Discrimination of Various Amine Vapors by a Triemissive Metal-Organic Framework Composite via the Combination of a Three-Dimensional Ratiometric Approach and a Confinement-Induced Enhancement Effect.

Multiemissive sensors are being actively pursued, because of their ratiometric luminescent detection capabilities, which demonstrates better sensitivity and selectivity than conventional single-emission sensors. Herein, we present a trichromatic white-light-emitting metal-organic framework (MOF) composite () by simultaneously incorporating red/green-emitting Pt/Ru complex cations into porous blue-emitting bio-MOF-1 through post-synthetic modification. With the help of a three-dimensional (3-D) dual-ratiometric luminescence recognition method, and unique turn-on responses of the red emission toward amine compounds (ACs), including NH and aliphatic amines, via confinement-induced luminescence enhancement effect, can work as a dual-ratiometric luminescent sensor for discrimination of 7 out of 11 AC vapors.

Effect of Intermolecular Interactions on Metal-to-Metal Charge Transfer: A Combined Experimental and Theoretical Investigation.

Understanding the effects of intermolecular interactions on metal-to-metal charge transfer (MMCT) is crucial to develop molecular devices by grafting MMCT-based molecular arrays. Herein, we report a series of solvent-free {Fe Co } compounds sharing the same cationic tetranuclear {[Fe(PzTp)(CN) ] [Co(dpq) ] } (PzTp =tetrakis(pyrazolyl)borate, dpq=dipyrido[3,2-d:2',3'-f]quinoxaline) square units but having anions with different size, including BF , PF , OTf , and [Fe(PzTp)(CN) ] . Intermolecular π⋅⋅⋅π interactions between dpq ligands, which coordinate to cobalt ions in the {[Fe(PzTp)(CN) ] [Co(dpq) ] } units, can be modulated by introducing different counterions, regulating the distortion of the CoN octahedron and ligand field around the cobalt ions.

Fluorescent Recognition of 4-Amino-2,6-dinitrotoluene by a Cerium-Based Metal-Organic Tetrahedron.

A cerium-based metal-organic tetrahedron has been developed as a highly selective and sensitive fluorescence sensor for the recognition of 4-amino-2,6-dinitrotoluene (4-ADNT). The redox-active tetrahedron could encapsulate 4-ADNT through weak interaction and spatial stereoselectivity, resulting in an enhanced fluorescence. The tetrahedral sensor Ce-ZPS is capable of realizing fluorescent sensing in urine and in cells and thus has the potential to detect 4-ADNT in organisms.

Simultaneous Modulation of Magnetic and Dielectric Transition via Spin-Crossover-Tuned Spin Arrangement and Charge Distribution.

Magnetic and dielectric properties have been tuned simultaneously by external stimuli with rapid and sensitive response, which is crucial to monitor the magnetic state via capacitive measurement. Herein, positive charged Fe ions were linked via negative charged [(Tp)Fe (CN) ] (Tp=hydrotris(pyrazolyl)borate) units to form a neutral chain. The spin-crossover (SCO) on Fe sites could be sensitively triggered via thermal treatment, light irradiation, and pressure.

A trichromatic MOF composite for multidimensional ratiometric luminescent sensing.

Low-cost, high-performance luminescent probes with wide application potential have been actively pursued. Conventional luminescent probes, which rely on single or dual emissions responsive to analyte molecules, demonstrate limited sensitivity and selectivity because the single emissions can be easily affected by many non-analyte factors, while the dual emissions can only offer single-ratiometric luminescent sensing. Here we report a white-light-emitting trichromatic MOF composite () as the first multidimensional ratiometric luminescent probe.

Fluorescence modulation photoinduced spin crossover switched energy transfer from fluorophores to Fe ions.

Molecular materials possessing phototunable fluorescence properties have attracted great interest owing to their potential applications in optical switches and storage. However, most fluorescence modulation is realized through light-responsive structural isomerization in solution. It is a formidable challenge to achieve phototunable fluorescence emission with high fatigue resistance and a fast response rate in the solid state for the development of devices.

Two-dimensional nickel hydroxide/sulfides nanosheet as an efficient cocatalyst for photocatalytic H evolution over CdS nanospheres.

The intriguing features of two-dimensional (2D) materials such as better charge carrier separation and abundant surface reaction sites endow them with potential applications as cocatalysts in photocatalysis. In this paper, a ternary 2D nickel hydroxide/sulfides nanosheet composed of Ni(OH), NiS and NiS was loaded on CdS nanospheres by a simple chemical deposition route. The composition of nickel hydroxide/sulfides was determined clearly through an overall analysis using X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy.

