Copper(II) template synthesis of a new N 2S 2-donor macrocycle incorporating a pendent pyridyl substituent

Abstract

The synthesis of the new potentially pentadentate ligand, 2,2′-(2-methyl-2-(pyridin-2-yl)propane-1,3-diyl)bis(sulfanediyl) diethanamine (L 1 ), containing two thioether sulfurs, two -NH 2 amines and a pyridyl nitrogen heteroatom is described. Reaction of L 1 with copper(II) chloride and addition of hexafluorophosphate anion has led to isolation of the mixed anion complex Cu 2(L 1 ) 2Cl(PF 6) 3. The synthesis and X-ray structure of cobalt(III) species, [Co(L 1 )Cl](PF 6) 2, is also reported. In situ reaction of L 1 with copper(II) as a metal template in the presence of formaldehyde and the carbon acid nitroethane together with triethylamine (as base) led to macrocycle ring closure to yield [Cu(L 2 )Cl]PF 6 (where L 2 = 6,13-dimethyl-6-nitro-13-(pyridin-2-yl)-1,11-dithia-4,8- diazacyclotetradecane) whose X-ray structure shows that the copper centre has a distorted square pyramidal coordination geometry being bound by both -NH 2 nitrogens and both sulfurs of L 2 while the pyridyl nitrogen remains uncoordinated. © 2010 Springer Science+Business Media B.V.