Yue-Hua Li

Photoluminescence, electrochemical behavior and photocatalytic activities of cobalt(II) coordination polymer nanostructures synthesized by sonochemical process

Nanostructures of a new Co(II) coordination polymer (CP), [Co(Hbibp)(nbta)]n (1), (bibp=4,4-bis(1-imidazolyl)biphenyl, H3nbta=5-nitro-1,2,3-benzenetricarboxylic acid) was synthesized by a sonochemical method. The nano-sized CP 1 was characterized by elemental analysis, IR spectroscopy, X-ray powder diffraction and scanning electron microscopy (SEM). Structural analysis show that CP 1 exhibits a 1D chain structure with a 3-connected SP 1-periodic net (4,4)(0,2) topology, which can be further extended into a 2D supramolecular layer by the NH⋯O hydrogen bond interactions. The thermal stability for CP 1 as bulk and nanoparticles were investigated. The photoluminescence properties and electrochemical behavior for nano-sized CP 1 have also been explored. Moreover, nano-sized CP 1 shows high photocatalytic activities for the degradation of MB under UV irradiation and the photodegradation process is mainly caused by OH radicals. Effects of the sonication time and ultrasonic power on the morphology and size of nanoparticles were studied.

Sonochemical synthesis and properties of two new nanostructured silver(I) coordination polymers

Two new Ag(I) coordination polymers (CPs), namely, Ag(L)(Htp) (1) and [Ag(L)]·(Htp)·2H2O (2) were synthesized from the long flexible ligand of 1,6-bis(2-methylbenzimidazolyl)hexane (L), terephthalic acid (H2tp) and different silver(I) salts using hydrothermal and sonochemical methods, These CPs were characterized by elemental analysis, IR spectra, scanning electron microscopy, single-crystal and powder X-ray diffraction analysis. 1 features a uninodal 3-connected 2D hcb layered structure, while 2 exhibits an infinite 1D linear chain and ultimately extended into 3D supramolecular framework via O-H⋯O and Ag⋯O interactions. In addition, the effect of various sonication concentrations of the initial reagents, ultrasonic time and power of ultrasound irradiation on the size and morphology of nanostructured 1 and 2 were evaluated. Nano-sized 1 and 2 exhibit relatively high performance as UV light driven photocatalysts for the degradation of methylene blue.

Synthesis, structures and characterization of two cobalt(II) coordination polymers with 2,5-dichloroterephthalic acid and flexible bis(benzimidazole) ligands

Two Co(II) coordination polymers (CPs), namely [Co(L1)(DCTP)]n (1) and [Co(L2)(DCTP)]n (2) [L1u2009=u20091,4-bis(5,6-dimethylbenzimidazol-1-yl)butane, L2u2009=u20091,5-bis(5,6-dimethylbenzimidazol-1-yl)pentane, H2DCTPu2009=u20092,5-dichloroterephthalic acid] were synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, powder X-ray diffraction (PXRD) and infrared spectroscopy. CP 1 has a 2D (4,4) corrugated sheet structure, which is further extended into a 2D double layer by C–H···O weak hydrogen bonding interactions, while CP 2 displays a 2D layer with hcb network, which is assembled into a 3D supramolecular framework through C–H···O hydrogen bonding. Both CPs exhibited promising photocatalytic activities for the degradation of methylene blue under UV irradiation. In addition, the thermal stabilities and the luminescence properties of both CPs have been investigated.

Two 3D Supramolecular Architectures Based on Cobalt(II) Coordination Polymers with Dichloroterephthalate and Semi-rigid Bis(benzimidazole) Ligands

Two Co(II) coordination polymers (CPs) [Co(DCTP)(L1)]n (1) and [Co(DCTP)(L2)·(H2O)2]n (2), were synthesized from hydrothermal reaction of Co2+ ions with the 2,5-dichloroterephthalic acid (H2DCTP) and two semi-rigid bis(benzimidazole) ligands (L1u2009=u20091,3-bis(benzimidazol-1-ylmethyl)benzene, L2u2009=u20091,2-bis(benzimidazol-1-ylmethyl)benzene), and structurally characterized by X-ray single crystal diffraction analysis and FT–IR. The thermal stabilities and luminescence properties of 1–2 were investigated. The two CPs exhibit 2D (4,4)-connected layer structures, which are further extended to 3D supramolecular architectures by π⋯π stacking interactions for 1 and classical O–H⋯O hydrogen-bonding interactions for 2, respectively. In addition, two complexes show promising photocatalytic activities for the degradation of methylene blue under UV irradiation.

Two luminescent cobalt(II) coordination polymers for selective sensing of MnO4− in water

Two luminescent Co(II)-based coordination polymers (CPs) with the formulae of [Co(L1)(1,4-ndc)·H2O]n (CP 1) and [Co2(L2)(1,4-chdc)2]n (CP 2) (L1u2009=u20091,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), 1,4-H2ndcu2009=u20091,4-naphthalenedicarboxylic acid, L2u2009=u20091,1′-(1,4-butanediyl)bis(2-methylbenzimidazole), 1,4-H2chdcu2009=u20091,4-cyclohexanedioic acid) have been synthesized. Both CPs were characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, IR spectroscopy, and powder X-ray diffraction. CP 1 reveals a 2D 3,5L2 framework, while CP 2 has a 2D (4,5)-connected 4,5L51 network. Both CPs are luminescent and can be employed for the selective detection of free MnO4− in water.

Synthesis, Crystal Structure, Luminescence Sensing, and Photocatalytic Properties of a 2D Cobalt(II) Coordination Polymer Containing Bis(benzimidazole) Moieties

A new cobalt(II) coordination polymer, namely [Co(L)(Ndc)]n (I), where L = 1,5-bis(5,6- dimethylbenzimidazole)pentane, H2Ndc = 2,6-naphthalenedicarboxylic acid, was synthesized and characterized by elemental analysis, IR spectra, powder X-ray diffraction and single-crystal X-ray diffraction (CIF file CCDC no. 1548044). Complex I displays a 2D (4,4) layer which further extended into a 3D supramolecular framework via weak C–H···O hydrogen bondings. The luminescence explorations demonstrated that I exhibits highly selective and sensitive sensing for Cr2O72− with high quenching efficiency Ksv value of 9.87 × 103 L mol−1 and low detection limit (0.24 μM (S/N = 3)). Meanwhile I also exhibits highly selective and sensitive sensing for Fe3+ with quenching efficiency Ksv = 3.6 × 104 L mol–1 and low detection limit (0.32 μM (S/N = 3)). Complex I exhibits higher photocatalytic activities for the degradation of methylene blue under UV irradiation. Additionally, the thermal behavior and electrochemical properties of the compound are also presented.