LAUSR

Abstract A novel cobalt-based metal-organic framework, {[Co2(DPNDI)(2,6-NDC)2]·7(DMF)}n (1), has been solvothermally synthesized from mixed ligands, N,N′-Di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide (DPNDI) and naphthalene-2,6-dicarboxylic acid (2,6-NDC). In the crystal structure of 1, the paddle-wheel {Co2} clusters were linked by two DPNDI ligands and four deprotonated 2,6-NDC ligands, which were further extended into a 2-fold interpenetrated 3D pillared-layer MOF with pcu topology. Interestingly, 1 exhibits high thermal stability (up to 400 °C) and high solvatochromic sensitivity to water within 10s. This is the first naphthalenediimide-based Co-MOFs with remarkable sensitivity and fast response for traces of water detection as low as 0.6% in dry DMF solvent. What's more, it could be used as a naked-eye colorimetric sensor to humidity in practical application.