Jun Ni

A colorimetric/luminescent benzene compound sensor based on a bis(σ-acetylide) platinum(II) complex: enhancing selectivity and reversibility through dual-recognition sites strategy

A square-planar bis(σ-acetylide) Pt(II) complex containing dual-recognition sites was designed, synthesized and used as a colorimetric/luminescent sensor for detecting the vapor of benzene compounds.

Two (5,5)-connected isomeric frameworks as highly selective and sensitive photoluminescent probes of nitroaromatics

Herein we report the first two (5,5)-connected isomeric frameworks, namely, (Me2NH2)[Zn2L(H2O)]·3.5DMF (1) and (Me2NH2) [Zn2L(H2O)]·6DMF·4H2O (2) (DMF = dimethylformamide, H5L = 5,5′-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino) diisophthalic acid), obtained via assembly reactions between Zn2+ and a semi-rigid pentacarboxylate ligand (L5−). Single-crystal X-ray diffraction analyses reveal that both compounds are three dimensional metal–organic frameworks (MOFs) built of the same {Zn2(CO2)5} molecular building blocks (MBBs) and L5− ligands but have different topologies (point symbols of (44·66) and (46·64)(46·64) for 1 and 2, respectively). The mechanisms of the selective and efficient quenching of their photoluminescence (PL) by a series of nitroaromatic (NACs) solutions could be explained by electron transfer, long range energy transfer and/or electrostatic interactions. Remarkably, 1 and 2 can impressively detect the concentrations of dinoseb in solutions down to 0.09 and 0.11 ppm, respectively. Their PL could also be quenched by nitrobenzene (NB) and 4-nitrotoluene (4-NT) vapors, and the emission from 2 can be more quickly quenched than that from 1 possibly due to 2s larger pores and faster uptake of NAC vapors. 1 and 2 demonstrate significantly better performances than the two previously reported 4-connected MOFs using Zn2+ and a ligand isomeric to L5− in detecting NACs in both suspension and vapour mainly due to the ligands different LUMOs and arrangements of carboxylate groups (L. Di, J. J. Zhang, S. Q. Liu, J. Ni, H. Zhou and Y. J. Sun, Cryst. Growth Des., 2016, 16, 4539). This work sheds light on not only understanding of the formation of framework isomers but also the development of MOF-based NAC probes with better performances via judicious selection of suitable ligands.

A One Dimensional 3d–4f Heterometallic Chain Based on Gd3+ Nodes and Tetranuclear {Cr4(hdpta)2} Complex Ligands: Synthesis, Structure and Magnetic Properties

Assembly reaction of 1,3-diamino-2-hydroxy-propane-N,N,N′,N′-tetraacetic acid (H5hdpta), sodium acetate and Cr3+ ion at pH 6.7 in aqueous solution leads to the formation of Na[Cr2(hdpta)(Ac)2] (1). Single crystal X-ray analysis show that 1 bears a 3D (4,4)-connected lon framework based on mononuclear Na+ nodes and dinuclear [Cr2(hdpta)(Ac)2]− complex ligands in which two Cr3+ ions are chelated by one hdpta5− and also bridged by two acetate auxiliary ligands. Further assemble of 1 with Gd3+ ions give rise to [Gd(NO3)3(H2O)4][Cr4Gd(hdpta)2(OH)4(H2O)5]·(NO3)·32H2O (2). The [Cr4Gd(hdpta)2(OH)4(H2O)5]+ cation of 2 exhibit a 1D chain structure based on [Cr4(hdpta)2(OH)4]2− complex ligands and mononuclear Gd3+ nodes. [Cr4(hdpta)2(OH)4]2− has a tetranuclear {Cr4} rectangular metal skeleton. Detailed synthesis experiments indicate heating is a simple and effective way to activate the inert Cr3+ ions to prepare oxygen-bridged Cr–Ln heterometallic compounds. Magnetic studies reveal that compound 2 shows overall antiferromagnetic interaction.Graphical AbstractStepwise synthesis of a Cr–Na compound based on dinuclear {Cr2} unit and a Cr–Gd compound bearing tetranuclear {Cr4} unit are presented.

A Trichromatic and White-Light-Emitting MOF Composite for Multi-Dimensional and Multi-Response Ratiometric Luminescent Sensing

Present here is a new dual ratiometric luminescent probe D which is a trichromatic and white-light-emitting metal-organic framework (MOF) composite facilely obtained by incorporating red/green-emitting complex modules into a blue-emitting MOF. Probe D exhibits remarkable capabilities of sensing different volatile organic solvents (VOSs) via 2D code recognition of the two VOS-dependent MOF ligand-to-module ratios of the emission-peak intensities. For specific VOSs, the resultant luminescent color changes from the starting white color are sharp enough to be visible to the naked eye. Remarkably, D can differentiate solution-phase nitroaromatics and metal ions by recording the evolution of the two ratios during titration processes, enabling an unusual 3D code recognition using the titrant amount as the third dimension for the first time. D also can be used to detect dinoseb, Fe3+ and Al3+ ions quantitatively by analysis of the ratios with detection limits as low as 0.050, 0.41, and 0.12u2005ppm, respectively. Clearly, such a self-referencing trichromatic probe can maximize the output information and significantly enhance the detection selectivity and sensitivity via multi-dimensional sensing, and has great potentials for practical applications.