Polymorphic Equilibrium Responsive Thermal and Mechanical Stimuli in Light-emitting Crystals of <i>N</i>‑Methylaminonaphthyridine

Crystal polymorphs of 1,8-naphthyridine derivative, being <i>anti</i> and <i>syn</i> conformers, show a reversible transformation from <i>anti</i> to <i>syn</i> by heating and from <i>syn</i> to <i>anti</i> by grinding with the alteration of emittance intensity, and notably, thermal transformation from <i>anti</i> to <i>syn</i> conformer took place in single-crystal-to-single-crystal (SC-to-SC) form, which was confirmed by a single crystal X-ray crystallography

Associations between various factors and rod deformation at the concave side (°) using multiple stepwise linear regression analysis.

<p>Associations between various factors and rod deformation at the concave side (°) using multiple stepwise linear regression analysis.</p

Crystal Structures, Thermal Properties, and Emission Behaviors of <i>N</i>,<i>N</i>‑R-Phenyl-7-amino-2,4-trifluoromethylquinoline Derivatives: Supercooled Liquid-to-Crystal Transformation Induced by Mechanical Stimuli

<i>N</i>,<i>N</i>-R-Phenyl-7-amino-2,4-trifluoromethylquinoline derivatives (R = Me (<b>1</b>), Et (<b>2</b>), isopropyl (<b>3</b>), and Ph (<b>4</b>)) were prepared as a new type of fluorophore responsive to external stimuli. <b>1</b>, <b>2</b>, <b>3</b>, and <b>4</b> were obtained as single crystals including three crystal polymorphs (<b>1α</b>, <b>1β</b>, and <b>1γ</b>) of <b>1</b> and two (<b>2α</b> and <b>2β</b>) of <b>2</b>. In <b>4</b>, a phase transition from <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> between 173 and 90 K was observed. The solid-state emission showed a red shift by 30–58 nm compared with the emission in <i>n</i>-hexane, and their emission properties depended on the molecular arrangements. The modes of molecular arrangements for <b>1α</b>, <b>1β</b>, and <b>1γ</b> were a slipped parallel (SP), head-to-tail γ-type herringbone (HT-γ-HB), and head-to-head γ-type herringbone (HH-γ-HB); those for <b>2α</b> and <b>2β</b> were HT-γ-HB and head-to-tail dimer (HT-dimer), and that for <b>3</b> was head-to-tail columnar (HTC). <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> were similar HT-γ-HB. The crystal-to-crystal transformations from <b>1γ</b> to <b>1β</b> and from <b>2β</b> to <b>2α</b> were observed by heating and grinding the crystal, respectively, with emittance changes. After melting, on cooling, all crystals formed supercooled liquid (SCL) and then glass states. In the SCL state, molecules were amorphous and were quickly crystallized by a mechanical stimulus such as scratching. By taking advantage of the difference of emitting intensity between the SCL and the crystal states for <b>1</b>, “writing” and “erasing” of a letter with scratching and heating, respectively, were demonstrated

Implant rod angle of curvature at the concave and convex sides of the deformity.

<p>(<b>A</b>) θ1 and θ2 at the concave side of each patients. (<b>B</b>) θ1 and θ2 at the convex side of each patients. (<b>C</b>) Comparison between θ1 and θ2 at the concave side. (<b>D</b>) Comparison between θ1 and θ2 at the convex side. (<b>E</b>) Comparison between Δθ at the concave side and Δθ at the convex side.</p

Crystal Structures, Thermal Properties, and Emission Behaviors of <i>N</i>,<i>N</i>‑R-Phenyl-7-amino-2,4-trifluoromethylquinoline Derivatives: Supercooled Liquid-to-Crystal Transformation Induced by Mechanical Stimuli

<i>N</i>,<i>N</i>-R-Phenyl-7-amino-2,4-trifluoromethylquinoline derivatives (R = Me (<b>1</b>), Et (<b>2</b>), isopropyl (<b>3</b>), and Ph (<b>4</b>)) were prepared as a new type of fluorophore responsive to external stimuli. <b>1</b>, <b>2</b>, <b>3</b>, and <b>4</b> were obtained as single crystals including three crystal polymorphs (<b>1α</b>, <b>1β</b>, and <b>1γ</b>) of <b>1</b> and two (<b>2α</b> and <b>2β</b>) of <b>2</b>. In <b>4</b>, a phase transition from <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> between 173 and 90 K was observed. The solid-state emission showed a red shift by 30–58 nm compared with the emission in <i>n</i>-hexane, and their emission properties depended on the molecular arrangements. The modes of molecular arrangements for <b>1α</b>, <b>1β</b>, and <b>1γ</b> were a slipped parallel (SP), head-to-tail γ-type herringbone (HT-γ-HB), and head-to-head γ-type herringbone (HH-γ-HB); those for <b>2α</b> and <b>2β</b> were HT-γ-HB and head-to-tail dimer (HT-dimer), and that for <b>3</b> was head-to-tail columnar (HTC). <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> were similar HT-γ-HB. The crystal-to-crystal transformations from <b>1γ</b> to <b>1β</b> and from <b>2β</b> to <b>2α</b> were observed by heating and grinding the crystal, respectively, with emittance changes. After melting, on cooling, all crystals formed supercooled liquid (SCL) and then glass states. In the SCL state, molecules were amorphous and were quickly crystallized by a mechanical stimulus such as scratching. By taking advantage of the difference of emitting intensity between the SCL and the crystal states for <b>1</b>, “writing” and “erasing” of a letter with scratching and heating, respectively, were demonstrated

