1.Homolytic Cleavage of B-B Bond by the Cooperative Catalysis of Two Lewis Bases: Computational Design and Experimental Verification.
Wang G1, Zhang H2, Zhao J1, Li W1, Cao J1, Zhu C3, Li S4. Angew Chem Int Ed Engl. 2016 Apr 8. doi: 10.1002/anie.201511917. [Epub ahead of print]
Density functional theory (DFT) investigations revealed that 4-cyanopyridine was capable of homolytically cleaving the B-B σ bond of diborane via the cooperative coordination to the two boron atoms of the diborane to generate pyridine boryl radicals. Our experimental verification provides supportive evidence for this new B-B activation mode. With this novel activation strategy, we have experimentally realized the catalytic reduction of azo-compounds to hydrazine derivatives, deoxygenation of sulfoxides to sulfides, and reduction of quinones with B2 (pin)2 at mild conditions.
2.A one-step synthesis of water-soluble MoS2 quantum dots via hydrothermal method as fluorescent probe for hyaluronidase detection.
Gu W, Yan Y, Zhang C, Ding C, Xian Y. ACS Appl Mater Interfaces. 2016 Apr 15. [Epub ahead of print]
In this work, a bottom-up strategy is developed to synthesize water-soluble molybdenum disulfide quantum dots (MoS2 QDs) through a simple, one-step hydrothermal method using ammonium tetrathiomolybdate ((NH4)2MoS4) as precursor and hydrazine hydrate as the reducing agent. The as-synthesized MoS2 QDs are few-layered with a narrow size-distribution, and the average diameter is about 2.8 nm. The resultant QDs show excitation-dependent blue fluorescence due to the polydispersity of QDs. Moreover, the fluorescence can be quenched by hyaluronic acid (HA) functionalized gold nanoparticles (AuNPs) through a photoinduced electron transfer mechanism. Hyaluronidase (HAase), an endoglucosidases, can cleave HA into proangiogenic fragments and lead to the aggregation of gold nanoparticles. As a result, the electron transfer is blocked and fluorescence is recovered. Based on this principle, a novel fluorescence sensor for HAase is developed with a linear ranging from 1 to 50 U/mL and a detection limit of 0.
3.Influence of the 5f Orbitals on the Bonding and Reactivity in Organoactinides: Experimental and Computational Studies on a Uranium Metallacyclopropene.
Zhang L1, Hou G1, Zi G1, Ding W1, Walter MD2. J Am Chem Soc. 2016 Apr 12. [Epub ahead of print]
The synthesis, structure, and reactivity of a uranium metallacyclopropene were comprehensively studied. Reduction of (η5-C5Me5)2UCl2 (1) with potassium graphite (KC8) in the presence of bis(trimethylsilyl)acetylene (Me3SiC≡CSiMe3) allows the first stable uranium metallacyclopropene (η5-C5Me5)2U[η2-C2(SiMe3)2] (2) to be isolated. Magnetic susceptibility data confirm that 2 is a U(IV) complex, and density functional theory (DFT) studies indicate substantial 5f orbital contributions to the bonding of the metallacyclopropene U-(η2-C═C) moiety, leading to more covalent bonds between the (η5-C5Me5)2U2+ and [η2-C2(SiMe3)2]2- fragments than those in the related Th(IV) compound. Consequently, very different reactivity patterns emerge, e.g., 2 can act as a source for the (η5-C5Me5)2U(II) fragment when reacted with alkynes and a variety of heterounsaturated molecules such as imines, bipy, carbodiimide, organic azides, hydrazine, and azo derivatives.
4.Tuning the field distribution and fabrication of an Al@ZnO core-shell nanostructure for a SPR-based fiber optic phenyl hydrazine sensor.
Tabassum R1, Kaur P, Gupta BD. Nanotechnology. 2016 Apr 15;27(21):215501. [Epub ahead of print]
We report the fabrication and characterization of a surface plasmon resonance (SPR)-based fiber optic sensor that uses coatings of silver and aluminum (Al)-zinc oxide (ZnO) core-shell nanostructure (Al@ZnO) for the detection of phenyl hydrazine (Ph-Hyd). To optimize the volume fraction (f) of Al in ZnO and the thickness of the core-shell nanostructure layer (d), the electric field intensity along the normal to the multilayer system is simulated using the two-dimensional multilayer matrix method. The Al@ZnO core-shell nanostructure is prepared using the laser ablation technique. Various probes are fabricated with different values of f and an optimized thickness of core-shell nanostructure for the characterization of the Ph-Hyd sensor. The performance of the Ph-Hyd sensor is evaluated in terms of sensitivity. It is found that the Ag/Al@ZnO nanostructure core-shell-coated SPR probe with f = 0.25 and d = 0.040 μm possesses the maximum sensitivity towards Ph-Hyd.