2 4-NITROPYRIDINE N-OXIDE ADDUCTS - C5H4N2O3)2.AGNO3 AND (C5H4N2O3)2.CO(NO3)2.4H2O

Two new addition compounds of the optically non-linear molecule 4-nitropyridine N-oxide (NPO) have been synthesized and characterized: bis(4-nitropyridine N-oxide)silver nitrate and bis(4-nitropyridine N-oxide)cobalt nitrate tetrahydrate. Their structural features are described and compared, in particular the arrangement of the NPO molecules, the type of linkage in the inorganic entities (the cationic polyhedra and the nitrate anions) which make up the host matrice for the organic molecules and the hydrogen-bonding scheme contributing to the packing cohesion. Certain characteristics of both these centrosymmetric structures are also discussed with respect to some non-linear optical NPO derivatives.