Date of Award
Winter 1980
Abstract
The syntheses of two trans-dimethylcobalt(III) complexes are reported. The complex {(CH(,3))(,2)Co(Me(,4){14}tetraeneN(,4))}ClO(,4), where (Me(,4){14}tetraeneN(,4)) is the tetradentate macrocycle 2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclo-tetradeca-1,3,8,10-tetraene that coordinates cobalt in a planar fashion with two conjugated (alpha)-diimines, was prepared by standard methods via the corresponding cobalt(I) derivative. The complex (CH(,3))(,2)Co({14}tetraenato(1-)N(,4)), where ({14}tetraenato(1-)N(,4)) is the tetradentate pseudo macrocycle 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundeca-1,3,8,10-tetraen-11-ol-1-olato that coordinates cobalt in a planar fashion with two conjugated (alpha)-imine-oximes, was also prepared by standard methods via the corresponding cobalt(I) derivative. The complexes were characterized by electronic, IR, and NMR spectroscopy.
The methyl-transfer reactions of the two dimethyl complexes with the metallic electrophiles, Zn('2+), Cd('2+), Pb('2+), Cr('3+), and Cu('2+) in acetonitrile were studied. The organometallic products of these reactions are dependent upon the mole ratio of M('2+)/dimethyl complex used. Reactions with the metal ion in excess produced monomethylcobalt(III) complex and an unstable CH(,3)M('n+).
When Zn('2+), Cd('2+), and Pb('2+) were reacted with excess (CH(,3))(,2)Co(chel), the products were found to be dependent upon the metal ion used. The reaction of Zn('2+) and Cd('2+) with excess dimethyl complex yielded the dimethylmetal compounds, (CH(,3))(,2)Zn and (CH(,3))(,2)Cd.
When Pb('2+) was reacted with (CH(,3))(,2)Co({14}tetraenato-(1-)N(,4)), the intermediate (CH(,3))(,2)Pb disproportionated to yield (CH(,3))(,4)Pb and Pb('0) as the ultimate products. The reaction of Pb('2+) with {(CH(,3))(,2)Co(Me(,4){14}tetraeneN(,4))}('+) is unique. Approximately 75% of the Pb('2+) added to this reaction was obtained as lead metal and 10% as (CH(,3))(,4)Pb. The data obtained suggest that a complex mechanism not observed in the other demethylation reactions is in effect.
Document Type
Dissertation
Department or Program
Chemistry
Degree Name
Doctor of Philosophy
Recommended Citation
DIMMIT, JEFFREY HOWARD, "THE SYNTHESIS OF TRANS-DIMETHYLCOBALT(III) COMPLEXES OF TETRADENTATE MACROCYCLIC LIGANDS AND THEIR REACTIONS WITH METALLIC ELECTROPHILES" (1980). Doctoral Dissertations. 1279.
https://scholars.unh.edu/dissertation/1279