Synthesis of trans-disubstituted cyclam ligands appended with two 6-hydroxymethylpyridin-2-ylmethyl sidearms: Crystal structures of the 1,8-dimethyl-4,11-di(6-hydroxymethylpyridin-2-ylmethyl)cylam ligand and its Co(II) and Ni(II) complexes

Abstract

Two new trans-disubstituted cyclam ligands; 1,8-di(6-hydroxymethylpyridin-2-ylmethyl)-1,4,8,11-tetra-azacyclotetradecane (5) and 1,8-dimethyl-4,11-di(6-hydroxymethylpyridin-2-ylmethyl)- 1,4,8,11-tetraaza-cyclotetradecane (6); have been synthesized and characterized. The crystal structures of ligand 6 and its Ni(II) and Co(II) complexes have been determined. Crystal data are given for 6, space group, P21/c, a = 11.095 (6) Å, b = 9.467 (5) Å, c = 13.283 (8) Å; β = 106.95 (5)°, Z = 2, R = 0.0715; for [Ni 6](ClO4)2, space group P21/c, a = 9.4848 (14) Å, b = 33.941(6) Å, c = 9.793(2) Å, β = 95.264(14)°, Z = 4, R = 0.0567; for [Co 6](ClO4)2, space group, P21/c, a = 9.440 (6) Å, b = 33.848 (13) Å, c = 9.820 (3) Å, β = 95.16(3)°, Z = 4, R = 0.0718. In both complexes, the metal atoms are six-coordinate with only one of the pendants interacting with the central metal atom and the other pendant remaining uncoordinated.