TY - JOUR

T1 - Formate modulated solvothermal synthesis of ZIF-8 investigated using time-resolved in situ X-ray diffraction and scanning electron microscopy

AU - Cravillon, Janosch

AU - Schröder, Christian A.

AU - Bux, Helge

AU - Rothkirch, André

AU - Caro, Jürgen

AU - Wiebcke, Michael

PY - 2012/1/21

Y1 - 2012/1/21

N2 - Time-resolved investigations using in situ energy-dispersive X-ray diffraction in tandem with ex situ scanning electron microscopy revealed that solvothermal crystallisation of ZIF-8 in methanol solvent and in the presence of sodium formate as a simple monodentate ligand (modulator) is a rapid process yielding big, high-quality single crystals in short time (<4 h). Kinetic analysis of crystallisation curves was performed by applying the Avrami-Erofe'ev and Gualtieri models. The analyses revealed that the weakly basic formate modulator acts as a base in deprotonation equilibria (deprotonation of the bridging 2-methylimidazole ligand) rather than as a competitive ligand in coordination equilibria at the metal (Zn2+) centres. This is in contrast to the coordination modulation function of formate in ZIF-8 synthesis at room temperature. Crystal shape evolves with time in the presence of formate from cubes with truncated edges to rhombic dodecahedra. The latter shape represents most likely the stable equilibrium morphology of ZIF-8.

AB - Time-resolved investigations using in situ energy-dispersive X-ray diffraction in tandem with ex situ scanning electron microscopy revealed that solvothermal crystallisation of ZIF-8 in methanol solvent and in the presence of sodium formate as a simple monodentate ligand (modulator) is a rapid process yielding big, high-quality single crystals in short time (<4 h). Kinetic analysis of crystallisation curves was performed by applying the Avrami-Erofe'ev and Gualtieri models. The analyses revealed that the weakly basic formate modulator acts as a base in deprotonation equilibria (deprotonation of the bridging 2-methylimidazole ligand) rather than as a competitive ligand in coordination equilibria at the metal (Zn2+) centres. This is in contrast to the coordination modulation function of formate in ZIF-8 synthesis at room temperature. Crystal shape evolves with time in the presence of formate from cubes with truncated edges to rhombic dodecahedra. The latter shape represents most likely the stable equilibrium morphology of ZIF-8.

UR - http://www.scopus.com/inward/record.url?scp=84555179089&partnerID=8YFLogxK

U2 - 10.1039/c1ce06002c

DO - 10.1039/c1ce06002c

M3 - Article

AN - SCOPUS:84555179089

VL - 14

SP - 492

EP - 498

JO - CRYSTENGCOMM

JF - CRYSTENGCOMM

SN - 1466-8033

IS - 2

ER -