SOLID-STATE DEAMINATION OF TRIS(ETHYLENEDIAMINE)- AND TRIS(PROPYLENEDIAMINE)CHROMIUM(3) THIOCYANATE

The solid state deamination of [Cr(en)3](NCS)3 and [Cr(pn)3](NCS)3 to the corresponding dithiocyanato compounds has been studied isothermogravimetrically. The reaction is catalyzed by ammonium thiocyanate and amine hydrothiocyanates and is first order in catalyst over a wide range of catalyst/salt ratios. Activation energies for the uncatalyzed and catalyzed deamination of [Cr(en)3](NCS)3 are 47.4 ± 2.4 and 33.1 ±1.6 kcal/mol, respectively, while those for the deamination of [Cr(pn)3](NCS)3 are 55.2 ±2.8 and 44.6 ± 2.2 kcal/mol. The mechanism of the deamination is discussed in terms of the acid catalysis and kinetic observations. © 1969, American Chemical Society. All rights reserved.