Mechanochemical Reaction of Polymeric Oxovanadium(IV) Complexes with Schiff Base Ligands Derived from 5Nitrosalicylaldehyde and Diamines

Light brown [VO(5-NO2salen)]·2H2O (1; H2(5-NO2 salen)=N,Nʹ-di-5-nitrosalicylidene-1,2-ethanediamine) and orange [VO (5-NO2sal-meso-stien)]·0.5H2O (2; H2(5-NO2sal-meso-stien)=N,Nʹ-di-5-nitrosalicylidene-(R,S)(S,R)-1,2-diphenyl-1,2ethanediamine) which have linear chain structures in the solid state turn dark brown and yellow-brown, respectively, when ground thoroughly in mortars. The IR spectra of 1 and 2 in Nujol mulls show strong V=O stretching bands at 875 and 905 cm-1, respectively. On the other hand, the spectra of the finely ground complexes in Nujol mulls show very weak V=O stretching bands. X-ray powder diffraction patterns of the ground complexes scarcely show diffraction peaks. The spectroscopic and magnetic data suggest that the linear chain structures in the crystals of 1 and 2 are destroyed on grinding to yield the fragments of the polymeric chains.