Synthesis of a Cis-N2s2 Donor Macrocycle by Metal-Directed Condensation of Formaldehyde, Nitroethane and a Diaminodithiaalkane - Crystal-Structure of the (6-Methyl-6-Nitro-1,11-Dithia-4,8-Diazacyclotetradecane)-Copper(II) Perchlorate Product

Abstract

Reaction of (3,7-dithianonane-1,9-diamine)copper(II) ion with nitroethane and formaldehyde in basic methanol gives the macrocyclic complex ion (6-methyl-6-nitro-1,II-dithia-4,8- diazacyclotetradecane )copper(II) in high yield. The complex as the perchlorate salt crystallizes in the monoclinic space group P2₁/n, a 15.008(5), b 8.606(3), c 17.967(4)Ǻ, β 113.79(2)°. The copper ion lies in a square plane of two nitrogen (average Cu-N 2.02 Ǻ) and two thioether (average Cu-S 2.295 Ǻ) donors, with perchlorate oxygens (Cu-O 2.46 and 2.70 Ǻ) in axial sites. Physical and structural properties of the Cu^III complexes of the 14-membered cis-N₂S₂ macrocycle and the known analogous 14-membered N₄-donor macrocycle 6-methyl-6-nitro-1,4,8,11- tetraazacyclotetradecane are compared.