Reactivity and Stability of Metalloporphyrin Complex Formation: DFT and Experimental Study

The interaction of three cationic porphyrins—meso-tetrakis (N-methylpyridinium-4-yl) porphyrin (TMPyP), meso-tetrakis (1,3-dimethylimidazolium-2-yl) porphyrin (TDMImP), and meso-tetrakis (1,2-dimethylpyrazolium-4-yl) porphyrin (TDMPzP)—with five heavy metals was studied computationally, and binding constants were calculated based on data obtained by an experimental method and compared. The reactivity and stability of their complexes formed with lead, cadmium, mercury, tin, and arsenic ions were observed in DFT global chemical reactivity descriptors: the electronic chemical potential (µ), chemical hardness (η), and electrophilicity (ω). The results show that M-TDMPzP has higher chemical hardness and lower electrophilicity compared to M-TMPyP and M-TDMImP, indicating the reaction of TDMPzP with metals will form a more stable complex. Specifically, Cd-TDMPzP complexes can stabilize the system, with a lower energy and electronic chemical potential, higher chemical hardness, smaller electrophilicity, and higher binding constant value compared to Pb-TDMPzP and Hg-TDMPzP. This result suggests that the interaction of the Cd2+ ion with TDMPzP will produce a stable complex.

Theoretical Study of Diels-Alder Reaction of But-3-en-2-one with Hexa-1,2,4-triene: A Density Functional Theory Study

The Diels-Alder reaction between but-3-en-2-one with hexa-1,2,4-triene was studied using density functional theory method at B3LYP-D3/6-311++G(d,p) level of theory. The geometries of the transition states were determined. Moreover, calculations of the vibrational frequencies permitted computation of the activation enthalpies and entropies. The computational results show that the cycloadducts from trans conformer have the lower relative energies (−46.48 and −47.50 kcal/mol) as compared to the cis conformer of cycloadducts (−44.45 and −45.87 kcal/mol). The global reactivity indices were analyzed at the ground state of reactants to predict the reactivity of the studied organic molecules in the cycloaddition reactions. The electronic chemical potential of hexa-1,2,4-trien found to be than but-3-en-2-one, which indicates that the net charge transfer will be from hexa-1,2,4-trien toward the electron-deficient but-3-en-2-one reactant.

New Quantum Chemical Method for Assessing the Relative Activity of Antioxidants

A new method for evaluating the antioxidant activity of organic compounds based on quantum chemical calculations of their electronic structure using the DFT B3LYP/6-31G (d, p) method has been proposed. The geometric parameters of antioxidant molecules were optimized and the reactivity indices were determined from the energy values of the highest occupied and the lowest unoccupied molecular orbitals: absolute electronegativity; electronic chemical potential; absolute "chemical hardness". The found indicators allow us to quantify the antioxidant activity by building their dependence on the energy of the lower vacant molecular orbitals. The correlation of the obtained parameters with the standard, such as trolox, allows determining the relative antioxidant activity of the test substance.

Going beyond the three-state ensemble model: the electronic chemical potential and Fukui function for the general case

The analytical working equations for the chemical potential and the Fukui function for the case of any number of ground and excited states is presented.

Benchmark values of chemical potential and chemical hardness for atoms and atomic ions (including unstable anions) from the energies of isoelectronic series

We present benchmark values for the electronic chemical potential and chemical hardness from reference data for ionization potentials and electron affinities.

DFT study and microbiology of some coumarin-based compounds containing a chalcone moiety

In the present investigation, a series of coumarin-based compounds containing a chalcone moiety were studied for their in vitro and in silico properties. DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential and electrophilicity) are calculated for four synthesized compounds and used to predict their relative stability and reactivity. The antibacterial activities of all compounds have been screened against Bacillus subtilis (ATCC No. 6633) and Bacillus cereus (ATCC No. 11778). Quantum-chemical calculations indicate that antibacterial activity correlates well with chemical reactivity descriptors of molecules.