Symmetry considerations preclude the possibility of twist or continuous helical symmetry in bulk crystalline structures. However, as has been shown nearly a century ago, twisted molecular crystals are ubiquitous and can be formed by about 1/4 of organic substances. Despite its ubiquity, this phenomenon has so far not been satisfactorily explained. In this work we study twisted molecular crystals as geometrically frustrated assemblies. We model the molecular constituents as uniaxially twisted cubes and examine their crystalline assembly. We exploit a renormalization group (RG) approach to follow the growth of the rod-like twisted crystals these constituents produce, inquiring in every step into the evolution of their morphology, response functions and residual energy. The gradual untwisting of the rod-like frustrated crystals predicted by the RG approach is verified experimentally using silicone rubber models of similar geometry. Our theory provides a mechanism for the conveyance of twist across length-scales observed experimentally and reconciles the apparent paradox of a twisted single crystal as a finite size effect.
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http://dx.doi.org/10.1039/c8sm01290c | DOI Listing |
Angew Chem Int Ed Engl
January 2025
The University of Tennessee Knoxville, Chemistry, UNITED STATES OF AMERICA.
Single crystals that do not obey translational symmetry have been reported in various material systems. In polymers, twisted crystals are typically formed in banded spherulites, while a class of non-flat polymer single crystals (PSCs) has been observed. Herein, we report the formation of scrolled single crystals of biodegradable polymer poly(L-lactic acid) (PLLA).
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai, China.
Functional materials, possessing specific properties and performing particular functions beyond their mechanical or structural roles, are the foundation of modern matter science including energy, environment, and quantum sciences. The atomic and electronic structures of these materials can be significantly altered by external stimuli such as pressure. High-pressure techniques have been extensively utilized to deepen our understanding of structure-property relationships of materials, while also enabling emergent or enhanced properties.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Tsinghua University, Institute of Nuclear and New Energy Technology, Room A320, Nengke Building, Qinghua Yuan No.1, Beijing, CHINA.
Exploring host-guest interactions to regulate hydrogen-bonding assembly offers a promising approach for developing advanced porous crystal materials (PCMs). However, screening compatible guests with appropriate geometries and host-guest interactions that could inhibit the dense packing of building blocks remains a primary challenge. This study presents a novel guest-induced crystallization (GIC) strategy, guided by thermodynamic calculations, to develop porous hydrogen-bonded organic frameworks (HOFs) using structurally challenging tetrazole building units.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, University of Houston, Houston, Texas 77204, USA.
Rubrene is one of the leading organic semiconductors in scientific and industrial research, showing good conductivities and utilities in devices such as organic field-effect transistors. In these applications, the rubrene crystals often contact ionic liquids and other materials. Consequently, their surface properties and interfacial interactions influence the device's performance.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Bernal Institute and Department of Chemical Sciences, University of Limerick, Limerick V94 T9PX, Ireland.
2D and 3D porous coordination networks (PCNs) as exemplified by metal-organic frameworks, MOFs, have garnered interest for their potential utility as sorbents for molecular separations and storage. The inherent modularity of PCNs has enabled the development of crystal engineering strategies for systematic fine-tuning of pore size and chemistry in families of related PCNs. The same cannot be said about one-dimensional (1D) coordination polymers, CPs, which are understudied with respect to porosity.
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