Resumen de Novel Preparation of a Tetraaza Macrocycle:: An Advanced Inorganic Chemistry Laboratory
Jerry W. Hayes, Cynthia J. Taylor, Richard P. Hotz
The microwave oven synthesis of a sterically congested macrocycle 6,8,15,17-tetraphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecinato nickel(II), abbreviated [Ni(Ph4Bzo2[14]tetraeneN4)], is presented as an advanced inorganic chemistry laboratory. The template reaction is done in a commercial microwave oven and the reaction is complete in about 20 minutes. After chromatography and recrystallization, a sufficient amount of macrocycle (50-100 mg) for IR, NMR, UV-vis, or electrochemical studies is obtained. The experiment can be completed within the time-span of most laboratory classes and the yield from microwave synthesis is comparable to that of the published method which requires more extreme reaction conditions. [Ni(Ph4Bzo2[14]tetraeneN4)] is an attractive macrocycle for study because of its stability and solubility in organic solvents. The 1H and 13C NMR spectra illustrate the high symmetry of this compound and the signals are easily assigned. The electronic spectrum shows five major absorptions and this complex is an excellent substrate for electrochemical analysis because it does not electropolymerize on the electrode surface.
