Role of intermolecular interactions and conformational changes in the polymorphism and vitrification process of 2,2 ''-bis-substituted para-terphenyls

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62690094%3A18470%2F20%3A50017092" target="_blank" >RIV/62690094:18470/20:50017092 - isvavai.cz</a>

Výsledek na webu

<a href="https://pubs.rsc.org/en/content/articlelanding/2020/CE/D0CE00351D#!divAbstract" target="_blank" >https://pubs.rsc.org/en/content/articlelanding/2020/CE/D0CE00351D#!divAbstract</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d0ce00351d" target="_blank" >10.1039/d0ce00351d</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Role of intermolecular interactions and conformational changes in the polymorphism and vitrification process of 2,2 ''-bis-substituted para-terphenyls

Popis výsledku v původním jazyce

In the past decades, para-terphenyls have been attracting tremendous attention due to their polymorphism and conformational diversity. In this work we report the synthesis, crystal structure, polymorphism and dielectric properties of two 2,2 &apos;&apos;-bis-substituted para-terphenyls: 2,2 &apos;&apos;-bis(hydroxymethyl)-para-terphenyl and 2,2 &apos;&apos;-bis(acetyloxymethyl)-para-terphenyl. On the basis of calorimetric and X-ray studies, we showed that the latter compound occurs in at least four polymorphic forms with melting points equal to 364, 345, 341 and 326 K, differentiated also in terms of thermodynamic stability and crystal symmetry. The most stable polymorph I is characterized by the P2(1)/n space group. 2,2 &apos;&apos;-Bis(hydroxymethyl)-para-terphenyl crystallizes in the monoclinic P2(1)/c space group. Both 2,2 &apos;&apos;-bis-substituted para-terphenyls can undergo vitrification, which is a highly exceptional feature for this class of chemical compounds and has not been reported before. Consequently, the molecular dynamics and conformational changes in the glassy and supercooled liquid states were analyzed by means of IR and broadband dielectric spectroscopy. Two relaxation processes were observed for both compounds: structural alpha-relaxation, connected with reorientational motions of molecules in supercooled liquid, and intermolecular.-relaxation, ascribed to rotational motions of substituents of the para-terphenyl skeleton. Taking into account the ongoing discussion about the conformational diversity of the para-terphenyl skeleton, we showed that although free rotation of benzene rings is suppressed, the molecules in the glassy and liquid states can adopt both twisted and helical conformations, which results in diversity of the polymorphic forms.

Název v anglickém jazyce

Role of intermolecular interactions and conformational changes in the polymorphism and vitrification process of 2,2 ''-bis-substituted para-terphenyls

Popis výsledku anglicky

In the past decades, para-terphenyls have been attracting tremendous attention due to their polymorphism and conformational diversity. In this work we report the synthesis, crystal structure, polymorphism and dielectric properties of two 2,2 &apos;&apos;-bis-substituted para-terphenyls: 2,2 &apos;&apos;-bis(hydroxymethyl)-para-terphenyl and 2,2 &apos;&apos;-bis(acetyloxymethyl)-para-terphenyl. On the basis of calorimetric and X-ray studies, we showed that the latter compound occurs in at least four polymorphic forms with melting points equal to 364, 345, 341 and 326 K, differentiated also in terms of thermodynamic stability and crystal symmetry. The most stable polymorph I is characterized by the P2(1)/n space group. 2,2 &apos;&apos;-Bis(hydroxymethyl)-para-terphenyl crystallizes in the monoclinic P2(1)/c space group. Both 2,2 &apos;&apos;-bis-substituted para-terphenyls can undergo vitrification, which is a highly exceptional feature for this class of chemical compounds and has not been reported before. Consequently, the molecular dynamics and conformational changes in the glassy and supercooled liquid states were analyzed by means of IR and broadband dielectric spectroscopy. Two relaxation processes were observed for both compounds: structural alpha-relaxation, connected with reorientational motions of molecules in supercooled liquid, and intermolecular.-relaxation, ascribed to rotational motions of substituents of the para-terphenyl skeleton. Taking into account the ongoing discussion about the conformational diversity of the para-terphenyl skeleton, we showed that although free rotation of benzene rings is suppressed, the molecules in the glassy and liquid states can adopt both twisted and helical conformations, which results in diversity of the polymorphic forms.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

CRYSTENGCOMM

ISSN

1466-8033

e-ISSN

—

Svazek periodika

22

Číslo periodika v rámci svazku

18

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

15

Strana od-do

3164-3178

Kód UT WoS článku

000536772800011

EID výsledku v databázi Scopus

2-s2.0-85084950940