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A combined LX-NMR and molecular dynamics investigation of the bulk and local structure of ionic liquid crystals.
Soft Matter 2019; 15(22):4486-4497SM

Abstract

The unique power of NMR spectroscopy in anisotropic media (LX-NMR) as a tool to obtain local and bulk structural information, combined with the effectiveness of molecular dynamics simulations at the atomistic level, shows very attractive potentialities for the study of interesting, even though still poorly understood, materials such as Ionic Liquid Crystals (ILCs). In this work, we focused our attention, in particular, on the orientational ordering of two mesophases: 1-dodecyl-3-methylimidazolium chloride, [C12C1im]Cl, and 1-dodecyl-3-methylimidazolium tetrafluoroborate, [C12C1im][BF4]. Both ILCs were studied by a 2H NMR direct investigation of the molecules forming the phases, suitably deuterated, and by 1H NMR spectroscopy, using the small rigid probe-solutes 1,4-dichlorobenzene (DCB), dissolved in [C12C1im][BF4] and [C12C1im]Cl, and 1,4-dibromobenzene (DBB) dissolved in [C12C1im][BF4], to probe the local, internal structure and organization of the mesophases. The experimental results were then compared with the predictions, by atomistic MD simulations, of the structure of the smectic phase of the two salts, at two selected temperatures, containing a single DCB molecule as a probe. The MD simulations show that the DCB solute is distributed only within the hydrophobic layers of the ILC. Orientational order parameters of the imidazolium cations and of the DCB molecule were obtained and compared with the experiments, showing a general good agreement and allowing a deeper understanding of the microscopic structure of the systems.

Authors+Show Affiliations

Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via P. Bucci, cubo 14C, 87036 Rende, CS, Italy. giorgio.celebre@unical.it giuseppina.deluca@unical.it.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31093625

Citation

Di Pietro, Maria Enrica, et al. "A Combined LX-NMR and Molecular Dynamics Investigation of the Bulk and Local Structure of Ionic Liquid Crystals." Soft Matter, vol. 15, no. 22, 2019, pp. 4486-4497.
Di Pietro ME, Margola T, Celebre G, et al. A combined LX-NMR and molecular dynamics investigation of the bulk and local structure of ionic liquid crystals. Soft Matter. 2019;15(22):4486-4497.
Di Pietro, M. E., Margola, T., Celebre, G., De Luca, G., & Saielli, G. (2019). A combined LX-NMR and molecular dynamics investigation of the bulk and local structure of ionic liquid crystals. Soft Matter, 15(22), pp. 4486-4497. doi:10.1039/c9sm00612e.
Di Pietro ME, et al. A Combined LX-NMR and Molecular Dynamics Investigation of the Bulk and Local Structure of Ionic Liquid Crystals. Soft Matter. 2019 Jun 5;15(22):4486-4497. PubMed PMID: 31093625.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A combined LX-NMR and molecular dynamics investigation of the bulk and local structure of ionic liquid crystals. AU - Di Pietro,Maria Enrica, AU - Margola,Tommaso, AU - Celebre,Giorgio, AU - De Luca,Giuseppina, AU - Saielli,Giacomo, PY - 2019/5/17/pubmed PY - 2019/5/17/medline PY - 2019/5/17/entrez SP - 4486 EP - 4497 JF - Soft matter JO - Soft Matter VL - 15 IS - 22 N2 - The unique power of NMR spectroscopy in anisotropic media (LX-NMR) as a tool to obtain local and bulk structural information, combined with the effectiveness of molecular dynamics simulations at the atomistic level, shows very attractive potentialities for the study of interesting, even though still poorly understood, materials such as Ionic Liquid Crystals (ILCs). In this work, we focused our attention, in particular, on the orientational ordering of two mesophases: 1-dodecyl-3-methylimidazolium chloride, [C12C1im]Cl, and 1-dodecyl-3-methylimidazolium tetrafluoroborate, [C12C1im][BF4]. Both ILCs were studied by a 2H NMR direct investigation of the molecules forming the phases, suitably deuterated, and by 1H NMR spectroscopy, using the small rigid probe-solutes 1,4-dichlorobenzene (DCB), dissolved in [C12C1im][BF4] and [C12C1im]Cl, and 1,4-dibromobenzene (DBB) dissolved in [C12C1im][BF4], to probe the local, internal structure and organization of the mesophases. The experimental results were then compared with the predictions, by atomistic MD simulations, of the structure of the smectic phase of the two salts, at two selected temperatures, containing a single DCB molecule as a probe. The MD simulations show that the DCB solute is distributed only within the hydrophobic layers of the ILC. Orientational order parameters of the imidazolium cations and of the DCB molecule were obtained and compared with the experiments, showing a general good agreement and allowing a deeper understanding of the microscopic structure of the systems. SN - 1744-6848 UR - https://www.unboundmedicine.com/medline/citation/31093625/A_combined_LX-NMR_and_molecular_dynamics_investigation_of_the_bulk_and_local_structure_of_ionic_liquid_crystals L2 - https://doi.org/10.1039/c9sm00612e DB - PRIME DP - Unbound Medicine ER -