Here we report two highly emissive perylene diimide (PDI)-based metallacages and explore their complexation with polycyclic aromatic hydrocarbons, such as pyrene, triphenylene and perylene. The fluorescence quantum yields of metallacages exceed 90% and their binding constants with perylene can reach as high as 2.41 × 10 4 M -1 in acetonitrile. These features enable further tuning of the emission of the host-guest complexes to obtain white-light emission based on the complementary orange emission of the metallacages and the blue emission of perylene. Moreover, owing to the huge differences of their quantum yields in solution and in the solid state, the hostguest complexes are successfully employed for information encryption. This study offers a general approach for the construction of emissive metallacages and explores their application for information encryption.

Cyclothianthrenes, a series of sulphur‐embedded hydrocarbon belts proposed a decade ago, were successfully constructed through a stepwise bottom‐up synthesis. The belt [6]cyclothianthrene ([6]CT) is the smallest and most strained member of the family yet reported. Both [6]CT and [8]CT are the first examples of cyclothianthrene characterized by single crystal X‐ray diffraction. An unprecedented chiral belt [7]CT and a Möbius‐shaped [9]CT were also achieved via modular synthesis. Crystallographic and computational studies show that belts [6]CT‐[8]CT have prism‐like conformations with well‐defined tubular cavities which have potential for guest molecule inclusion. Cyclic voltammograms further revealed that these belts are redox‐active. The success of constructing sulphur‐embedded hydrocarbon belts, that is, cyclothianthrenes, greatly enriches the chemistry of heteroatom‐doped molecular belts and tubes.

An unprecedented molecular pumping cassette was designed and implemented for the construction of molecular necklaces, that is, radial [n]catenanes. The mechanism was fully confirmed on a model [2]pseudorotaxane, and the novel clippingfollowed-by-pumping strategy was used to prepare a series of [n]catenanes (n = 2−5). A pair of [3]catenane diastereomers sequentially threaded with two different wheels was also accomplished. The success of utilizing molecular pumping to construct molecular necklaces offers new insights into complex molecular architectures and expands the application of molecular machines in synthesis.

To overcome the drawback of the traditional lumping method, a new method constructed from structure oriented lumping (SOL) combined with Monte Carlo (MC) to simulate the secondary reactions process of fluid catalytic cracking (FCC) gasoline was developed. The SOL method was applied to represent the feedstocks and products configuration framework; then, more than 60 item reaction rules were established to produce all the reaction networks for the secondary reactions of FCC gasoline. By integral calculating each molecule reaction probability using the MC method, the product distribution thus can be obtained. Three samples of catalytic cracking gasoline, taken from the industrial FCC units of China have been used as feedstock of the simulation to check the validity of the proposed method. Some integral properties, such as average molecular weight, element compositions, and hydrocarbon compositions were predicted. The yield of upgraded gasoline, dry gas, liquefied petroleum gas (LPG), light cycle oil (LCO), heavy oil, coke, and olefin changes with extent of reaction were also simulated with this method and the predicted results agreed well with the experimental data.

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Peroxy acetyl nitrate (PAN) is an important photochemical product formed from the reactions between volatile organic compounds (VOCs) and nitrogen oxides (NO x ) under sunlight. In this study, a field measurement was conducted at a rural site (the backgarden site, or BGS) of the Pearl River Delta (PRD) region in 2006, with the 10 min maximum PAN mixing ratios of 3.9 ppbv observed. The factors influencing the abundance of PAN at the BGS site was evaluated by the process analysis through the Weather Research and Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model. The results suggested that the increase of PAN abundance at the BGS site was mainly controlled by the gas-phase chemistry, followed by vertical transport, while its loss was modulated mainly by dry deposition and horizontal transport. As the dominant important role of gas-phase chemistry, to provide detailed information on the photochemical formation of PAN, a photochemical box model with near-explicit chemical mechanism (i.e., the master chemical mechanism, MCM) was used to explore the relationship of photochemical PAN formation with its precursors based on the measured data at the BGS site. It was found that PAN formation was VOC-limited at the BGS site, with the oxidation of acetaldehyde the most important pathway for photochemical PAN production, followed by the oxidation and photolysis of methylglyoxal (MGLY). Among all the primary VOC precursors, isoprene and xylenes were the main contributors to PAN formation. Overall, our study provides new insights into the PAN photochemical formation and its controlling factors, and highlighted the importance of gas chemistry on the PAN abundance in the PRD region.Atmosphere 2018, 9, 372 2 of 16 nitrogen oxides (NO x ), PAN could also be formed in air far away from these sources. PAN is relatively stable at low temperatures; however, it can be decomposed when the atmospheric temperature is high [2]. As a NO 2 reservoir species, it reduces NO 2 concentrations near the emission sources but releases NO 2 in regions remote from fresh emission sources [3]. It is, hence, concerning that PAN can affect NO x abundance and, ultimately, influence tropospheric ozone formation on local and regional scales.PAN is formed from the reaction of NO 2 and peroxy acetyl (PA) radical which is produced through photolysis and oxidation of a small number of oxygenated volatile organic compounds (OVOCs) (e.g., acetaldehyde (CH 3 CHO), acetone, methacrolein (MACR), methyl vinyl ketone (MVK), methyl ethyl ketone, and methylglyoxal (MGLY)) initiated by OH, NO 3 , and O 3 . Therefore, the abundances of aforementioned OVOCs will directly impact PAN levels in the atmosphere. Since PAN was first discovered in photochemical smog in Los Angeles in the 1950s, numerous studies have investigated the distribution and source contributions of PAN through field measurements and model simulations [3][4][5][6]. The characterization includes the abundance of PAN, the relationship with its precursors, and the contributions of regional transport i...