Polarization engineering in porous organic polymers for charge separation efficiency and its applications in photocatalytic aerobic oxidations

Photocatalytic aerobic oxidation reactions are largely governed by the efficiency of charge separation and subsequent reactive oxygen species(ROS) generation. Herein, we report a polarization engineering strategy to promote the charge separation and ROS generation efficiency by substituting the benzene unit with furan/thiophene in porous organic polymers(POPs). Benefiting from the extent of local polarization, the thiophene-containing POP(JNU-218) exhibits the best photocatalytic performance in aerobic oxidation reactions, with a yield much higher than those for the furan-containing POP(JNU-217) and the benzenecontaining POP(JNU-216). Experimental studies and theoretical calculations reveal that the increase of local polarization can indeed reduce the exciton binding energy, and therefore facilitate the separation of electron-hole pairs. This work demonstrates a viable strategy to tune charge separation and ROS generation efficiency by modulating the dipole moments of the building blocks in porous polymeric organic semiconductors.

DNA Nanotechnology-Enabled Fabrication of Metal Nanomorphology

In recent decades,DNA nanotechnology has grown into a highly innovative and widely established field.DNA nanostructures have extraordinary structural programmability and can accurately organize nanoscale materials,especially in guiding the synthesis of metal nanomaterials,which have unique advantages in controlling the growth morphology of metal nanomaterials.This review started with the evolution in DNA nanotechnology and the types of DNA nanostructures.Next,a DNA-based nanofabrication technology,DNA metallization,was introduced.In this section,we systematically summarized the DNA-oriented synthesis of metal nanostructures with different morphologies and structures.Furthermore,the applications of metal nanostructures constructed from DNA templates in various fields including electronics,catalysis,sensing,and bioimaging were figured out.Finally,the development prospects and challenges of metal nanostructures formed under the morphology control by DNA nanotechnology were discussed.

Metal-organic frameworks as photocatalysts for aerobic oxidation reactions

Metal-organic frameworks(MOFs)are emerging as one of the most intriguing classes of heterogeneous photocatalysts owing to their abundant structures,tunable porosity,and versatile functions.The advantages of bottom-up design and reticular synthesis render MOF materials with desired photocatalytic properties for targeted reactions.In this review,we discussed the design and synthesis of MOF-based photocatalysts as well as strategies for enhancing photocatalytic performance.Recent progress on MOFs as platforms for photocatalytic aerobic oxidation reactions was summarized and categorized according to the types of bond formation.We hope this review will give an in-depth insight into MOF-based photocatalytic systems for not only aerobic oxidation reactions but also other organic transformations.A brief outlook on the challenges and opportunities of MOFs as heterogeneous photocatalysts is provided at the end of the review.

Metal-organic cages containing two types of binding sites:trapping hydrocarbon gas in solution

The design and synthesis of artificial molecular containers for the encapsulation of hydrocarbon gases to study their host-guest chemistry are highly important for potential application in gas storage,separation,and understanding of their biological functions.In this work,we report the subcomponent self-assembly of four cubic Zn_(8)L_(12)Br_(4)(HL=N-(4-R)-1-(5-methyl-1Himidazole-4-yl)methanimine)cages with good solubility in chloroform,which are capable of binding hydrocarbon gases including methane,ethane,and ethene in solution at ambient temperature.Two types of gas binding sites(one is in the cavity,and the other is at the window)are discovered in these cages,which are documented by nuclear magnetic resonance(NMR)spectra and density functional theory(DFT)calculations.Their performance of encapsulation of hydrocarbon gases can be tuned by carefully adjusting substituent groups.These metal-organic cages containing two types of binding sites provide new artificial models to mimic the structures and functions of biological systems in binding and transforming hydrocarbon gases.

Polarization-dispersive imaging spectrometer for scattering circular dichroism spectroscopy of single chiral nanostructures

Circular dichroism spectroscopy is one of the most important tools in nanoscopic chiroptics.However,there is lack of simple,fast and reliable method for measuring the circular dichroism responses of single nanostructures.To tackle this issue,we report a polarization-dispersive imaging spectrometer which is capable of measuring the scattering circular dichroism response of a single chiral nanostructure with a single shot.Using this technique,we studied the scattering circular dichroism spectra of a model system,the vertically coupled plasmonic nanorod pair.Both experimental and theoretical results indicate that the polarization-dispersive spectrometer measures the imaginary part of nonlocal susceptibility of the structure.We further applied the technique to 3-dimensional Au nanorod structures assembled on DNA origami templates together with correlated scanning electron microscopic measurements.Rich chiroptical phenomena were unveiled at the single nanostructure level.