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A novel Se-annulated perylene diimide derivative tethered with polyhedral oligosilsesquioxane (POSS) nanoparticles (POSS-2SePDI-POSS) was designed and prepared. The introduction of selenium atoms endows POSS-2SePDI-POSS with significant fluorescence quenching but enhanced excited-state absorption. As a result, POSS-2SePDI-POSS exhibits a distinct reverse saturable absorption characteristic, suggesting its potential application in optical limiting.

A two-dimensional (2D) Co-based metal-organic framework (MOF) with porphyrinic skeleton forms crystalline plates, flower-shaped clusters, and ultrathin films under optimized conditions, including the use of polyvinylpyrrolidone (PVP) as a surfactant. Ultrathin films demonstrate the best solution-based third-order nonlinear optical properties, featuring a nonlinear transmittance (T) value of 0.54, absorption coefficient (α2) of 9.5 × 10-10 m W-1 and second hyperpolarizability (γ) value of 1.37 × 10-28 esu, which are slightly better than those of the flower-shaped clusters (T = 0.65, α2 = 7.0 × 10-10 m W-1; γ = 1.27 × 10-28 esu), but marginally better than those of the crystalline thin plates (T = 0.94, α2 = 2.4 × 10-10 m W-1; γ = 0.24 × 10-28 esu).

A novel perylene diimide derivative equipped with polyhedral oligosilsesquioxane nanocages (POSS-AMPDI) was designed and synthesized for application in optical limiting. Moreover, due to the dual mechanisms of POSS collapse and intermolecular proton transfer, POSS-AMPDI exhibits high sensitivity and rapid selectivity to fluoride ions, with a detection limit as low as 1.64 × 10-8 M.

Reaction of [Et4N][Tp*WS3] (1) with [Cu(MeCN)4]PF6, CsCl, isonicotinic acid and CuCN, and treatment of [Et4N][Tp*WS3(CuCl)3] (2)/[Et4N][{Tp*WS3Cu3Cl}2(μ-Cl)2(μ4-Cl)] (3) with AgOTf and bpp (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate; bpp = 1,3-di(4-pyridyl)propane) give rise to [Et4N]2[{Tp*WS3Cu3(CN)0.5}2(μ-Cl)2(μ4-Cl)]2(PF6)2 (4) and [(Tp*WS3Cu3)2(μ3-Cl)2(bpp)3]2(OTf)4 (5), respectively. Compounds 4 and 5 feature cluster-based rectangle and [2]catenane architecture, and both exhibit enhanced third-order nonlinear optical responses relative to those of 1.