Crystal engineering, crystals and crystallography

Abstract

Crystal engineering is moving into new domains with reducing distance and time scales and new ways of thinking about crystals and crystallography. Its intersections with other subjects are varied and numerous.

What is isostructurality? Questions on the definition

“…An increasing number of new substances with tailor-made properties are produced by crystal engineering (Desiraju, 2018(Desiraju, , 2001(Desiraju, , 2002Russell & Ward, 1996). The attempt to fine-tune structural properties requires mastering the supramolecular packing architecture (Galcera et al, 2013;Bombicz et al, 2014;de Vries et al, 2016;Bombicz, 2017).…”

Reversible Switching of Frameworks through Single-Crystal-to-Single-Crystal Structural Transformation in Two Entangled Coordination Polymers and Their Impact on Adsorption Properties

“…Despite this negative point of compromise, it is worth mentioning that the entangled frameworks are frequently found to show various interesting functionalities such as stepwise adsorption, − sensing, − and enhancement of framework rigidity. − A movement from the entangled frameworks to the individual networks can endorse their general structural flexibility which is also found to be very effective for selective gas storage and separation. , Therefore, to synthesize entangled frameworks with fascinating tailor-made properties, a better understanding of such frameworks is very much essential. It is always helpful when such transformations occurs in a solid state single-crystal-to-single-crystal (SC–SC) manner, which makes it more interesting in the field of crystal engineering. − When the CPs are exposed to single and/or multiple stimuli, although their microcrystallinity has been maintained at that time, in most of the cases those are not suitable for single crystal structure analyses. , It is already well-known that the external stimuli such as heat, pressure, solvent removal/addition, and/or exchange can introduce the structural flexibility in a CP because at this time so many mechanical processes, e.g., bond rotation, bending, sliding, swinging, shrinking, or swelling have been operated on the whole framework of CPs. − Because of this massive alteration of forces, retaining of the single crystallinity is a hard criteria for a flexible CP after structural transformation. , It has become even harder when it comes to temperature-mediated guest removal followed by structural transformation in an entangled CP; as in most of the cases, the single crystallinity has been lost at elevated temperature, except for a few exceptions. − Now this kind of solvent-mediated transformation is under the eagle’s eye of the relevant field, as the presence or absence of guest molecules greatly influences the weak bonding in a CP, which gently tunes its versatile physical as well as chemical properties. − The structural transformation in an entangled framework and point-to-point study of such transformations could able to extract a clear idea regarding how the crystal structure is changing during the solid state structural transformation process and how it could navigate the passages to build the CPs with fascinating properties …”