1234510-08-7Relevant articles and documents
Synthesis and kinetics of sterically altered photochromic dithizonatomercury complexes
Alabaraoye, Ernestine,Von Eschwege, Karel G.,Loganathan, Nagarajan
, p. 10894 - 10901 (2015/02/19)
Following a previous study where 12 electronically altered dithizones were synthesized, here we report on attempts to synthesize 26 dithizones. The purpose was to explore the boundaries within which dithizones may be synthesized, explore spectral tuning possibilities, and investigate steric effects on the photochromic reaction of its mercury complexes. Contrary to expectation, large substituents like phenoxy groups increased the rate of the photochromic back-reaction. In the series H-, 2-CH3-, 4-CH3-, 3,4-(CH3)2-, 2-OC6H5-, and 4-OC6H5-dithizonatophenylmercury(II), the lowest rate of 0.0004 s-1 was measured for the 2-CH3 complex, while the rate for the 2-OC6H5 derivative was 20 times higher. A solvent study revealed a direct relationship between dipole moment and the rate of the back-reaction, while the relationship between temperature and rate is exponential, with t1/2 = 2 min 8 s for the 4-phenoxy complex. The crystal structures of two dithizone precursors, 2-phenoxy- and 4-phenoxynitroformazan, are reported. (Figure Presented).
Chemical and electrochemical oxidation and reduction of dithizone
von Eschwege, Karel G.,Swarts, Jannie C.
experimental part, p. 1727 - 1733 (2010/07/04)
A non-aqueous electrochemical study of dithizone, H2Dz, 1, is compared with the chemical oxidation and reduction profile of this versatile ligand. Chemical oxidation of 1 by I2 initially leads to an isolatable disulfide-bridged species, (HDz)2, 22, but ultimately monomeric dehydrodithizone, Dz, 3, is formed. Electrochemically, in CH2Cl2/0.1 mol dm-3 [N(nBu)4][B(C6F5)4], two oxidation processes are observed for 1. Evidence of the electrochemical formation of the dimer 22 was found, but on a CV timescale the fully oxidized species, 22 oxidized, did not convert to the chemically stable species 3. Regeneration of 1 during an irreversible electrochemical reduction of the electrochemically generated fully oxidized species, 22 oxidized, was detected. Two further one-electron electrochemical irreversible reduction steps were also identified to ultimately generate H3Dz-, 8, one of the synthetic precursors to 1. In contrast, resolution and identification of the electron transfer steps of 1 in both dimethylsulfoxide, DMSO, or in CH2Cl2/0.1 mol dm-3 [N(nBu)4][PF6] were hampered by solvation and ion paring of [PF6]- especially with the oxidized species of 1. A metathesis of water-soluble potassium dithizonate, KHDz, 4b, led to lipophilic [N(nBu)4][HDz], 4c.
