Co(NCS)2(abpt)2 and Ni(NCS)2(abpt)2 [abpt is 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole]: structural characterization of polymorphs A and B

Acta Crystallogr C Struct Chem. 2021 Dec 1;77(Pt 12):777-781. doi: 10.1107/S2053229621010251. Epub 2021 Nov 16.

Abstract

The synthesis and structures of bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ2N2,N3]bis(thiocyanato-κN)cobalt(II), [Co(NCS)2(C12H10N6)2] or Co(NCS)2(abpt)2, and bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-κ2N2,N3]bis(thiocyanato-κN)nickel(II), [Ni(NCS)2(C12H10N6)2] or Ni(NCS)2(abpt)2, are reported. In both cases, two polymorphs, A and B, were identified and structurally characterized. For both polymorphs, the structures obtained with the different metals, i.e. CoII or NiII, were found to be isostructural. All of the structures contained an intramolecular N-H...N hydrogen bond, C-H...N interactions and π-π stacking interactions. No structural evidence was observed for a thermal spin crossover for either of the Co(NCS)2(abpt)2 polymorphs between 300 (2) and 120 (2) K.

Keywords: 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole; abpt; crystal structure; polymorphism.