TETRACYANOQUINODIMETHANE DERIVATIVES OF MACROCYCLIC NICKEL(II) COMPLEXES - SYNTHESIS AND CRYSTAL-STRUCTURE OF BIS(7,7,8,8-TETRACYANOQUINODIMETHANIDO)(1,8-BIS(2-HYDROXYETHYL)-1,3,6,8,10,13-HEXAAZACYCLOTETRADECANE)NICKEL(II)

The reactivity of the dichloro(1,8-disubstituted-1,3,6,8,10,13-hexaazacyclotradecane)nickel(II) complex [NiCl2LR] (R = C2H40H, C2H5, CH2C6H5) toward LiTCNQ leads to a complete replacement of the chloride groups by the anionic TCNQ.- with formation of complexes of formulas [NiL(R)(TCNQ)2]. The crystal structure of the hydroxyethyl derivative has been solved. The nickel atom is hexacoordinated surrounded by four nitrogens of the macrocyclic ligand and two axial monodentate TCNQ- ligands, being the first nickel-TCNQ complex showing sigma-bonds between the organic acceptor and the metal atom. Intermolecular interactions between TCNQ groups from adjacent molecules forming dimeric units and hydrogen bonds involving the hydroxo groups and one of the nitrogen atoms of a neighboring TCNQ unit are the most significant features of the crystal structure. These compounds behave virtually as insulators at room temperature.