Spin–Lattice Relaxation Times of H2and D2in Aqueous Solutions

Gilboa, Haggai; Chapman, Bogdan E.; Kuchel, Philip W.

doi:10.1006/jmra.1996.0044

Cited by 11 publications

(15 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A maximum of the value of T 1 with temperature is also found in 1,1,2,2-tetrachloroethane-d 2 and chloroform-d 1 . For benzene-d 6 and 1,2-dichlorobenzene-d 4 in the available range of temperatures, only a decrease of T 1 with increasing temperature was observed.…”

mentioning

confidence: 90%

“…2,3 However, there are few reports of the magnetic resonance of H 2 in solution 4,5 and none in ordinary organic solvents. To generate data for comparison with H 2 @C 60 we measured the T 1 values of H 2 in a range of organic solvents.…”

mentioning

confidence: 99%

“…The temperature dependences of T 1 for H 2 and H 2 @C 60 were investigated in detail for toluene-d 8 ( Figure 1) and for benzene-d 6 , 1,1,2,2-tetrachloroethane-d 2 , 1,2-dichlorobenzene-d 4 , and chloroformd 1 . Striking features of the data are the occurrence of a maximum for T 1 at ∼240 K for both the H 2 and H 2 @C 60 in toluene-d 8 and a ratio of T 1 values which is nearly independent of temperature.…”

mentioning

confidence: 99%

“…Further theoretical studies are required to determine the validity of these speculations. (9) In the only study 4 of the temperature dependence of the H2 relaxation in a homogeneous molecular solvent (D2O), the value of T1 was found to increase as the temperature increased in the range 283-323 K. 2 is the theory of gas phase relaxation of H2. 2 In gas phase both the dipolar and the spin-rotation interaction depend on J through: 1/T1sr ) 2/3γH 2 H′ 2 J(J + 1)τc and 1/T1dip ) 6γH 2 H′′ 2 (J(J + 1)/((2J -1)(2J + 3)))τc, respectively, where H′ ) 27 G and H′′ ) 34 G 10 and τc depends on the frequency of collisions.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

et al. 2006

View full text Add to dashboard Cite

We report an investigation of the nuclear spin-lattice relaxation of H 2 and H 2 @C 60 1 as a function of solvent and temperature. These studies explore and compare the nature of the interactions of a guest H 2 molecule confined transiently within the walls of a solvent cavity and a guest H 2 molecule encapsulated within the walls of the C 60 cavity.The relaxation time (T 1 ) of H 2 has been extensively studied in the gas phase and in liquid hydrogen at low temperatures. 6 The values of T 1 are 10-20 times smaller for H 2 @C 60 than for H 2 even though the ratios of T 1 for H 2 and H 2 @C 60 are similar in all the solvents.The temperature dependences of T 1 for H 2 and H 2 @C 60 were investigated in detail for toluene-d 8 ( Figure 1) and for benzene-d 6 , 1,1,2,2-tetrachloroethane-d 2 , 1,2-dichlorobenzene-d 4 , and chloroformd 1 . Striking features of the data are the occurrence of a maximum for T 1 at ∼240 K for both the H 2 and H 2 @C 60 in toluene-d 8 and a ratio of T 1 values which is nearly independent of temperature. A maximum of the value of T 1 with temperature is also found in 1,1,2,2-tetrachloroethane-d 2 and chloroform-d 1 . For benzene-d 6 and 1,2-dichlorobenzene-d 4 in the available range of temperatures, only a decrease of T 1 with increasing temperature was observed.This kind of dependence of T 1 on temperature is uncommon, although a maximum of T 1 has previously been observed for small molecules such as H 2 O, 7 HCl, and HBr in solution, 8,9 and it is consistent with two relaxation mechanisms with different temperature dependences dominating in turn below and above 240 K for both H 2 and H 2 @C 60 . Since the value of T 1 for both H 2 and H 2 @C 60 does not significantly change in going from benzene-h 6 to benzened 6 (Table 1), the dominating interactions determining H 2 and H 2 @C 60 nuclear relaxation must be intramolecular. Furthermore, the intramolecular dipole-dipole interaction and spin-rotation interaction are known 2 to be responsible for the relaxation of gaseous H 2 and their magnitude has been measured for H 2 in molecular beams. 10 Therefore it is likely that the relaxation of H 2 in solution also depends on the competition between intramolecular dipole-dipole interaction and spin-rotation interaction.The contribution to 1/T 1 (in extreme narrowing conditions) from intramolecular dipolar and spin-rotation interaction may be estimated by eq 1 2 and eq 2, 11,12 respectively:where γ H is the magnetogyric ratio for the proton, r is the equilibrium internuclear distance of H 2 (0.74 Å), C is the spinrotation coupling constant (7.16 × 10 5 rad s -1 ), 10 I is the moment of inertia of H 2 (4.6 × 10 -48 kg m 2 ), and k B is the Boltzmann constant. The correlation times τ dip and τ sr are measures of the timedependent fluctuations in the orientation and angular velocity of H 2 , respectively. Both correlation times are expected to be functions of viscosity and temperature which depend on the details of the motion of H 2 molecules and the surrounding medium. 11 Qualitatively, the dipole-...

