Single crystal of a one-dimensional metallo-covalent organic framework
Hai‐Sen Xu, Yi Luo, Xing Li, Pei Zhen See, Zhongxin Chen, Tianqiong Ma, Lin Liang, Kai Leng, Ibrahim Abdelwahab, Lin Wang, Runlai Li, Xiangyan Shi, Yi Zhou, Xiu Fang Lu, Xiaoxu Zhao, Cuibo Liu, Junliang Sun, Kian Ping Loh
Abstract
Although polymers have been studied for well over a century, there are few examples of covalently linked polymer crystals synthesised directly from solution. One-dimensional (1D) covalent polymers that are packed into a framework structure can be viewed as a 1D covalent organic framework (COF), but making a single crystal of this has been elusive. Herein, by combining labile metal coordination and dynamic covalent chemistry, we discover a strategy to synthesise single-crystal metallo-COFs under solvothermal conditions. The single-crystal structure is rigorously solved using single-crystal electron diffraction technique. The non-centrosymmetric metallo-COF allows second harmonic generation. Due to the presence of syntactic pendant amine groups along the polymer chains, the metallopolymer crystal can be further cross-linked into a crystalline woven network.