Structural and spectral studies of N-(2-pyridyl)-N '-tolylthioureas

N-(2-pyridyl)-N'-o-tolylthiourea, monoclinic, P2(1)/c, a=5.127(1), b=19.854 (2), c=12.077(2) Angstrom, beta=94.96(1)degrees, V = 1224.7(2) Angstrom(3), Z = 4, mu = 2.177 mm(-1), N-(2-pyridyl)-N'-m-tolylthiourea, triclinic, P - 1, a = 9.811(2), b = 9.887(4), c = 13.595(3) Angstrom, alpha = 74.91(3), b eta = 83.58(2), gamma = 76.27(2)degrees, V = 1235.(7) Angstrom, Z = 4, in = 2.469 mm(-1) and N-(2-pyridyl)-N'-p-tolylthiourea, triclinic,P - I,a = 9.9 35(2), b = 11.488(2), c = 12.569(2) Angstrom, alpha = 63.91(2), beta = 88.6 0(2), gamma = 75.04(2)degrees, V = 1238.1(2) Angstrom(3), Z = 4, mu = 2.154 mm(-1) all have an intramolecular hydrogen bond between N'H and the pyridy l nitrogen, as well as intermolecular hydrogen bonding between NH and a thi one sulfur of a second molecule to form centrosymmetric dimers. Solution H- 1 NMR studies (CDCI3) show the N'H resonance considerably downfield for eac h thiourea and its position, as well as that of NH, are affected by substit uents on the phenyl ring. (C) 1999 Elsevier Science B.V. All rights reserve d.