Latest Publications

DOI: 10.1002/qua.26233

International Journal of Quantum Chemistry

DH‐SVPD is a tailored atomic basis set originally developed to enhance the domain of applicability of double‐hybrid density functionals to large molecular systems in weak interactions. In combination with any density functional belonging to this approximation, it provides an accurate estimate of noncovalent interaction energies at the cost of a double‐ζ basis set, without adding a posteriori an empirical dispersion correction. Here, we show that the accuracy/cost ratio observed previously for energy properties can be safely extended to the modeling of structural parameters of small‐ and medium‐sized organic molecules. In particular, we demonstrate that, in combination with the nonempirical PBE‐QIDH double hybrid, DH‐SVPD is competitive with very large quadruple‐ζ basis sets when modeling both covalent and noncovalent structural parameters.

DOI: 10.1002/jcc.26191

Journal of Computational Chemistry

In this article, we explore an alternative to the analytical Gauss–Bonnet approach for computing the solvent‐accessible surface area (SASA) and its nuclear gradients. These two key quantities are required to evaluate the nonelectrostatic contribution to the solvation energy and its nuclear gradients in implicit solvation models. We extend a previously proposed analytical approach for finite systems based on the stereographic projection technique to infinite periodic systems such as polymers, nanotubes, helices, or surfaces and detail its implementation in the Crystal code. We provide the full derivation of the SASA nuclear gradients, and introduce an iterative perturbation scheme of the atomic coordinates to stabilize the gradients calculation for certain difficult symmetric systems. An excellent agreement of computed SASA with reference analytical values is found for finite systems, while the SASA size‐extensivity is verified for...

DOI: 10.1021/jacs.9b13620

Journal of the American Chemical Society

The utilization of photodynamic therapy (PDT) for the treatment of various types of cancer has gained increasing attention over the last decades. Despite the clinical success of approved photosensitizers (PSs), their application is sometimes limited due to poor water solubility, aggregation, photodegradation, and slow clearance from the body. To overcome these drawbacks, research efforts are devoted toward the development of metal complexes and especially Ru(II) polypyridine complexes based on their attractive photophysical and biological properties. Despite the recent research developments, the vast majority of complexes utilize blue or UV-A light to obtain a PDT effect, limiting the penetration depth inside tissues and, therefore, the possibility to treat deep-seated or large tumors. To circumvent these drawbacks, we present the first example of a DFT guided search for efficient PDT PSs with a substantial spectral red s...

DOI: 10.1002/qua.26193

International journal of Quantum chemistry

We investigate here the lowest‐energy (spin‐conserving) excitation energies for the set of He‐Ne atoms, with the family of nonempirical PBE, PBE0, PBE0‐1/3, PBE0‐DH, PBE‐CIDH, PBE‐QIDH, and PBE0‐2 functionals, after employing a wide variety of basis sets systematically approaching the basis set limit: def2‐nVP(D), cc‐pVnZ, aug‐cc‐pVnZ, and d‐aug‐cc‐pVnZ. We find that an accuracy (ie, mean unsigned error) of 0.3 to 0.4 eV for time‐dependent density functional theory (DFT) atomic excitation energies can be robustly achieved with modern double‐hybrid methods, which are also stable with respect to the addition of a double set of diffuse functions, contrarily to hybrid versions, in agreement with recent findings employing sophisticated multiconfigurational DFT methods.

DOI:10.1039/C9CP06590C

Physical Chemistry Chemical Physics

A dithienylethene (DTE) photochromic compound functionalized by ureidopyrimidinone (UPy) quadruple hydrogen bonding blocks was synthesized by Takeshita and coworkers [Takeshita et al., Chem. Commun., 2005, 761] in order to form a light-responsive supramolecular self-assembling system. In solution, the formation of supramolecular assemblies was only observed for one DTE isomer, namely the closed-form isomer. To rationalize this experimental finding, with the help of Molecular Dynamics (MD) and (time-dependent) DFT calculations, the behaviour of open-form and closed-form monomers, dimers, hexamers and π-stacked dimers in solution is investigated. Our simulations show that, for the open-form oligomers, the progression of the supramolecular assembly is hindered due to (i) the possible formation of a very stable cyclic dimer for the open-form parallel isomer, (ii) the relative flexibility of the open-form oligomers compared to their c...

