An iron(II) complex of trans, trans, trans-bis (azido)bis(4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole): insight into molecular and supramolecular structures using Hirshfeld surface analysis and DFT studies

The solvothermal synthesis and structural characterization of the new high-spin iron(II) complex trans,trans,trans-[bis(azido)bis(4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole)iron(II)] is reported. The complex crystallizes in the triclinic space group Pī with Z = 1, a = 6.6648(3) Å, b = 8.4012(3) Å, c = 11.7970(5) Å, α = 85.063(2)°, β = 95.063(2)°, γ = 98.5080(10)°. It is centrosymmetric with mutually trans pairs of azido, pyridyl and triazole N atoms, the Fe–N distances indicate a high-spin configuration. A combination of NH···N hydrogen bonds and π···π stacking interactions generates a sheet structure in which the shortest Fe···Fe distance is 6.6648(3) Å.

Hirshfeld surface analysis has been performed for visualizing, exploring and quantifying intermolecular interactions that stabilize the crystal packing of the complex. Non-covalent interactions present in the crystal structure have also been analysed by means of computational tools. The interaction energies associated with the different interaction topologies were calculated and QTAIM and NBO analyses were applied to study the origin and nature of the attractive forces.