1
|
Engelbrecht LDV, Ji X, Carbonaro CM, Laaksonen A, Mocci F. MD simulations explain the excess molar enthalpies in pseudo-binary mixtures of a choline chloride-based deep eutectic solvent with water or methanol. Front Chem 2022; 10:983281. [DOI: 10.3389/fchem.2022.983281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
The addition of molecular liquid cosolvents to choline chloride (ChCl)-based deep eutectic solvents (DESs) is increasingly investigated for reducing the inherently high bulk viscosities of the latter, which represent a major obstacle for potential industrial applications. The molar enthalpy of mixing, often referred to as excess molar enthalpy HE—a property reflecting changes in intermolecular interactions upon mixing—of the well-known ChCl/ethylene glycol (1:2 molar ratio) DES mixed with either water or methanol was recently found to be of opposite sign at 308.15 K: Mixing of the DES with water is strongly exothermic, while methanol mixtures are endothermic over the entire mixture composition range. Knowledge of molecular-level liquid structural changes in the DES following cosolvent addition is expected to be important when selecting such “pseudo-binary” mixtures for specific applications, e.g., solvents. With the aim of understanding the reason for the different behavior of selected DES/water or methanol mixtures, we performed classical MD computer simulations to study the changes in intermolecular interactions thought to be responsible for the observed HE sign difference. Excess molar enthalpies computed from our simulations reproduce, for the first time, the experimental sign difference and composition dependence of the property. We performed a structural analysis of simulation configurations, revealing an intriguing difference in the interaction modes of the two cosolvents with the DES chloride anion: water molecules insert between neighboring chloride anions, forming ionic hydrogen-bonded bridges that draw the anions closer, whereas dilution of the DES with methanol results in increased interionic separation. Moreover, the simulated DES/water mixtures were found to contain extended hydrogen-bonded structures containing water-bridged chloride pair arrangements, the presence of which may have important implications for solvent applications.
Collapse
|
2
|
Batista PR, Ducati LC, Autschbach J. Solvent effect on the 195Pt NMR properties in pyridonate-bridged Pt III dinuclear complex derivatives investigated by ab initio molecular dynamics and localized orbital analysis. Phys Chem Chem Phys 2021; 23:12864-12880. [PMID: 34075921 DOI: 10.1039/d0cp05849a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ab initio molecular dynamics investigation of the solvent effect (water) on the structural parameters, 195Pt NMR spin-spin coupling constants (SSCCs) and chemical shifts of a series of pyridonate-bridged PtIII dinuclear complexes is performed using Kohn-Sham (KS) Car-Parrinello molecular dynamics (CPMD) and relativistic hybrid KS NMR calculations. The indirect solvent effect (via structural changes) has a dramatic effect on the 1JPtPt SSCCs. The complexes exhibit a strong trans influence in solution, where the Pt-Pt bond lengthens with increasing axial ligand σ-donor strength. In the diaqua complex, where the solvent effect is more pronounced, the SSCCs averaged for CPMD configurations with explicit plus implicit solvation agree much better with the experimental data, while the calculations for static geometry and CPMD unsolvated configurations show large deviations with respect to experiment. The combination of CPMD with hybrid KS NMR calculations provides a much more realistic computational model that reproduces the large magnitudes of 1JPtPt and 195Pt chemical shifts. An analysis of 1JPtPt in terms of localized and canonical orbitals shows that the SSCCs are driven by changes in the s-character of the natural atomic orbitals of Pt atoms, which affect the 'Fermi contact' mechanism.
Collapse
Affiliation(s)
- Patrick R Batista
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo, SP, Brazil.
| | | | | |
Collapse
|
3
|
Engelbrecht LDV, Farris R, Vasiliu T, Demurtas M, Piras A, Cesare Marincola F, Laaksonen A, Porcedda S, Mocci F. Theoretical and Experimental Study of the Excess Thermodynamic Properties of Highly Nonideal Liquid Mixtures of Butanol Isomers + DBE. J Phys Chem B 2021; 125:587-600. [PMID: 33428423 DOI: 10.1021/acs.jpcb.0c10076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Binary alcohol + ether liquid mixtures are of significant importance as potential biofuels or additives for internal combustion engines and attract considerable fundamental interest as model systems containing one strongly H-bonded self-associating component (alcohol) and one that is unable to do so (ether), but that can interact strongly as a H-bond acceptor. In this context, the excess thermodynamic properties of these mixtures, specifically the excess molar enthalpies and volumes (HE and VE), have been extensively measured. Butanol isomer + di-n-butyl ether (DBE) mixtures received significant attention because of interesting differences in their VE, changing from negative (1- and isobutanol) to positive (2- and tert-butanol) with increasing alkyl group branching. With the aim of shedding light on the differences in alcohol self-association and cross-species H-bonding, considered responsible for the observed differences, we studied representative 1- and 2-butanol + DBE mixtures by molecular dynamics simulations and experimental excess property measurements. The simulations reveal marked differences in the self-association of the two isomers and, while supporting the existing interpretations of the HE and VE in a general sense, our results suggest, for the first time, that subtle changes in H-bonded topologies may contribute significantly to the anomalous volumetric properties of these mixtures.
