PREPARATION AND CHARACTERIZATION OF ORGANOCOBALT(III) COMPLEXES OF TETRAAZA MACROCYCLIC LIGANDS - CRYSTAL-STRUCTURES OF ETHYL-COBALT(III) AND PROPYL-COBALT(III) COMPLEXES OF 3,7,11,17-TETRAAZABICYCLO[11.3.1]HEPTADECA-1(17),13,15-TRIENE

Several organocobalt(III) complexes of general formula trans-[CoR(L)(OH2)][ClO4](2) have been prepared in moderate yield using a photochemical route (L = a tetraaza macrocycle; R = Me, Et, Pr or Bu). The complexes have been isolated and characterised by microanalyses, H-1, C-13 and Co-59 NMR spectroscopies, and fast atom bombardment (FAB) mass spectrometry. Crystal structures of two of the complexes, trans-[CoR(L)(OH2)][ClO4](2) (L = 3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene; R = Et or Pr) establish the trans-geometry, with relatively long Co-O bond lengths of 2.121(3) and 2.29(3) Angstrom respectively, showing the trans influence of the alkyl groups.