Protonation Thermochemistry of Gaseous 2,2'-, 4,4'- and 2,4'-Bipyridines and 1,10-phenanthroline

Abstract

Abstract. Quantum chemical composite methods G3MP2B3, G3B3, G4MP2 and G4 have been used to calculate enthalpies of formation and gas phase basicities of the title compounds. Comparison of the results with the available experimental heats of formation values reveals correct agreement (to within ≈ 2 kJ/mol) with G3B3 and G4 methods. Systematic errors on the heats of formation of these aromatic molecules are detected when calculated using the G3MP2B3 and G4MP2 methods. Using G3B3 and G4 atomization energies, ΔfH°298 of 2,2'-bipyridine, 1, 1,10-phenanthroline, 2, 4,4'-bipyridine, 3, and 2,4'-bipyridine, 4, equal to 269, 316, 287 and 282 kJ/mol, respectively were obtained. Homodesmotic reactions confirm these ΔfH° estimates for the three isomeric bipyridines 1, 3 and 4. G3MP2B3, G3B3, G4MP2 and G4 methods lead to comparable proton affinities (PA) values for the four molecules 1−4, in particular because of error compensation in the case of G3MP2B3 and G4MP2 results. Excellent agreement is found with experimental PA values of reference nitrogen bases (within less than 1.2 kJ/mol) allowing us to safely predict PA values of 974, 999, 933 and 958 kJ/mol for 2,2'-bipyridine, 1, 1,10-phenanthroline, 2, 4,4'-bipyridine, 3, and 2,4'-bipyridine (protonated at the most basic site N(4')), 4, respectively. Estimate of the corresponding gas phase basicities is also proposed after consideration of the entropy of hindered rotations: GB(1) = 943, GB(2) = 966, GB(3) = 900, GB(4) = 927 kJ/mol.

Non-PGM Electrocatalysts for PEM Fuel Cells: Thermodynamic Stability and DFT Evaluation of Fluorinated FeN4-Based ORR Catalysts

“…] framework, is numerically equal to minus the proton affinity of the partially fluorinated 1,10phenanthroline molecule, the value of which is somewhat less exothermic, comparing with 1,10-phenanthroline (PA 1,10-phen. = −999.0 kJ mol −1 ), 18 because of the high electron withdrawn ability of fluorine atoms leading, as it was mentioned above, to a decrease in negative partial charges on nitrogen atoms of 1,10-phenanthroline. Thus, the corrected value of the proton affinity (PA * 1,10−phen. )…”

Thermodynamic Stability in Acid Media of FeN4-Based Catalytic Sites Used for the Reaction of Oxygen Reduction in PEM Fuel Cells

“…, is numerically equal to the proton affinity of 1,10-phenanthroline molecule (PA = −999 kJ mol −1 ). 47 Thus, on the basis of the thermochemical data presented in Table II, the enthalpy change in reaction 12 of around 31.0 ± 10 kJ mol −1 was obtained. Considering the enthalpy of Fe 2+ /H + ion exchange as the sum of the enthalpies of reactions 12 and 13, a value of enthalpy change of 5.3 ± 10 kJ mol −1 was found for reaction 14.…”

Selenomethionine alleviated Ochratoxin A induced pyroptosis and renal fibrotic factors expressions in MDCK cells

“…For the cell model studied in this paper, OTA could influence cell adhesion and gap junction and induce DNA single‐strand breaks, apoptosis and necrosis concentration‐dependently in MDCK cells. [ 33–35 ] In our experiment, OTA was observed to induce excessive ROS generation in MDCK cells.…”