NEW MACROCYCLIC DIOXOTETRAAMINES BEARING 2-PYRIDYLMETHYL AS FUNCTIONAL DONOR PENDANT(S) - SYNTHESIS, PROPERTIES AND CRYSTAL-STRUCTURE OF THEIR COPPER(II) COMPLEXES

Two new macrocyclic dioxotetraamines ethy1)-1,4,7,10-tetraazacyclotrid ecane-11,13-dione (H2L1) and 4,7-bis( pyridin-2-ylmethyl)-1,4,7,1 O-te traazacyclotridecane-11,13-dione (H2L1) have been synthesized and char acterized. The solution behaviors of their copper(II) complexes have b een studied with ESR, UV/VIS and cyclic voltammetric techniques. React ion of H2L2 with Cu(O2CMe)(2) in methanol solution yielded a doubly de protonated dioxotetraamine copper(II) complex, [CuL2]. 6H(2)O, the str ucture of which has been determined by X-ray diffraction analysis. The Cu atom is five-co-ordinated by four basal nitrogens and one pendant pyridine nitrogen, forming a distorted square pyramid in which N(21) o f the pendant pyridine nitrogen is at the apical site. The Cu-N(21) bo nd distance [2.203(7) Angstrom] is longer than the basal average Cu-N bond length [1.985(4) Angstrom] due to the Jahn-Teller effect.