RESUMO
A novel 3D metal-organic framework (MOF){[Tb3(CBA)2(HCOO)(µ3-OH)4(H2O)]·2H2O·0.5DMF} n (S-1) was synthesized by the solvothermal method. The crystal structure indicates that [Tb4O4] cubane clusters self-assemble into an infinite chain by sharing vertex, which is further linked to adjacent chains through 1,1-cyclobutanedicarboxylic acid ligand (H2CBA), resulting in a honeycomb arrayed framework. S-1 possesses excellent water stability and still retains intact structure after exposure to water for 10 weeks or boiling water for 10 weeks. Interestingly, S-1 acts as a luminescence sensor to selectively and sensitively detect quercetin with the limit of detection (LOD) as low as 0.23 ppm (7.6 × 10-7 M). The relationship between relative luminescence intensity and concentration obeys linear in the range of 0-300 ppm (0-993 µM), which allows quantitative detection of quercetin. Importantly, S-1 can be reused at least six times with almost no change in luminescent intensity. Compared with the high performance liquid chromatography-mass spectrometry (HPLC-MS) method, S-1 was used to determine the content of quercetin in onionskin and apple peel samples with satisfactory results. Furthermore, a portable S-1 test paper is also developed and expected to be applied in practice. To our knowledge, S-1 is the first example of MOFs as luminescent sensor for quercetin.
Assuntos
Substâncias Luminescentes/química , Estruturas Metalorgânicas/química , Quercetina/análise , Reutilização de Equipamento , Limite de Detecção , Substâncias Luminescentes/síntese química , Medições Luminescentes/instrumentação , Medições Luminescentes/métodos , Malus/química , Estruturas Metalorgânicas/síntese química , Cebolas/química , Papel , Térbio/químicaRESUMO
Interlocking cages are of great interest due to their fascinating structures and potential applications. However, the interlocking of different cages has not been previously reported. Herein, quadruply interlocked [Cu8 ] and [Cu18 ] nanocages have been constructed and structurally characterized in cationic metal-organic framework {[CuI Cu4 II (XN)4 (PTA)4 (H2 O)4 ]0.5 SO4 â 5 H2 Oâ EtOH}n (1). 1 can trap the anionic pollutant CrO4 2- and the radioactive-contaminant simulant ReO4 - with an uptake capacity of 83.2 and 218â mg g-1 , respectively. Catalytic investigations reveal 1 is an efficient heterogeneous catalyst for the enamination of ethyl acetoacetate with aniline and the turnover frequency (TOF) can reach a record value of 4000â h-1 . More importantly, 1 represents the first of a catalyst of enamination to exhibit excellent size selectivity on different substrates. The robust catalyst can be reused at least ten times without obvious loss in catalytic activity.
RESUMO
Three isostructural Ln-BTB frameworks (Ln = Eu (1), Dy (2), Yb (3)) were synthesized and structurally characterized, in which mononuclear and trinuclear [Ln3] units as nodes construct unprecedented (3,4,10)-connected 3D frameworks with (4·6·8)4(4·8(2))2(4·8(5))(6(2)·8(4))(4(5)·6(8)·8(26)·10(6)) point symbol. The luminescent investigations revealed that compound 1 can sensitively and selectively detect Al(3+), but comparably compound 2 could not detect Al(3+) among various cations. More importantly, 1 as an Al(3+) sensor can be reused at least five times, which represents the first recyclable metal organic framework (MOF)-supported Al(3+) sensor. Additionally, magnetic investigations on 2 also were carried out, showing a single-molecule-magnet behavior.
RESUMO
Nine dinuclear Ln(iii) complexes, [Ln(dbm)2(L)]2 (Ln = Eu (), Tb (), Dy (), Ho (), Er ()) and [Ln(dbm)2(L')]2 (Ln = Tb (), Dy (), Ho (), Er ()) (dbm = 1,3-diphenyl-1,3-propanedione, HL = 2-[[(4-methoxy-phenyl)imino]methyl]-8-hydroxy-quinoline and HL' = 2-[[(4-ethoxyphenyl)imino]methyl]-8-hydroxyquinoline) have been synthesized, and structurally and magnetically characterized. The nine complexes are all phenoxo-O bridged binuclear complexes, in which Ln1 and Ln1a are in an eight-coordinated environment bridged by two phenoxido oxygen atoms of two 8-hydroxyquinoline Schiff base ligands. Although complexes and have very similar structures, magnetic studies reveal that they exhibit different magnetic relaxation behaviors with the effective barriers (ΔE/kB) of 34.5 K for and 67.6 K for . The dissimilar dynamic magnetic behaviors of and mostly result from the different electron-donating effect induced by the two alkoxy (-OCH3 and -OC2H5) of the 8-hydroxyquinoline Schiff base ligands. Meanwhile, for complexes , , and , there are no observed magnetic relaxation behaviors under a zero dc field. In addition, the luminescence properties of , and were studied.