Using fast scanning calorimetry to detect guest-induced polymorphism by irreversible phase transitions in the nanogram scale

Abstract

Fast scanning calorimetry with a heating rate of 1000 K s−1 enables successful screening of polymorphs for separate microcrystalline aggregates in thiacalixarene powder.

2D Monomolecular Nanosheets Based on Thiacalixarene Derivatives: Synthesis, Solid State Self-Assembly and Crystal Polymorphism

“…The total enthalpy of the two processes is 39 J/g. Such behavior is characteristic of calixarenes capable of polymorphism [ 30 , 39 ], and may be due to the presence of two polymorphic forms of 5 . The studied calixarenes do not crystallize on cooling the melts.…”

“…Compared to the conventional DSC, FSC provides faster temperature scanning rates both on cooling and heating and uses much smaller samples (typically 10–1000 ng). The latter trait is of particular interest in the investigation of the compounds with polymorphism [ 39 ].…”

Smart Molecular Recognition: From Key-to-Lock Principle to Memory-Based Selectivity

“…In many cases, metastability of a polymorph is in its lower melting point than that of the stable form. Such polymorphs may have more than one melting point with an intermediate exothermic cold crystallization to the more stable forms (Gataullina et al, 2017(Gataullina et al, , 2019. The formation of such polymorphs by guest inclusion and release may be also a kind of molecular recognition when it is selective enough, but in this case the problem is to find sufficient experimental proofs that the host treatment with different guests gives different polymorphs.…”

New Polymorph of Indomethacin: Screening by Solid-State Guest Exchange and Characterization Using Fast Scanning Calorimetry

“…In ordinary DSC data, this thermal behavior complicates the detection of the first melting point, which is a key parameter of polymorph metastability. Using FSC, microcrystals of dozens of nanograms with typical crystal habits may be studied by choosing from ordinary crystalline powder . The high scanning rate of several thousand kelvins per second may inhibit cold crystallization and, respectively, the next fusion of polymorph so that the first melting point becomes much more apparent …”

“…Using FSC, microcrystals of dozens of nanograms with typical crystal habits may be studied by choosing from ordinary crystalline powder. 42 The high scanning rate of several thousand kelvins per second may inhibit cold crystallization and, respectively, the next fusion of polymorph so that the first melting point becomes much more apparent. 19 ■ EXPERIMENTAL SECTION Materials and Sample Preparation.…”