An unusual [4 + 4 + 4] bishelical complex, Cu3(H2L)(L)·2H2O [H4L′ = N,N′-bis(3-hydroxysalicylidene)-1,4-diaminobutane]: synthesis and crystal structure

An electrochemical cell [Cu(+)|MeCN + H4L|Pt(–)] (H4L = title ligand), yielded powdery [Cu2(L)(H2O)]n and crystalline Cu3(H2L)(L)·2H2O; the crystal structure of the latter shows an unusual helicate with an isosceles triangle core assembled by two µ-phenoxo bridges [Cu···Cu 3.413(3) and 3.858(3) Å], in which tetracoordinated Cu ions are in tetrahedrally distorted square planar environments.