Reductive cleavage of dichalcogenide bonds

Electrochemical reduction of 1,2-di(2,4,6-triphenylpyridinium-l)ethane, 1,4-di(2,4,6-triphenylpyridinium-1)butane, 1,6-di(2,4,6-triphenylpyridinium-l)hexane, 1,4-di(N-methyl-4,6-diphenylpyridinium-2)benzene, and 2,7-di(N-methyl-4,6-diphenylpyridinium-2)fluorene in solutions of DMF and MeCN in the potential range from−0.8 to −1.7 V (SCE) was studied by CV. The successive formation of stable radical cations, biradicals, and dianions was investigated by semiempirical MO calculations at the PM3 level.     

Ligand-to-metal charge transfer excited states with unprecedented luminescence yield in fluid solution

A bridged d0 zirconocene dichloride is reported as a first group 4 metal complex possessing rare long-lived ligand-to-metal charge transfer (LMCT) excited states with high emission yields and excited-state lifetimes in fluid solutions (e.g., PhiLUM = 0.41 and tau = 17.6 micros in 1,2-dichlorobenzene at 20 degrees C). The basic emission parameters PhiLUM and tau are shown to be extremely solvent-dependent in fluids at room temperature. The first principle dependences of LMCT emission parameters on solvent properties are revealed with use of the target complex. For fluid solutions, the linear correlation between PhiLUM and tau is reported, thus suggesting that a solvent determines the rate constant for nonradiative decay, knr.     

Simulation of highly emissive states based on ligand-to-metal charge transfer

Properties of the frontier orbitals of a d⁰-organometallic complex with promising photoluminescent and photosensor characteristics have been systematically studied by modern quantum-chemical methods. It has been demonstrated that the lowest electronically excited states are related to charge transfer from high-lying ligand-centered molecular orbitals to the predominantly metal-centered lowest unoccupied molecular orbital. Such an approach makes it possible to predict complexes with promising spectral-luminescent properties, including catalytic precursors of early transition metals.     

Unusual effect of carborane ligands on the electronic properties of <Emphasis Type="Italic">d</Emphasis><Superscript>0</Superscript>-metal complexes

Modern quantum-chemical and photophysical methods have been used to study the structure of the frontier molecular orbitals and the nature of ligand-to-metal charge transfer (LMCT) transitions of structurally complex d ⁰-metallocenes. It has been shown that such metal complexes with carboranyl ligands have emissive LMCT states with preferential charge transfer from aromatic π-ligands to the metal and a large electric dipole moment. The electronic excitation and absorption spectra were simulated for the first time, and dipole moments of metal complexes containing metal–carbon σ- and π-bonds were estimated, which is of fundamental importance for the development of molecular photonics.