show abstract

mentioning

confidence: 90%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Unlike the situation in H 2, where molecules giving an NMR signal are predominantly in the J = 1 rotational energy level at room temperature, the ortho-D 2 molecules significantly populate the rotational energy levels J = 0 to 4. This introduces additional complexity to the analysis of the spin-lattice relaxation behavior [11].…”

Section: Introductionmentioning

confidence: 99%

Deuteron spin-lattice relaxation study of D2 secluded in the supercages of zeolite NaY

et al. 2004

View full text Add to dashboard Cite

The theory of deuteron spin-lattice relaxation for free D 2 quantum rotors is developed.Relaxafion rates are calculated for ortho-D z and p a r a -D 2. The spin-rotational interaction as well as quadrupole and dipole-dipole interactions under interference condition are taken into account. Relaxation rates, to be compared with experiment, are derived as weighted sums of cont¡ from different rotational states according to their Boltzmann populations. The theory is applied to explain relaxation rates measured in a wide temperature range for D 2 molecules in NaY zeolite cages. At high temperatures (above 110 K), a scattering of molecules on the cage walls provides the relaxation mechanism. At low temperatures, molecules stay close to the surface and undergo reorientations in a potential introduced by the adsorption centers.

show abstract

P Csp³ P and P Csp² P Palladium(II) Hydride Pincer Complexes: Small Structural Difference—Large Effect on Reactivity

Gerber

Fox

Frech

2010

Chemistry A European J

View full text Add to dashboard Cite

An olfactory factory: Using a novel polydimethylsiloxane (PDMS) elastomer‐based device, the switchable release of specific gases is demonstrated. Heating elements trigger the gas release by warming the gas‐containing capsule (see scheme). The release can be switched on and off by repeated thermal cycles. An X–Y addressable matrix of such capsules results in an odor‐releasing system for multiple odors for virtual‐reality applications.

show abstract

Spin–Lattice Relaxation Times of H2and D2in Aqueous Solutions

Cited by 11 publications

References 9 publications

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

Deuteron spin-lattice relaxation study of D2 secluded in the supercages of zeolite NaY

P Csp³ P and P Csp² P Palladium(II) Hydride Pincer Complexes: Small Structural Difference—Large Effect on Reactivity

Contact Info

Product

Resources

About

Spin–Lattice Relaxation Times of H2and D2in Aqueous Solutions

Cited by 11 publications

References 9 publications

Nuclear Relaxation of H2 and H2@C60 in Organic Solvents

Nuclear Relaxation of H2 and H2@C60 in Organic Solvents

Deuteron spin-lattice relaxation study of D2 secluded in the supercages of zeolite NaY

P Csp3 P and P Csp2 P Palladium(II) Hydride Pincer Complexes: Small Structural Difference—Large Effect on Reactivity

Contact Info

Product

Resources

About

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

Nuclear Relaxation of H₂ and H₂@C₆₀ in Organic Solvents

P Csp³ P and P Csp² P Palladium(II) Hydride Pincer Complexes: Small Structural Difference—Large Effect on Reactivity