A carboxylic acid-substituted picolinic hydrazone ligand (pcoap) forms a homoleptic [2× 2] tetranuclear Cu (II) 4 complex with four six-coordinate Cu (II) centers bridged by μ-O alkoxide groups in a square grid structure. The terminal carboxylic groups complete the six- coordinate structures at each copper centre, capping off external coordination positions, with two functioning as carboxylates, and two in neutral carboxylic acid form. Despite very ...
[Wang, Changsheng; Jung, Gun-Young; Batsanov, Andrei S.; Bryce, Martin R.; Petty, Michael C. Journal of Materials Chemistry, 2002 , vol. 12, # 2 p. 173 - 180]