Abstract
The in situ low-temperature (co)crystallization of liquids and gases, followed by a detailed structural study, represents an approach to engineer and discover novel materials that are not formed under ambient conditions. Single-crystal X-ray diffraction revealed dimorphism along with a hierarchy of particular interactions in pentafluoroiodobenzene, C6F5I (1), and its benzene cocrystal (C6F5I)2·C6H6 (2). There are four polymorphs, two of 1, 1-I and 1-II, and two of 2, 2-I and 2-II, and they all are principally dominated by I···F and F···F halogen interactions. The nature and the contribution of different interactions were identified as important factors responsible for the polymorphic behavior of the studied systems. The only attractive interactions between C6F5I and C6H6 molecules in both polymorphs of 2 are F···H contacts, whereas σ-hole C–X···πC6H6-type interactions are absent. A reversible polymorphic phase transition in 2 is associated with the formation of new contacts, including relatively long π-hole···π (CC6F5I···CC6H6) interactions.
Highlights
Molecular systems are usually characterized by a rich spectrum of noncovalent interactions.[1,2]. Those with a significant impact on the aggregation of molecules in solids include hydrogen and halogen bonds as well as van der Waals interactions. van der Waals interactions can be subdivided into dipole/dipole forces (Keesom forces), dipole/induced dipole forces (Debye forces), and London dispersion forces like alkane chain interactions.[3−7] They all are characterized mainly by their strength and directionality
It is noteworthy that most of these intermolecular interactions are rather weak, they often have a decisive impact on the physicochemical properties and symmetry of crystals and play a crucial role in the supramolecular chemistry, crystal engineering, and materials science.[1,6,8,9]
We report our investigation on understanding the occurrence and the role played by weak intermolecular interactions along with their temperature-induced transformations
Summary
Molecular systems are usually characterized by a rich spectrum of noncovalent interactions.[1,2] Those with a significant impact on the aggregation of molecules in solids include hydrogen and halogen bonds as well as van der Waals interactions. van der Waals interactions can be subdivided into dipole/dipole forces (Keesom forces), dipole/induced dipole forces (Debye forces), and London dispersion forces (between induced dipoles) like alkane chain interactions.[3−7] They all are characterized mainly by their strength and directionality. The unit cells and the settings for the novel polymorph of C6F5I (1II) as well as both monoclinic (2-I) and triclinic (2-II) polymorphic phases of (C6F5I)2·C6H6 were chosen to correspond as closely as possible to one another and to the already reported, at 150 K, structure of C6F5I (1-I).[28] The selected crystal data and structure determination summary are listed in Table 1 (cf Table S1).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
