16026-13-4Relevant articles and documents
Femtosecond laser spectroscopy and DFT studies of photochromic dithizonatomercury complexes
Von Eschwege, Karel G.,Bosman, Gurthwin,Conradie, Jeanet,Schwoerer, Heinrich
, p. 844 - 855 (2014/03/21)
The ultrafast dynamics of the photochromic reaction of dithizonatophenylmercury(II) was recently reported. For purpose of investigating the effect of electronically different substituents (X = o-F, m-F, p-F, p-Cl, o-CH3, m-CH3, p-CH3, m,p-diCH3, p-OCH3, o-SCH3, and p-SCH3) on this reaction, a series of phenyl-substituted dithizones were synthesized and complexed with phenylmercury(II). A variation of more than 3 ps in ground state repopulation times was observed, with the o-methyl derivative absorbing both at shortest wavelength and having the fastest repopulation time, while the p-S-methyl derivative lies at the opposite extremity. An increase in both decay times and λmax values is generally reflected by an increase in electron density in the chromophore. Ultrafast rates also proved to be dependent on solvent polarity, while a profound solvatochromic effect was observed in the transition state absorbance. Density functional theory realistically simulated isomer stabilities, electronic spectra and molecular orbitals. Increased electron density enhances stability in the photoexcited blue isomer relative to the orange resting state, as seen from a comparison between orange and blue isomer total bonding energies. A linear trend between computed HOMO energies and experimental λmax of related aliphatic substituted derivatives was found.
Synthesis and kinetics of electronically altered photochromic dithizonatophenylmercury(II) complexes
Von Eschwege, Karel G.
, p. 159 - 166 (2013/03/13)
A series of phenyl-substituted dithizones were synthesized, and preparation of the corresponding series of photochromic phenylmercury(II) complexes is for the first time reported. Adaption of previous methods enhanced synthesis convenience and product yields. A single crystal X-ray data collection of the ortho-S-methyl nitroformazan reaction intermediate was done. ADF computed molecular orbitals of the title compound show the HOMO and LUMO orbitals stretching along the entire ligand. The spontaneous back reaction kinetics of dithizonatophenylmercury(II) was studied at varied concentrations, temperatures and in different solvents. An exponential correlation was found between the rate of reverse isomerization and temperature, while increased solvent polarity and decreased molar mass facilitate higher return rates. The kinetic study of the series of twelve electronically altered complexes yielded a lowest rate of 0.0002 s-1 for the ortho-methyl derivative, while the highest rate of 0.0106 s-1 was measured for the meta-methoxy derivative.
