Probing Antioxidant-Related Properties for Phenolic Compounds.

In this work, properties related to antioxidant-potential mechanisms (such as the bond dissociation enthalpy, BDE, for the homolytic cleavage of the O-H bond and ionization energies, IEs) were determined for phenol, pyrocatechol, and gallic acid (GA). Both the protonated and deprotonated forms of GA were investigated. The Feller-Peterson-Dixon (FPD) composite method was employed with a variety of computational approaches, i.

A density functional theory benchmark on antioxidant-related properties of polyphenols.

In this work, we present a density functional theory benchmark on antioxidant-related properties for a series of six polyphenols that are well-known antioxidants: caffeic acid, cyanidin, ellagic acid, gallic acid, myricetin, and phloretin. Computations on the 24 O-H bond dissociation enthalpies (BDEs) and 6 ionization potentials (IPs) were performed using twenty-three exchange-correlation functionals combined with four different basis sets in the gas-phase, water, and methanol; calibration against the Domain-based Local Pair Natural Orbital CCSD(T) (DLPNO-CCSD(T)) approach was employed. Mean absolute deviation (MAD) as well as linear fitting results suggested the LC-PBE approach as the most suitable for O-H BDEs in the gas-phase.

A high level theory investigation on the lowest-lying ionization potentials of glycine (NHCHCOOH).

In this work, an investigation on the ionization potentials (IPs) of the glycine molecule (NHCHCOOH) is presented. IPs ranging up to ∼20 eV were probed for each of the six conformations considered, with the referred threshold being chosen based on both: (i) the observations by recent photoelectron-photoion coincidence (PEPICO) experiments and (ii) the energy range of relevance to the modeling of other photo-induced processes (, photoionization). For computing the IPs, the equation-of-motion ionization potential coupled-cluster with single and double excitations method (EOMIP-CCSD) was employed with large correlation consistent aug-cc-pVXZ and aug-cc-pCVXZ (X = D, T, and Q) basis sets.

Ionization potentials for the HCO trimer.

In this work, a computational study on the ionization potentials (IPs) of the formaldehyde trimer, (HCO), is presented. Twelve lowest-lying vertical IPs were determined through the use of the coupled-cluster level of theory using correlation consistent basis sets with extrapolation to the complete basis set limit and consideration of core electron correlation effects. Specifically, the equation-of-motion ionization potential coupled-cluster with single and double excitations method with the aug-cc-pVnZ and aug-cc-pCVnZ (n = D and T) basis sets was used.

Probing the ionization potentials of the formaldehyde dimer.

In this work, we present a computational investigation on the ionization potentials (IPs) of the formaldehyde dimer, (HCO). Twelve lowest lying IPs (corresponding to the entire valence orbitals) for both C and C symmetry conformers have been computed at the coupled cluster level of theory using large correlation consistent basis sets with extrapolation to the complete basis set limit and consideration of core electron correlation effects. Specifically, the equation-of-motion ionization potential coupled-cluster with single and double (EOMIP-CCSD) excitations method with the aug-cc-pVXZ and aug-cc-pCVXZ (X = T, Q, and 5) basis sets combined with the Feller-Peterson-Dixon approach was employed, as well as CCSD with perturbative triples [CCSD(T)] with the aug-cc-pVTZ basis sets.

Benchmarking Antioxidant-Related Properties for Gallic Acid through the Use of DFT, MP2, CCSD, and CCSD(T) Approaches.

We present a benchmark investigation on the O-H bond dissociation enthalpies (BDEs) and ionization potential (IP) for gallic acid (GA), a widely known polyphenolic antioxidant. These properties were determined in the gas-phase and in water through the use of density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2), coupled-cluster with single and double excitations (CCSD), and coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)). The 6-311++G(df,p), cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ basis sets were used.

Photoinduced degradation of indigo carmine: insights from a computational investigation.

In this work, we present a computational investigation on the photoexcitation of indigo carmine (IC). Physical insights regarding IC photoexcitation and photolysis were obtained from a fundamental perspective through quantum chemistry computations. Density functional theory (DFT) was used to investigate the ground state while its time-dependent formalism (TD-DFT) was used for probing excited state properties, such as vertical excitation energies, generalized oscillator strengths (GOS), and structures.

