Close-Up Look at Electronic Spectroscopic Signatures of Common Pharmaceuticals in Solution.

Simulating electronic properties and spectral signals requires robust computational approaches that need tuning with the system's peculiarities. In this paper, we test implicit and fully atomistic solvation models for the calculation of UV-vis and electronic circular dichroism (ECD) spectra of two pharmaceutically relevant molecules, namely, (2)-captopril and ()-naproxen, dissolved in aqueous solution. Room temperature molecular dynamics simulations reveal that these two drugs establish strong contacts with the surrounding solvent molecules via hydrogen bonds.

Electrified methane steam reforming on a washcoated SiSiC foam for low-carbon hydrogen production.

In view of largely available renewable electricity as a green future resource, here we report the electrification of a Rh/AlO washcoated SiSiC foam for methane steam reforming (MSR). We show that, thanks to the suitable bulk resistivity of the SiSiC foam, its direct Joule heating up to relevant temperatures is feasible; the interconnected geometry greatly reduces heat and mass transfer limitations, which results in a highly active and energy efficient system for low-carbon H production. The foam-based electrified MSR (eMSR) system showed almost full methane conversion above 700°C and methane conversions approaching equilibrium were obtained in a range of conditions.

Quantum Mechanics/Fluctuating Charge Protocol to Compute Solvatochromic Shifts.

Despite the potentialities of the quantum mechanics (QM)/fluctuating charge (FQ) approach to model the spectral properties of solvated systems, its extensive use has been hampered by the lack of reliable parametrizations of solvents other than water. In this paper, we substantially extend the applicability of QM/FQ to solvating environments of different polarities and hydrogen-bonding capabilities. The reliability and robustness of the approach are demonstrated by challenging the model to simulate solvatochromic shifts of four organic chromophores, which display large shifts when dissolved in apolar, aprotic or polar, protic solvents.

A Fundamental Investigation of Gas/Solid Heat and Mass Transfer in Structured Catalysts Based on Periodic Open Cellular Structures (POCS).

In this work, we investigate the gas-solid heat and mass transfer in catalytically activated periodic open cellular structures, which are considered a promising solution for intensification of catalytic processes limited by external transport, aiming at the derivation of suitable correlations. Computational fluid dynamics is employed to investigate the Tetrakaidekahedral and Diamond lattice structures. The influence of the morphological features and flow conditions on the external transport properties is assessed.

Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study.

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations.

Production and characterization of copper periodic open cellular structures made by 3D printing-replica technique.

Additive manufacturing by 3D printing comprises a set of methods for production of 3D objects starting from a CAD file. Advantages of additive manufacturing combine high manufacturing resolution, a reduction of waste material, and the possibility of computer-aided design (CAD). When applied to the manufacturing of structured catalyst substrates, the latter enables the optimization of transport properties of the catalyst support.

Electronic transitions for a fully polarizable QM/MM approach based on fluctuating charges and fluctuating dipoles: Linear and corrected linear response regimes.

The fully polarizable Quantum Mechanics/Molecular Mechanics (QM/MM) approach based on fluctuating charges and fluctuating dipoles, named QM/FQFμ [T. Giovannini et al., J.

Quantum Confinement Effects on Solvatochromic Shifts of Molecular Solutes.

We demonstrate the pivotal role of quantum mechanics density confinement effects on solvatochromic shifts. In particular, by resorting to a quantum mechanics/molecular mechanics (QM/MM) approach capable of accounting for confinement effects we successfully reproduce vacuo-to-water solvatochromic shifts for dark → π* and bright π → π* transitions of acrolein and dark → π* transitions of pyridine and pyrimidine without the need of including explicit water molecules in the QM portion. Remarkably, our approach is also able to dissect the effects of the single forces acting on the solute-solvent couple and allows for a rationalization of the experimental findings in terms of physicochemical quantities.

Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles.

The fully polarizable QM/MM approach based on fluctuating charges and fluctuating dipoles, named QM/FQFμ ( , , 2233-2245), is extended to the evaluation of nuclear gradients and the calculation of IR spectra of molecular systems in condensed phase. To this end, analytical equations defining first and second energy derivatives with respect to nuclear coordinates are derived and discussed. The potentialities of the approach are shown by applying the model to the calculation of IR spectra of methlyoxirane, glycidol, and gallic acid in aqueous solution.

Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions.

We present the extension of the quantum/classical polarizable fluctuating charge model to the calculation of single residues of quadratic response functions, as required for the computational modeling of two-photon absorption cross sections. By virtue of a variational formulation of the quantum/classical polarizable coupling, we are able to exploit an atomic orbital-based quasienergy formalism to derive the additional coupling terms in the response equations. Our formalism can be extended to the calculation of arbitrary order response functions and their residues.

Polarizable QM/MM Approach with Fluctuating Charges and Fluctuating Dipoles: The QM/FQFμ Model.

The novel polarizable FQFμ force field is proposed and coupled to a quantum mechanical (QM) SCF Hamiltonian. The peculiarity of the resulting QM/FQFμ approach stands in the fact the polarization effects are modeled in terms of both fluctuating charges and dipoles, which vary as a response to the external electric field/potential. Remarkably, QM/FQFμ is defined in terms of three parameters: electronegativity and chemical hardness, which are well-defined in density functional theory, and polarizability, which is physically observable.

A 4,4'-bis(2-benzoxazolyl)stilbene luminescent probe: assessment of aggregate formation through photophysics experiments and quantum-chemical calculations.

A combination of experimental and quantum mechanical investigations is applied to the study of the optical features of 4,4'-bis(2-benzoxazolyl)stilbene (BBS) dissolved in solution or in a poly(l-lactic acid) (PLA) thermoplastic matrix at different concentrations. The experimental analyses allow the characterization of BBS solutions and dispersions in terms of absorption and emission features, along with the collection of some key parameters such as fluorescence quantum yield, anisotropy and lifetime, while the computational approach gives a detailed description of the photophysical behavior of BBS in the different environments. For the 10 M BBS solution, the fluorescence spectra show the expected peaks at 425 and 455 nm of the non-interacting BBS molecules with a single fluorescence lifetime of 0.