Concave reagents part 33: transition metal complexes of 1,10-phenanthroline bridged calix[6]arenes

1,10-Phenanthroline bridged calix[6]arenes 1a and 1b have been synthesized and metal salt complexes with Cu+, Cu2+, Co2+, Ni2+ and Eu3+ have been isol ated. In contrast to the concave 1,10-phenanthrolines 2, which only form 1 : 1 complexes with metal salts, 1 also forms 2:1 complexes with Cu2+, Co2and Ni2+. Only Cu+ forms 1:1 complexes exclusively.