33861-17-5Relevant articles and documents
Selenenate Anions (PhSeO?) as Organocatalyst: Synthesis of trans-Stilbenes and a PPV Derivative
Zheng, Zhipeng,Trofymchuk, Oleksandra S.,Kurogi, Takashi,Varela, Elena,Mindiola, Daniel J.,Walsh, Patrick J.
supporting information, p. 659 - 666 (2020/01/02)
The selenenate anion (RSeO?) is introduced as an active organocatalyst for the dehydrohalogen coupling of benzyl halides to form trans-stilbenes. It is shown that RSeO? is a more reactive catalyst than the previously reported sulfur analogues (sulfenate anion, RSO?) and selenolate anions (RSe?) in the aforementioned reaction. This catalytic system was also applied to the benzylic-chloromethyl-coupling polymerization (BCCP) of a bis-chloromethyl arene to form ppv (poly(p-phenylene vinylene))-type polymers with high yields, Mn (average molecular weight) up to 13,000 and ? (dispersity) of 1.15. (Figure presented.).
Generation and Mesolysis of PhSeSiR3.-: Mechanistic Studies by Laser Flash Photolysis and Application for Bimolecular Group Transfer Radical Reactions
Pandey, Ganesh,Sesha Poleswara Rao,Palit,Mittal
, p. 3968 - 3978 (2007/10/03)
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET promoted reductive activation of selenosilane 1a to its radical anion 1a.-. PET activation of 1a is achieved through a photosystem comprising a light-absorbing electron-rich aromatic (ERA), such as DMN or DMA, as an electron donor and ascorbic acid as a co-oxidant. The evidence for the ET from excited singlet states of DMN as well as DMA to 1a is suggested by estimating negative ΔGet (-51 and -43.46 kcal mol-1, respectively) values and nearly diffusion- controlled fluorescence quenching rate constants (kqTR) 0.36 × 1010 M-1 s-1 and 0.28 × 1010 M-1 s-1, respectively, from time-resolved fluorescence quenching study. The transient absorption spectra of DMN.+, DMA.+, and 1a.- are obtained initially by pulse radiolysis in order to correlate the time- resolved absorption spectral data. Laser flash photolysis studies in the nanosecond time domain have confirmed the generation of 1a.-, DMN.+, and DMA.+, supporting the participation of the triplet state of DMN or DMA in the ET reaction. Mesolytic cleavage of 1a.- produced a silyl radical and a phenyl selenide anion. The preparative PET activation of 1a in acetonitrile in the presence of DMN or DMA leads to the formation of 5 and 6, confirming the fragmentation pattern of la.-. The overall ET rate constants (kr(DMN) = 0.99 × 1010 M-1 s-1 and kr(DMA) = 1.62 × 1010 M-1 s-1) and limiting quantum yields (φlim(DMN) = 0.034 and φlim(DMA) = 0.12) are estimated from the inverse plot (1/[1a] vs 1/φdis) obtained by measuring the dependence of photodissociation quantum yields of 1a at its maximum concentration in the presence of DMN or DMA. Silicon-centered radical species generated from the mesolysis of 1a.- are utilized for initiating a radical reaction by the abstraction of halogen atom from -C-X (X = Cl, Br) bonds, while PhSe-1 terminates the radical sequences via PhSeSePh. This concept is successfully applied for the bimolecular group transfer (BMGT) radical reactions and intermolecular radical chain addition reactions.
ORGANOSELENIUM COMPOUNDS VII. METHODS OF CONTROLLING THE REACTION OF ORGANIC HALIDES WITH MAGNESIUM AND SELENIUM
Nedugov, A. N.,Pavlova, N. N.,Lapkin, I. I.
, p. 1829 - 1832 (2007/10/02)
The action of aryl bromides on a mixture of magnesium and selenium in ether in ratios of 1.5-2:1:1 leads to diaryl selenides and bis(bromomagnesium) selenide, which gives organic selenides with electrophiles.The reaction of Grignard reagents with an excess of selenium (ArBr:Mg:Se ratios of 1:1:1.5) in ether leads to diaryl diselenides, while the reaction in THF leads to a mixture of polyselenides and diaryl diselenides.
