STRUCTURAL INVESTIGATIONS OF 2 2-AMINO-5-NITROPYRIDINIUM SALTS - C5H6N3O2+NO3- AND (C5H6N3O2+)2CUCL4(2-)

Through chemical preparations and crystal structures of the 2-amino-5-nitropyridinium nitrate and the bis(2-amino-5-nitropyridinium)tetrachlorocuprate, an attempt at polar crystal engineering using the 2-amino-5-nitropyridinium cation and inorganic counter anions is illustrated. The role of the ratio of anion charge to dimension in the building of centric packings is illustrated and discussed. In the tetrachlorocuprate salt, distorted CuCl42- tetrahedral anions of D2d symmetry are present. C5H6N3O2+NO3- is monoclinic, P2(1)/n, with a = 13.672(3), b = 7.762(1), c = 7.577(1) angstrom, beta = 101.45(5)-degrees, Z = 4, d(x) = 1.703. The crystal structure has been solved using 1386 independent reflections with a final R value of 0.044. (C5H6N3O2+)2CuCl42- is monoclinic, P2(1)/c, with a = 7.701(3), b = 31.99(5), c = 7.107(3) angstrom, beta = 92.65(5)-degrees, Z = 4, d(x) = 1.844. The crystal structure has been solved using 3367 independent reflections with a reliability factor of 0.039.