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1.
ChemSusChem ; : e202400289, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38503687

RESUMO

Furfural is an industrially relevant biobased chemical platform. Unlike classical furan, or C-alkylated furans, which have been previously described in the current literature, the =C5H bond of furfural is unreactive. As a result, on a large scale, C=C and C=O bond hydrogenation/hydrogenolysis is mainly performed, with furfuryl alcohol and methyl tetrahydrofuran being the two main downstream chemicals. Here, we show that the derivatization of the -CHO group of furfural restores the reactivity of its =C5H bond, thus permitting its double condensation on various alkyl aldehydes. Overcoming the recalcitrance of the =C5H bond of furfural has opened an access to a biobased monomer, whose potential have been investigated in the fabrication of renewably-sourced poly(silylether). By means of a combined theoretical-experimental study, a reactivity scale for furfural and its protected derivatives against carbonylated compounds has been established using an electrophilicity descriptor, a means to predict the molecular diversity and complexity this pathway may support, and also to de-risk any project related to this topic. Finally, by using performance criteria for industrial operations in the field of fuels and commodities, we discussed the industrial potential of this work in terms of cost, E-factor, reactor productivity and catalyst consumption.

2.
RSC Adv ; 13(48): 33943-33956, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-38019991

RESUMO

Metallo-dithiaporphyrin small molecules have been designed by substituting Ru(ii) with various transition metals at the same oxidation state (M = Mn, Fe, Ni, Cu) as donor materials for Bulk Heterojunction Organic Solar Cells (BHJ-OSCs). Density functional theory (DFT) and time-dependent DFT (TD-DFT) have been used to study the optoelectronic properties of metallo-dithiaporphyrin at various functionals and basis sets. We discovered that the open-circuit voltage (VOC) value increases when Ru(ii) in Ru(S2TTP)Cl2 (S2TTP = tetra-p-tolyldithiaporphyrin) is substituted. In addition, the light harvesting efficiency (LHE) of nickel, manganese, and iron complexes was found to be similar to that of ruthenium, and the iron complex furthermore presented a comparable charge transfer in the excited state corresponding to the Q-band, compared to Ru(S2TTP)Cl2. Hence M(S2TTP)Cl2 (M = Mn, Fe, Ni) appear to be potential low cost candidate donor molecules within a bulk heterojunction solar cell. We further propose suitable engineered acceptor pigments, fitted to provide a good overall solar cell efficiency.

3.
Phys Chem Chem Phys ; 25(43): 29506-29515, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37889104

RESUMO

The discovery of novel two-dimensional (2D) materials is a significant obstacle for contemporary materials science. Research in the field of 2D materials has mainly focused on materials possessing 6-membered rings, high symmetry, and isotropic features. The examination of 2D materials presenting 5-membered rings, low symmetry and anisotropic characteristics properties has received scarce attention. In this study, we employed evolutionary algorithms and heuristic approaches combined with first-principles calculations to predict penta-MX2 structures (M = Zn, Cd; X = P, S, Se). All selected 2D penta-MX2 phases are dynamically, thermodynamically, mechanically, and thermally stable. Further discussion focuses on their structural, bonding, electronic and optoelectronic features. Our HSE06 calculations reveal that the penta-MP2, ZnPS, and MSSe structures are semiconductors with a band gap of 0.80-3.08 eV. Conversely, the 2D penta-MPSe (M = Zn, Cd) and CdPS phases are metallic. We additionally note that penta ß-ZnP2 and CdP2 display direct band gaps (1.39 eV and 1.18 eV, respectively), while the penta α-ZnP2, ZnPS, ZnSSe, α-CdSSe and ß-CdSSe possess indirect band gaps. Remarkably, 2D pentagonal MP2 (M = Zn, Cd), MSSe (M = Zn, Cd) and ZnPS 2D monolayers exhibit substantial optical absorption (>105 cm-1) throughout a broad range of the visible light spectra. Our results for crystal structure prediction expand the 2D penta-family of phosphides and chalcogenides, and demonstrate the potential of 2D penta-MX2 materials for optoelectronic applications.

4.
RSC Adv ; 13(43): 30369-30377, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37849695

RESUMO

Here, we study a sequence Diels-Alder/aromatization reaction between biobased furanic derivatives and alkynes, paving the way to renewable phenols. Guided by DFT calculations, we revealed that, in the case of dimethylfuran, the methyl group can migrate during the aromatization step, making this substrate also eligible to access renewable phenols. This reaction has been then successfully transposed to furfural and furfuryl alcohol, allowing molecular diversity and complexity to be created on phenol ring starting from two cheap biobased furanic derivatives available on large scale.

