Ligand isomerism-controlled structural diversity of cadmium(II) perchlorate coordination polymers containing dipyridyladipoamide ligands

The syntheses, structures and ligand conformations of three Cd(II) coordination polymers [Cd( L-1)(ClO4)(2)] infinity [L-1 N,N'-di(2-pyridyl)adipoamide], 1, {[Cd(L-2)(2)(CH3OH) 2](ClO4)(2)center dot 2CH(3)OH} infinity [L-2 = N,N'-di(3-pyridyl)adipoamide], 2 and [Cd(L-3)(2)(ClO4)(2)(CH3CH2OH)(2)] N [L-3 = N,N'-di(4-pyridyl) adipoamide], 3, are reported. Their structures have been characterized by X-ray crystallography. Complex 1 forms 1D zigzag chains, while complex 2 forms 2D pleated sheets which are positioned in an ABAB manner. Complex 3 shows a rare 3D entanglement from parallel polycatenation of 3-fold interpenetrated square layers. While the L-1 ligands in 1 adopt AAA trans conformations and the L2 ligands in 2 adopt GAG trans conformations, the L3 ligands in 3 adopt AAA trans and AGA trans conformations. The structural types of the Cd(II) coordination polymers can be directed by ligand isomerism.