Synthesis, characterization and X-ray structure of 3,4-lutidinyl-, 3-/4-picolyl- and pyridylselenium compounds

Synthesis of Pyridine– and Pyrazine–BF3 Complexes and Their Characterization in Solution and Solid State

“…The resonances of these complexes in the 11 B MAS spectra at 7.05 T are very narrow and consistent with tetrahedral B sites with spherical symmetry (less than 1 MHz). We then acquired 11 B MAS spectra at 17.6 T in order to accurately extract the C Q values and confirmed measurement with spectra obtained from 7.05 T. Analysis of N-BF 3 -pyridine 1 did not show visible second-order quadrupolar powder pattern on the CT for these peaks; however, C Q is nonzero due to the presence of the spinning sidebands, resulting from satellite transitions.…”

“…33 Three-coordinated species chemical shifts vary from +90 to −20 ppm with respect to BF 3 •OEt 2 at 0 ppm, whereas the fourcoordinated species have chemical shifts ranging from +20 to −120 ppm. 34 Recently, Bryce and co-workers analyzed twocoordinated borinium cations by 11 B ssNMR, which exhibit a chemical shift range of +100 to −30 ppm. 35 The overlap between chemical shift regions makes it difficult to distinguish coordination geometries.…”

“…We found few literature reports on the redox activity of heteroaromatic complexes, with limited characterization on BF 3 -adducts, most of which discussed the pyridine system. − For example, Meulen and co-workers first synthesized the N -BF 3 –pyridine complex 1 and determined the notably strong N–B bond energy dissociation in the solid state . Since then, pyridine–BF 3 complex 1 was used in a study to probe donor/acceptor interactions .…”

A Study on the Antioxidant Activity of Pyridylselenium Compounds and their Slow Release from Poly(acrylamide) Hydrogels

“…× 0.25 μm) capillary column. The spectroscopic data of all the synthesized compounds agreed well with the literature values 37,38,42,43. The UV-Vis spectrophotometer experiments were carried on Shimadzu PharmaSpec UV-1700, spectrophotometer.Antioxidant Activity AssayReduction of DPPH Free Radical Method.…”

“…37 The diselenides of 4-and 5-picoline, 3,5-, and 3,4-lutidine were synthesized by the lithiation of picolinium-BF 3 or lutidinium-BF 3 adduct with lithium diisopropylamide (LDA) at -78 • C followed by selenium insertion reaction and aerial oxidation. 42,43 The later methodology was also used to synthesize 3,5-dimethyl-2,6-bis(methylselenenyl)pyridine (1h). 42 Further, all the synthesized diselenides were reacted with bromine in dichloromethane to afford the corresponding 2-pyridylselenenylbromides in near quantitative yields.…”