Synthesis, characterization, and Cu(II) solution chemistry of dioxotetraazamacrocycles

The synthesis and characterization of four new dioxotetraazamacrocycles: 1, 4,8,11-tetraazacyclotetradecane-3,9-dione; 1,4,7,10-tetraazacyclotridecane- 2,9-dione 1,4,7,10-tetraazacyclotridecane-3,8-dione; and 1,4,7,10-tetraazac yclododecane-2,9-dione are described. Two related, previously prepared macr ocycles, are included in this study: 1,4,8,11-tetraazacyclotetradecane-5,7- dione and 1,4,7,10-tetraazacyclotridecane-11,13-dione. The protonation cons tants, stability constants with Cu2+ ions, as well as electronic spectra of the di-deprotonated copper(II) complexes are also reported. These results are discussed in terms of the suitability of this new class of Cu-62, Cu-64 , Cu-67 complexes in PET imaging or radiotherapeutic applications. The synt hetic schemes outlined provide a study of the relative Cu2+ behavior with a family of positional isomers of unsubstituted dioxotetraazamacrocycles.