Collapse
Affiliation(s)
- Leon de Villiers Engelbrecht
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Riccardo Farris
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Tudor Vasiliu
- Centre of Advanced Research in Bio-nanoconjugates and Biopolymers, Romanian Academy-Petru Poni (PP) Institute of Macromolecular Chemistry, 00487 Iasi, Romania
| | - Monica Demurtas
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Alessandra Piras
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Flaminia Cesare Marincola
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Aatto Laaksonen
- Centre of Advanced Research in Bio-nanoconjugates and Biopolymers, Romanian Academy-Petru Poni (PP) Institute of Macromolecular Chemistry, 00487 Iasi, Romania.,Department of Materials and Environmental Chemistry, Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University (SU), 106 91 Stockholm, Sweden.,State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University (NTU), 210009 Nanjing, China.,Department of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Silvia Porcedda
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| | - Francesca Mocci
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S.S. 554 Bivio Sestu, Monserrato, 09042 Cagliari, Italy
| |
Collapse
|
4
|
Quinson J, Jensen KM. From platinum atoms in molecules to colloidal nanoparticles: A review on reduction, nucleation and growth mechanisms. Adv Colloid Interface Sci 2020; 286:102300. [PMID: 33166723 DOI: 10.1016/j.cis.2020.102300] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 12/24/2022]
Abstract
Platinum (Pt) is one of the most studied materials in catalysis today and considered for a wide range of applications: chemical synthesis, energy conversion, air treatment, water purification, sensing, medicine etc. As a limited and non-renewable resource, optimized used of Pt is key. Nanomaterial design offers multiple opportunities to make the most of Pt resources down to the atomic scale. In particular, colloidal syntheses of Pt nanoparticles are well documented and simple to implement, which accounts for the large interest in research and development. For further breakthroughs in the design of Pt nanomaterials, a deeper understanding of the intricate synthesis-structures-properties relations of Pt nanoparticles must be obtained. Understanding how Pt nanoparticles form from molecular precursors is both a challenging and rewarding area of investigation. It is directly relevant to develop improved Pt nanomaterials but is also a source of inspiration to design other precious metal nanostructures. Here, we review the current understanding of Pt nanoparticle formation. This review is aimed at readers with interest in Pt nanoparticles in general and their colloidal syntheses in particular. Readers with a strongest interest on the study of nanomaterial formation will find here the case study of Pt. The preferred model systems and characterization techniques used to perform the study of Pt nanoparticle syntheses are discussed. In light of recent achievements, further direction and areas of research are proposed.
Collapse
|
5
|
Volchek VV, Shuvaeva OV, Berdyugin SN, Vasilchenko DB, Korenev SV. The study of Rh(iii) hydroxocomplexes using capillary zone electrophoresis with a UV-Vis detector: the development of the method. Dalton Trans 2019; 48:12707-12712. [PMID: 31386710 DOI: 10.1039/c9dt01879d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The expediency of capillary zone electrophoresis application in the study of a mixture of rhodium(iii) hydroxocomplexes is shown for the species formed during the thermal treatment of [Rh(OH)6]3- at 60 °C in alkaline media. As these compounds are unstable in solution because of polycondensation at pH > 10 and the formation of insoluble rhodium(iii) hydroxides at pH 5-10, their acidic derivatives with terminal aqua ligands acted as the objects of the study. Optimal separation conditions were achieved using sodium perchlorate as a background electrolyte, a voltage of +20 kV and pH 2.6. Rhodium(iii) species with different nuclearities were identified in accordance with their UV spectra and the regularities of electrophoretic migration in the capillary. The presence of a dimer was also verified by the spiking of the mixture under investigation with a previously synthesised complex [Rh2(μ-OH)2(H2O)8](NO3)4, which confirms the correct identification.
Collapse
Affiliation(s)
- Victoria V Volchek
- Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia.
| | - Olga V Shuvaeva
- Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia. and Novosibirsk State University, 2 Pirogova str., 630090 Novosibirsk, Russia
| | - Semen N Berdyugin
- Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia.
| | - Danila B Vasilchenko
- Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia. and Novosibirsk State University, 2 Pirogova str., 630090 Novosibirsk, Russia
| | - Sergey V Korenev
- Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Acad. Lavrentiev Ave., 630090 Novosibirsk, Russia. and Novosibirsk State University, 2 Pirogova str., 630090 Novosibirsk, Russia
| |
Collapse
|