DOI: 10.1021/acsomega.9b03964 

Journal of the American Chemical Society

The reaction mechanism involved in the decomposition of ammonium nitrate (AN) in the presence of CaCO3 and CaSO4, commonly used for stabilization and the reduction of explosivity properties of AN, was theoretically investigated using a computational approach based on density functional theory. The presented computational results suggest that both carbonate and sulfate anions can intercept an acid proton from nitric acid issued from the first step of decomposition of AN, thus inhibiting its runaway decomposition and the generation of reactive species (radicals). The reaction then leads to the production of stable products, as experimentally observed. Our modeling outcomes allow for tracing a relationship between the capability of proton acceptance of both carbonate and sulfate anions and the macroscopic behavior of these two additives as inhibitor or inert in the AN mixture.

DOI: 10.1021/jacs.9b12464

Journal of the American Chemical Society

Due to the great potential expressed by an anticancer drug candidate previously reported by our group, namely, Ru-sq ([Ru(DIP)2(sq)](PF6) (DIP, 4,7-diphenyl-1,10-phenanthroline; sq, semiquinonate ligand), we describe in this work a structure–activity relationship (SAR) study that involves a broader range of derivatives resulting from the coordination of different catecholate-type dioxo ligands to the same Ru(DIP)2 core. In more detail, we chose catechols carrying either an electron-donating group (EDG) or an electron-withdrawing group (EWG) and investigated the physicochemical and biological properties of their complexes. Several pieces of experimental evidences demonstrated that the coordination of catechols bearing EDGs led to deep-red positively charged complexes 1–4 in which the preferred oxidation state of the dioxo ligand is the uninegatively charged semiquinonate. Complexes 5 and 6, on the other hand, are blue/viol...

DOI: 10.1021/jacs.9b12762

ACS Publications

Molecular-level multielectron handling toward electrical storage is a worthwhile approach to solar energy harvesting. Here, a strategy which uses chemical bonds as electron reservoirs is introduced to demonstrate the new concept of “structronics” (a neologism derived from “structure” and “electronics”). Through this concept, we establish, synthesize, and thoroughly study two multicomponent “super-electrophores”: 1,8-dipyridyliumnaphthalene, 2, and its N,N-bridged cyclophane-like analogue, 3. Within both of them, a covalent bond can be formed and subsequently broken electrochemically. These superelectrophores are based on two electrophoric (pyridinium) units that are, on purpose, spatially arranged by a naphthalene scaffold. A key characteristic of 2 and 3 is that they possess a LUMO that develops through space as the result of the interaction between the closely positioned electrophoric units. In the context of electron storage, this “super-LUMO...

DOI: 10.1002/jcc.26170

Journal of Computational Chemistry

In this paper we present the implementation and benchmarking of a Time Dependent Density Functional Theory approach in conjunction with Double Hybrid (DH) functionals. We focused on the analysis of their performance for through space charge‐transfer (CT) excitations which are well known to be very problematic for commonly used functionals, such as global hybrids.Two different families of functionals were compared, each of them containing pure, hybrid and double‐hybrid functionals.The results obtained show that, beside the robustness of the implementation, these functionals provide results with an accuracy comparable to that of adjusted range‐separated functionals, with the relevant difference that for DHs no parameter is tuned on specific compounds thus making them more appealing for a general use. Furthermore, the algorithm described and implemented is characterized by the same computational cost scaling as that of the ground sta...

DOI: 10.1002/cssc.201903182

Chemistry-Sustainability-Energy-Materials

The anchoring group of a sensitizer may strongly affect the overall properties and stability of the resulting dye‐sensitized solar cells (DSSCs) and dye‐sensitized photoelectrosynthetic solar cells (DSPECs). The properties of seven perylene monoimide (PMI) dyes have been comprehensively studied for their immobilization on nanocrystalline NiO film. The PMI dyes differ only by the nature of the anchoring group, which are: carboxylic acid (PMI‐CO2H), phosphonic acid (PMI‐PO3H2), acetyl acetone (PMI‐acac), pyridine (PMI‐Py), aniline (PMI‐NH2), hydroxyquinoline (PMI‐HQ), and dipicolinic acid (PMI‐DPA). The dyes are investigated by cyclic voltammetry and spectroelectrochemistry and modeled by TD‐DFT quantum chemical calculations. The mode of binding of these anchoring groups is investigated by infrared spectroscopy and the stability of the binding to NiO surface is studied by desorption experiments in acidic and basic media....

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