Reversed crystal growth of metal organic framework MIL-68(In)

Kirsty Mcroberts,Wuzong Zhou

doi:10.1039/d1ce01120k

Abstract

A reversed crystal growth mechanism of MIL-68(In) is revealed. Nanorods of MIL-68 aggregate in parallel into microrods, followed by surface recrystallisation into a single crystal hexagonal shell and extension of crystallisation from surface to core.

Highlights

Classical crystal growth theory follows the Bravais–Friedel– Donnay–Harker (BFDH) law, with the building units deposited layer-by-layer onto a nucleus.[1,2,3] Since crystal growth rate is inversely proportional to interplanar distance, the final morphology is normally dominated by faces with the largest inter-planar distances, as these have the slowest growth rates.[4]
We have found that cubic metal organic frameworks (MOFs)-5 crystals were not developed from a single nucleus
It is obvious that the morphology, crystallinity and porosity of MOF particles vary significantly with the growth time, and their physico-chemical properties would be expected to change.[21,22,23,24]

Summary

Introduction

Classical crystal growth theory follows the Bravais–Friedel– Donnay–Harker (BFDH) law, with the building units (atoms, molecules or ions) deposited layer-by-layer onto a nucleus.[1,2,3] Since crystal growth rate is inversely proportional to interplanar distance, the final morphology is normally dominated by faces with the largest inter-planar distances, as these have the slowest growth rates.[4]. Low density polycrystalline microcubes formed first, followed by surfaceto-core recrystallisation into single crystals.[17] It is obvious that the morphology, crystallinity and porosity of MOF particles vary significantly with the growth time, and their physico-chemical properties would be expected to change.[21,22,23,24] MIL-68(In) is an interesting member of the MOF family, constructed by corner sharing indium– oxygen octahedra chains, connected with organic 1,4benzenedicarboxylate (BDC) ligands. The particle size and morphology of the produced MIL68(In) crystals were observed from SEM images.

Results

Conclusion