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The self-assembly of chiral unit forms hydrogen-bonded metal-organic frameworks with multiple level chirality can effectively enhance chiroptical activity. [Display omitted] • Chiral coordination compounds with formula Cd[D-OH-bim] 2 (NO 3) 2 (1-D) and Cd[L-OH-bim] 2 (NO 3) 2 (1-L) were synthesized • The self-assembly of chiral unit forms hydrogen-bonded metal-organic frameworks with multiple level chirality. • The aggregation of chiral coordination unit with multilevel chirality can effectively enhance chiroptical activity. In this work, a pair of chiral coordination compounds with formula as Cd[D-OH-bim] 2 (NO 3) 2 (1-D) and Cd[L-OH-bim] 2 (NO 3) 2 (1-L) (L-OH-bim = (L)-2-(1-Hydroxyethyl)benzimidazole; D-OH-bim = (D)- 2-(1-Hydroxyethyl)benzimidazole) are synthesized for circular polarization luminescence (CPL). Single crystal X-ray diffraction (SCXRD) results show that the 1-D and 1-L contain chiral Cd[OH-bim] 2 (NO 3) 2 units composed of Cd center and chiral OH-bim ligand (D- or L-OH-bim) as well as NO 3 –. The self-assembly of these chiral units by hydrogen bonding interaction generates a 3D hydrogen-bonded framework containing multiple chirality, such as chiral ligand, helical chain, chiral spatial arrangement and chiral framework (chiral space group and chiral topology). The bulk phase with multilevel chirality shows enhanced circular dichroism response and obvious CPL than that of the organic ligands as well as Cd[OH-bim] 2 (NO 3) 2 unit. [ABSTRACT FROM AUTHOR]

The as-synthesized PCN-222(Fe) nanosheet can efficiently immobilize aptamers to fabricate an electrochemical aptasensor, which is used as an efficient platform for impedimetric sensing toward tobramycin. [Display omitted] • A PCN-222(Fe) nanosheet is prepared successfully. • It can efficiently immobilize aptamers to fabricate an electrochemical aptasensor. • It is used as an efficiently impedimetric sensor toward tobramycin. A zirconium metal-organic framework nanosheet, namely PCN-222(Fe) NS, is prepared using [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]-Fe(III) chloride and Zr clusters, which is further investigated in detail by various technologies. The as-synthesized PCN-222(Fe) NS can efficiently immobilize aptamers to construct an electrochemical aptasensor for impedimetric sensing toward tobramycin (TOB). The fabricated electrochemical aptasensor can sensitively monitor TOB with outstanding specificity, fine long-term preservation, acceptable repeatability as well as good actual usability. [ABSTRACT FROM AUTHOR]