Structural properties of cyclopentanone-bridged bis-macrocyclic ligand dicopper(II) complexes in the solid and in solution: a successful test of the MM-EPR method

Peter Comba; Marion Kerscher; Yaroslaw D Lampeka; Lutz Lötzbeyer; Hans Pritzkow; Lyudmyla V Tsymbal

doi:10.1021/ic026265r

Structural properties of cyclopentanone-bridged bis-macrocyclic ligand dicopper(II) complexes in the solid and in solution: a successful test of the MM-EPR method

Inorg Chem. 2003 Jun 2;42(11):3387-9. doi: 10.1021/ic026265r.

Authors

Peter Comba¹, Marion Kerscher, Yaroslaw D Lampeka, Lutz Lötzbeyer, Hans Pritzkow, Lyudmyla V Tsymbal

Affiliation

¹ Anorganisch-Chemisches Institut der Universität Heidelberg, INF 270, D-69120 Heidelberg, Germany. comba@akcomba.oci.uni-heidelberg.de

PMID: 12767169
DOI: 10.1021/ic026265r

Abstract

The copper(II)-assisted condensation of 2,3,2-tet (3,7-diazanonane-1,9-diamine) with formaldehyde and cyclopentanone yields the mono- and bis-macrocyclic Mannich condensation products L(1) and L(2), as well as the Schiff-base product L(3), all with cyclam-type tetraaza macrocycles, coordinated to copper(II). The combination of molecular mechanics and EPR spectroscopy (MM-EPR) reveals that all three isomers of [Cu(2)(L(2))(OH(2))(n)](2+) (n = 0-4), with the expected trans-III (R,R,S,S) configuration of the 14-membered tetraaza macrocycles, are of similar stability, and that the isomer whose structure is solved by X-ray crystallography has a different structure in solution.