Kinetic and Thermodynamic acidities of Thiocarbene complexes. Effect of the p-donor group.

MARTIN E. ZOLOFF MICHOFF; DIEGO M. ANDRADA; ALEJANDRO M. GRANADOS; RITA H. DE ROSSI

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2008 vol. 32 p. 65 - 65

ate constants for the proton transfer reaction from Fischer thiocarbene complexes (CO)5MQC(SR1)CH3 (M = Cr or W; R1 = n-butyl, isopropyl, tert-butyl, cyclohexyl) to OHÀ and various primary and secondary amines were determined in 50% acetonitrile?50% water at 25 C. These measurements allowed the determination of the thermodynamic and kinetic acidities for these substrates. The results obtained show that there is a slight effect of the substituent on the thermodynamic acidity, which is governed by its hydrophobicity; whereas the effect on the kinetic acidity is more noticeable and is due to the steric effect of the substituent.