Structure of M(18-crown-6)+ (M=T1, NH4) oximate complexes: effective control of the molecular geometry employing a crystal engineering approach

Abstract

The synthesis and structural characterization of one-dimensional coordination/H-bonded polymers M(18-crown-6) [H{ONC(CN)C(O)C₆H₅}₂] (M=NH₄, Tl) is reported. The hydrogen oximate anion is formed by means of strong hydrogen bonding O-H-O between two nitroso groups, it possesses a centrosymmetric structure and bridges two macrocyclic fragments. In both the structures these fragments M(18-crown-6) adopt unusual geometry with the large cations being situated exactly in the center of the crown ether cavity.