Crystal engineering of nanomaterials: current insights and prospects

Abstract

The rather loosely defined field of crystal engineering offers a wide variety of approaches towards the precise design of nanocrystals for different applications. Thereby, inorganic nanomaterials have been in the...

Metal–Organic Frameworks (MOFs) Morphology Control: Recent Progress and Challenges

“…The ability of an additive to be adsorbed depends on various factors of its chemical nature such as functionality and structural resemblance with the host molecule. Another aspect of additive use is that high concentrations of additives, sometimes 100 times more than the linkers, create variations in solubility, ionic strength, pH, supersaturation, and viscosity that lead to additional effects in the crystallization process. , For additives with functionalities mimicking those of the organic linker, competitive interactions between linker and additive toward the metal clusters are introduced during MOF phase formation, which leads to the change in relative crystal growth rates, and thus habit modification of the MOF crystalline phase. − Note that this occurs typically with rejection of the additive from the crystals through the reversibility of coordination; in cases where both compounds are incorporated, it can lead to defects and/or mixed linker MOFs . Additionally, relative crystal growth rates can be tuned by varying the concentration of the additive. ,,− …”

“…13 In contrast, for nanoparticles complex morphologies are often obtained through additives, and many complex shapes include twinning as an essential feature. 3,14,15 Against this background, the lack of progress in morphology engineering of metal−organic frameworks (MOFs) is glaring.…”

“…The morphology (shape) of crystals significantly influences handling properties such as filterability/flow, drying, and milling, as well as functional properties such as packing density, mechanical strength, compressibility, wettability, and efficiency of heterogeneous catalysis. − Each substance has an equilibrium morphology that is based on the expression of crystal facets with minimum surface energy . The observation of deviations from this morphology speaks to the central role of kinetics in determining the relative growth rate of crystal facets.…”

“…The crystallization of pharmaceuticals has seen much scrutiny of morphology control due to the importance of isolation by crystallization to yield sufficient impurity rejection to meet the high purity standards needed for regulatory compliance. ,− It should be noted that changing solvents is a mainstay of such studies . In contrast, for nanoparticles complex morphologies are often obtained through additives, and many complex shapes include twinning as an essential feature. ,, Against this background, the lack of progress in morphology engineering of metal–organic frameworks (MOFs) is glaring.…”

Alkalinity-controlled zeolite nucleation and growth: ultrafast synthesis of total-morphology zeolite L mesocrystals and adsorption evaluation

“…Exploring the crystallization mechanism is one of the most fundamental and vital parts of research on crystalline materials because it leads to endless possibilities for the engineering and functionalization of material structures [1][2][3][4][5][6][7] . In the crystallization system of inorganic materials, such as zeolites, it is widely accepted that crystal growth not only depends on the addition of simple ions or small molecules (classical crystallization mechanism [8,9] ) but also involves the assembly of a series of more complex and evolvable "particles" [9,10] -including crystalline [11] , semi-crystalline [12] or amorphous oligomers, clusters, and nanoparticles [13] (nonclassical crystallization mechanism).…”