TY - JOUR
T1 - Multirotations of (anilinium)([18] crown-6) supramolecular cation structure in magnetic salt of [Ni(dmit)2]-
AU - Nishihara, Sadafumi
AU - Akutagawa, Tomoyuki
AU - Sato, Daisuke
AU - Takeda, Sadamu
AU - Noro, Shin Ichiro
AU - Nakamura, Takayoshi
PY - 2007
Y1 - 2007
N2 - A solid-state dynamic supramolecular structure consisting of (anilinium)([18]crown-6) was arranged as the cation in a salt of [Ni(dmit) 2]- (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate). With the ammonium moiety of anilinium located within the cavity of [18]crown-6, a hydrogen-bonded supramolecular structure is formed, with an orthogonal arrangement between the π plane of anilinium and the mean O6 plane of [18]crown-6. In this supramolecular cation, both anilinium and [18]crown-6 act as dynamic units with different rotational modes in the solid state. The uniform stacks of cations form an antiparallel arrangement, thus producing a layer structure. Sufficient space for the 180° flip-flop motion of the phenyl ring and the rotation of [18]crown-6 was observed in the cation layer. Thermally activated 180° flip-flop motions, with a frequency of 6 MHz at room temperature and an activation energy of 31 kJ mol1, were confirmed by temperature-dependent 2H NMR spectra of ([D5]anilinium) ([18]crown-6)[Ni(dmit)2]. A double-minimum potential for the molecular rotation of anilinium, with a barrier of approximately 40 kJ mol 1, was indicated by ab initio calculations. The wide-line 1HNMR spectra indicated a thermally activated rotation of [18]crown-6 at temperatures above 250 K. Therefore, multiple molecular motions of the 180° flip-flop motion of the phenyl ring and the rotation of [18]crown-6 occur simultaneously in the solid state. The temperature-dependent dielectric constants revealed that the molecular motion of [18]crown-6. other than the flip-flop motion, dominates the dielectric response in the measured temperature and frequency range.
AB - A solid-state dynamic supramolecular structure consisting of (anilinium)([18]crown-6) was arranged as the cation in a salt of [Ni(dmit) 2]- (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate). With the ammonium moiety of anilinium located within the cavity of [18]crown-6, a hydrogen-bonded supramolecular structure is formed, with an orthogonal arrangement between the π plane of anilinium and the mean O6 plane of [18]crown-6. In this supramolecular cation, both anilinium and [18]crown-6 act as dynamic units with different rotational modes in the solid state. The uniform stacks of cations form an antiparallel arrangement, thus producing a layer structure. Sufficient space for the 180° flip-flop motion of the phenyl ring and the rotation of [18]crown-6 was observed in the cation layer. Thermally activated 180° flip-flop motions, with a frequency of 6 MHz at room temperature and an activation energy of 31 kJ mol1, were confirmed by temperature-dependent 2H NMR spectra of ([D5]anilinium) ([18]crown-6)[Ni(dmit)2]. A double-minimum potential for the molecular rotation of anilinium, with a barrier of approximately 40 kJ mol 1, was indicated by ab initio calculations. The wide-line 1HNMR spectra indicated a thermally activated rotation of [18]crown-6 at temperatures above 250 K. Therefore, multiple molecular motions of the 180° flip-flop motion of the phenyl ring and the rotation of [18]crown-6 occur simultaneously in the solid state. The temperature-dependent dielectric constants revealed that the molecular motion of [18]crown-6. other than the flip-flop motion, dominates the dielectric response in the measured temperature and frequency range.
KW - Anilinium
KW - Crown compounds
KW - Molecular machines
KW - Molecular motors
KW - Supramolecular chemistry
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U2 - 10.1002/asia.200700010
DO - 10.1002/asia.200700010
M3 - Article
C2 - 17676564
AN - SCOPUS:34548583878
VL - 2
SP - 1083
EP - 1090
JO - Chemistry - An Asian Journal
JF - Chemistry - An Asian Journal
SN - 1861-4728
IS - 9
ER -