Abstract
In this study, in order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n﹣ where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calculations are performed at the B3LYP/6-311g(d,p) level of theory. The binding energies of Fe2+ and Fe3+ in high-spin state are higher than intermediate and low-spin states which show that the complex formation in a high spin state is more favorable. The calculated binding energies at different solvents indicate that the binding energies in polar solvents are lower than non-polar solvents. Furthermore, spectroscopic studies including FTIR and Raman spectrum in various solvents reveal that the formation of intermolecular bonds between the oxygen atom of carbonyl group and the hydrogen atom of solvent causes a spectral red shift. The calculated FTIR and geometry parameters are in good agreement with previous experimental data. Donor-acceptor interaction energies are evaluated due to the importance of the charge transfer in the complex formation. It is observed that the free electrons of oxygen atom interact with the antibonding orbitals of the iron. Finally, some correlations between the quantum chemical reactivity indices of the complexes and solvent polarity are considered. The study indicates a linear correlation between chemical hardness and binding energies of [Fe(cat)3]3﹣ complex.
Highlights
Iron is a pivotal nutrient for life which is one of the most abundant elements on the earth
In order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n− where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calculations are performed at the B3LYP/6-311g(d,p) level of theory
The effect of oxidation states and spin states of iron for the binding in [Fe(cat)3]n− complexes are studied theoretically using quantum chemical approach based on the B3LYP/6-311G (d,p) level of the theory
Summary
Iron is a pivotal nutrient for life which is one of the most abundant elements on the earth. Liu et al have simulated the Fe3+-DOPA mediated bridging at both wet(water) and gas phase conditions [25] at the B3LYP/LACVP* level of theory They calculated the entropy, Gibbs free energy and cohesion force for mechanical strength. We have performed a theoretical investigation on the structure, binding energies, stability and spectroscopic properties of the [Fe(cat)3]n− complexes (for Fe(II) and Fe(III) oxidation states) in the gas phase and different solvents using the first principles HF/DFT hybrid approach. We have studied the chemical reactivity indices such as chemical hardness (η) [27] and electronic chemical potential (μ) [28], as determined by using the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy gap These findings help us understand the thermodynamic behavior of such systems as a function of the quantum chemistry descriptors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
