146746-37-4Relevant academic research and scientific papers
Synthesis and photochemical behaviour of novel uranyl-salophen complexes bearing anthracenyl side arms
Mihan, Francesco Yafteh,Bartocci, Silvia,Credi, Alberto,Silvi, Serena,Dalla Cort, Antonella
, p. 109 - 115 (2013)
In this paper, we report the synthesis and physico-chemical investigation of two uranyl-salophen receptors, bearing either one or two anthracenyl moieties appended to the salophen skeleton. Despite the presence of the anthracenyl fluorophores, no fluorescence emission was detected. Photophysical data and cyclic voltammetric experiments show that photoinduced electron transfer from the anthracene-localised first singlet excited state to the metal centre is strongly exergonic, thus suggesting that this is the main fluorescence quenching mechanism in these complexes. The investigated compounds are photoreactive upon UV irradiation, yielding either anthracene photooxidation or photodimerisation products depending on the specific complex and the experimental conditions.
Formaldehyde-Extruding Homolytic Aromatic Substitution via C→O Transposition: Selective ‘Traceless-Linker’ access to Congested Biaryl Bonds
Poonpatana, Pabhon,dos Passos Gomes, Gabriel,Hurrle, Thomas,Chardon, Kimhoa,Br?se, Stefan,Masters, Kye-Simeon,Alabugin, Igor
, p. 9091 - 9097 (2017)
A new, selective way to form C?C bonds has been developed. In this report, we disclose the homolytic aromatic substitution via C→O transposition coupled with the elimination of formaldehyde (as a traceless linker). Computational analysis indicates the sel
Stereoselective Alkali-Metal Catalysts for Highly Isotactic Poly(rac-lactide) Synthesis
Sun, Yangyang,Xiong, Jiao,Dai, Zhongran,Pan, Xiaobo,Tang, Ning,Wu, Jincai
, p. 136 - 143 (2016)
A high degree of chain end control in the isoselective ring-opening polymerization (ROP) of rac-lactide is a challenging research goal. In this work, eight highly active sodium and potassium phenolates as highly isoselective catalysts for the ROP of rac-l
Direct Transformation of Esters into Arenes with 1,5-Bifunctional Organomagnesium Reagents
Link, Achim,Fischer, Christian,Sparr, Christof
supporting information, p. 12163 - 12166 (2015/10/12)
A direct transformation of carboxylic acid esters into arenes with 1,5-bifunctional organomagnesium reagents is described. This efficient and practical method enables the one-step defunctionalization of various carboxylic acid esters to prepare benzene, anthracene, tetracene, and pentacene derivatives. A double nucleophilic addition of the 1,5-organodimagnesium reagent to the ester is followed by an immediate 1,4-elimination reaction that leads to the direct [5+1] formation of a new aromatic ring.
Photoaddition of water and alcohols to the anthracene moiety of 9-(2′-hydroxyphenyl)anthracene via formal excited state intramolecular proton transfer
Flegel, Mitchel,Lukeman, Matthew,Huck, Lawrence,Wan, Peter
, p. 7890 - 7897 (2007/10/03)
The title compound undergoes efficient photoaddition of a molecule of a hydroxylic solvent (H2O, MeOH, (Me)2CHOH) across the 9- and 10-positions of the anthracene moiety to give isolable triphenylmethanol or triphenylmethyl ether type products. The reaction is believed to proceed via a mechanism involving water-mediated formal excited state intramolecular proton transfer (ESIPT) from the phenolic OH to the 10-position of the anthracene ring, generating an o-quinone methide intermediate that is observable by nanosecond laser flash photolysis, and is trappable with nucleophiles. A "water-relay" mechanism for proton transfer seems plausible but cannot be proven directly with the data available. Irradiation in deuterated solvents led to incorporation of one deuterium atom at the methylene position in the photoaddition product, and partial deuterium exchange of the 10-position of recovered starting material, consistent with the proposed formal excited state proton transfer mechanism. The deuterium exchange and photoaddition reach maximum quantum efficiency at ~5 M water (in CH3CN or CH 3OH), with no reaction observed in the absence of a hydroxylic solvent, demonstrating the sensitivity of this type of ESIPT to solvent composition.
An Intramolecular Arene-Triflate Coupling Reaction for the Regiospecific Synthesis of Substituted Benzofluoranthenes
Rice, Joseph E.,Cai, Zhen-Wei
, p. 1415 - 1424 (2007/10/02)
An intramolecular triflate-arene coupling reaction mediated by bis(triphenylphosphine)palladium(II) chloride has been developed for the synthesis of each of the isomeric benzofluoranthenes.This reaction, which results in formation of a new five-membered ring, proceeds in highest yields when performed using 0.1 equiv of the palladium catalyst, 3 eqiv of lithium chloride, and 1.2 eqiv of 1,8-diazabicycloundec-7-ene in N,N-dimethylformamide at 140 deg C.The biaryl precursors needed for the coupling reaction can be prepared by nickel(II) chloride catalyzed coupling of an aryl bromide with an magnesium bromide (prepared by ortho-lithiation of an aryl methoxymethyl ether followed by transmetalation with magnesium bromide).Using this procedure benzofluoranthene, benzofluoranthene, benzofluoranthene, and benzofluoranthene were prepared in yields of 84percent, 85percent, 93percent and 64percent, respectively.The reaction to prepare benzofluoranthene was regiospecific and afforded none of the six-membered ring product, perylene.This method was extended to the preparation of benzofluoranthene (BbF) derivatives with fluoro or methoxy groups on the benzo ring.The cyclization of compounds posessing a methoxy group on the same ring as the triflate required the addition of 0.4 equiv of triphenylphosphine to the reaction mixture.Strategies are reported for the regiospecific preparation of 4-, 5-, 6-, and 7-substituted benzofluoranthenes.Evidence is presented wich suggests the intermediacy of radicals in the oxidative-addition of aryl triflates to the palladium catalyst.
A Palladium-Catalyzed Intramolecular Arene-Triflate Coupling for the Synthesis of Fluoranthrenes and Benzofluoranthrenes
Rice, Joseph E.,Cai, Zhen-Wei
, p. 1663 - 1678 (2007/10/02)
A method for the preparation of fluoranthrenes and benzofluoranthrenes from aryl bromides and aryl methoxymethyl ethers is described.The key step in this synthesis is an intramolecular triflate-arene coupling mediated by bis(triphenylphosphine)palladium(II)chloride.Fluoranthrene, benzofluoranthrene, benzofluoranthrene, and indenopyrene were prepared in yields of 84-91percent.The regiospecific synthesis of substituted benzofluoranthrenes was demonstrated by the preparation of 6-fluorobenzofluoranthrene (72percent yield) and 5- and 6-methoxybenzofluoranthrene in yields of 73percent and 62percent respectively when the reaction was conducted in the presence of excess triphenylphosphine.Key Words: synthesis; palladium; triflate; fluoranthrene; benzofluoranthrene
