Building Feedback-Regulation System Through Atomic Design for Highly Active SO2 Sensing.

Reasonably constructing an atomic interface is pronouncedly essential for surface-related gas-sensing reaction. Herein, we present an ingenious feedback-regulation system by changing the interactional mode between single Pt atoms and adjacent S species for high-efficiency SO2 sensing. We found that the single Pt sites on the MoS2 surface can induce easier volatilization of adjacent S species to activate the whole inert S plane. Reversely, the activated S species can provide a feedback role in tailoring the antibonding-orbital electronic occupancy state of Pt atoms, thus creating a combined system involving S vacancy-assisted single Pt sites (Pt-Vs) to synergistically improve the adsorption ability of SO2 gas molecules. Furthermore, in situ Raman, ex situ X-ray photoelectron spectroscopy testing and density functional theory analysis demonstrate the intact feedback-regulation system can expand the electron transfer path from single Pt sites to whole Pt-MoS2 supports in SO2 gas atmosphere. Equipped with wireless-sensing modules, the final Pt1-MoS2-def sensors array can further realize real-time monitoring of SO2 levels and cloud-data storage for plant growth. Such a fundamental understanding of the intrinsic link between atomic interface and sensing mechanism is thus expected to broaden the rational design of highly effective gas sensors.

Boosting Solid-State Luminescence of Thiazolothiazole Viologen by Incorporating Metal Halide Clusters to Hinder π-Stacking.

A new strategy is developed herein to improve the solid fluorescence of thiazolothiazole viologen by using the ZnCl42- cluster as a scaffold to hinder π-stacking. Importantly, the Cl···H bonds are formed in the solid state to sustain the framework and can be automatically dissociated when dissolved in H2O, thus having no impact on the strong emission in aqueous solution. As such, the first case of organic-inorganic viologen-zinc halide named 4PV·ZnCl4 was designed and synthesized, and a significant increase in photoluminescence quantum yield (ΦF) is realized from 4PV·2Br (ΦF = 0%) to 4PV·ZnCl4 (ΦF = 27.0%) in solid and from 97% to 98% in H2O. 4PV·ZnCl4 also displays pH stimuli-responsive naked-eye chromic behavior and photoluminescence with different coloring states and intensities. The multifunctional performance of 4PV·ZnCl4 provides a prerequisite for carrying different information, expanding their promising application in multilevel information encryption.

Efficient Synthesis of Yellow-Green Carbon Quantum Dots as a Sensitive Fluorescent Probe of Folic Acid.

Bright yellow-green carbon quantum dots (YGCDs) have been successfully synthesized by a simple and efficient hydrothermal method. Their luminescent absolute quantum yield reached 30.0% in 4 h. Compared with commonly reported solvothermal methods, the synthesis time was reduced by more than 70% by using tin oxide nanoparticles as a catalyst. Moreover, the fluorescence of YGCDs could be selectively quenched by folic acid (FA) molecules, and the relative fluorescence intensities of F/F0 was fitted perfectly in line decay curve versus the concentration of FA in the range of 2.0×10-8  mol/l to 1.0×10-5  mol/l (R2 =0.9988). The detection limit of FA was below 2.0×10-8  mol/l, suggesting a promising fluorescent probe of folic acid.

5,5'-(p-Phenyl-ene)di-1H-tetra-zole.

Crystals of the title organic compound, C(8)H(6)N(8), were generated in situ through the [2 + 3]-cyclo-addition reaction involving the precursor 1,4-dicyano-benzene and azide in water with Zn(2+) as Lewis acid. The asymmetric unit consists of one half-mol-ecule, and a twofold axis of symmetry passes through the centre of the benzene ring. There is an inter-molecular N-H⋯N hydrogen bond. The mol-ecules are assembled into a three-dimensional supra-molecular framework by π-π stacking inter-actions, with a perpendicular distance of 3.256 Š[centroid-centroid = 3.9731 (8) Å] between two tetra-zole ring planes, and 3.382 Šbetween the benz-ene ring and tetra-zole ring planes [centroid-centroid = 3.5010 (9) Å].

Synthesis and luminescence of a novel conjugated europium complex with 6-aniline carbonyl 2-pyridine carboxylic acid.

A novel organic ligand, 6-aniline carbonyl 2-pyridine carboxylic acid (HAP), and the corresponding europium complex, tris(6-aniline carbonyl 2-pyridine carboxylato) europium (III) (Eu-AP) have been designed and synthesized. The results showed that Eu-AP was a conjugated complex, emitting strong red luminescence. The lifetimes of (5)D(0) of Eu(3+) in the complex were examined using time-resolved spectroscopic analysis, and the lifetime value was 0.55 +/- 0.01 ms for solid Eu(AP)(3). Thermogravimetric analysis showed that the europium complex had good thermal stability.