Carignani,+,? L. Calucci,+ A. Mandoli?, E. Juszyns?ka-Ga?a?zka,§ M. Massalska-Arod?,§ C. Forte,+ M. Geppi? +Istituto di Chimica dei Composti Organo Metallici - CNR, via G. Moruzzi 1, 56124 Pisa, Italy ?Dipartimento di Chimica e Chimica Industriale - Università di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy §Institute of Nuclear Physics, 31-342 Krakow, Radzikowskiego 152, Poland E-mail: elisa.carignani@for.unipi.it The study of dynamic and thermodynamic properties of glass forming compounds plays a key role for understanding the mechanism of glass transition. Also plastic crystals, in which molecules have the average positions of the centres of mass ordered in a lattice, but dynamically disordered orientations, often present properties characteristic of the conventional molecular glass formers, and their study is an excellent way to focus on the role of the orientational degrees of freedom in glass transition. In this context, neohexanol (2,2-dimethyl-1-butanol) and some of its isomers constitute an interesting class of compounds, since they have nearly globular shapes and show a rich polymorphism in the solid state including plastic crystalline and glass phases [1]. In particular, some isomers form orientationally disordered phases (ODIC) due to the ease of rotational motions in the solid state. In this work, 1H Fast Field-Cycling (FFC) NMR relaxometry (at Larmor frequencies from 10 kHz to 35 MHz) and static solid state 1H and 13C NMR spectroscopy have been applied to neohexanol and two of its isomers (3,3-dimethyl-1-butanol and 3,3-dimethyl-2-butanol) in the temperature range from -60 to 30 °C. Moreover, 1H FFC NMR relaxometry and static 2H NMR spectroscopy have been employed to investigate two selectively deuterated samples of 3,3-dimethyl-2-butanol. The spectroscopic and relaxation data acquired for the different isomers have been analyzed and compared to obtain information on the dynamic processes occurring in the different solid phases as well as to establish relationships between chemical structure and dynamic properties. References [1] E. Juszy?ska, M. Massalska-Arod?, I. Natkaniec, J. Krawczyk Physica B, 403, 109-114 (2008); E. Juszy?ska-Ga??zka, P.M. Zieli?ski, M. Massalska-Arod?, J. Krawczyk Acta Phys. Pol. A, 124, 917-925 (2013)
POLYMORPHISM AND DYNAMICS OF GLASS FORMING ALCOHOLS STUDIED BY NMR SPECTROSCOPY AND RELAXOMETRY
Elisa Carignani;Lucia Calucci;Claudia Forte;Marco Geppi
2016
Abstract
Carignani,+,? L. Calucci,+ A. Mandoli?, E. Juszyns?ka-Ga?a?zka,§ M. Massalska-Arod?,§ C. Forte,+ M. Geppi? +Istituto di Chimica dei Composti Organo Metallici - CNR, via G. Moruzzi 1, 56124 Pisa, Italy ?Dipartimento di Chimica e Chimica Industriale - Università di Pisa, via G. Moruzzi 13, 56124 Pisa, Italy §Institute of Nuclear Physics, 31-342 Krakow, Radzikowskiego 152, Poland E-mail: elisa.carignani@for.unipi.it The study of dynamic and thermodynamic properties of glass forming compounds plays a key role for understanding the mechanism of glass transition. Also plastic crystals, in which molecules have the average positions of the centres of mass ordered in a lattice, but dynamically disordered orientations, often present properties characteristic of the conventional molecular glass formers, and their study is an excellent way to focus on the role of the orientational degrees of freedom in glass transition. In this context, neohexanol (2,2-dimethyl-1-butanol) and some of its isomers constitute an interesting class of compounds, since they have nearly globular shapes and show a rich polymorphism in the solid state including plastic crystalline and glass phases [1]. In particular, some isomers form orientationally disordered phases (ODIC) due to the ease of rotational motions in the solid state. In this work, 1H Fast Field-Cycling (FFC) NMR relaxometry (at Larmor frequencies from 10 kHz to 35 MHz) and static solid state 1H and 13C NMR spectroscopy have been applied to neohexanol and two of its isomers (3,3-dimethyl-1-butanol and 3,3-dimethyl-2-butanol) in the temperature range from -60 to 30 °C. Moreover, 1H FFC NMR relaxometry and static 2H NMR spectroscopy have been employed to investigate two selectively deuterated samples of 3,3-dimethyl-2-butanol. The spectroscopic and relaxation data acquired for the different isomers have been analyzed and compared to obtain information on the dynamic processes occurring in the different solid phases as well as to establish relationships between chemical structure and dynamic properties. References [1] E. Juszy?ska, M. Massalska-Arod?, I. Natkaniec, J. Krawczyk Physica B, 403, 109-114 (2008); E. Juszy?ska-Ga??zka, P.M. Zieli?ski, M. Massalska-Arod?, J. Krawczyk Acta Phys. Pol. A, 124, 917-925 (2013)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
