First Example of a double stranded helicate with square-planar coordination for the metal

Reaction of dichlorobis(benzildihydrazone)Ni(II) with biacetylmonoxime in 1:4 molar proportion generates diamagnetic Ni2L2 where LH2 (H = dissociable oximato proton) is HO-N=C(CH3)-C(CH3)=N-N=C(C6H5)-C(C6H5)=N-N=C(CH3)-C(CH3)=N-OH. Our molecular mechanics calculations show that Ni2L2 is an unprecedented double stranded homotopic helicate with the metal ion having a square-planar N4 coordination