Tetraazatetraenato Ligands and Their Metal Complexes

MACROCYCLIC TETRAAZATETRAENATO LIGANDS AND THEIR METAL COMPLEXES 

Submitted by DENNIS P. RILEY and DARYLE H. BUSCH Checked by DAVID E. FENTON and RICHARD L. LINTVEDT+ 

Department of Chemistry, Wayne State University, Detroit, MI 48202. 

One hundred grams (0.64 mole) of crude 3-(ethoxymethylene)-2,4-pentanedione (procedure A) is dissolved in 1 L of absolute ethanol in a 2-L Erlenmeyer flask. Absolute ethanol (500 mL) containing 19.2 g (0.32 mole) of freshly distilled (from KOH) anhydrous ethylenediamine is added dropwise over a 30-minute period. An immediate reaction is observed to occur with the formation of a white precipitate. The solution is then filtered and the fine white crystalline material is collected by filtration, washed with absolute ethanol and diethyl ether, and dried in vacuo over P4O10 for several hours. The yield is 72 g (0.26 mole, 80%). The checkers obtained a 55% yield. Tlris material is suitable for use without further purification. Anal. Calcd. for C14H20N2O4 C. 60.0 H, 7.15 N, 10.0. Found C, 60.51 H, 7.21 N, 9.81. 

This square planar nickel complex is prepared by the reaction of the ligand prepared in the previous procedure (B above) with nickel(Il) acetate tetrahydrate in warm (55°) methanol. In a typical preparation 74 g (0.265 mole) of the linear quadridentate ligand is slurried in 1 L of warm methanol in a 2-L flask. To this 

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