Structure and Dynamics of the Crystalline Stable Phase of 2-Chlorothiophene

ROMANINI, MICHELA; NEGRIER, PHILIPPE; BARRIO, MARIA; MONDIEIG, DENISE; SERRA, PABLO; ZURIAGA, MARIANO J.; MACOVEZ, ROBERTO; TAMARIT, JOSEP-LLUÍS

CRYSTAL GROWTH & DESIGN

AMER CHEMICAL SOC

Lugar: Washington; Año: 2019 vol. 19 p. 6405 - 6413

1528-7483

The dynamics of a simple and rigid molecule (2-chlorothiophene) has beenstudied by means of broadband dielectric spectroscopy (BDS) within the low-temperaturestable crystalline phase, whose structure has been determined by means of powder X-raydiffraction (PXRD) measurements. The triclinicP1 structure consists of two molecules perasymmetric unit (Z′= 2) with site occupancies of 80:20 and 60:40 for each molecule ofthe asymmetric unit. Such a statistical intrinsic disorder is associated with two dynamicalrelaxation processes corresponding respectively to out-of-plane relaxations around the C−Cl 2-fold molecular axis and in-plane reorientational motions as proposed previously(Fujiromi and Oguni,J. Phys. Chem. Solids1993,54, 437−612). The PXRD and BDSmeasurements allow rationalizing published nuclear quadrupole resonance data. We showthat only the concurrent use of different experimental techniques provides the answer to a complicated case of orientational molecular dynamics in the solid state.