5.
J Chem Theory Comput ; 19(21): 7960-7971, 2023 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-37856841

RESUMO

Metastable materials are abundant in nature and technology, showcasing remarkable properties that inspire innovative materials design. However, traditional crystal structure prediction methods, which rely solely on energetic factors to determine a structure's fitness, are not suitable for predicting the vast number of potentially synthesizable phases that represent a local minimum corresponding to a state in thermodynamic equilibrium. Here, we present a new approach for the prediction of metastable phases with specific structural features and interface this method with the XtalOpt evolutionary algorithm. Our method relies on structural features that include the local crystalline order (e.g, the coordination number or chemical environment), and symmetry (e.g, Bravais lattice and space group) to filter the breeding pool of an evolutionary crystal structure search. The effectiveness of this approach is benchmarked on three known metastable systems: XeN8, with a two-dimensional polymeric nitrogen sublattice, brookite TiO2, and a high pressure BaH4 phase, which was recently characterized. Additionally, a newly predicted metastable melaminate salt, P1̅ WC3N6, was found to possess an energy that is lower than that of two phases proposed in a recent computational study. The method presented here could help in identifying the structures of compounds that have already been synthesized, and in developing new synthesis targets with desired properties.

6.
Nanoscale ; 15(16): 7472-7481, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37016969

RESUMO

In the present study, ab initio evolutionary algorithms and heuristic approach were used to predict new two-dimensional (2D) hydrogen cyanide crystalline phases based on HCN and HNC molecular building blocks. Our research revealed thirty-seven 2D HCN and HNC structures within six topological families which contain N1, N2 dimers, N3 trimers, infinite poly-N motifs, or zigzag C-C chains. HSE06 functional calculations indicated that 2D 1Pmn21 HCN, 2Pma2 HCN, 3P21212 HCN, and 6Pbcm HNC are direct semiconductors with band gaps Eg of 5.1, 4.2, 4.3, and 2.8 eV, respectively, and isovalent element substitutions (C by Ge/Si, and H by F) were performed to tune the electronic band gaps of the resulting 2D structures (Eg = 1.2-7.4 eV). Moreover, it has been found that the high in-plane Young's modulus (330.3-445.8 N m-1) and strong tolerance of direct band transitions (Eg = 1.2-5.3 eV) against the external biaxial strains in these four 2D HCN structures endow them with potential applications in photofunctional and flexible electronic devices. Finally, ab initio molecular dynamics simulations showed that at 50 GPa and 400 K, HCN molecules in a bulk I4mm hydrogen cyanide molecular crystal can extend to 2D HCN covalent nets.

7.
J Phys Chem Lett ; 13(40): 9316-9325, 2022 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-36178176

RESUMO

In this work, we unveiled a new class of two-dimensional (2D) group IV nitride AxNy (A = Sn, Ge, or Si) prototypes, C2/m A4N, P3̅m1 A3N, P3m1 A2N, P3̅m1 A3N2, P6̅m2 AN, P3̅m1 AN, P6̅2m A3N4, P3m1 A2N3, P4̅21m AN2, and P3̅m1 AN3, by using evolutionary algorithms combined with first-principles calculations. Using HSE06 functional calculations, a wide range of band gaps from metal to semiconductor (0.405-5.050 eV) and ultrahigh carrier mobilities (1-24 × 103 cm2 V-1 s-1) were evidenced in these 2D structures. We found that 2D P3m1 Sn2N3, Ge2N3, and Si2N3 are intrinsic ferromagnetic semiconductors with gaps of 0.677, 1.285, and 2.321 eV, respectively. The lattice symmetry and Si-to-N2 charge transfer upon strain lead to large anisotropic negative Poisson's ratios (-0.281 to -0.146) along whole in-plane directions in 2D P4̅21m SiN2. Our findings not only enrich the family of 2D nitrides but also highlight the promising optoelectronic and nanoauxetic applications of 2D group IV nitrides.

8.
J Comput Chem ; 43(20): 1334-1341, 2022 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-35670154

RESUMO

Mechanistic details of cellulose depolymerization by non-thermal (atmospheric) plasma (NTAP) remains under-explored given the complexity of the medium. In this study, we have investigated the reaction mechanism of glycosidic-bond degradation triggered by reaction with hydroxyl radicals, considered as the principal reactive species in NTAP medium. In the first step of reaction sequence, H-abstraction reactions by HO‧ . radical on different CH sites of the pyranose ring were found to be non-selective and markedly exergonic giving rise to a set of cellobiosyl carboradicals likely to undergo further reactions. We then showed that cellobiosyl carboradicals are protected against direct hydrolysis, no activation of the (1-4)- ß -glycosidic bond being characterized. Interestingly, a simple homolytic bond cleavage allowed to obtain desired monomer. Among the 18 possible fragmentations, involving CC and CO bond breaking from cellobiosyl carboradicals, 14 transition states were successfully identified, and only three reaction pathways proved kinetically and thermodynamically feasible. Natural bond orbital (NBO) analysis was performed to shed light on electronic structures of different compounds.


