Date of Award
Winter 1980
Project Type
Dissertation
Program or Major
Chemistry
Degree Name
Doctor of Philosophy
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.
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