The crystal structures of three 3-methyl-1H-1,2,4-triazole-5-thio-nes, including a second polymorph of 4-[(E)-(5-bromo-2-hy-droxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione and a redetermination of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione

Padmanabha S Manjula; Balladka K Sarojini; Hemmige S Yathirajan; Mehmet Akkurt; Cem Cüneyt Ersanlı; Christopher Glidewell

doi:10.1107/S205698901501422X

The crystal structures of three 3-methyl-1H-1,2,4-triazole-5-thio-nes, including a second polymorph of 4-[(E)-(5-bromo-2-hy-droxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione and a redetermination of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione

Acta Crystallogr E Crystallogr Commun. 2015 Aug 6;71(Pt 9):1003-9. doi: 10.1107/S205698901501422X. eCollection 2015 Sep 1.

Authors

Padmanabha S Manjula¹, Balladka K Sarojini², Hemmige S Yathirajan³, Mehmet Akkurt⁴, Cem Cüneyt Ersanlı⁵, Christopher Glidewell⁶

Affiliations

¹ Department of Chemistry, P. A. College of Engineering, Nadupadavu, Montepadavu 574 153, Mangaluru, D. K., India.
² Department of Industrial Chemistry, Mangalore University, Mangalagangothri 574 199, Mangaluru, D. K., India.
³ Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India.
⁴ Department of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Turkey.
⁵ Department of Physics, Faculty of Arts and Sciences, Sinop University, 57010 Sinop, Turkey.
⁶ School of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland.

Abstract

The structures of three 3-methyl-1H-1,2,4-triazole-5-thione derivatives are reported. The structure of 4-amino-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C3H6N4S, (I), has been redetermined with an improved model for the H atoms: the non-H atoms of (I) all lie on mirror planes in space group Pbcm, and the H atoms of the methyl group are disordered over two sets of reflection-related atomic sites having occupancy 0.5: two independent N-H⋯S hydrogen bonds link the mol-ecules of compound (I) into complex sheets. The non-H atoms in the mol-ecules of 4-[(E)-(3,4-di-meth-oxy-benzyl-idene)amino]-3-methyl-1H-1,2,4-tri-azol-5(4H)-thione, C12H14N4O2S, (II), despite lying in general positions are close to planar, with a dihedral angle between the two rings of 6.31 (10)°: the mol-ecules of compound (II) are linked by a three-centre N-H⋯(O)2 hydrogen bond into a C(10)C(11)[R 1 (2)(5)] chain of rings. A second polymorph of 4-[(E)-(5-bromo-2-hy-droxy-5-bromo-benzyl-idene)amino]-3-methyl-1H-1,2,4-triazole-5(4H)-thione, C10H9BrN4OS, (III), has been identified; the non-H atoms are nearly co-planar with a dihedral angle between the two rings of 1.9 (4)°. There is an intra-molecular O-H⋯N hydrogen bond and the mol-ecules are linked by N-H⋯S hydrogen bonds, forming centrosymmetric R 2 (2)(8) dimers. Comparisons are made with some related structures.

Keywords: 1H-1,2,4-triazole-5-thiones; crystal structures; hydrogen bonding; polymorphism.