Assuntos
Celulose , Radical Hidroxila , Celulose/química , Hidrólise
9.
Phys Chem Chem Phys ; 23(38): 22086-22095, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34570852

RESUMO

In this study, the ternary phase diagram of the Tc-Al-B system is constructed by a combination of an evolutionary algorithm and density functional theory calculations. Four novel phases are predicted, including three binary compounds (P1̄ Al7B15, Cmcm TcAl2, and C2 TcAl3) and one ternary compound (Cmmm Tc2AlB2). All predicted structures are mechanically, dynamically, and thermodynamically stable. Among the predicted phases, P1̄ Al7B15 resembles the experimental structure of Al0.93B2 and Cmmm Tc2AlB2 corresponds to the 212-type MAB phase. Due to the in- and out-of-plane anisotropic chemical bonding in Cmmm Tc2AlB2, a tetragonal two-dimensional (2D) Tc2B2 structure could be possibly exfoliated by chemical removal of Al atoms. The electronic structure calculations indicate that the 2D Tc2B2 structure and its potential layered precursors are all metallic. Furthermore, the chemical reactivity of H, F, O and, OH ligands with the 2D Tc2B2 surface is studied and the associated 2D surface-functionalized Tc2B2 derivatives are found to be metallic. It is revealed that the F and O functional groups strengthen the surface atomic layer of 2D Tc2B2 and enhance the Young's moduli.

10.
Nat Commun ; 12(1): 3605, 2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34127660

RESUMO

Designing and synthesising new metastable compounds is a major challenge of today's material science. While exploration of metastable oxides has seen decades-long advancement thanks to the topochemical deintercalation of oxygen as recently spotlighted with the discovery of nickelate superconductor, such unique synthetic pathway has not yet been found for chalcogenide compounds. Here we combine an original soft chemistry approach, structure prediction calculations and advanced electron microscopy techniques to demonstrate the topochemical deintercalation/reintercalation of sulfur in a layered oxychalcogenide leading to the design of novel metastable phases. We demonstrate that La2O2S2 may react with monovalent metals to produce sulfur-deintercalated metastable phases La2O2S1.5 and oA-La2O2S whose lamellar structures were predicted thanks to an evolutionary structure-prediction algorithm. This study paves the way to unexplored topochemistry of mobile chalcogen anions.

11.
J Comput Chem ; 42(22): 1602-1626, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34101205

RESUMO

A popular first principles simulation code, the Vienna Ab initio Simulation Package (VASP), and a crystal structure prediction (CSP) package, the Universal Structure Predictor: Evolutionary Xtallography (USPEX) have been integrated into the GDIS visualization software. The aim of this integration is to provide users with a unique and simple interface through which most of the steps of a typical crystal optimization or prediction work. This involved, for the latter, not only setting up a CSP calculation with complete support for the latest version of USPEX, but also displaying the many structure results by linking each structure geometry and its energy via interactive graphics. For the optimization part, any structure displayed by GDIS can now be the starting point for VASP calculations, with support for its most commonly used parameters. Atomic and electronic structures can be displayed as well as dynamic properties such as total energy, force, volume, and pressure for each ionic step. It is not only possible to start calculations from the GDIS visualization software, using an in-place task manager, but a running calculation can also be followed, allowing a greater control of the simulation process. The GDIS software is available under the GNU public license in its second version.

12.
RSC Adv ; 11(48): 29965-29975, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35480238

RESUMO

In the present work, three new semiconducting two-dimensional (2D) Te phases containing three- and four-coordinated Te centers were proposed by using evolutionary algorithms combined with first-principles calculations. Using density functional theory calculations, we discussed the bonding and electronic properties in these phases, and subsequently rationalized their structures. The viability of these predicted structures was demonstrated by evaluating their thermodynamic, dynamic, mechanical, and thermal stabilities. Moreover, a significant direct band gap (0.951-1.512 eV) and excellent transport properties were evidenced in 2D Te nets, which suggests that they could be promising photovoltaic materials candidates. This is further supported by the stability of the associated bulk layered counterparts of the 2D Te nets.

