Dialkylaluminium 2-imidazolylphenolates: Synthesis, characterization and ring-opening polymerization behavior towards lactides

The stoichiometric reaction of the 2-imidazolylphenols (L1–L9) with the trialkylaluminium reagents AlR₃ (R = Me, Et and iBu), afforded the corresponding dialkylaluminium 2-imidazolylphenolate complexes [R₂Al(L1–L9)] (C1–C11), which were characterized by ¹H/¹³C NMR spectroscopy and by elemental analysis. The molecular structures of the representative complexes C1, C2, C4, C6 and C11 were determined by single-crystal X-Ray diffraction, and revealed a distorted tetrahedral geometry at aluminum. These dialkylaluminium 2-imidazolylphenolates (C1–C11) could efficiently catalyze the ring-opening polymerization of lactides to afford high molecular weight polylactide, both in the presence and absence of BnOH, and as such represent rare examples of the use of bi-dentate ligation at aluminum in such lactide polymerization systems. On the basis of the polymerization results for l-lactide, d-lactide and rac-lactide, the nature of the ligands and the aluminum bound alkyls were found to significantly affect the catalytic activity as well as the properties of the resultant polylactides

Zinc 2-((2-(benzoimidazol-2-yl)quinolin-8-ylimino)methyl)phenolates : synthesis, characterization and photoluminescence behavior

A series of 2-(2-(1H-benzoimidazol-2-yl)quinolin-8-yliminomethyl)phenol derivatives and their zinc complexes (C1 – C5) were synthesized and fully characterized. The molecular structure of the representative complex C2 was determined by single crystal X-ray diffraction, which revealed that the zinc was five-coordinated with the tetra-dentate ligand and a methanol bound to the metal afford a distorted square-pyramidal geometry. The UV-Vis absorption and fluorescence spectra of the organic compounds and their zinc complexes were measured and investigated in various solvents such as methanol, THF, dichloromethane, and toluene; significant influences by solvents were observed on their luminescent properties; red-shifts for the zinc complexes were clearly observed in comparisons to the free organic compounds

2-{2,6-Bis[bis(4-fluorophenyl)methyl]-4-chlorophenylimino} -3-aryliminobutylnickel(II) bromide complexes: Synthesis, characterization, and investigation of their catalytic behavior

The series of 2-{2,6-bis[di(4-fluorophenyl)methyl]-4-chlorophenylimino}-3- aryliminobutane derivatives (L1-L5) and their nickel(II) dibromide complexes (Ni1-Ni5) were synthesized, and all organic compounds were fully characterized by the Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy and by elemental analysis, while the nickel complexes were characterized by FT-IR spectroscopy, elemental analysis, as well as by single-crystal X-ray diffraction for two representative examples, namely Ni1 and Ni4. A distorted tetrahedral geometry was observed for these four-coordinate nickel complexes. Upon the activation with either Methylaluminoxane or modified methylaluminoxane as co-catalyst, all nickel complex precatalysts showed very high activity toward ethylene polymerization with activities of up to 10 7 g(PE)·mol -1 (Ni)·h -1 , and afforded highly branched polyethylene with a bimodal distribution. © 2014 Elsevier B.V

Quasi-Brittle Fracture Modeling of Preflawed Bitumen Using a Diffuse Interface Model

Fundamental understandings on the bitumen fracture mechanism are vital to improve the mixture design of asphalt concrete. In this paper, a diffuse interface model, namely, phase-field method is used for modeling the quasi-brittle fracture in bitumen. This method describes the microstructure using a phase-field variable which assumes one in the intact solid and negative one in the crack region. Only the elastic energy will directly contribute to cracking. To account for the growth of cracks, a nonconserved Allen-Cahn equation is adopted to evolve the phase-field variable. Numerical simulations of fracture are performed in bituminous materials with the consideration of quasi-brittle properties. It is found that the simulation results agree well with classic fracture mechanics

The Measurement of the Long-Term and Short-Term Risks of Chinese Listed Banks

In this paper, we employ Semi-APARCH model to measure and analyze the long-term and the short-term risk of Chinese 16 listed commercial banks between January 2007 and December 2013, and provide an early warning method for financial regulation by developing a scale function. We find that, first, during the financial crisis of 2008-2009, the long-term risk levels of Chinese banking industry as a whole and the individual commercial banks are very higher, they gradually declined to the normal level only after 2010. Secondly, the current risk of Chinese banks and banking industry is at lower level. Thirdly, the surging of overnight rate in 2013 increased the risk level of commercial banks, which could increase more, of which the regulator should be more cautious. Fourthly, the leverage-effects in the short-term risk of Chinese commercial banks are lower; t-distribution shows a fat-tail. Fifthly, the scale functions of commercial banks are highly correlated, the correlation coefficients are close to 1, which indicates a significantly systematically correlations between the long-term risk of Chinese commercial banks

The Measurement of the Long-Term and Short-Term Risks of Chinese Listed Banks

In this paper, we employ Semi-APARCH model to measure and analyze the long-term and the short-term risk of Chinese 16 listed commercial banks between January 2007 and December 2013, and provide an early warning method for financial regulation by developing a scale function. We find that, first, during the financial crisis of 2008-2009, the long-term risk levels of Chinese banking industry as a whole and the individual commercial banks are very higher, they gradually declined to the normal level only after 2010. Secondly, the current risk of Chinese banks and banking industry is at lower level. Thirdly, the surging of overnight rate in 2013 increased the risk level of commercial banks, which could increase more, of which the regulator should be more cautious. Fourthly, the leverage-effects in the short-term risk of Chinese commercial banks are lower; t-distribution shows a fat-tail. Fifthly, the scale functions of commercial banks are highly correlated, the correlation coefficients are close to 1, which indicates a significantly systematically correlations between the long-term risk of Chinese commercial banks

Animal waste use and implications to agricultural greenhouse gas emissions in the United States

Acknowledgements: Z. Q. and S. D. have been partially supported by the National Basic Research Program of China (2016YFA0602701), the National Natural Science Foundation of China (41975113), and the Guangdong Provincial Department of Science and Technology (2019ZT08G090). The input of P. S. contributed to the following projects: DEVIL (NE/M021327/1) and Soils-R-GRREAT (NE/P019455/1). Data availability: The data that support the findings of this study are openly available at the following URL/DOI: https://greet.es.anl.gov/. Publisher Copyright: © 2021 The Author(s). Published by IOP Publishing Ltd. Creative Commons Attribution 4.0 license, Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Peer reviewedPublisher PD