Probing structural properties and antioxidant activity mechanisms for eleocarpanthraquinone.

In this work, we present a computational investigation on the structure and energetics of eleocarpanthraquinone, a newly isolated polyphenolic anthrone-antraquinone. Properties such as bond lengths, angles, atomic charges, bond dissociation enthalpies (BDEs), and ionization potential (IP) were determined through the use of density functional theory (DFT). The B3LYP and M06-2X exchange-correlation functionals were employed along with the 6-31+G(d,p), 6-31+ +G(d,p), and 6-311+G(d,p) basis sets for performing computations in the gas-phase, water, methanol, and ethanol.

Examining the degradation of environmentally-daunting per- and poly-fluoroalkyl substances from a fundamental chemical perspective.

In this work, ground and excited-state properties were used as descriptors for probing mechanisms as well as to assess potential alternatives for tackling the elimination of perfluorobutane sulfonic acid (PFBS) - CFSOOH, perfluorooctane sulfonic acid (PFOS) - CFSOOH, and perfluorooctanoic acid (PFOA) - CFCOOH. For this purpose, density functional theory (DFT) and its time-dependent formalism (TD-DFT) at both CAM-B3LYP/6-311+G(2d,2p) and M06-2X/6-311+G(2d,2p) levels of theory in water (IEF-PCM) were employed. To gauge the accuracy of the DFT approaches for the current systems, wave function methods (Møller-Plesset, MP2, coupled-cluster with single and double excitations, CCSD, CCSD with perturbative triples, CCSD(T), and equation of motion CCSD, EOM-CCSD) and aug-cc-pVXZ (X = D and T) basis sets were used.

A computational study on the reaction between fisetin and 2,2-diphenyl-1-picrylhydrazyl (DPPH).

The strategy of investigating the antioxidant potential of flavonols through the explicit modeling of chemical reactions (initiated to be employed in a previous work from our group) was taken further in this work. Therefore, a theoretical investigation on the reaction between fisetin and 2,2-diphenyl-1-picrylhydrazyl (DPPH) is presented. All the computations were performed using the density functional theory with the B3LYP functional along with the 6-31G(d,p) basis set.

Evaluation of the antioxidant potential of myricetin 3-O-α-L-rhamnopyranoside and myricetin 4-O-α-L-rhamnopyranoside through a computational study.

In this work, we present a computational study on the antioxidant potential of myricetin 3-O-α-L-rhamnopyranoside (Compound M3) and myricetin 4-O-α-L-rhamnopyranoside (Compound M4). Structural parameters, bond dissociation enthalpies (BDEs), ionization potentials (IPs), proton dissociation enthalpies (PDEs), proton affinities (PAs), and electron transfer enthalpies (ETEs), which are properties connected with different mechanisms related to antioxidant activity, were determined using density functional theory (DFT) with B3LYP, LC-ωPBE, M06-2X, and BMK functionals along with the 6-311G(d,p) and 6-311+G(d,p) basis sets in the gas phase, water, and pentylethanoate. The values obtained were compared with results previously available in the literature for myricetin (the parent molecule and a well-known antioxidant) and myricetin 3,4-di-O-α-L-rhamnopyranoside (Compound M3,4).

Aerobic Solid State Red Phosphorescence from Benzobismole Monomers and Patternable Self-Assembled Block Copolymers.

The synthesis of the first bismuth-containing macromolecules that exhibit phosphorescence in the solid state and in the presence of oxygen is reported. These red emissive high molecular weight polymers (>300 kDa) feature benzobismoles appended to a hydrocarbon scaffold, and were built via an efficient ring-opening metathesis (ROMP) protocol. Moreover, our general procedure readily allows for the formation of cross-linked networks and block copolymers.

Examining the reaction between antioxidant compounds and 2,2-diphenyl-1-picrylhydrazyl (DPPH) through a computational investigation.

