Induction of gap junctional communication (GJC) and antioxidant activities of carotenoids have been considered as biochemical mechanisms underlying the cancer-preventive properties of these compounds. beta-Carotene and other carotenoids, including those lacking provitamin A activity, proved to be active in both these parameters. The beta-carotene analogs retrodehydro-beta-carotene, echinenone, ...

We investigate transport through a mononuclear transition-metal complex with strong tunnel coupling to two electrodes. The ground state of this molecule is a singlet, while the first excited state is a triplet. We show that a modulation of the tunnel-barrier due to a molecular distortion which couples to the tunneling induces a Kondo-effect, provided the discrete vibrational energy compensates ...

the synthesis, spectroscopic and magnetic characterization of a series of new alkoxo-bridged binuclear copper (ii) compounds are described. all complexes have the general formula [cu (m-or)(l)2]2(clo4)2 · x h2o, in which m-or = ch3o-, c2h5o- or c3h7o-, l = 2-amino-4-methylpyridine (abbreviated a4pic) and 2-amino-5-methylpyridine ( abbreviated a5pic). the title compounds all consist of dinuclear...

The combined effect of hydrostatic pressure and temperature on correlation energy in a triplet state of two electron spherical quantum dot with square well potential is computed. The result is presented taking GaAs dot as an example. Our result shows the correlation energies are i)negative in the triplet state contrast to the singlet state ii) it increases with increase in pressure  iii)further...

The molecular mechanism of the thermal rearrangement of singlet 1H-bicyclo[3.1.0]hexa-3,5-dien-2-one to give triplet 4-oxocyclohexa-2,5-dienylidene has been investigated using density functional theory (B3LYP and M05-2X functionals) as well as ab initio CASSCF and CASPT2 multiconfigurational methods. The reactant has a singlet ground state while the product can be found in three low lying elect...

The mechanistic aspects of ethylene addition to MO2(CH2)(CH3) (M=Co, Rh, Ir) have been investigated with a Hartree-Fock/DFT hybrid functional at the MO6/LACVP* and B3LYP/LACVP* levels of theory to elucidate the reaction pathways on the singlet, doublet and triplet potential energy surfaces (PES). In the reaction of the IrO2CH2CH3 complex with ethylene, [3 + 2]C,O addition is the most plausible ...

The geometries and energies of the electronic states of phenyloxenium ion 1 (Ph-O(+)) were computed at the multireference CASPT2/pVTZ level of theory. Despite being isoelectronic to phenylnitrene 4, the phenyloxenium ion 1 has remarkably different energetic orderings of its electronic states. The closed-shell singlet configuration ((1)A(1)) is the ground state of the phenyloxenium ion 1, with a...

The six-membered platinacycle complex, Pt((t)Bu(2)bpy)(C(6)H(4)OC(6)H(4)) (6) ((t)Bu(2)bpy = 4,4'-di-tert-butyl-2,2'-bipyridine) has been prepared from Pt((t)Bu(2)bpy)Cl(2) and 2,2'-dilithio-diphenyl ether. Platinacycle 6 and its analogs with X = CH(2) (4) and NMe (5) exhibit intense solid-state photoluminescence and nearly identical crystal structures. The photophysical properties of 4-6 in th...

The reactions of atomic carbon, C(P j), with benzene, C6H6(X A1g), and with d6-benzene, C6D6(X A1g) were investigated at twelve collision energies between 8.8 and 52.5 kJ mol 21 using the crossed molecular beams technique. Forward-convolution fitting of the data, high-level electronic structure calculations, and Rice–Ramsperger–Kassel–Marcus ~RRKM! investigations on the singlet and triplet C7H6...

Chemiluminescent techniques have been employed to investigate electronic energy transfer from ketone donors (acetone, acetophenone) to acceptors (e.g., 9,lO-diphenylanthracene and biphenyl) in films of polystyrene and polymethyl methacrylate at 50 "C. Tetramethyl-l,2-dioxetane and 3,4-diphenyl-3,4-dimethyldioxetane were used to generate excited (singlet and triplet) acetone and (triplet) acetop...