Solid-State NMR of 1-Propyltetrazole Complexes of Iron(II) and Zinc(II). 1.1H Spin–Lattice Relaxation Time

Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI:10.1006/jmra.1996.0191

Mónika Bokor , Tamás Marek , Kálmán Tompa

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引用次数: 9

Abstract

Proton spin–lattice relaxation times were measured between 2.2 K and room temperature in [Zn(ptz)₆](BF₄)₂(ptz = 1-n-propyl-1H-tetrazole) and in the spin-crossover complex [Fe(ptz)₆](BF₄)₂. Three different types of intramolecular motion of the propyl group are suggested in [Zn(ptz)₆](BF₄)₂, namely tunneling and classical rotation of methyl groups and rotation of methylene groups. Correlation times and activation energies are calculated for tunneling rotation of the CH₃group and for the classical (hindered) rotations of –CH₃and –CH₂–CH₃as reorientations over a three-well asymmetrical potential. In [Fe(ptz)₆](BF₄)₂the mechanism for the paramagnetic relaxation is found to be of the rapid-diffusion type according to the theory of Lowe and Tse, and the intramolecular motions are suggested to be the same as for the zinc complex.

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铁(II)和锌(II)的1-丙基四唑配合物的固体核磁共振。1.1H自旋-晶格弛豫时间

测量了[Zn(ptz)6](BF4)2(ptz = 1-n-丙基- 1h -四唑)和自旋交叉配合物[Fe(ptz)6](BF4)2在2.2 K和室温下的质子自旋-晶格弛豫时间。[Zn(ptz)6](BF4)2中丙基有三种不同类型的分子内运动，即甲基的隧道旋转和经典旋转以及亚甲基的旋转。计算了ch3基团隧穿旋转和- ch3和-CH2-CH3as在三阱不对称势上的经典(阻碍)旋转的相关时间和活化能。根据Lowe和Tse理论，发现[Fe(ptz)6](BF4)2的顺磁弛豫机制为快速扩散型，并认为其分子内运动与锌配合物相同。

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Journal of Magnetic Resonance, Series A

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