Molecular Box versus Helicate:  Selective Synthesis of Macrocyclic [Cu₂L₂]²⁺ and Helical [Cu₂L₃]⁴⁺ Species

We present here two different topologies that result from the bis-bidentate ligand bis(pyridine-4,4‘-diaminodiphenyl)methane, L, upon coordination to Cu(I) or Cu(II), namely, a metallo-cyclophane or “molecular-box” [Cu 2 L 2 (ClO 4 ) 2 ]·4(MeCN)·2(EtOH), 1, and a helicate [Cu 2 L 3 (ClO 4 ) 4 ]·3(MeCN), 2, and show that metal ion coordination preference is the major determinant in defining which topology results.