Novel Top-Down Synthesis of Covalent Organic Frameworks for Uranyl Ion Capture.

Seeking novel synthetic methodology to further promote the preparation of covalent organic frameworks (COFs) has long been our pursuit but remains a challenging task. Herein, we report a new protocol, a top-down approach for facile synthesis of COFs. Interestingly, our top-down route can impressively generate extended COFs by reticular chemistry which cannot be accessed by the commonly used bottom-up synthesis route.

Ultra-selective uranium separation by in-situ formation of π-f conjugated 2D uranium-organic framework.

With the rapid development of nuclear energy, problems with uranium supply chain and nuclear waste accumulation have motivated researchers to improve uranium separation methods. Here we show a paradigm for such goal based on the in-situ formation of π-f conjugated two-dimensional uranium-organic framework. After screening five π-conjugated organic ligands, we find that 1,3,5-triformylphloroglucinol would be the best one to construct uranium-organic framework, thus resulting in 100% uranium removal from both high and low concentration with the residual concentration far below the WHO drinking water standard (15 ppb), and 97% uranium capture from natural seawater (3.