Complexes of ligands providing endogenous bridges. Part 9. Copper(II) complexes of 1,11-diamino-6-hydroxy-4,8-diazaundecane: the use of fast atom bombardment mass spectrometry to monitor exogenous bridge strength

Abstract

Homodinuclear copper(II) complexes of 1,11-diamino-6-hydroxy-4,8-diazaundecane (HL¹), [Cu₂L¹(X)][ClO₄]₂, have been prepared. The ligand is deprotonated thus generating a single-atom endogenous bridge and exogenous bridges (X) are provided by hydroxide, benzoate, 3,5-dimethylpyrazolate, and azide anions. The fast atom bombardment mass spectra of the complexes have been run and used to monitor the nature and strength of the exogenous bridge. For this system it appears that anions capable of binding in the µ-1,3 mode provide the best match with the dinuclear moiety.