Cu-Catalyzed tandem N-arylation of phthalhydrazides with cyclic iodoniums to yield dihydrobenzo[c]cinnolines.

Dihydrocinnolines have significant pharmacological properties. Herein, we investigate a Cu-catalyzed tandem N-arylation reaction of phthalhydrazides with cyclic iodonium salts to construct dihydrobenzo[c]cinnoline derivatives. Various iodonium salts, such as symmetrical, unsymmetrical, aryl-aryl, and aryl-heteroaryl ones, could react with phthalhydrazides smoothly and give the title products in moderate to high yields. Moreover, the -NH2 group, which has been diarylated by cyclic iodonium salts to form carbazoles in previous reports, is also well tolerated in this work.

The C-H Activation/Bidirecting Group Strategy for Selective Direct Synthesis of Diverse 1,1'-Biisoquinolines.

Multidentate ligands are highly important but difficult to access. Herein we disclose an atom- and step-economic synthesis of highly substituted 1,1'-biisoquinolines by a C-H activation/bididirecting group strategy. Through rational design of a bididirecting group to "N-OH + N-OAc", selective unsymmetrical diannulation with two different alkynes in a one-pot reaction has been achieved for the first time to access unsymmetrical biisoquinolines. Moreover, the resultant biisoquinolines show tunable photoluminescence and serve as aggregation-induced emission (AIE) systems.

Domino N-/C- or N-/N-/C-arylation of imidazoles to yield polyaryl imidazolium salts via atom-economical use of diaryliodonium salts.

Herein, we disclose a Cu-mediated domino di-/triarylation reaction of imidazoles to efficiently access polyaryl imidazolium salts in a single step by using two aryls as well as an anion of a diaryliodonium salt. The diarylation shows high atom economy and excellent selectivity with unsymmetrical iodonium salts.

Utilization of rice husks functionalized with xanthates as cost-effective biosorbents for optimal Cd(II) removal from aqueous solution via response surface methodology.

Pristine rice husk (RH), a kind of agricultural waste based biosorbent, was chemically modified by introducing sulfur-bearing groups with the CS2 treatment under caustic medium. Using response surface methodology (RSM), the interactive effects of three preparation variables on the cadmium uptake and material yield of xanthate-modified rick husk (RH-X) were investigated, and two quadratic regression models were developed to correlate the preparation parameters to the two responses. Through process optimization, the optimal RH-X was finally obtained under the optimum synthesis conditions (i.e., 1.00 CS2-RH ratio, 60.00min xanthation contact time and 18.50°C xanthation temperature), resulting in 138.85mgg-1 of cadmium uptake, and 68.63% of RH-X yield, strictly similar to the values predicted from the models, with extremely small errors of 0.85 and 0.96%, respectively. Overall, cheap and abundant raw materials, low-cost and easily-controlled preparation and excellent cadmium adsorption ability can make RH-X a preferred biosorbent for wastewater decontamination.

Characteristic variation and original analysis of emergent water source pollution accidents in China between 1985 and 2013.

China has suffered various water source pollution incidents in the past decades, which have resulted in severe threats to the safety of the water supply for millions of residents. From the aspects of quantity fluctuation, temporal volatility, regional inequality, pollutant category variation, and accident type differences, this study first characterizes the current status of water source contaminations in China by analyzing 340 pollution events for the period spanning from 1985 to 2013. The results show a general increase in the number of accidents during the period 1985-2006 and then a rapid decline starting in 2007. Spring and summer are high-incidence seasons for pollution, and the accident rate in developed southeastern coastal areas is far higher than that in the northwestern regions. Hazardous chemicals and petroleum are the most frequently occurring pollutants, whereas heavy metals and tailings are becoming emerging contaminants during occasional pollutions. Most of the accidents that occurred before 2005 were blamed on illegal emissions or traffic accidents; however, leakage in production has gradually become a major accident type in the past decade. Then, in combination with government actions and policy constraints, this paper explores the deep inducements and offers valuable insight into measures that should be taken to ensure future prevention and mitigation of emergent source water pollution.