A highly sensitive and selective fluorescent sensor for detection of Al(3+) using a europium(III) quinolinecarboxylate.

Eu2PQC6 has been developed to detect Al(3+) by monitoring the quenching of the europium-based emission, with the lowest detection limit of ∼32 pM and the quantitative detection range to 150 µM. Eu2PQC6 is the first ever example that the europium(III) complex serves as an Al(3+) fluorescent sensor based on "competition-displacement" mode.

Three-Dimensional Printing of Yttrium Oxide Transparent Ceramics via Direct Ink Writing.

The utilization of 3D printing technology for the fabrication of intricate transparent ceramics overcomes the limitations associated with conventional molding processes, thereby presenting a highly promising solution. In this study, we employed direct ink writing (DIW) to prepare yttrium oxide transparent ceramics using a ceramic slurry with excellent moldability, solid content of 45 vol%, and shear-thinning behavior. A successfully printed transparent yttrium oxide ring measuring 30 mm in diameter, 10 mm in inner diameter, and 0.9 mm in thickness was obtained from the aforementioned slurry. After de-binding and sintering procedures, the printed ceramic exhibited in-line transmittance of 71% at 850 nm. This work not only produced complex yttria transparent ceramics with intricate shapes, but also achieved in-line transmittance that was comparable to that of the CIP method (79%), which can meet certain optical applications.

A series of octanuclear-nickel(II) complexes supported by thiacalix[4]arenes.

A series of discrete complexes, [Ni(8)(BTC4A)(2)(µ(6)-CO(3))(2)(µ-CH(3)COO)(4)(dma)(4)]·H(2)O (1), [Ni(8)(BTC4A)(2)(µ(6)-CO(3))(2)(µ-Cl)(2)(µ-HCOO)(2)(dma)(4)]·2DMF·2CH(3)CN (2), [Ni(8)(PTC4A)(2) (µ(6)-CO(3))(2)(µ-CH(3)COO)(4)(dma)(4)]·DMF (3), and [Ni(8)(PTC4A)(2)(µ(6)-CO(3))(2)(µ-OH)(µ-HCOO)(3) (dma)(4)] (4) (p-tert-butylthiacalix[4]arene = H(4)BTC4A, p-phenylthiacalix[4]arene = H(4)PTC4A, dma = dimethylamine, and DMF = N,N'-dimethylformamide), have been prepared under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses, powder XRD, and IR spectroscopy. These four complexes are stacked by dumbbell-like building blocks with one chairlike octanuclear-nickel(II) core, which is capped by two thiacalix[4]arene molecules and connected by two in situ generated carbonato anions and different auxiliary anions. This work implied that not only the solvent molecules but also the upper-rim groups of thiacalix[4]arenes have significant effects on the self-assembly of the dumbbell-like building blocks. The magnetic properties of complexes 1-4 were examined, indicating strong antiferromagnetic interactions between the nickel(II) ions in the temperature range of 50-300 K.

Self-assembly of discrete M6L8 coordination cages based on a conformationally flexible tripodal phosphoric triamide ligand.

Reactions of a tripodal ligand, N,N',N″-tris(3-pyridinyl)phosphoric triamide (TPPA), and a series of transition-metal ions result in the assembly of five discrete M(6)L(8) coordination cages [M(6)(TPPA)(8)(H(2)O)(12)](ClO(4))(12)·57H(2)O [M = Ni(2+) (1), Co(2+) (2), Zn(2+) (3), Cd(2+) (4)] and [Pd(6)(TPPA)(8)]Cl(12)·22H(2)O (5). X-ray structural analyses reveal that the cages have large internal cavities and flexible windows. The flexible ligand TPPA adopts the syn conformation in cages 1-4, but it transforms to the anti conformation in cage 5. Because of the conformational transformation, the sizes of the windows and the volume of the internal cavity of cage 5 are increased. (1)H NMR and electrospray mass spectrometric studies show that cage 5 maintains its structural integrity in solution. Additionally, compounds 3 and 4 exhibit strong blue fluorescent emissions, which are 1 order of magnitude higher than that of the free ligand.

Nanoassembled capsules as delivery vehicles for large payloads of high relaxivity Gd3+ agents.

Nanoassembled capsules (NACs) that incorporate a polymer aggregate inside a silica shell may be loaded with agents that are of particular interest for therapeutic or diagnostic applications. NACs formed using the MRI contrast agent GdDOTP(5-) in the internal polymer aggregate are reported herein, the smaller of which show promise as potential MRI contrast agents. Unlike many other nanoencapsulated systems, water access to the inner core of these NACs does not appear to be limited and consequently the water relaxivity per Gd(3+) agent can reach as high as 24 mM(-1) s(-1). Robust, spherical capsules were formed using polyallylamine or poly-L-lysine ranging from 0.2 to 5 microm in diameter. The greatest gains in relaxivity were observed for smaller NACs, for which water accessibility remained high but molecular rotation of the Gd(3+) chelate was effectively restricted. Larger NACs did not afford such large gains in relaxivity, the result of poorer water accessibility combined with less-effective rotational restriction.

Polymeric PARACEST agents for enhancing MRI contrast sensitivity.

