摘要:
A novel macrocyclic ligand containing catechol moieties, 9,10,21,22-tehrahydroxy-7,12,19,24-tetraoxo-2,3,4,5:8,9,10,11:14,15,16, 17:20,21,22,23-tetrabenzena-1,6,13,18-tctraazacyclotetracosane (H4L), was designed and synthesized. For comparison, an acyclic ligand, 1,4-bis(2,3-dihydroxybenzammido)benzene (H4La), was also synthesized. Their oxovanadium(IV) complexes K(ppn)[VO(L)] and K-2[VO(L-a)] were prepared and characterized by IR, UV-Vis and ESR spectroscopies. The ESR spectra of the complexes measured at 77 K in diethyl sulfoxide-ethanol revealed unusual rhombic characteristics of the complexes, suggesting the coordination geometry of the complexes was distorted square-pyramidal. Based on these data, the complex is proposed to possess a bowl-like structure capped by the VO2+ moiety with a hydrophobic cavity. (C) 2000 Elsevier Science Ltd All rights reserved.