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Journal of Physical Chemistry C
Volumn 112, Issue 49, 2008, Pages 19590-19603
Ordering of imidazolium-based ionic liquids at the α-quartz(001) surface: a molecular dynamics study
Author keywords

[No Author keywords available]
Indexed keywords

AMPHIPHILIC; ANISOTROPIC DISTRIBUTIONS; CONTACT SURFACES; H BONDINGS; IMIDAZOLIUM RINGS; IMIDAZOLIUM-BASED IONIC LIQUIDS; MODEL SURFACES; QUARTZ SURFACES; REPULSIVE INTERACTIONS; SILANOL GROUPS; SMALL PERTURBATIONS; SOLID SURFACES; SOLID/LIQUID INTERFACES; VAN DER WAALS INTERACTIONS;
EID: 64349122475     PISSN: 19327447     EISSN: 19327455     Source Type: Journal    
DOI: 10.1021/jp806882e     Document Type: Article
Times cited : (74)
References (85)
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    • Case, D. A. Pearlman, D. A. Caldwell, J. W. Cheatham III, T. E. Wang, J. Ross, W. S. Simmerling, C. L. Darden, T. A. Merz, K. M. Stanton, R. V. Cheng, A. L. Vincent, J. J. Crowley, M. Tsui, V. Gohlke, H. Radmer, R. J. Duan, Y. Pitera, J. Massova, I. Seibel, G. L. Singh, U. C. Weiner, P. K. Kollman, P. A., AMBER7, San Fransisco 2002.
    • Case, D. A. Pearlman, D. A. Caldwell, J. W. Cheatham III, T. E. Wang, J. Ross, W. S. Simmerling, C. L. Darden, T. A. Merz, K. M. Stanton, R. V. Cheng, A. L. Vincent, J. J. Crowley, M. Tsui, V. Gohlke, H. Radmer, R. J. Duan, Y. Pitera, J. Massova, I. Seibel, G. L. Singh, U. C. Weiner, P. K. Kollman, P. A., AMBER7, San Fransisco 2002.
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    • July, 2008
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    • As pointed out by a referee, the Berendsen,s thermostast does not generate a canonical (NVT) ensemble. We feel that this feature does not critically determine the ionic liquid ions distribution at the interface, as seen by the comparison of two drastically different conditions: quasiidentical results were obtained at 400 and 300 K for the BMI[Tf2N]/quartz interface
    • 2N]/quartz interface.
  • 54
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    • Tsoucaris, G, Atwood, J. L, Lipkowski, J, Eds, Kluwer Academic Publishers; Dordrecht, The Netherlands
    • Engler, E., Wipff, G. In Crystallography of Supramolecular Compounds; Tsoucaris, G., Atwood, J. L., Lipkowski, J., Eds.; Kluwer Academic Publishers; Dordrecht, The Netherlands, 1996; Vol. 480, pp 471.
    • (1996) Crystallography of Supramolecular Compounds , vol.480 , pp. 471
    • Engler, E.1    Wipff, G.2
  • 61
    • 64349118293 scopus 로고    scopus 로고
    • 2N] ILs, the anionic contributions decrease by ca. 100 and 50 kcal/mol, respectively, while the cationic contributions are less affected (by 30 and 10 kcal/mol, respectively) by adding water. As expected, the more hydrophilic the IL's anion and the higher the water content, the larger the effect of water. Similar features are observed for the SiH2 surface (Table 2).
    • 2N] ILs, the anionic contributions decrease by ca. 100 and 50 kcal/mol, respectively, while the cationic contributions are less affected (by 30 and 10 kcal/mol, respectively) by adding water. As expected, the more hydrophilic the IL's anion and the higher the water content, the larger the effect of water. Similar features are observed for the SiH2 surface (Table 2).
  • 65
    • 37349073029 scopus 로고    scopus 로고
    • Lynden-Bell, R. M.; Del, Pópolo, M. G.; Youngs, T. G. A.; Kohanoff, J.; Hanke, C. G.; Harper, J. B.; Pinilla, C. C. Acc. Chem. Res. 2007, 40, 1138.
    • Lynden-Bell, R. M.; Del, Pópolo, M. G.; Youngs, T. G. A.; Kohanoff, J.; Hanke, C. G.; Harper, J. B.; Pinilla, C. C. Acc. Chem. Res. 2007, 40, 1138.
  • 71
    • 64349113002 scopus 로고    scopus 로고
    • From the polar to the neutral quartz model, the IL anions become less attracted by the Si(OH)2 interface, and less repulsed by the SiH 2 interface. They thus readjust accordingly during the dynamics, as seen from the density curves (see Figures 3 and S7, In the case of the [BMI][Tf2N] liquid, one also observes an anion reorientation when the quartz surface becomes neutral. In fact, at the polar Si(OH)2 surface, the Tf2N- anions turn their SO2 oxygens to the Si(OH)2 protons, whereas they point their less polar CF3 groups to the apolar surface. Thus, as expected H-bonding interactions between the Si(OH)2 protons and Tf2N, or Cl- anions are suppressed when the quartz becomes apolar compare the RDFs in Figure S8 and 4