Light-Induced Bidirectional Metal-to-Metal Charge Transfer in a Linear Fe Co Complex.

It is a challenge to reversibly switch both magnetism and polarity using light irradiation. Herein we report a linear Fe Co complex, whereby interconversion between Fe (μ-CN)Co (μ-NC)Fe (LS=low-spin, HS=high-spin) and Fe (μ-CN)Co (μ-NC)Fe linkages could be achieved upon heating and cooling, or alternating laser irradiation at 808 and 532 nm. The electron spin arrangement and charge distribution were simultaneously tuned accompanying bidirectional metal-to-metal charge transfer, providing switchable polarity and magnetism in the complex.

Magnetic fluorescent bifunctional spin-crossover complexes.

The rational design of magnetic and fluorescent bifunctional materials is attracting increasing interest. In this study, two mononuclear Fe(ii) complexes, namely [Fe(L)(NCS)] (1) and [Fe(L)(NCSe)] (2) are synthesised by combining a spin-crossover unit and a fluorescent ligand (naphth-1-yl)-N-(3,5-di(pyridin-2-yl)-4H-1,2,4-triazol-4-yl)methanimine (L) to achieve bifunctionality. Single-crystal X-ray studies and magnetic measurements confirm the presence of spin crossover behaviours; these measurements agree with the results of the temperature depended Raman spectra and infrared spectra.

Single-molecule magnet behavior in three cyano-bridged heterometallic Fe(III)-Ni(II) clusters.

One trinuclear and two tetranuclear cyanide-bridged Fe(III)-Ni(II) complexes were synthesized via treatment of a tricyanometallate with divalent Ni salts in the presence of 1-butylimidazole, 2,2-bipyrimidyl and 1,10-phenanthroline, respectively. Magnetic property studies demonstrated that the three complexes exhibit single-molecule magnet behavior as a result of strong intracluster ferromagnetic coupling and weak intercluster magnetic interactions.

A cyano-bridged tubular coordination polymer with dominant ferromagnetic interactions.

It is a challenge to synthesize a porous tubular coordination polymer with magnetic properties. Utilizing [Fe(II)(bipy)(CN)4](2-) (bipy = 2,2'-bipyridine) as the building block to react with Mn(2+), we successfully synthesized a cyano-bridged tubular coordination polymer with dominant ferromagnetic interactions. The inner surface of the heterometallic tube is hydrophilic, whereas the outer surface is hydrophobic.

Slow magnetic relaxation in a cyano-bridged ferromagnetic {Fe(III)Ni(II)} alternating chain.

A cyano-bridged ferromagnetic {Fe(III)Ni(II)} alternating chain {[Fe(pzTp)(CN)3][Ni(chxn)2]}·ClO4·H2O (1) (pzTp = tetrakis(pyrazolyl)borate, chxn = (1R,2R)-1,2-diaminocyclohexane) was synthesized via rational design. Crystal structure analysis and magnetic studies demonstrated that compound had a one-dimensional zigzagging chain-like structure and slow magnetic relaxation.

New 3d-4f heterometallic clusters built from mixed glycine and iminodiacetate acid: dioctahedron {La2Ni9} and onion-like {Gd5}⊂{Ni12} with interesting magnetocaloric effect.

The preparation, structures and properties of 3d-4f compounds, undecanuclear [La2Ni9(Gly)12(IDA)3(μ3-OH)3][La(H2O)9][Na3(H2O)7(ClO4)3](ClO4)6·5H2O (1) and isostructural heptadecanuclear [Ln5Ni12(Gly)12(IDA)6(μ3-OH)9(H2O)3](ClO4)6·11H2O (Ln = Gd (2); Nd (3); Sm (4); Tb (5); Dy (6); Y (7)) based on mixed glycine (HGly) and iminodiacetate acid (H2IDA) ligands were described. The structure of the [La2Ni9(μ3-OH)3(IDA)3(Gly)12](3+) cationic cluster in 1 can be described as a face-shared and La-centered dioctahedron. However, the [Ln5Ni12(Gly)12(IDA)6(μ3-OH)9(H2O)3](6+) cationic clusters in 2-7 bear an onion-like {Ln5}⊂{Ni12} structure, where the trigonal bipyramid {Ln5} core is encapsulated by the outer triangular orthobicupola {Ni12} shell.

Two one-dimensional compounds based on pyramidal {TbCu4} units and formate ligand: chair-like [(H2O)2(ClO4)2]2- clusters and slow relaxation of magnetization.

With formate as ligand, two 1-D 3d-4f compounds (linear and zigzag) based on pyramidal {TbCu(4)} unit were obtained. Chair-like [(H(2)O)(2)(ClO(4))(2)](2-) clusters and μ(5)-η(1):η(4) bridging mode of formate were observed in the linear one which also displays slow relaxation of the magnetization.