In this work, we present a computational investigation on the reactions between two well-known antioxidants (quercetin and morin) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). A density functional theory (DFT) approach with the B3LYP functional and the 6-31G(d,p) basis set was used for the simulations. The structural and energetic parameters (Gibbs free-energy, ΔG, and Gibbs free-energy of activation, ΔG) were determined to provide information on the antioxidant activity as well as to evaluate the contributions of each hydroxyl group to the referred property.

Electronic and magnetic properties of the [Ni(salophen)]: An experimental and DFT study.

The effect of the coordination of a Ni(II) ion on the electronic and magnetic properties of the ligand salophen were experimentally and theoretically evaluated. The complex [Ni(salophen)] was synthesized and characterized through FTIR and an elemental analysis. Spectral data obtained using DMSO as a solvent showed that the ligand absorption profile was significantly disturbed after the coordination of the metal atom.

A computational investigation on the antioxidant potential of myricetin 3,4'-di-O-α-L-rhamnopyranoside.

In this work, we present a computational study on the antioxidant potential of myricetin 3,4[Formula: see text]-di-O-α-L-rhamnopyranoside (Compound M). A density functional theory (DFT) approach with the B3LYP and LC-ωPBE functionals and with both the 6-311G(d,p) and 6-311+G(d,p) basis sets was used. The focus of the investigation was on the structural and energetic parameters including both bond dissociation enthalpies (BDEs) and ionization potentials (IPs), which provide information on the potential antioxidant activity.

Probing the antioxidant potential of phloretin and phlorizin through a computational investigation.

The structures and energetics of two dihydrochalcones (phloretin and its glycoside phlorizin) were examined with density functional theory, using the B3LYP, M06-2X, and LC-ω PBE functionals with both the 6-311G(d,p) and 6-311 + G(d,p) basis sets. Properties connected to antioxidant activity, i.e.

Moving Beyond Boron-Based Substituents To Achieve Phosphorescence in Tellurophenes.

Previous research in our group showed that tellurophenes with pinacolboronate (BPin) units at the 2- and/or 5-positions displayed efficient phosphorescence in the solid state, both in the presence of oxygen and water. In this current study, we show that luminescence from a tellurophene is possible when various aryl-based substituents are present, thus greatly expanding the family of known (and potentially accessible) Te-based phosphors. Moreover, for the green phosphorescent perborylated tellurium heterocycle, 2,3,4,5-TeCBPin (4BTe), oxygen-mediated quenching of phosphorescence is an important contributor to the lack of emission in solution (when exposed to air); thus, this system displays aggregation-enhanced emission (AEE).

Probing the nature of peripheral boryl groups within luminescent tellurophenes.

In this article our attempts to tune the color of luminescence within a new class of aggregation-induced emission (AIE) active tellurophenes is reported along with computational details that include spin-orbit coupling effects so as to better understand the nature of emission in the phosphorescent tellurophene (B-Te-6-B). Despite not meeting some of the initial synthetic targets, the emission within a borylated tellurophene can be altered with the addition of an N-heterocyclic carbene.

A DFT investigation on the structural and antioxidant properties of new isolated interglycosidic O-(1 → 3) linkage flavonols.

We present a computational study on two flavonols that were recently isolated from Loranthaceae family plant extracts: kaempferol 3-O-α-L-arabinofuranosyl-(1 → 3)-α-L-rhamnoside and quercetin 3-O-α-L-arabinofuranosyl-(1 → 3)-α-L-rhamnoside. Their structures and energetics have been investigated at the density functional level of theory, up to B3LYP/6-31+G(d,p), incorporating solvent effects with polarizable continuum models. In addition, their potential antioxidant activities were probed through the computation of the (i) bond dissociation enthalpies (BDEs), which are related to the hydrogen-atom transfer mechanism (HAT), and (ii) ionization potentials (IPs), which are related to the single-electron transfer mechanism (SET).

Probing ground and low-lying excited states for HIO2 isomers.

We present a computational study on HIO2 molecules. Ground state properties such as equilibrium structures, relative energetics, vibrational frequencies, and infrared intensities were obtained for all the isomers at the coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)) level of theory with the aug-cc-pVTZ-PP basis set and ECP-28-PP effective core potential for iodine and the aug-cc-pVTZ basis set for hydrogen and oxygen atoms. The HOIO structure is confirmed as the lowest energy isomer.