Co-ordination of 1,4,7-tris(pyrazol-3-ylmethyl)-1,4,7-triazacyclononane with iron(III), nickel(II) and zinc(II). Crystal and molecular structures of [ML][ClO4]2·nH2O (M = Ni, n= 0.5; M = Zn, n= 1)

Abstract

The new potentially hexadentate compound 1,4,7-tris(pyrazol-3-ylmethyl)-1,4,7-triazacyclononane (L) has been synthesised. In protonated form, L·6HCl, it reacted with metal perchlorates to give the complexes [ML][ClO₄]₂·nH₂O (M = Ni, n= 0.5; M = Zn, n= 1 ) and [FeL][ClO₄]₃·H₂O. The crystal structures of the nickel(II)1 and zinc(II)2 complexes have been determined by single-crystal X-ray diffraction: 1, monoclinic, space group C2/c, a= 18.270(4), b= 14.179(6), c= 21.714(4)Å, β= 115.57(2)°, Z= 8; 2 triclinic, space group Pa= 10.322(4), b= 10.563(3), c= 14.460(4)Å, α= 92.61 (3). β= 108.25(3), γ= 116.07(3)°, Z= 2. In both complex cations the metal ion is co-ordinated by the six nitrogen donor atoms of the ligand.