The thermal decomposition of transition-metal complexes containing heterocyclic ligands: 3. Substituted pyridine complexes of cobalt

Abstract

Enthalpies of the overall decomposition reactions CoX 2L 2(c) → CoX 2(c)+2L(g) and of the intermediate stepwise loss of ligand, L, where X is Cl or Br, and L is 3-chloropyridine, 3-bromopyridine, 2-chloropyridine, 2-bromopyridine, or 2-methoxypyridine have been measured by use of a differential scanning calorimeter. Enthalpies of sublimation of CoCl 2(3-chloropyridine) 2, CoBr 2(3-chloropyridine) 2, CoCl 2(3-bromopyridine) 2, CoCl 2(2-chloropyridine) 2, CoCl 2(2-bromopyridine) 2, CoBr 2(2-bromopyridine) 2, CoCl 2(2-methylpyridine) 2 and CoBr 2(2-methylpyridine) 2 have been determined. Values of the cobalt-nitrogen bond dissociation energies have been calculated. Specific heats of a number of the complexes are reported.