Controlled growth of imine-linked two-dimensional covalent organic framework nanoparticles

Abstract

Highly crystalline, monodisperse, imine-linked covalent organic framework nanoparticles were obtained under Sc(OTf)3-catalyzed conditions and enlarged by a slow monomer addition technique that prevents secondary nucleation.

Solving the COF trilemma: towards crystalline, stable and functional covalent organic frameworks

“…Slowly supplying solutions of boronic acid and diol precursor monomers by a syringe pump has been shown by Dichtel and co-workers for the formation of boronic acid COFs and imine COFs. 115,116 By this approach the nucleation and growth of the particles could be separated leading to only homoepitaxial growth of the COF crystallites. 104 This method was then successfully applied to grow COFs in suspension featuring larger single crystalline dimensions than what is normally possible.…”

The role of nanoparticle size and ligand coverage in size focusing of colloidal metal nanoparticles

“…Colloidal synthesis offers a versatile bottom-up approach and has been constantly advancing over the past few decades, with better control over size, shape, composition, super-lattice structure and consequently the nanoparticles' properties (catalytic, electronic, optical, etc.). [1][2][3][4][5][6] For example, recent synthetic methods enabled fabrication of colloidal nanoparticles with different sizes by simply altering the reaction conditions (solvent, ligand, precursor, and synthesis temperature). [7][8][9][10][11] However, since the size distribution of the nanoparticles is oen key to their specic, desired physical and chemical properties, [12][13][14][15][16][17][18] a fundamental understanding of how to control the nucleation and growth is key to enable predictive synthesis of nanoparticles with the desired properties.…”

Small-angle X-ray scattering as a multifaceted tool for structural characterization of covalent organic frameworks

“…The valuable information that these approaches can give about fractal dimension, radius of gyration, hierarchical structure and structure peaks, respectively, makes SAXS an elegant choice for the study of reticular porous materials. Despite its wide application in silica, zeolites and more recently MOFs (Tsao et al, 2007;Goesten et al, 2013;Zhao et al, 2011;Stavitski et al, 2011), the use of SAXS for studying COFs is still rare (Evans et al, 2018;Das & Mandal, 2018;Li et al, 2019;Li et al, 2020). Smith et al (2017) investigated the kinetics of COF-5 crystalline nanoparticle formation by evaluation of the integrated area of the emerging structure peaks, which describe the ordered spacing of atoms, over reaction time.…”