Hydrogen-Bonding Networks in Heterocyclic Thioureas

The synthesis of heterocyclic thioureas from heterocyclic amines with phenylor methylisothiocyanate or CS2 is described. Seven new X-ray crystal structures are reported: In N-(3-pyridyl)-N0-phenylthiourea (Pna21, a = 10.1453(3), b = 17.6183(5), c = 6.4787(2), V = 1158.02(6), Z = 4) hydrogen-bonding results in formation of a 3D network consisting of helices, which form channels parallel to the c-axis. In N-(4-pyridyl)-N0-phenylthiourea (P21/c, a = 16.9314(3), b = 10.3554(2), c = 13.5152(3), b = 106.5080 (10), V = 2271.96(8), Z = 4, two independent molecules) hydrogen-bonding results in N–H S bridged dimers and N–H Py chains, forming a 2D sheet network. In N(2-pyrimidyl)-N0-phenylthiourea (P21/c, a = 5.45900(10), b = 13.8559(2), c = 14.3356(3), b = 94.9800(10), V = 1080.24(3), Z = 4) and N-(2-pyrimidyl)-N0-methylthiourea (P21/c, a = 8.8159(5), b = 11.2386(5), c = 7.7156(4), b = 95.629(2), V = 760.76(7), Z = 4) pairs of intraand intermolecular N–H N interactions produce dimers. Dimer formation through N–H S occurs for N-(2-thiazolyl)-N0methylthiourea (C2/c, a = 17.9308(3), b = 7.78260(10), c = 10.8686(2), b = 105.3740(10), V = 1462.42(4), Z = 8). Two symmetrically disubstituted thioureas were examined: N,N0-bis(2-pyridyl)thiourea (Fdd2, a = 15.1859(2), b = 30.1654(3), c = 9.44130(10), V = 4324.95(8), Z = 16) forms intraand intermolecular N–H Py hydrogen-bonds, forming a 1D zigzag chain and N,N0-bis(3-pyridyl)thiourea (P21/c, a = 13.2461(2), b = 6.26170(10), c = 12.3503(2), b = 96.0160(10), V = 1018.73(3), Z = 4) forms intermolecular N–H Py hydrogen-bonds, resulting in 2D sheets.