Linear polymers of PARACEST agents were prepared by using classical free radical chain polymerization conditions. The Eu3+-polymers exhibited similar intermediate-to-slow water exchange and CEST characteristics as the Eu3+-monomers. This provided an avenue to lower the detection limit of these imaging agents substantially and makes them potentially useful as MRI sensors for molecular imaging.

Lanthanide-transition metal coordination polymers based on multiple N- and O-donor ligands.

Lanthanide-transition metal (Ln-M) coordination polymers have attracted extensive interest because they exhibit novel physical properties originating from the interactions between distinct metal ions. This review mainly describes our recent work in the design of Ln-M coordination polymers through the assembly of different metal ions and organic ligands, especially the ligands with multiple N- and O-donor atoms. Many of these crystalline Ln-M materials exhibit intriguing structural motifs and interesting magnetic properties.

Highly graphitized nitrogen-doped porous carbon nanopolyhedra derived from ZIF-8 nanocrystals as efficient electrocatalysts for oxygen reduction reactions.

Nitrogen-doped graphitic porous carbons (NGPCs) have been synthesized by using a zeolite-type nanoscale metal-organic framework (NMOF) as a self-sacrificing template, which simultaneously acts as both the carbon and nitrogen sources in a facile carbonization process. The NGPCs not only retain the nanopolyhedral morphology of the parent NMOF, but also possess rich nitrogen, high surface area and hierarchical porosity with well-conducting networks. The promising potential of NGPCs as metal-free electrocatalysts for oxygen reduction reactions (ORR) in fuel cells is demonstrated. Compared with commercial Pt/C, the optimized NGPC-1000-10 (carbonized at 1000 °C for 10 h) catalyst exhibits comparable electrocatalytic activity via an efficient four-electron-dominant ORR process coupled with superior methanol tolerance as well as cycling stability in alkaline media. Furthermore, the controlled experiments reveal that the optimum activity of NGPC-1000-10 can be attributed to the synergetic contributions of the abundant active sites with high graphitic-N portion, high surface area and porosity, and the high degree of graphitization. Our findings suggest that solely MOF-derived heteroatom-doped carbon materials can be a promising alternative for Pt-based catalysts in fuel cells.

Three novel organic-inorganic complexes based on decavanadate [V10O28]6- units: special water layers, open 3D frameworks and yellow/blue luminescences.

Three unusual polyoxovanadate-based inorganic-organic hybrid complexes, [Zn(Im)(2)(DMF)(2)](2)[H(2)V(10)O(28)]·Im·DMF (1), [Zn(3)(Htrz)(6)(H(2)O)(6)][V(10)O(28)]·10H(2)O·Htrz (2) and {[Zn(3)(trz)(3)(H(2)O)(4)(DMF)](2)[V(10)O(28)]·4H(2)O}(n) (3) (Im = imidazole, Htrz = 1,2,4-triazole, DMF = N,N'-dimethylammonium) have been synthesized at room temperature via evaporative crystallization, and characterized by single-crystal X-ray diffraction. Complex 1 shows the structure of a discrete [V(10)O(28)](6-) cluster grafted by two [Zn(Im)(2)(DMF)(2)](2+) fragments through two bridged oxygen atoms, representing a rarely observed coordination mode. Complex 2 consists of a linear trinuclear Zn(II) unit bridging six Htrz ligands and a [V(10)O(28)](6-) cluster as the counter anion, where the extensive hydrogen-bonding interactions lead to {Zn(3)-V(10)}(SMF) and a special water layer involving (H(2)O)(36) rings, and consequently forms a unique 3D metal-organic-water supramolecular network. Complex 3 can be described as a 3,4-connected fsc-type network, and is the first example of open coordination 3D framework based on [V(10)O(28)](6-) and the other two different secondary building units, involving mononuclear and binuclear Zn(II)-Htrz motifs. The optical properties of complexes 1-3 in the solid state are investigated at room temperature. The results show that complexes 1 and 3 emit intense blue luminescences attributed to the ligands, while complex 2 exhibits an infrequent fluorescent property, emitting both blue and yellow luminescences at 472 and 603 nm simultaneously. Furthermore, powder X-ray diffraction and thermogravimetric analyses of 1-3 are also investigated, which demonstrate their high purities and thermal stabilities.

A basket tetradecavanadate cluster with blue luminescence.

A blue luminescent tetradecavanadate compound, [Et4N]5[V14O36Cl], has been synthesized. It possesses an unprecedented half-open basket framework. Through the {ABAB}-type stacking, the {V14O36} clusters form infinite one-dimensional channels with considerable accessible volume in the crystalline state.

A novel bilayer cobalt(II)-organic framework with nanoscale channels accommodating large organic molecules.

A unique noninterpenetrated 2D bilayer cobalt(II)-organic framework, [[Co(dpe)(NO(2)-BDC)].0.5(dpe)](n).nH(2)O (1), possessing nanoscale rectangular channels that clathrate large organic molecules, has been hydrothermally synthesized by reaction of cobalt(II) salt with 5-nitro-1,3-benzenedicarboxylic acid (NO(2)-H(2)BDC) and 1,2-bis(4-pyridyl)ethylene (dpe).