Temperature-Dependent Phase Transition Studies Of Multicomponent Crystals Of Hexamethylenetetramine And Isonicotinamide
Loading...
Date
2018-07
Authors
Chia, Tze Shyang
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In this research, thirty-one multi-component crystals of
hexamethylenetetramine and isonicotinamide were successfully prepared and seven
of them undergo temperature-dependent phase transitions, which were investigated
by using variable-temperature single-crystal X-ray diffraction analysis. These seven
multi-component crystals are hexamethylenetetramine‒2-methylbenzoic acid (1/2)
(monoclinic P21/c ↔ orthorhombic Pccn, Tc = 164.5 (5) K),
hexamethylenetetramine‒benzoic acid (1/2) (monoclinic Pn ↔ orthorhombic Fmm2,
Tc = 257.5 (5) K), hexamethylenetetramine‒4-methylbenzoic acid (1/2) (monoclinic
P21/n ↔ orthorhombic Cmcm, Tc = 265.5 (5) K), hexamethylenetetramine‒succinic
acid (1/1) (monoclinic P21/n ↔ monoclinic P21/c, Tc = 219 (1) K),
hexamethylenetetramine‒adipic acid (1/1) (monoclinic P21 ↔ monoclinic P2/n ↔
orthorhombic Pna21 ↔ orthorhombic Pbcn ↔ orthorhombic Cmcm, Tc,1 = 202 (2) K,
Tc,2 = 249 (2) K, Tc,3 = 258 (2) K, Tc,4 = 293 (2) K), isonicotinamide‒4-
methoxybenzoic acid (1/1) (monoclinic I2/a ↔ monoclinic I2/a, Tc = 142.5 (5) K)
and isonicotinamide‒malonic acid (2/1) (triclinic P1
↔ monoclinic C2/c, Tc = 295 (1)
K). These non-ambient crystallography studies were carried out to study the
structural changes of multi-component crystals between different phases from 100 to
300 K. The structural phase transitions of hexamethylenetetramine‒2-methylbenzoic
acid (1/2), hexamethylenetetramine‒benzoic acid (1/2), hexamethylenetetramine‒4-
methylbenzoic acid (1/2), hexamethylenetetramine‒succinic acid (1/1) and
hexamethylenetetramine‒adipic acid (1/1) are associated with the structural orderdisorder
transformations as a function of temperature in their crystal structures.
Description
Keywords
Temperature-dependent phase transition , of hexamethylenetetramine And isonicotinamide