The first example of rare-earth organic frameworks with 3-aminopyrazine-2-carboxylic acid (Hapca) was synthesized under hydrothermal conditions and characterized by elemental analysis, IR, PL, TG, powder and single-crystal X-ray diffraction. These ten complexes exhibit three different structure types with decreasing lanthanide radii: [La(apca)(3)](n) () for type I, {[Ln(apca)(ox)(H(2)O)(2)].H(2)O}(n) (Ln = Pr (2), Nd (3), ox = oxalate) for type II, and [Ln(2)(apca)(4)(OH)(2)(H(2)O)(2)](n) (Ln = Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Y (10)) for type III. The structure of type I consists of 1D "snowflake" chains along a-axis, which are further interconnected by hydrogen bonds to produce a 3D sra net topology containing infinite (-C-O-La-)(n) rod-shaped SBU. Type II has 2D Ln-apca-ox 4(4)-net, in which a planar udud water tetramers (H(2)O)(4) are formed by coordinated and free water molecules. Type III also comprises of 2D 4(4)-layer network constructed from Ln-apca-OH. The structure diversity is mainly caused by the variation of coordinated ligand and lanthanide contraction effect. Remarkably, the oxalate in type II was in situ synthesized from 3-aminopyrazine-2-carboxylic acid through an oxidation-hydrolysis reaction. The luminescent investigations reveal that complex exhibits strong blue emission and complex exhibits characteristic luminescence of Eu(3+).

Nano-drug delivery systems (nano-DDSs) with an existing specific interaction to tumor cells and intelligent stimulus-triggered drug delivery performance in a tumor microenvironment (TME) remain hotspots for effective cancer therapy. Herein, multifunctional pH/H2O2 dual-responsive chiral mesoporous silica nanorods (HA-CD/DOX-PCMSRs) were creatively constructed by first grafting phenylboronic acid pinacol ester (PBAP) onto the amino-functioned nanorods, then incorporating doxorubicin (DOX) into the mesoporous structure, and finally coating with the cyclodextrin-modified hyaluronic acid conjugate (HA-CD) through a weak host–guest interaction. Under a physiological environment, the gatekeeper CD could avoid the premature leakage of DOX and minimize the side effects to normal cells. After the uptake by the tumor cells, the H2O2-sensitive moieties of PBAP were exposed and a small amount of DOX was leaked along with the shift of the supramolecular switch HA-CD under the acidic condition. Notably, the self-supplying H2O2 mediated by the released DOX in turn accelerated the PBAP disintegration, further promoted the rapid release of DOX, and increased the DOX accumulation in tumor regions. Innovatively, this nano-DDS could simultaneously achieve the tumor-targeting ability via CD44 receptor-mediated endocytosis and pH/H2O2 dual responsiveness activated by the TME and hence exhibited superior antitumor efficacy. Furthermore, HA acting as the hydrophilic shell could improve the biocompatibility of this nano-DDS.

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