James H. Timmons

Chelating tendencies of pyridyl-containing polyamines and oxygenation of the cobaltous complexes

The synthesis of the new pyridyl-containing, pentadentate ligands 1,9-bis(2-pyridyl)-2,5,8-triazanonane (pydien), 1 , l l bis(2-pyridyl)-2,6,1O-triazaundecane (pydpt), and 2,6-bis(5-( 1,4-diazahexyl))pyridine (epyden) is described. Acid dissociation constants, the stability constants of the Co(II), Ni(II), Cu(II), and Zn(I1) chelates, and the oxygenation constants (KO, = [MLO2ML]/[MLI2[O2]) of the cobaltous chelates have been determined. The cobalt(I1) chelates are shown to be exceptionally effective at coordinating molecular oxygen at low pH. Electronic spectra of the cobalt(I1) and nickel(I1) chelates indicate that the ligands form high-spin octahedral complexes in aqueous solution.

THE SYNTHESIS AND CHARACTERIZATION OF COPPER(II) AND NICKEL(II) COMPLEXES OF NOVEL 16-MEMBERED MACROCYCLIC LIGANDS HAVING VARYING DEGREES OF SATURATION

Abstract Novel tetraaza[16] diene macrocyclic complexes of nickel(II) and copper(II) have been synthesized by the reaction of 4,4,9,9-tetramethyl-5,8-diazadodeca-2,11-dione with 1,4-butanediamine in the presence of the corresponding metal ion. The C[sbnd]N double bonds of the macrocycle have been hydrogenated using NaBH4 for both the nickel(II) and copper(II) complexes. The preparation and properties of a series of complexes of macrocycles having a varying degree of saturation are described.