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Semiconductor-based photocatalysts have received extensive attention for their promising capacity in confronting global energy and environmental issues. In photocatalysis, a large band gap with suitable edge-position is necessary to warrant enough driving force for reaction, whereas a much smaller band gap is needed for visible-light response and high solar energy conversion efficiency. This paradox hinders the development of photocatalysts. Via state-of-the-art first-principles calculations, we find that the transition dipole moments (TDMs) are changed significantly in O-doped partly polymerized g-C3N4, i.e., OH-terminated polymeric heptazine imide (PHI-OH), and concomitantly, an enhancement of visible-light absorption is achieved; meanwhile a large enough band gap can provide a powerful driving force in the photocatalytic watersplitting reaction. Furthermore, by using TDM analysis of the PHI-OH/BC3N heterostructure, direct light excited transition between two building layers can be confirmed, suggesting it as a candidate catalyst for hydrogen evolution. From TDM analysis of the PHI-OH/BCN heterostructure, we also verify a Z-scheme process, which involves simultaneous photoexcitations with strong reducibility and oxidizability. Thus, TDM could be a good referential descriptor for revealing photocatalytic mechanisms in semiconductor photocatalysts and interlayer photoexcitation behavior in layered heterostructures. Hopefully, more strategies via modification of TDMs would be proposed to enhance the visible-light response of a semiconductor without sacrificing its photocatalytic driving force. [ABSTRACT FROM AUTHOR]

Organic metal complexes as a type of hybrid materials have been used for gene delivery. In the present study, a metal organic complex of zoledronate–calcium (CaZol) was prepared for transporting pDNA. Then, the effects of different molar ratios of Ca2+ to Zol (Ca/Zol) on the formulation characteristics were investigated. The results showed that the CaZol/pDNA complexes generated small particles and efficiently encapsulated pDNA when the Ca/Zol ratio was 30. In addition, CaZol complexes could protect pDNA from being degraded by the serum protein since pH-sensitive CaZol exhibited high stability in the physiological environment (pH 7.4), whereas the encapsulated pDNA could be released in a weakly acidic environment (pH 5.5). Moreover, the complex had better cellular uptake efficiency and desired gene expression efficiency in vitro and in vivo. Overall, these results indicated that CaZol, as a potential nanocarrier, was suitable for pDNA delivery. [ABSTRACT FROM AUTHOR]

Since the turn of the new century, the increasing demand for high-performance energy storage systems has generated considerable interest in rechargeable ion batteries (IBs). However, current IB technologies are not entirely satisfactory, especially the electrodes. We report here, via density functional theory calculations and first principles molecular dynamics simulations, that a borophene anode material has the fascinating properties of ultrahigh energy storage and ultrafast ion diffusion in metal (Li, Na, K, Mg, Al) IBs. Particularly for Li IBs with a borophene anode, a specific density of 3306 mA h g−1 and a high charging voltage of 1.46 V can be maintained at room temperature. Furthermore, non-ideal borophene anodes, including those with defects or oxidation and nanoribbon samples, still possess good properties for practical applications. This theoretical exploration will provide helpful guidance in searching for available or novel boron nanosheets as promising anode materials to advance commercial IB technology. [ABSTRACT FROM AUTHOR]

Three rigid, linear ligands, namely 2′,5′-dimethyl-[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylic acid (H2L1), triphenyl-6,6′-dicarboxylic acid (H2L2), and 2,2′-bipyridine-5,5′-dicarboxylic acid (H2L3), were used for constructing metal–organic frameworks (MOFs) with Pb(ii). With a similar nature of solvent conditions (DMF/EtOH, with different volumes' rates), four structurally diverse MOFs, namely, [Pb(L1)(DMF)] 1, [Pb(L1)(DMF)] 2, [Pb(L2)] 3, and [Pb3(L3)2(Cl−)2] 4, were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, and powder X-ray diffraction measurements. As the numbers of the central benzene ring contained in the ligands changed from three to two, the length of the ligands varied from 15.64 Å to 10.89 Å, and steric functional groups endowed the three ligands with more variations, such as a 1D zigzag chain of 1, a 2D wave-like layer of 2, a 3D Pb–O–C-based layer of 3, and a 3D Pb–O–Cl-based chain of 4. Solid-state photoluminescence studies were carried out for all the complexes at room temperature. [ABSTRACT FROM AUTHOR]

A 3D non-interpenetrating porous metal–organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER). [ABSTRACT FROM AUTHOR]

Quantitative determination of the density and conformation of DNA molecules tethered to the surface can help optimize and understand DNA nanosensors and nanodevices, which use conformational or motional changes of surface-immobilized DNA for detection or actuation. We present an interferometric sensing platform that combines (i) dual-color fluorescence spectroscopy for precise axial co-localization of two fluorophores attached at different nucleotides of surface-immobilized DNA molecules and (ii) independent label-free quantification of biomolecule surface density at the same site. Using this platform, we examined the conformation of DNA molecules immobilized on a three-dimensional polymeric surface and demonstrated simultaneous detection of DNA conformational change and binding in real-time. These results demonstrate that independent quantification of both surface density and molecular nanoscale conformation constitutes a versatile approach for nanoscale solid-biochemical interface investigations and molecular binding assays. [ABSTRACT FROM AUTHOR]

A 3D non-interpenetrating porous metal-organic framework [Pb2(H2TCPP)]·4DMF·H2O (Pb-TCPP) (H6TCPP = 5,10,15,20-tetra(carboxyphenyl)porphyrin) was synthesized by employment of a robust porphyrin ligand. Pb-TCPP exhibits a one-dimensional channel possessing fairly good capability of gas sorption for N2, H2, Ar, and CO2 gases, and also features selectivity for CO2 over CH4 at 298 K. Furthermore, Pb-TCPP shows electrocatalytic activity for water oxidation in alkaline solution. It is the first 3D porous Pb-MOF that exhibits both gas adsorption properties and electrocatalytic activity for an oxygen evolution reaction (OER).