Synthesis and X-ray crystal structure of a new macrocyclic Schiff base ligand containing thiocarbonohydrazide unit

Schiff base complexes have remained an important and popular area of research due to their simple synthesis, versatility and divers range of applications.1 Schiff base condensations have long been used to form macrocyclic ligands from diamines and dicarbonyl compounds.2 In this work, macrocyclic ligand (L) has been synthesized from thiocarbohydrazide and 2-[2-(2-formylphenoxy)propoxy]benzaldehyde. The new macrocycle was characterized by elemental analysis, MS, IR, 1H and 13C NMR spectroscopy and the structure of ligand was determined by a X-Ray crystallographic procedure and shows [2+2] cyclodondensation (Fig 1). In the IR spectrum of ligand a band at about 1603 cm-1 indicated the formation of C=N bonds, no peaks attributed to NH2 and carbonyl groups implied that the condensation reaction have been completed.