Multicomponent Anti-Kasha’s Rule Emission from Nanotubular Metal–Organic Frameworks for Selective Detection of Small Molecules
Yangbin Xie, Luying Liu, Zetao Huang, Huixian Miao, Wenjiang Zhaxi, Fengnan Duan, Wei Huang, Dayu Wu
Abstract
The peak photoluminescence (PL) of conventional fluorophores is independent of the excitation wavelength (called Kasha’s rule), while the search of metal–organic framework materials with the so-called anti-Kasha’s rule emission remains very limited. Herein, we report the observation of anti-Kasha’s rule emission in a multicomponent PL three-dimensional nanotubular metal–organic framework ( abbr. MOF-NT ), [Zn(μ-L)(μ-bix)] n ·0.33 n H 2 O [H 2 L = biphenyl-3,5-dicarboxylic acid; bix = 1,4-bis(imidazole-1-ylmethyl)benzene]. The MOF-NT crystalline sample represents a notable example of strong excitation-dependent fluorescence from the ultraviolet to the visible spectral region. Moreover, by virtue of electronic flexibility and high PL efficiency, MOF-NT shows a discriminative PL response between isomeric nitroaromatic compounds. The work demonstrated the intrinsic anti-Kasha’s rule emission in the crystalline-state MOF materials, providing new visions for the development of advanced solid-state emissive materials.