252735-68-5Relevant articles and documents
Tunable photochromism of spirobenzopyran via selective metal ion coordination: An efficient visual and ratioing fluorescent probe for divalent copper ion
Shao, Na,Jian, Yu Jin,Wang, Hao,Zhang, Ying,Rong, Hua Yang,Wing, Hong Chan
, p. 3466 - 3475 (2008)
In the present paper, a new spirobenzopyran derivative was synthesized and applied in simultaneously colorimetric and fluorescence ratiometric detections of Cu2+. In contrast to the virtually photochromic character of the common spirobenzopyrans in most organic solvents, this spirobenzopyran is colorless in organic aqueous solution even irradiating by ultraviolet light. The formation of red merocyanine in an ethanol-aqueous solution is only induced by Cu2+ coordination. Furthermore, the closed form of the spirobenzopyran is highly fluorescent. Upon complexation with Cu2+, it displays not only decreasing in the initial fluorescence emission band but also appearing in a new emission at long wavelength. Thus, the Cu2+ quantitative measure can be achieved by fluorescence ratiometry. With the optimum conditions described, the Cu2+ concentration can be determined from 5.13 × 10-7 M to 3.81 × 10-4 with a detection limit of 1.06 × 10-7 M. Both the color and the fluorescence changes of the spirobenzopyran are extremely specific for Cu 2+ over biologically relevant substrates, which meet the selectivity requirements for biomedical application. Serum divalent copper values were determined using this spirobenzopyran, which fell into the normal range of the content reported in the literature and were in good agreement with those obtained by atomic absorption spectroscopy. The combined data from fluorescence titrations and 1H NMR measurements indicate that the new emission of the spirobenzopyran generated by Cu2+ is the result of the metal-induced ring opening and conformation restriction by Cu2+ liganding with the opened merocyanine form and the subsequent reduction of the intramolecular charge transfer of the merocyanine.
METHOD OF PREPARING POLY(ALKYLENE CARBONATE) VIA COPOLYMERIZATION OF CARBON DIOXIDE/EPOXIDE IN THE PRESENCE OF NOVEL COMPLEX
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, (2014/10/04)
Provided is a method of preparing poly(alkylene carbonate) using a molecular weight regulator in a process of preparing a copolymer of carbon dioxide/epoxide using a novel complex synthesized from salen-type ligand including a quaternary ammonium salt as a catalyst. According to the present invention, even though the molecular weight regulator is used, an activity of the catalyst may be stably maintained, whereby the low molecular weight of poly(alkylene carbonate) having a desirable level may be effectively provided. In addition, it is expected that since the novel complex as the catalyst of the present invention has a simple structure as compared to the existing copolymerization catalyst, due to the economical preparation cost thereof, the novel complex may be effectively applied to a large-scale commercial process.
Direct C-H bond arylation of 2-hydroxybenzaldehydes with arylboronic acids via ligand-free palladium catalysis
Weng, Fei,Wang, Chengming,Xu, Bin
supporting information; experimental part, p. 2593 - 2596 (2010/07/04)
A mild and efficient ligand-free palladium-catalyzed direct C-H bond arylation reaction was developed to afford 2-hydroxybenzophenones in good to excellent yields from easily available 2-hydroxybenzaldehydes and arylboronic acids. The given reaction provided one of the easiest pathways for accessing 2-hydroxybenzophenones, and a variety of functional groups could be tolerated in this process.
