Size Control of the MOF NU-1000 through Manipulation of the Modulator/Linker Competition

Abstract

NU-1000 is a stable, zirconium-based metal–organic framework (MOF) that has been used extensively as a scaffold for the installation of catalytic species, among other applications. The synthesis of NU-1000 follows a two-step modulated procedure, whereby the MOF grows as modulator molecules bound to the node are replaced with organic linker molecules. Manipulating the competition between the modulator and linker molecules for the binding sites on the node leads to control of reaction rate and the resulting NU-1000 particle size. By modifying the linker, modulator, and base concentrations and zirconium precursor, we can synthesize high-purity and monodisperse NU-1000 from 300 nm to almost 10 μm in length. Despite a wide range of particle sizes and synthetic conditions, the uptake of a dicobalt complex remained consistent per node. Further control over particle size can lead to more facile high-resolution characterization using methods like electron microscopy and spectroscopy as well as open a wider range of potential applications, including nanoscale applications like biological imaging.

Zirconium-Based Metal–Organic Frameworks as Acriflavine Cargos in the Battle against Coronaviruses─A Theoretical and Experimental Approach

“…The morphology of pristine materials was in good agreement with the literature data. 20 , 40 The MOF-808 shows well-defined cubic nanocrystals with ca . 250 nm particle size.…”

Experimental evidence for a general model of modulated MOF nanoparticle growth

“…[35][36][37] While excess trimesic acid increases grain sizes of Cu 3 BTC 2 particles, in NU-1000, another carboxylate MOF, particle sizes decrease as excess linker is used. 38,39 In the report of NU-1000 particles, a strong base is added as well, which likely counters any increase in [H + ]. We attribute this difference to the fact that imidazole linkers contain just single protic sites, whereas multitopic carboxylates contain several, which, according to the seesaw model, increase solution acidity and hinder the ability of ligands to trap metal ions.…”

Pyrene-based metal organic frameworks: from synthesis to applications

“…111 Due to its attractive properties such as having a high Brauner-Emmett-Teller (BET) surface area (2320 m 2 g À1 ) and pore volume (1.4 cm 3 g À1 ), good thermal stability, fluorescence properties and the suitability of the structure for metalation or other types of functionalization, NU-1000 has drawn attention since its first synthesis. As a result, the chemical and structural properties of NU-1000 have been deeply studied experimentally and computationally; by exploring its synthesis conditions, [112][113][114][115][116][117] structural stability, 118,119 proton topology and surface chemistry, 120-123 and designing organic linkers for its better crystallinity. 124…”