Title: Microporous Cyclic Titanium-Oxo Clusters with Labile Surface Ligands
Author: Dr. Chaowei Zhao, Ying-Zi Han, Shuqi Dai, Xumao Chen, Juanzhu Yan, Dr. Weijie Zhang, Dr. Haifeng Su, Dr. Shuichao Lin, Prof. Zichao Tang, Prof. Boon K. Teo, Prof. Nanfeng Zheng*
Summary:
By using ethylene glycol and monocarboxylic acid as surface ligands, a series of cyclic Ti-oxo clusters (CTOC) with permanent microporosity are successfully synthesized. With a cyclic {Ti32O16} backbone made of eight connected Ti4tetrahedral cages that are arranged in a zigzag fashion, the clusters have a “donut” shape with an inner diameter of 8.3 Å, outer diameter of 26.9 Å and height of 10.4 Å. While both inner and outer walls of the “donut” clusters are modified by double-deprotonated ethylene glycolates, their upper and lower surfaces are bound by carboxylates and mono-deprotonated ethylene glycolates. The clusters are readily packed into one-dimensional tubes which are further arranged in two different modes into crystalline microporous solids with surface areas over 660 m2 g−1, depending on the surface carboxylates. The solid with olefin-bearing carboxylates exhibits a superior CO2 adsorption capacity of 40 cm3 g−1 at 273 K under 1 atm. Moreover, the mono-deprotonated ethylene glycolates on the clusters are demonstrated to be highly exchangeable by other alcohols, providing a nice platform for creating microporous solids or films with a wide variety of surface functionalities.
Full Link: http://onlinelibrary.wiley.com/doi/10.1002/anie.201709096/full
