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N7-(carboxymethyl)guanine-Lithium Crystalline Complex: A Bioinspired Solid Electrolyte.

Dutta D, Nagapradeep N, Zhu H, Forsyth M, Verma S, Bhattacharyya AJ - Sci Rep (2016)

Bottom Line: G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content.The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C).Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination.

View Article: PubMed Central - PubMed

Affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012 (Karnataka), India.

ABSTRACT
Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries.

No MeSH data available.


Related in: MedlinePlus

(a) Static 1H-NMR spectra, (b) 1Hline width (FWHM: full width at half maximum) of the narrow component,(c) 1H line width of the broad component, and(d) the integration percentage of the narrow component as afunction of temperature for G7Li solid powder.
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f6: (a) Static 1H-NMR spectra, (b) 1Hline width (FWHM: full width at half maximum) of the narrow component,(c) 1H line width of the broad component, and(d) the integration percentage of the narrow component as afunction of temperature for G7Li solid powder.

Mentions: To investigate whether protons in G7Li also contribute to the overall ionicconductivity as evident from the transference number measurements, the1H solid state MAS NMR experiments are performed as a function oftemperature. The 1H MAS NMR chemical shift spectra (c/f Figure S12a)shows two broad peaks centering at 1.04 ppm and 4.96 ppmcorresponding probably to the free mobile water proton(Li → OH2) and the static protoncovalently bonded to the nitrogen atoms of the guanine respectively. The broadeningof the peaks partially might be a result of the hydrogen bonding in the system. Thesolid-state 1H MAS NMR spectra of G7Li (c/f Fig.6a) are deconvoluted into a narrow component (mobile protons) and a broadcomponent (rigid protons) using the mixed Gaussian and Lorentzian function (c/fexample in Figure S12b) in order to obtain the line-width and integration for boththe components. At 293 K the spectrum is dominated by the rigid latticecomponent (Fig. 6a), with recognizable contributions from themobile protons. As the temperature increases the population of the mobile protonsincreases (Fig. 6d), suggesting the breach of the hydrogenbonding at elevated temperatures and thus more protons become mobile. This willnegatively affect the conductivity as in ‘dry’ state theproton transport is achieved via breach and formation of hydrogen bonding (Grotthussmechanism). The line-width that is observed to be 2.53 kHz at293 K gradually decreases to 1.21 kHz at 343 Kindicating an enhancement of proton mobility with temperature in the mobile region.However, an increase in line-width to 1.3 kHz with further increase intemperature to 348 K may be due to the onset of water molecules exitingfrom the system. The line-width of the rigid component is quite constant in thestudied temperature range as shown in Fig. 6(c) indicating aquite stable structure and molecular dynamics in the lattice molecules. For protonto hop between different sites, the ideal distance between the sites normally iswithin 2.5 Å5556. In G7Li theH···O distance between water molecules attachedto two adjacent Li-tetrahedra (c/f Figure S4) is around 2 Å(<2.5 Å) suggesting that the facile proton conductingpathways is through these water molecules coordinately bonded to Li+ions.


N7-(carboxymethyl)guanine-Lithium Crystalline Complex: A Bioinspired Solid Electrolyte.

Dutta D, Nagapradeep N, Zhu H, Forsyth M, Verma S, Bhattacharyya AJ - Sci Rep (2016)

(a) Static 1H-NMR spectra, (b) 1Hline width (FWHM: full width at half maximum) of the narrow component,(c) 1H line width of the broad component, and(d) the integration percentage of the narrow component as afunction of temperature for G7Li solid powder.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835778&req=5

f6: (a) Static 1H-NMR spectra, (b) 1Hline width (FWHM: full width at half maximum) of the narrow component,(c) 1H line width of the broad component, and(d) the integration percentage of the narrow component as afunction of temperature for G7Li solid powder.
Mentions: To investigate whether protons in G7Li also contribute to the overall ionicconductivity as evident from the transference number measurements, the1H solid state MAS NMR experiments are performed as a function oftemperature. The 1H MAS NMR chemical shift spectra (c/f Figure S12a)shows two broad peaks centering at 1.04 ppm and 4.96 ppmcorresponding probably to the free mobile water proton(Li → OH2) and the static protoncovalently bonded to the nitrogen atoms of the guanine respectively. The broadeningof the peaks partially might be a result of the hydrogen bonding in the system. Thesolid-state 1H MAS NMR spectra of G7Li (c/f Fig.6a) are deconvoluted into a narrow component (mobile protons) and a broadcomponent (rigid protons) using the mixed Gaussian and Lorentzian function (c/fexample in Figure S12b) in order to obtain the line-width and integration for boththe components. At 293 K the spectrum is dominated by the rigid latticecomponent (Fig. 6a), with recognizable contributions from themobile protons. As the temperature increases the population of the mobile protonsincreases (Fig. 6d), suggesting the breach of the hydrogenbonding at elevated temperatures and thus more protons become mobile. This willnegatively affect the conductivity as in ‘dry’ state theproton transport is achieved via breach and formation of hydrogen bonding (Grotthussmechanism). The line-width that is observed to be 2.53 kHz at293 K gradually decreases to 1.21 kHz at 343 Kindicating an enhancement of proton mobility with temperature in the mobile region.However, an increase in line-width to 1.3 kHz with further increase intemperature to 348 K may be due to the onset of water molecules exitingfrom the system. The line-width of the rigid component is quite constant in thestudied temperature range as shown in Fig. 6(c) indicating aquite stable structure and molecular dynamics in the lattice molecules. For protonto hop between different sites, the ideal distance between the sites normally iswithin 2.5 Å5556. In G7Li theH···O distance between water molecules attachedto two adjacent Li-tetrahedra (c/f Figure S4) is around 2 Å(<2.5 Å) suggesting that the facile proton conductingpathways is through these water molecules coordinately bonded to Li+ions.

Bottom Line: G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content.The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C).Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination.

View Article: PubMed Central - PubMed

Affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012 (Karnataka), India.

ABSTRACT
Electrochemical device with components having direct significance to biological life processes is a potent futuristic strategy for the realization of all-round green and sustainable development. We present here synthesis design, structural analysis and ion transport of a novel solid organic electrolyte (G7Li), a compound reminiscent of ion channels, derived from regioisomeric N7-guanine-carboxylate conjugate and Li-ions. G7Li, with it's in-built supply of Li(+)-ions, exhibited remarkably high lithium-ion transference number (= 0.75) and tunable room temperature ionic conductivity spanning three decades (≈10(-7) to 10(-3) Ω(-1) cm(-1)) as a function of moisture content. The ionic conductivity show a distinct reversible transition around 80-100 °C, from a dual Li(+) and H(+) (<100 °C) to a pure Li(+) conductor (>100 °C). Systematic studies reveal a transition from water-assisted Li-ion transport to Li hopping-like mechanism involving guanine-Li coordination. While as-synthesized G7Li has potential in humidity sensors, the anhydrous G7Li is attractive for rechargeable batteries.

No MeSH data available.


Related in: MedlinePlus