HL·(PF6) (L = 2,4-dimethyl-8-phenyl[1,2,4]triazolo[4,3-a][1,8]naphthyridin-9-ylidene) was synthesized from the
nucleophilic reaction of 7-chloro-2,4-dimethyl-1,8-naphthyridine with
phenylhydrazine and subsequent acidification, anion exchange, and
condensation with triethyl orthoformate. Its silver, copper, cobalt,
and nickel complexes [Ag2(L)2(CH3CN)2](PF6)2 (1), [CuL(CH3CN)2](PF6) (2), [CuL(phen)](PF6) (3), [CuL(dppe)](PF6) (4), [Co(L)2(CH3CN)2](PF6)2 (5), and [Ni(L)3](PF6)2 (6) have been synthesized and fully characterized
by NMR, elemental analysis, and X-ray diffraction analysis. The copper
complex 2 exhibits excellent catalytic activity in the
Cu(I)-catalyzed azide–alkyne cycloaddition reaction of 2,2,6,6-tetramethylpiperidinyl-1-oxy-tethered
alkynes in an air atmosphere at 50 °C.
Abstract. Atmospheric aerosols play a crucial role in regional radiative
budgets. Previous studies on clear-sky aerosol direct radiative forcing
(ADRF) have mainly been limited to site-scale observations or model
simulations for short-term cases, and long-term distributions of ADRF in
China have not been portrayed yet. In this study, an accurate fine-resolution
ADRF estimate at the surface was proposed. Multiplatform datasets, including
satellite (MODIS aboard Terra and Aqua) and reanalysis datasets, served as
inputs to the Santa Barbara Discrete Atmospheric Radiative Transfer (SBDART)
model for ADRF simulation with consideration of the aerosol vertical profile
over eastern China during 2000–2016. Specifically, single-scattering albedo
(SSA) from the Modern-Era Retrospective Analysis for Research and
Application, Version 2 (MERRA-2) was validated with sun photometers over eastern
China. The gridded asymmetry parameter (ASY) was then simulated by matching
the calculated top-of-atmosphere (TOA) radiative fluxes from the radiative
transfer model with satellite observations (Clouds and the Earth's Radiant
Energy System, CERES). The high correlation and small discrepancy (6–8 W m−2) between simulated and observed radiative fluxes at three sites
(Baoshan, Fuzhou, and Yong'an) indicated that ADRF retrieval is feasible and
has high accuracy over eastern China. Then this method was applied in each grid
of eastern China, and the overall picture of ADRF distributions over eastern China
during 2000–2016 was displayed. ADRF ranges from −220 to −20 W m−2, and
annual mean ADRF is −100.21 W m−2, implying that aerosols have a strong
cooling effect at the surface in eastern China. With the economic development
and rapid urbanization, the spatiotemporal changes of ADRF during the past 17 years are mainly attributed to the changes of anthropogenic emissions in
eastern China. Our method provides the long-term ADRF distribution over eastern
China for the first time, highlighting the importance of aerosol radiative
impact under climate change.
Copper-catalyzed sequential 1,3-dipolar cycloadditions of azomethine imines and alkynes and electrophilic thiolations are described. The CÀS, CÀN, and CÀC bonds were simultaneously formed in one pot, leading to N,N-bicyclic pyrazolidinones in good to excellent yields. The process is proposed to proceed via reaction of a cuprate pyrazolidinonate intermediate and benzenesulfonothioate.
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