Direct Spectroscopic Evidence of the Mechanism behind the Phase Transition of [2,2]-Paracyclophane

TY - JOUR

T1 - Direct Spectroscopic Evidence of the Mechanism behind the Phase Transition of [2,2]-Paracyclophane

AU - Wolf, Hilke

AU - Lock, Nina

AU - Parker, Stewart F.

AU - Stalke, Dietmar

PY - 2015/3/16

Y1 - 2015/3/16

N2 - [2,2]-Paracyclophane undergoes phase transitions at 45 and 60K. Based on simultaneous Raman spectroscopy and inelastic neutron scattering experiments (12-70K), it was shown that a twisting motion of the ethylene bridge perpendicular to the plane of the aromatic rings drives the phase transition. The low-temperature (60K) conformers only differ by this twisting motion, which freezes out below 45K and is thermally averaged above 60K. Between 45 and 60K, the system gains energy until the phase transition is complete.

AB - [2,2]-Paracyclophane undergoes phase transitions at 45 and 60K. Based on simultaneous Raman spectroscopy and inelastic neutron scattering experiments (12-70K), it was shown that a twisting motion of the ethylene bridge perpendicular to the plane of the aromatic rings drives the phase transition. The low-temperature (60K) conformers only differ by this twisting motion, which freezes out below 45K and is thermally averaged above 60K. Between 45 and 60K, the system gains energy until the phase transition is complete.

KW - inelastic neutron scattering

KW - non-destructive phase transition

KW - paracyclophane

KW - Raman spectroscopy

KW - structure determination

KW - NORMAL HARMONIC VIBRATIONS

KW - MOLECULAR DISTORTIONS

KW - ELECTRONIC-SPECTRUM

KW - CYCLOPHANES

KW - <2.2>PARACYCLOPHANE

KW - CHEMISTRY

KW - CRYSTAL

U2 - 10.1002/chem.201405948

DO - 10.1002/chem.201405948

M3 - Journal article

C2 - 25678295

SN - 0947-6539

VL - 21

SP - 4556

EP - 4560

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

IS - 12

ER -