A spin-crossover cluster of iron(II) exhibiting a mixed-spin structure and synergy between spin transition and magnetic interaction.

How low can you go? An Fe(II) (4) square was prepared by self-assembly and exhibits both thermally induced and photoinduced spin crossover from a system with four high-spin (HS) centers to one with two high-spin and two low-spin (LS) centers. The spin-crossover sites are located on the same side of the square, and the spin transition and magnetic interactions (see picture) are synergistically coupled.

Ligand-to-metal ratio controlled assembly of nanoporous metal-organic frameworks.

Two bilayered metal-organic frameworks with nanoporous channels were synthesized at different ligand-to-metal ratios, which demonstrated an interesting crystal-to-crystal transformation property and a special fluorescent response to the different guest molecules included.

Thiourea-based molecular clips for fluorescent discrimination of isomeric dicarboxylates.

A new clip-like receptor, which comprises two thiourea-based binding groups and two naphthalene units, has been designed and synthesized as a fluorescent chemosensor for distinguishing o-phthalate from two other isomers of dicarboxylates. Upon the addition of these three ions, the emission intensity at 420 nm (excitation at 340 nm) decreases drastically through PET. When excited at 380 nm, a new emission band at 460 nm appears and develops gradually upon the addition of the o-phthalate ion and the fluorescent intensity increases markedly over time, but the presence of m-phthalate or p-phthalate do not cause this kind of change.

Metal complexes formed by metal-assisted solvolysis of di-pyridylketone azine: structures and magnetic properties.

A series of metal complexes were achieved from the metal-assisted solvolysis reaction of di-pyridylketone azine (dpka). The tetranuclear nickel cluster , [Ni(2)[dpk(O)(OH)][dpk(O)(OCH(3))](N(3))(2)](2), is centrosymmetric with a central core described as an edge-shared triangle core. Neighboring Ni(II) ions are alternately bridged by (micro(2)-N(3), micro(3)-O) and (micro(2)-O, micro(3)-O) double bridges.

Chromium(III) complexes of D-glucosaminic acid and their effect on decreasing blood sugar in vivo.

Two chromium(III) complexes of glucosaminic acid were synthesized by neutralization and exchange reaction. The formation of 1 : 1 and 2 : 3 (Cr : glucosaminate) complexes was confirmed by elemental analyses and spectroscopic studies. The effect of the complexes on decreasing blood sugar was investigated on type-2 diabetes model rats induced by tetraoxypyrimidine.

A highly selective chromo- and fluorogenic dual responding fluoride sensor: naked-eye detection of F- ion in natural water via a test paper.

A highly selective and sensitive chromogenic and fluorogenic dual signal responding fluoride-sensor 1, comprising a Ru-bipy fluorophore (bipy = 2,2'-bipyridine) and a 2,4-dinitrophenylhydrazone chromophore was prepared and spectroscopically characterized. Uv-vis titrations with F- revealed the appearance of a new intense absorption band centered at about 580 nm which was accompanied by a dramatic change in color from yellow to magenta, with the association constant logK being 6.71 +/- 0.

Quinoline-based molecular clips for selective fluorescent detection of Zn2+.

New selective Zn2+ fluorescent sensors, di(2-quinoline-carbaldehyde)-2,2'-bibenzoyl-hydrazone (QB1) and di(2-quinolinecarbaldehyde)-6,6'-dicarboxylic acid hydrazone-2,2'-bipyridine (QB2), have been designed and prepared. Both QB sensors exhibit an emission band centered at 405 nm (excitation at 350 nm) with low quantum yield. Zinc binding not only red-shifts the emission band to 500 nm, but also enhances the fluorescence intensity by an order of magnitude based on the deprotonization strategy via self-assembly.

Porous material for absorption and luminescent detection of aromatic molecules in water.

A two-dimensional porous framework, which was formed from neutral discrete hexanuclear copper clusters via self-assembly, exhibited highly selective absorption of aromatic molecules in water with special fluorescent response.

Host-guest complexation of a fluorescent and electrochemical chemsensor for fluoride anion.

Host-guest complexation of a ferrocenenylphalene dyad 1, 1,1'-diaceylferrocenyl-3-hydroxyl-2-naphthoylhydrazone, as a fluorescent and electrochemical chemosensor for fluoride anion, was investigated. Crystal structure analysis revealed that the two naphthyl arms of compound 1 positioned in the same side about the ferrocene moiety and interacted through pi-pi stacking interactions. The intermolecular pi-pi stacking interactions and the C-H.