Investigation of Oxygen Influence to the Optical Properties of Tirapazamine

New data on 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine) fluorescence has been obtained using the Perkin–Elmer UV-vis-NIR spectrophotometer Lambda 950 experimental technique in combination with the extensive DFT-theory approach. Based on the results obtained, we revealed that theoptical properties of the molecule under study remain significantly unchanged when the number of oxygen substitutions decreases from 2 to 0. Here we also present the results of the study of the influence of acetonitrile and ethyl acetate on the fluorescence of tirapazamine with the different number of oxygen atoms. Results of our investigation indicate the formation of anion in the case of 3-amino-1,2,4-benzotriazine 1,4-dioxide with two oxygen atoms and their transformation to tirapazamine with one oxygen atom.

OPTIMIZED QUASIPARTICLE DENSITY FUNCTIONAL APPROACH FOR MULTIELECTRON ATOMIC SYSTEMS

We present the optimized version of the quasiparticle density functional theory (DFT), constructed on the principles of the Landau-Migdal Fermi-liquids theory and principles of the optimized one-quasiparticle representation in theory of multielectron systems. The master equations can be naturally obtained on the basis of variational principle, starting from a Lagrangian of an atomic system as a functional of three quasiparticle densities. These densities are similar to the Hartree-Fock (HF) electron density and kinetical energy density correspondingly, however the third density has no an analog in the Hartree-Fock or the standard DFT theory and appears as result of account for the energy dependence of the mass operator S. The elaborated approach to construction of the eigen-functions basis can be characterized as an improved one in comparison with similar basises of other one-particle representations, namely, in the HF, the standard Kohn-Sham approximations etc.

Magnetic and vibrational properties of small chromium clusters on the Cu(111) surface

The structure and magnetic properties of small Cr clusters adsorbed on the Cu(111) surface have been investigated using DFT theory and their vibrational properties have been calculated using tight-binding second moment approximation interatomic interaction potentials.

Computational study on optical and NLO properties of Donor-Acceptor interaction molecules containing triazolobenzothiadiazole or benzothiadiazole central acceptor core

In this paper, based on the reported OTTAB, OTTTB and eight newly designed compounds, the DFT/TD-DFT theory is utilized to study the influence of the electron-accepting ability of the central...

Novel ultrahard carbon structures by cold-compressing tubes

Four novel superhard carbon structures named L-, CM-, and K-carbon and Cco-C160 are proposed by cold-compressing carbon nanotubes based on DFT theory, which adopt the 5 + 6 + 7, 5 + 6 + 8, 6 + 14 and 4 + 6 + 8 topological structures, respectively.

The selective oxidation of glycerol over metal-free photocatalysts: insights into the solvent effect on catalytic efficiency and product distribution

Solvent effect in selective aerobic oxidation of glycerol over O-doped g-C3N4 was studied combining with control experiments and DFT theory calculation. Notably, a novel oxidative esterification of glycerol to yield esters was discovered in CH3CN.

Calculation of CO adsorption capacity of single iron(II)- porphyrin and related electron transfer behavior by DFT theory

The effect of CO adsorption on the electron transport behavior of single iron(II)-porphyrin molecular wire with sulfur end groups bonded to two gold electrodes isinvestigated using nonequilibrium Green's function formalism combined with firstprinciples density functional theory. The current-voltage characteristics of the singleFe-porphyrin molecular wires with and without CO adsorption are calculated. Theresults demonstrate that Fe-porphyrin molecular wire shows a negative differentialresistance (NDR) at 2.0 V

Calculation of frontier orbitals, electronic coupling and paramagnetic interaction of conjugated porphyrin arrays based on DFT theory

Electronic donor–acceptor communication in porphyrin-based molecular electronics is addressed theoretically. The order of the a1u and a2u frontier occupied orbitals has been proposed by others to affect excited energy transfer. We examined the effects of the nature and pattern of substituents upon analog monomer porphyrin orbitals using DFT (B3LYP/6-31G(d,p)) and the four-orbital model of porphyrin electronic structure. The excited state energy transfer rate was found to be very sensitive to these orbitals' contributions to porphyrin uv/visible absorptions (B- and Q-band). Ground state homodimer calculations validated the monomer results.