Isokinetic relationships at the thermal decomposition of tetranuclear copper(II)‐complexes

A dependence of the activation energy upon the extent of conversion has been discovered for the thermal decomposition of Cu4OCl6L4 with piperidine (1), morpholine (2), and triphenylphosphine oxide (3) as the ligand (L). Within the interval of conversions 0–0.3 the process shows a decrease in the activation energy (230–130 (1), 130–50 (2), and 200–100 (3) kJ mol−1). The processes considered show an isokinetic relationship with Tiso = 255 ± 15 K which corresponds to a vibrational frequency of viso = 177 ± 10 cm−1. This value accords well with IR absorption bands assigned to the stretching vibration in the trigonal CuCl3 chromophore as predicted by theory. Based on this, an assumption about the CuCl3-group as a central site of the reaction can be made. The IR- and X-ray data are presented to support the assumption made. © 1995 John Wiley & Sons, Inc.

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