16333-84-9Relevant academic research and scientific papers
The Acidity of Weak Carbon Acids. Part 4. The Kinetic Acidities of 4-Nitro-, 4,4'-Dinitro- and 4,4',4''-Trinitrotriphenylmethanes
Bowden, Keith,Hirani, Shamin I. J.
, p. 1885 - 1888 (2007/10/02)
Rate coefficients for the base-catalysed detritiation of 4,4',4''-trinitro-, 4,4'-dinitro- and 4-nitrotriphenylmethanes in dimethyl sulphoxide have been measured at 25.0 deg C.The bases are a series of secondary aliphatic amines and tetramethylguanidine and of benzoate anions.For 4,4'-dinitrotriphenylmethane and piperidine, the rate coefficients for detritiation at 55.0 deg C and for α-1>-4,4'-dinitrotriphenylmethane and piperidine, dedeuteriation at 25.0 deg C were also measured.The kinetic isotope effect and activation parameters indicate the rate-determining step to be the ionisation process.Bronsted coefficients, β, have been calculated using the known or previously measured pKa values of the conjugate acids of the bases in dimethyl sulphoxide.The β values for both carbon acids are significantly greater for the benzoate anion than for the nitrogen base catalysis, and those for the dinitro-carbon acid are less than those for the trinitro-acid.No reactivity-selectivity relationship exists.This behaviour is discussed in relation to Marcus and related theories.
Solvent Dependence of the Ionization of Nitrophenylmethanes
Fogel, Paula,Farrel, Patrick G.,Lelievre, Jacques,Chatrousse, Alain P.,Terrier, Francois
, p. 711 - 716 (2007/10/02)
The solvent dependence of proton abstraction from various nitrophenylmethanes has been examined for aqueous dimethyl sulphoxide and methanolic dimethyl sulphoxide solutions.Even though the compounds studied vary considerably in thermodynamic acidity (pKa), their proton-abstraction rates all show the same solvent dependence.It is suggested that the transition states for these reactions all occur at similar positions on the reaction pathway, and that transition state imbalances exist for these proton transfers.
