Organic linker geometry controlled synthesis of coordination polymer spheres and their thermal transformation to yolk–shell metal oxides?

Journal of Materials Chemistry A Pub Date: 2014-07-24 DOI: 10.1039/C4TA02535K

Abstract

Precise control over size, morphology and composition of coordination polymers (CPs) is challenging but important for using these hybrid materials for many more applications. Herein, we report a protocol of preparing unitary and multinary metal–carboxylic acid coordination polymers without additives. We found that the CPs morphology was controlled by the geometric angle (∠) of carboxylic groups in the organic linkers. At the ∠120°, the mono-dispersed and uniform spherical CPs were obtained with the central distribution size ranging from nanoscale to microscale, adjusted by the precursor concentration and reaction time. We also obtained a series of spherical metal-CPs, including transition and rare earth metals (Mg, Ni, Zn, In, Y, Sm, Eu, Gd, Er, Ho, Yb and Lu) and homogeneously distributed multinary metal-CPs. Moreover, the calcination of these CPs generated unitary and multinary metal oxides with yolk–shell structure. In addition, metal-CPs contain coordinatively unsaturated metal sites, which is confirmed by probe molecule adsorption-IR spectroscopy, and could catalyze the cyanosilylation of carbonyl substrates at 25 °C. Sixteen examples were tested and produced good to excellent yields over Eu-CPs.

Graphical abstract: Organic linker geometry controlled synthesis of coordination polymer spheres and their thermal transformation to yolk–shell metal oxides
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