13.
J Phys Chem Lett ; 11(20): 8861-8866, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33016707

RESUMO

The never-elucidated crystal structure of metastable iron disulfide FeS2 resulting from the full deintercalation of Li in Li2FeS2 has been cracked thanks to crystal structure prediction searches based on an evolutionary algorithm combined with first-principles calculations accounting for experimental observations. Besides the newly layered C2/m polymorph of iron disulfide, two-dimensional dynamically stable FeS2 phases are proposed that contain sulfides and/or persulfide S2 motifs.

14.
RSC Adv ; 10(14): 8016-8026, 2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-35497853

RESUMO

On the basis of first-principles calculations, we discuss a new class of two-dimensional materials-CuXSe2 (X = Cl, Br) nanocomposite monolayers and bilayers-whose bulk parent was experimentally reported in 1969. We show the monolayers are dynamically, mechanically and thermodynamically stable and have very small cleavage energies of ∼0.26 J m-2, suggesting their exfoliation is experimentally feasible. The monolayers are indirect-gap semiconductors with practically the same moderate band gaps of 1.74 eV and possess extremely anisotropic and very high carrier mobilities (e.g., their electron mobilities are 21 263.45 and 10 274.83 cm2 V-1 s-1 along the Y direction for CuClSe2 and CuBrSe2, respectively, while hole mobilities reach 2054.21 and 892.61 cm2 V-1 s-1 along the X direction). CuXSe2 bilayers are also indirect band gap semiconductors with slightly smaller band gaps of 1.54 and 1.59 eV, suggesting weak interlayer quantum confinement effects. Moreover, the monolayers exhibit high absorption coefficients (>105 cm-1) over a wide range of the visible light spectra. Their moderate band gaps, very high unidirectional electron and hole mobilities, and pronounced absorption coefficients indicate the proposed CuXSe2 (X = Cl, Br) nanocomposite monolayers hold significant promise for application in optoelectronic devices.

15.
Sci Rep ; 8(1): 10702, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-30013226

RESUMO

Electronic cigarette has the potential to serve as a tobacco cessation aid if the prerequisites which are safety and efficacy in term of nicotine delivery are achieved. The nicotine-based liquids are mainly composed by propylene glycol and glycerol playing the important role of airborne carriers. 1,3 propanediol is proposed as a propylene glycol substitute to potentially improve the thermal stability, nicotine delivery and to decrease inhaled flavors concentrations. We have implemented various thermal, physicochemical and computational methods to evaluate the use of 1,3 propanediol as a substitute (or additional ingredient) to propylene glycol in e-liquids compositions. Our results indicate that 1,3 propanediol is stable upon heating when electronic cigarette are used in recommended conditions. We demonstrate that 1,3 propanediol gave better thermic profile compared to propylene glycol and glycerol, showing less thermal decomposition by-products. In addition, 1,3 propanediol gives to nicotine a more basic environment ensuring a high level of free base nicotine form. We have also established a quantum mechanical based computational method to validate e-liquids as flavor enhancer. Our findings showed that globally 1,3 propanediol seems to have better flavoring properties than glycerol and propylene glycol. Finally, 1,3 propanediol seems to induce quite similar aerodynamic properties compared to propylene glycol and glycerol.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina/métodos , Aromatizantes/química , Nicotina/administração & dosagem , Propilenoglicol/química , Propilenoglicóis/química , Simulação por Computador , Aromatizantes/efeitos adversos , Glicerol/química , Temperatura Alta , Modelos Químicos , Propilenoglicol/efeitos adversos , Propilenoglicóis/efeitos adversos , Espectroscopia de Prótons por Ressonância Magnética , Dispositivos para o Abandono do Uso de Tabaco
16.
J Am Chem Soc ; 140(1): 413-422, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29189008

RESUMO

We report the discovery of novel CO2-based networks stabilized by Li+ cations in solid-state phases. Our exploration of the energy landscape of the Li-CO2 binary phase diagram using ab initio evolutionary structure searches revealed that in addition to the well-characterized C2O42- oxalate in Li2C2O4 viable covalent CO2-based nets emerge upon compression within the 0-100 GPa pressure range. Novel molecular units are described, such as ethene-like C2O44- in C2/m Li2(CO2), finite C4O86- chains in P1̅ Li3(CO2)2, one-dimensional polymeric forms based on 1,4-dioxane rings in P2/c LiCO2, and the C(O-)2 moieties in Pnma Li2CO2. This investigation shows the oxalate motif is maintained when the concentration of lithium increases from 1 to 2 in LixCO2; this interesting property may have potential in the development of renewable Li-ion batteries. Moreover, a variety of metastable phases were predicted, such as the covalent CO2-based layer in P1̅ Li(CO2)2.

