GROUP 13 TETRAAZAMACROCYCLIC COMPLEXES - THE SYNTHESIS AND CHARACTERISATION OF THE MONOMETHYL- AND DIMETHYL-ALUMINIUM(III) AND GALLIUM(III) COMPLEXES OF THE TWO TETRAAZAMACROCYCLIC LIGANDS OMTAA(2-) (H(2)OMTAA=2,3,6,8,11,12,15,17-OCTAMETHYL-5,14-DIHY

摘要

Reactions of the tetraazamacrocyclic ligands H(2)tmtaa (I) and H(2)omtaa (II) with AlMe(3) and GaMe(3) give the dimethyl metal complexes [M(2)Al(Htmtaa)] (III) and [Me(2)Ga(Homtaa)] (IV), respectively. On heating, (III) and (IV) lose an additional molecule of methane to form quantitatively the respective monomethyl derivatives [MeAl(tmtaa)] (V) and [MeGa(omtaa)] (VI). These new macrocyclic complexes have been characterised by H-1 and C-13 NMR, by FAB mass spectrometry and by elemental analyses. A single crystal X-ray diffraction study of VI reveals a five coordinate square-pyramidal coordination geometry, and the usual saddle-shape observed for this type of ligand. The gallium(III) lies 0.656(1) Angstrom above the mean plane of the four nitrogen atoms, with Ga-C 1.966(3) and Ga-N (average) 2.03(1) Angstrom. [References: 10]