is utmost importance in biochemistry and environmental chemistry. Despite the huge body data, mechanism reaction between hypochlorous acid aqueous environment remains unclear. In this work, three different pathways for chlorination N-methylacetamide by HOCl have been considered: one-step N-chlorination amide, via O-chlorinated intermediate, iminol intermediate. The high-level quantum chemical G3B3 composite procedure, double-hybrid B2-PLYPD, B2K-PLYP methods, global...

In order to perform a complete search for prereactive complexes between arenes and chlorine, the stochastic method was employed. Stationary points are optimized at B3LYP, M05-2X, MP2 levels, while improved energetics calculated using B2PLYP-D method, which includes corrections important accurate description of dispersion forces. New intermediates were located their mechanistic relevance has been discussed. It suggested that, least in gas-phase, T-shaped complex precedes formation classical...

Novel O ‐alkylated quinoline and N 4‐quinolone derivatives attached to the ferrocene moiety through 4,1‐ ( 7a–d , 8a–d 12a–d ) 1,4‐disubstituted 9a 9b 10a 10b 1,2,3‐triazole were synthesized. The observed regioselectivity of ‐ vs. ‐alkylation was explored by use NMR computational techniques. Among derivatives, quinolone‐ferrocene conjugate displayed marked activities against chronic myeloid leukemia in blast crisis (K562) Burkitt lymphoma (Raji). 6‐chloroquinolone‐ferrocene 12c with...

Hybrid density functionals have been regularly applied in state-of-the-art computational models for predicting reduction potentials. Benchmark calculations of the absolute potential ferricenium/ferrocene couple, IUPAC-proposed reference nonaqueous solution, include B3LYP/6-31G(d)/LanL2TZf protocol. We used this procedure to calculate ionization energies and potentials a comprehensive set ferrocene derivatives. The protocol works very well number However, significant discrepancy (>1 V)...

The exploitation of silver nanoparticles (AgNPs) in biomedicine represents more than one third their overall application. Despite wide use and significant amount scientific data on effects biological systems, detailed insight into vivo fate is still lacking. This study aimed to elucidate the biotransformation patterns AgNPs following oral administration. Colloidal stability, biochemical transformation, dissolution, degradation behaviour different types were evaluated systems modelled...

Abstract The enantioselective synthesis and electrochemistry of the first ferrocenyl GNA nucleosides is reported. These compounds were obtained by a Sharpless asymmetric dihydroxylation reaction [3‐( N 1‐thyminyl)‐1‐(ferrocenyl)]propene as S , R enantiomers in about 70 % yield with enantiomeric excesses >99 71 %, respectively. absolute configurations chiral carbon atoms assigned single‐crystal X‐ray diffraction analysis methyl derivatives solid state. also studied circular dichroism (CD)...

The tranquilizer and hypnotic drug oxazepam undergoes the racemization process in aqueous medium, which is relevant for its pharmacological profile.

The most prominent features responsible for binding of flavonoid aglycones to the IIA region human serum albumin (HSA) were determined based on<italic>in vitro</italic>fluorescence measurements and density functional theory calculations.

Hydrogen migration reactions in piperidine radicals and their protonated counterparts were studied by quantum chemical calculations. G3B3 G3(MP2)-RAD levels of theory used as reference procedures order to evaluate the efficiency other computational models. In gas phase, 1,4-[N↔C]-H 1,4-[C↔C]-H shifts are most feasible rearrangements radical cation neutral radical, respectively. However, if one explicit water molecule is well placed facilitate hydrogen migrations, 1,2-[N↔C]-H shift becomes...

Abstract N ‐Chlorination reactions of alkyl‐, cycloalkyl‐, heterocyclic, and aromatic amines by HOCl have been investigated in the gas aqueous phase. Density functional (B3LYP), double hybrid (B2PLYPD), composite theoretical model (G3B3) used to assess steric, electronic, solvent effects on reactivity different families toward HOCl. When are included using CPCM/UAHF model, all computational methods predict same order within each group amines. In agreement with experimental data, heterocyclic...

The mechanism of the degenerate 1,5-hydride shift in 2,6-dimethyl-2-heptyl cations has been investigated using ab initio MP2 and density functional theory (DFT) hybrid (B3LYP) calculations. potential-energy profile for consists three minima corresponding to two equivalent acyclic carbocations one symmetrically μ-hydrido-bridged carbocation, while unsymmetrically hydrido-bridged were located as transition-state structures. calculated relative energy differences between structure are...

A stochastic search procedure for locating energy minimum structures was applied to the sec-butyl cation. previously unreported structure 3' with strong H-hyperconjugative stabilization of carbocation center found at several levels theory (HF, B3LYP, and MP2). The theoretical equilibrium isotope effect (EIE) monodeutero isotopomer (Keq = 1.4; t −130 °C) indicates that new is likely be largely responsible experimentally observed EIE.