17.
Phys Chem Chem Phys ; 19(12): 8236-8242, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-28275779

RESUMO

HCl is a textbook example of a polar covalent molecule, and has a wide range of industrial applications. Inspired by the discovery of unexpected stable sodium and potassium chlorides, we performed systematic ab initio evolutionary searches for all stable compounds in the H-Cl system at pressures up to 400 GPa. Besides HCl, four new stoichiometries (H2Cl, H3Cl, H5Cl and H4Cl7) are found to be stable under pressure. Our predictions substantially differ from previous theoretical studies. We evidence a high significance of zero-point energy in determining phase stability. The newly discovered compounds display a rich variety of chemical bonding characteristics. At ambient pressure, H2, Cl2 and HCl molecular crystals are formed by weak intermolecular van der Waals interactions, and adjacent HCl molecules connect with each other to form asymmetric zigzag chains, which become symmetric under high pressure. In H5Cl, triangular H3+ cations are stabilized by electrostatic interactions with the anionic chloride network. Further increase of pressure drives H2 dimers to combine with H3+ cations to form H5+ units. We also found chlorine-based Kagomé layers which are intercalated with zigzag HCl chains in H4Cl7. These findings could help to understand how varied bonding features can co-exist and evolve in one compound under extreme conditions.

18.
Sci Rep ; 5: 17764, 2015 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-26626579

RESUMO

Chromium hydride is a prototype stoichiometric transition metal hydride. The phase diagram of Cr-H system at high pressures remains largely unexplored due to the challenges in dealing with the high activation barriers and complications in handing hydrogen under pressure. We have performed an extensive structural study on Cr-H system at pressure range 0 ∼ 300 GPa using an unbiased structure prediction method based on evolutionary algorithm. Upon compression, a number of hydrides are predicted to become stable in the excess hydrogen environment and these have compositions of Cr2Hn (n = 2-4, 6, 8, 16). Cr2H3, CrH2 and Cr2H5 structures are versions of the perfect anti-NiAs-type CrH with ordered tetrahedral interstitial sites filled by H atoms. CrH3 and CrH4 exhibit host-guest structural characteristics. In CrH8, H2 units are also identified. Our study unravels that CrH is a superconductor at atmospheric pressure with an estimated transition temperature (T c) of 10.6 K, and superconductivity in CrH3 is enhanced by the metallic hydrogen sublattice with T c of 37.1 K at 81 GPa, very similar to the extensively studied MgB2.

19.
Phys Chem Chem Phys ; 17(17): 11763-9, 2015 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-25869225

RESUMO

We have performed first-principles evolutionary searches for stable Ti-N compounds and have found, in addition to the well-known rock-salt TiN, new ground states Ti3N2, Ti4N3, Ti6N5 at atmospheric pressure, and Ti2N and TiN2 at higher pressures. The latter nitrogen-rich structure contains encapsulated N2 dumbbells with a N-N distance of 1.348 Å at 60 GPa. TiN2 is predicted to be mechanically stable and quenchable. Our calculations on the mechanical properties (bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and hardness) are in excellent agreement with the available experimental data. Further analyses of the electronic density of states, crystal orbital Hamilton population and the electron localization function reveal that the hardness is enhanced by strengthening directional covalent bonds and disappearance of Ti-Ti metallic bonding.

20.
Phys Rev Lett ; 110(16): 165504, 2013 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-23679618

RESUMO

Diborane (B(2)H(6)), a high energy density material, was believed to be stable in a wide P, T interval. A systematic investigation of the B-H system using the ab initio variable-composition evolutionary simulations shows that boron monohydride (BH) is thermodynamically stable and can coexist with solid B, H(2), and B(2)H(6) in a wide pressure range above 50 GPa. B(2)H(6) becomes unstable and decomposes into the Ibam phase of BH and H(2) (C2/c) at 153 GPa. The semiconducting layered Ibam structure of BH at 168 GPa transforms into a metallic phase with space group P6/mmm and a 3D topology with strong B-B and B-H covalent bonds. The Ibam-P6/mmm transformation pathway suggests the possibility of obtaining the metastable Pbcm phase on cold decompression of the P6/mmm phase. The electron-phonon coupling calculations indicate that P6/mmm-BH is a phonon-mediated superconductor with a critical temperature of superconductivity (T(c)) of 14.1-21.4 K at 175 GPa.

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