Crystal chemical characterization and computational modeling of a μ-oxo Fe(III) complex with 1,10-phenanthroline clarify its interaction and reactivity with montmorillonite

Abstract

This work provides a systematic study of the μ-oxo-di-fac-[triaqua-(1,10-phenanthroline-κ2N,N′)-iron(III)]bis(sulfate), [(OH2)3(phen)FeOFe(phen)(OH2)3] (SO4)2 (phen = phenanthroline). Crystal structure is determined by single-crystal X-ray diffraction data and refined to R = 0.039. The crystal structure is monoclinic (Z = 2), space group P21 with unit cell dimensions a = 8.5157(3), b = 17.6434(5), c = 9.9678(3) Å, β = 90.133(2)°, V = 1497.62(8) Å3. The triaqua(1,10-phenanthroline)iron(III) parts are linked through one oxo-bridge. Both Fe(III) cations show a distorted octahedral coordination. The single-crystal data are complemented by computational chemistry modeling at quantum mechanical level, X-ray powder diffraction at room and high temperature conditions and by thermal analysis. Molecular modeling suggests that the role of the crystallization water molecules is critical to establish the intermolecular interactions for the stability of the crystal structure

Experimental and Theoretical Investigation of Intercalation and Molecular Structure of Organo-Iron Complexes in Montmorillonite

“…The mesh cutoff energy does not represent the energy of the structure, but it is only a control parameter for improving the level of the calculation . A wide range of mesh cutoff energy values in steps of 50 Ry was explored following a similar procedure in previous work by calculating the total energy of the experimental molecular structure of the Fe complex in the Γ point of the Brillouin zone . With a mesh cutoff energy value higher than 150 Ry, the total energy decreases asymptotically with the increase of the cutoff energy, reaching a stability value with cutoff energy values greater than 600 Ry (slope lower than 0.0004 eV/Ry).…”

Chemical trapping of gaseous H 2 S at high and low partial pressures by an iron complex immobilized inside the montmorillonite interlayer

“…Fig. 5a compares XANES spectrum of Mt-FePhen-H 2 S with those of Mt-Fe(III)Phen, α-Fe 2 O 3 (the mineral hematite) and Fe(III)Phen complex [36], the last two selected as the reference compounds. The energy values of absorption edges associated with 1s→4p transitions are similar in Mt-Fe(III)Phen and in the selected reference compounds where iron is in the trivalent form.…”

A new material based on montmorillonite and Cu(II)-phenanthroline complex for effective capture of ammonia from gas phase

“…The derived hybrid materials are of great importance not only under the perspective of fundamental investigation, but also for their applications in different fields, from biomedicine and pharmacy to energy storage and environmental protection (Bergaya and Lagaly, 2011). One example of these materials, where the functionalization of the interlayer leads to intriguing properties, is montmorillonite intercalated with a μ-oxo Fe 3+ -phenanthroline complex (Mt-Fe 3+ Phen) (Bernini et al, 2015;Brigatti et al, 2017;Sainz-Díaz et al, 2018). This hybrid material was proved to efficiently trap sulfur-bearing gas phases such as thiols and H 2 S, even at extremely low concentration, with a relevant environmental benefit.…”