Structural and spectral studies of thiosemicarbazones derived from 3-and 4-formylpyridine and 3-and 4-acetylpyridine

Crystal structures of thiosemicarbazones prepared from 3- and 4-formylpyridine and 3- and 4-acetylpyridine are included along with their UV spectra. 4-Formylpyridine thiosemicarbazone has the following structural properties: monoclinic, P2(1)/n, a = 7.2420(5), b = 13.961(1), c = 8.415(1) Angstrom, beta = 90.90(1)degrees. V = 850.7(1) Angstrom (3) and Z = 4, for 3-formylpyridine thiosemicarbazone: monoclinic, C2/c, a = 13.661(2), b = 7.1120(4), c = 19.046(2) Angstrom, beta = 107.71(1)degrees, V = 1762.8(3) Angstrom (3) and Z = 8, for 4-acetylpyridine thiosemicarbazone: triclinic, P-1, a = 8.104(3), b = 8.512(2), c = 8.708(3) Angstrom, alpha = 83.85(0), beta = 66.66(0), gamma = 62.87(0)degrees, V = 488.9(3) Angstrom (3) and Z = 2; for 3-acetyipyridine thiosemicarbazone monoclinic, P2(1)/a, a = 8.408(1), b = 11.853(2), = c = 9.777(3) Angstrom, beta = 97.66(2)degrees. V = 985.7(3) Angstrom (3) and Z = 4. Intramolecular and intermolecular hydrogen bonding are both present. There is a difference in the angles between the mean planes of the pyridine ring and thiosemicarbazone moiety in the two series. (C) 2001 Elsevier Science B.V. All rights reserved.