Investigations on the transfer of the ligand, imidazole (HIm), between two covalently linked redox centres--zinc porphyrin and phenylenediamine (PD)--and the influence of the length of the linker are reported. Since the binding affinity of the ligand with zinc porphyrin is different from that of the ligand with the phenylenediamine moiety, the transfer of the ligand could be electrochemically c...

Abstract Visualization of electron delocalization and aromaticity in some selected arynes, including nonplanar examples, their Diels–Alder or dimerization reactions was achieved through multidimensional isotropic magnetic shielding contour maps. These maps showed that arynes are generally less aromatic than the corresponding arenes, peaks during when approaching transition state.

The ketoenamine-enolimine tautometic equilibrium has been studied by the analysis of aromaticity and electron-topological parameters. The influence of substituents on the energy of the transition state and of the tautomeric forms has been investigated for different positions of chelate chain. The quantum theory of atoms in molecules method (QTAIM) has been applied to study changes in the electr...

In the present work, we report an investigation on quantum entanglement in the doubly excited 2s S resonance state of the positronium negative ion by using highly correlated Hylleraas type wave functions, determined by calculation of the density of resonance states with the stabilization method. Once the resonance wave function is obtained, the spatial (electron-electron orbital) entanglement e...

Much evidence has been collected to date which shows that repulsive electron-electron interaction can lead to the formation of particle pairs in a one-dimensional random energy landscape. The localization length 2 of these pair states is nite, but larger than the localization length 1 of the individual particles. After a short review of previous work, we present numerical evidence for this eeec...

Assembly of paramagnetic Cu(2) complexes with a Schiff base scaffold possessing extended electron delocalization together with a quasi-planar structure onto carbon nanotubes induces a diameter-selective charge transfer from the complex to the nanotubes leading to an interestingly large and tunable ambipolar effect. We used complementary techniques such as electron paramagnetic resonance, absorp...

Enthalpies of reaction for the initial steps in the pyrolysis of lignin have been evaluated at the CBS-4m level of theory using fully substituted b-O-4 dilignols. Values for competing unimolecular decomposition reactions are consistent with results previously published for phenethyl phenyl ether models, but with lowered selectivity. Chain propagating reactions of free radicals with a closed-she...

The AIM parameters at the ring critical point (the electron density and its Laplacian, the total electron energy density and both its components, potential and kinetic electron energy densities), have been intercorrelated with aromaticity indices: the geometry-based HOMA and the magnetism-based NICS, NICS(1), and NICS(1)(zz). A set of 33 phenylic rings having possibly a diversified aromatic cha...

In the title compound, C(10)H(11)ClN(4)O(2)S, the triazole ring carries methyl and ethoxy-carbonyl groups and is bound via a methyl-ene bridge to a chloro-thia-zole unit. There is also evidence for significant electron delocalization in the triazolyl system. Intra- and inter-molecular C-H⋯O hydrogen bonds together with strong π-π stacking inter-actions [centroid-centroid distance 3.620 (1) Å] s...

In the title compound, C(14)H(10)N(2)O(4)S(2),the furoxan heterocyclic ring and the two S atoms are almost co-planar, with a mean deviation of 0.036 Å. The bond lengths in the penta-gonal ring show electron delocalization and the furoxan N-O bond length is quite short [1.211 (3) Å]. The dihedral angles between the central ring and pendant phenyl rings are 78.05 (14) and 84.28 (2)°.