TY - JOUR
T1 - Polymorphs and structural phase transition of [Ni(dmit)2] - crystals induced by flexible (trans -cyclohexane-1,4-diammonium) (benzo[18]crown-6)2 supramolecule
AU - Ye, Qiong
AU - Akutagawa, Tomoyuki
AU - Hoshino, Norihisa
AU - Kikuchi, Takemitsu
AU - Noro, Shin Ichiro
AU - Xiong, Ren Gen
AU - Nakamura, Takayoshi
PY - 2011/9/7
Y1 - 2011/9/7
N2 - Structurally flexible trans-cyclohexane-1,4-diammonium (CHDA2+) forms a hydrogen-bonded sandwich-type supramolecule with benzo[18]crown-6 in (CHDA2+)(benzo[18]crown-6)2[Ni(dmit)2] 2 (1) (dmit2-: 2-thioxo-1,3-dithiole-4,5-dithiolate). During the crystallization, the three crystal polymorphs 1a, 1b, and 1c were obtained in the space groups P21/c, P1̄, and P1̄, in which the orientation of the benzene rings of benzo[18]crown-6 in the sandwich-type supramolecular cations and the [Ni(dmit)2]- arrangements were different. Crystal 1c had a structural phase transition at ∼200 K, at which the unit cell volume of the low-temperature phase (1d) became twice that of the high-temperature phase (1c). The [Ni(dmit)2] π-dimer was observed in crystals 1a, 1b, 1c, and 1d. A double-minimum-type potential energy profile was observed for the rigid rotation of CHDA2+ around the N-N axis. Among four new crystals, the relatively low potential energy barrier of ∼120 kJ mol-1 for crystal 1b was consistent with the temperature- and frequency-dependent dielectric constants. The crystal polymorph and structural phase transition were coupled in (CHDA2+)(benzo[18]crown- 6)2[Ni(dmit)2]-2.
AB - Structurally flexible trans-cyclohexane-1,4-diammonium (CHDA2+) forms a hydrogen-bonded sandwich-type supramolecule with benzo[18]crown-6 in (CHDA2+)(benzo[18]crown-6)2[Ni(dmit)2] 2 (1) (dmit2-: 2-thioxo-1,3-dithiole-4,5-dithiolate). During the crystallization, the three crystal polymorphs 1a, 1b, and 1c were obtained in the space groups P21/c, P1̄, and P1̄, in which the orientation of the benzene rings of benzo[18]crown-6 in the sandwich-type supramolecular cations and the [Ni(dmit)2]- arrangements were different. Crystal 1c had a structural phase transition at ∼200 K, at which the unit cell volume of the low-temperature phase (1d) became twice that of the high-temperature phase (1c). The [Ni(dmit)2] π-dimer was observed in crystals 1a, 1b, 1c, and 1d. A double-minimum-type potential energy profile was observed for the rigid rotation of CHDA2+ around the N-N axis. Among four new crystals, the relatively low potential energy barrier of ∼120 kJ mol-1 for crystal 1b was consistent with the temperature- and frequency-dependent dielectric constants. The crystal polymorph and structural phase transition were coupled in (CHDA2+)(benzo[18]crown- 6)2[Ni(dmit)2]-2.
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U2 - 10.1021/cg2007556
DO - 10.1021/cg2007556
M3 - Article
AN - SCOPUS:80052544331
SN - 1528-7483
VL - 11
SP - 4175
EP - 4182
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 9
ER -