Crystal Structures, Thermal Properties, and Emission Behaviors of <i>N</i>,<i>N</i>‑R-Phenyl-7-amino-2,4-trifluoromethylquinoline Derivatives: Supercooled Liquid-to-Crystal Transformation Induced by Mechanical Stimuli

<i>N</i>,<i>N</i>-R-Phenyl-7-amino-2,4-trifluoromethylquinoline derivatives (R = Me (<b>1</b>), Et (<b>2</b>), isopropyl (<b>3</b>), and Ph (<b>4</b>)) were prepared as a new type of fluorophore responsive to external stimuli. <b>1</b>, <b>2</b>, <b>3</b>, and <b>4</b> were obtained as single crystals including three crystal polymorphs (<b>1α</b>, <b>1β</b>, and <b>1γ</b>) of <b>1</b> and two (<b>2α</b> and <b>2β</b>) of <b>2</b>. In <b>4</b>, a phase transition from <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> between 173 and 90 K was observed. The solid-state emission showed a red shift by 30–58 nm compared with the emission in <i>n</i>-hexane, and their emission properties depended on the molecular arrangements. The modes of molecular arrangements for <b>1α</b>, <b>1β</b>, and <b>1γ</b> were a slipped parallel (SP), head-to-tail γ-type herringbone (HT-γ-HB), and head-to-head γ-type herringbone (HH-γ-HB); those for <b>2α</b> and <b>2β</b> were HT-γ-HB and head-to-tail dimer (HT-dimer), and that for <b>3</b> was head-to-tail columnar (HTC). <b>4</b>_<b>173</b> and <b>4</b>_<b>90</b> were similar HT-γ-HB. The crystal-to-crystal transformations from <b>1γ</b> to <b>1β</b> and from <b>2β</b> to <b>2α</b> were observed by heating and grinding the crystal, respectively, with emittance changes. After melting, on cooling, all crystals formed supercooled liquid (SCL) and then glass states. In the SCL state, molecules were amorphous and were quickly crystallized by a mechanical stimulus such as scratching. By taking advantage of the difference of emitting intensity between the SCL and the crystal states for <b>1</b>, “writing” and “erasing” of a letter with scratching and heating, respectively, were demonstrated

Correlation analysis between rod deformation and variable in patients with rod deformation ≥14 ° at the concave side.

<p>Correlation analysis between rod deformation and variable in patients with rod deformation ≥14 ° at the concave side.</p

Rod angle before and after implantation.

<p>(<b>A</b>) Prior to implantation, the surgeon traced the rod shapes on paper. The angle between the proximal and distal tangential line was measured (θ1). (<b>B</b>) Postoperative implant rod geometry (θ2) was obtained after the surgical operation using computed tomography.</p

Unique Reversible Crystal-to-Crystal Phase TransitionStructural and Functional Properties of Fused Ladder Thienoarenes

Donor–acceptor type molecules based on fused ladder thienoarenes, indacenodithiophene (IDT), and dithienocyclopenta–thienothiophene (DTCTT), coupled with benzothiadiazole, are prepared, and their solid-state structures are investigated. They display a rich variety of solid phases ranging from amorphous glass states to crystalline states, upon changes in the central aromatic core and side group structures. Most notably, the DTCTT-based derivatives showed reversible crystal-to-crystal phase transitions in heating and cooling cycles. Unlike what has been seen in π-conjugated molecules, variable temperature XRD revealed that structural change occurs continuously during the transition. A columnar self-assembled structure with slip-stacked π–π interaction is proposed to be involved in the solid state. This research provides the evidence of unique structural behavior of the DTCTT-based molecules through the detailed structural analysis. This unique structural transition paves the way for these materials to have self-healing of crystal defects, leading to improved optoelectronic properties