    • - anions are suppressed when the quartz becomes apolar (compare the RDFs in Figure S8 and 4).
  • 72
    • 64349092423 scopus 로고    scopus 로고
    • 2 interfaces, they are more similar with the neutral than with the polar quartz model, as the IL displays only van der Waals contacts with the neutral quartz.
    • 2 interfaces, they are more similar with the neutral than with the polar quartz model, as the IL displays only van der Waals contacts with the neutral quartz.
  • 73
    • 64349113213 scopus 로고    scopus 로고
    • It should also be noted that modulations observed as a function of the cation's alkyl chain, or as a function of the anion for a given cation, perturb not only the average orientations at the contact surface, but also the degree of anisotropy more deeeply into the IL, likely also contributing to different spectral signatures.
    • It should also be noted that modulations observed as a function of the cation's alkyl chain, or as a function of the anion for a given cation, perturb not only the average orientations at the contact surface, but also the degree of anisotropy more deeeply into the IL, likely also contributing to different spectral signatures.
  • 76
    • 64349117423 scopus 로고    scopus 로고
    • 2 surface with negatively charged H-atoms should display some similarities with the more frequently observed Si-O-Si structure where negatively charged oxygens are most accessible to the solvent.
    • 2 surface with negatively charged H-atoms should display some similarities with the more frequently observed Si-O-Si structure where negatively charged oxygens are most accessible to the solvent.
  • 77
    • 64349112176 scopus 로고    scopus 로고
    • In the force field representation of the energy, the van der Waals interactions at the quartz surface depend on the (ε, R*) parameters of the partners. Given the high magnitude of van der Waals interactions obtained with the Si parameters from the literature, we decided to resimulate the [BMI][Y] ILs (Y-, Cl, BF4, PF6, Tf2 N, at the quartz interface, reducing the e(Si) parameter from 0.60 to 0.32 kcal/mol. The results (Figures S11-S14 and Table S4) show that the quartz/IL interaction energies are somewhat reduced, as expected (by ca. 100 kcal/mol, but the ordering of IL ions at the interfaces with the two van der Waals models is quite the same see order parameters in Figures S11 and S12, densities in Figure S13, and RDFs in Figure S14, Thus, the high van der Waals contribution to the quartz-IL interaction energy does not stem from an overestimated representation of the latter in o
    • -) at the quartz interface, reducing the e(Si) parameter from 0.60 to 0.32 kcal/mol. The results (Figures S11-S14 and Table S4) show that the quartz/IL interaction energies are somewhat reduced, as expected (by ca. 100 kcal/mol), but the ordering of IL ions at the interfaces with the two van der Waals models is quite the same (see order parameters in Figures S11 and S12, densities in Figure S13, and RDFs in Figure S14). Thus, the high van der Waals contribution to the quartz-IL interaction energy does not stem from an overestimated representation of the latter in our calculations.
  • 78
    • 64349118704 scopus 로고    scopus 로고
    • In our calculated system, the order parameter of the end CH 3(alkyl) group (Figure S1) shows a first negative peak (ca.-0.25) at the Si(OH)2 surface, indicating that this group prefers to be rather normal to the Z-direction, i.e, parallel to the quartz surface, as concluded from the orientation of the ring normal and of the N2-CH3 vectors
    • 3 vectors.
  • 79
    • 64349124758 scopus 로고    scopus 로고
    • 2N) atoms. See also Sieffert and Wipff (J. Phys. Chem. B 2006, 110, 13076) for simulations, and Cammarata et al. (Phys. Chem. Chem. Phys. 2001, 3, 5192-5200) for an IR spectroscopy study.
    • 2N) atoms. See also Sieffert and Wipff (J. Phys. Chem. B 2006, 110, 13076) for simulations, and Cammarata et al. (Phys. Chem. Chem. Phys. 2001, 3, 5192-5200) for an IR spectroscopy study.
  • 84
    • 34547246840 scopus 로고    scopus 로고
    • 2N] ionic liquid at the interfaces (J. Phys. Chem. B 2007, 111, 7253).
    • 2N] ionic liquid at the interfaces (J. Phys. Chem. B 2007, 111, 7253).

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.