Dynamics of a glycine molecule in a new ferroelectric glycine phosphite studied by proton NMR

Tritt‐Goc, Jadwiga; Piślewski, N.; Szcz̀epańska, L.; Goc, Roman

doi:10.1016/s0038-1098(98)00331-7

Cited by 31 publications

(22 citation statements)

References 15 publications

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“…The proton NMR studies of Blinc et al [36] in Triglycine sulphate (TGS) and beryllate (TGBe) and selenate (TGSe) and of Tritt-Goc et al [37] in GPI showed that the relaxation is dominated by the NH 3 group reorientation and the CH 2 group relaxes via spin diffusion. Like in GPI, the two CH 2 protons and the protons in the O-H-O groups in BP and BPI relax via spin diffusion through CH 3 groups.…”

Section: H Nmr T 1 Results In Betaine Phosphite (Bpi)mentioning

confidence: 99%

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

2006

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Proton NMR relaxation measurements have been carried out in anti-ferroelectric Betaine phosphate (BP), ferroelectric Betaine phosphite (BPI) and the mixed system BPI (1Àx) BP x , at 11.4 MHz and 23.3 MHz from 300 K to 80 K for x ¼ 0.0, 0.25, 0.45, 0.85, and 1.0. The temperature dependence of spin lattice relaxation time T 1 exhibits two minima as expected from the BPP model in BP and BPI. The Larmor frequency dependence of T 1 in the mixed system is rather unusual and exhibits different slopes for the low temperature wings at the two frequencies, which is a clear experimental evidence of the presence of different methyl groups with different activation energies (E a ) indicating disorder.

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Section: H Nmr T 1 Results In Betaine Phosphite (Bpi)mentioning

confidence: 99%

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

2006

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“…CH 3 , NH 3 and TrMA, contribute to the relaxation mechanism in the mixed system, and the observed relaxation rate is the sum of the individual relaxation rates weighted by their concentration. Among these, NH 3 groups are strongly hindered with an activation energy of about 25 kJ/mol (as in GPI 10 ). TrMA groups have an activation energy of about 20 kJ/mol and CH 3 groups have an activation energy of about 11 kJ/mol similar to that in BPI 1 x BP x .…”

Section: Discussionmentioning

confidence: 99%

“…The corresponding values of TrMA are 18.2 and 18.8 kJ/mol and those for NH 3 are 23.7 and 24.3 kJ/mol, respectively. The NH 3 group is strongly hindered, as the glycine ions form three hydrogen bonds to the phosphite oxygens of which two are via the NH 3 group from one side, 10 and hence the NH 3 group has a much higher E a compared to CH 3 and the TrMA groups. The T 1 minimum of the NH 3 group (Fig.…”

Section: Experimental Preparation and Characterizationmentioning

confidence: 99%

Disorder in condensed matter systems: proton spin lattice relaxation study of the mixed systems of betaine phosphate and glycine phosphite, BP_xGPI_(1−x)

Ramanuja

Ramesh

Ramakrishna

2007

Magnetic Reson in Chemistry

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Proton NMR relaxation measurements have been carried out in the mixed system of antiferroelectric (AFE) betaine phosphate (BP) and ferroelectric (FE) glycine phosphite (GPI), BPxGPI(1-x), at 11.4 and 23.3 MHz from 300 to 100 K for x=0.3, 0.4, 0.5, 0.6, 0.7 and 0.8. The temperature dependence of spin lattice relaxation (SLR) time follows the BPP model in the parent compounds, while the Larmor frequency dependence of T1 in the mixed system is rather unusual. The T1 curve exhibits different slopes for the low-temperature wings at the two frequencies, which is a clear experimental evidence of the presence of different methyl groups with different activation energies (Ea), indicating disorder. For x=0.3 and 0.4, biexponential recovery of magnetization has been observed below 190 K, showing that the degree of disorder varies with the concentration. The temperature dependence of relaxation time data has been interpreted in terms of NH3, trimethyl ammonium and methyl group reorientations.

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“…Proton NMR studies were interpreted by assuming that the proton ordering was triggered by a rotation of the glycinium ion about its long axis [3]. A previous vibrational study on powdered and on crystalline samples of GPI and in its deuterated analog corroborates this interpretation [4,5].…”

Section: Introductionmentioning

confidence: 96%

Ferroelectric Phase in Glycinium Phosphite Studied by Raman Scattering

et al. 2005

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In this work we present a detailed study of the temperature evolution (290 K-20 K) of the polarized Raman spectra in a single crystal of glycinium phosphite. The phase transition manifests itself by the activation of new Raman bands and by the occurrence of anomalies in the temperature dependence of the wavenumber of some external and internal modes. The results show that occurring deformations in molecular units contribute relevantly to the spontaneous polarization in GPI. The anomalous behaviour of the wavenumber and of the damping constant of some bands is in good agreement with a theoretical model based in a pseudospin-phonon interaction.

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Dynamics of a glycine molecule in a new ferroelectric glycine phosphite studied by proton NMR

Cited by 31 publications

References 15 publications

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

Disorder in condensed matter systems: proton spin lattice relaxation study of the mixed systems of betaine phosphate and glycine phosphite, BP_xGPI_(1−x)

Ferroelectric Phase in Glycinium Phosphite Studied by Raman Scattering

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Dynamics of a glycine molecule in a new ferroelectric glycine phosphite studied by proton NMR

Cited by 31 publications

References 15 publications

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

NMR relaxation study of disorder in condensed matter: solid solutions of betaine phosphate and phosphite

Disorder in condensed matter systems: proton spin lattice relaxation study of the mixed systems of betaine phosphate and glycine phosphite, BPxGPI(1−x)

Ferroelectric Phase in Glycinium Phosphite Studied by Raman Scattering

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Disorder in condensed matter systems: proton spin lattice relaxation study of the mixed systems of betaine phosphate and glycine phosphite, BP_xGPI_(1−x)