Crystal structure of bis-{3-(3-bromo-4-methoxyphenyl)-5-[6-(1 H-pyrazol-1-yl)pyridin-2-yl]-1,2,4-triazol-3-ato}-iron(II) methano-l disolvate

Acta Crystallogr E Crystallogr Commun. 2022 Oct 28;78(Pt 11):1138-1142. doi: 10.1107/S2056989022010179. eCollection 2022 Nov 1.

Abstract

The unit cell of the title compound, [FeII(C17H12BrN6O)2]·2MeOH, consists of a charge-neutral complex mol-ecule and two independent mol-ecules of methanol. In the complex mol-ecule, the two tridentate ligand mol-ecules 2-[5-(3-bromo-4-meth-oxy-phen-yl)-4H-1,2,4-triazol-3-yl]-6-(1H-pyrazol-1-yl)pyridine coordinate to the FeII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo-octa-hedral coordination sphere around the central ion. In the crystal, neighbouring asymmetric mol-ecules are linked through weak C-H(pz)⋯π(ph) inter-actions into chains, which are then linked into layers by weak C-H⋯N/C inter-actions. Finally, the layers stack into a three-dimensional network linked by weak inter-layer C-H⋯π inter-actions between the meth-oxy groups and the phenyl rings. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 34.2%, H⋯C/C⋯H 25.2%, H⋯Br/Br⋯H 13.2%, H⋯N/N⋯H 12.2% and H⋯O/O⋯H 4.0%. The average Fe-N bond distance is 1.949 Å, indicating the low-spin state of the FeII ion. Energy framework analysis at the HF/3-21 G theory level was performed to qu-antify the inter-action energies in the crystal structure.

Keywords: crystal structure; energy frameworks; spin transition; spin-crossover.

Grants and funding

Funding for this research was provided by: Ministry of Education and Science of Ukraine (grant No. 22BF037-03, 22BF037-04).