Tetranuclear copper complexes with new beta-diketone and beta-iminoketone-containing ligands

Novel tetranuclear copper complexes, Cu-4(OH)(2)(ClO4)(3) (HA). H2O (1) and Cu-4(ClO4)(5)(H3B). 3H(2)O (2), were synthesized by reacting 1,5-bis(1'-ph enyl-3'-methyl-5'-pyrazolone-4')-1 ,5-pentanedione with 1,3-propanediamine and 2-hydroxyl-1,3-propanediamine in the presence of a template reagent cop per ion. New [2+2] type open cyclic multidentate ligands are also obtained from the reaction (H4A and H6B stand for new compounds from 1,3-propanediam ine and 2-hydroxyl-1,3-propanediamine, respectively). They each contain fiv e C = O, three C = N and one NH2 groups. The complexes were characterized b y elemental analyses, conductivity, FT-i.r. (micro-i.r., deconvolution tech nique), FAB-MS, e.s.r., electronic spectra and extended X-ray absorption fi ne structure (EXAFS). Copper ions in (1) are basically four coordinate with tetragonal geometry. The average coordination bond distances of Cu-N and C u-O are 1.91 Angstrom and 2.05 Angstrom. In (2), copper ions are primarily five coordinate with square-based pyramidal geometry. The average coordinat ion bond distances of Cu-N and Cu-O are 1.93 Angstrom and 2.08 Angstrom. Fo ur copper atoms in molecules may be arranged tetragonally. Both the ligand field and the coordination bonds in complex (1) are stronger than those in (2). Investigations on variable temperature susceptibilities show that some antiferromagnetic exchange interaction exist in the complexes. The plots o f chi(-1) versus T obey the Curie-Weiss law only at low temperature. Prelim inary results of a bioassay indicate that the two complexes have some antit umour activity in vitro.