Nuclear Magnetic Resonance of Aromatic Heterocyclics. I. The Proton and 19F Spectra of 2- and 3-Fluorothiophene.

Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

“…A very small isotope effegt in t3C NMR due to sulfur isotopes has recently been detected [8]. In 19F NMR spectra sulfur [6,7], silicium [6,11] and selenium [12] induced effects have been reported earlier. Nitrogen induced effects were observed in 59C0 spectra [10] and oxygen induced effects in 55Mn and 95Mo spectra of oxyanions [5,13].…”

Synthesis and NMR studies of 2- and 3-fluorosubstitued five-membered heterocycles

“…Some procedures require expensive and/or hazardous reagents such as, for example, perchloryl fluoride, others are difficult to repeat and/or are of limited applicability. Most of the papers published so far have been devoted to variously substituted fluorothiophenes [6][7][8][9][10][11][12][13][14][15][16][17], considerably fewer to pyrroles [16][17][18][19][20][21][22], and only a few to Journal of Fluorine Chemistry 124 (2003) [159][160][161][162][163][164][165][166][167][168] furans [16,17,23,24]. Though the methods of the synthesis of the fluoro-substituted heterocycles were not our primary goal, we had to check and/or modify the procedures chosen in order to synthesize the required model compounds.…”

29/28, 30/28Silicon, 34/32sulfur and 80/77selenium isotope‐induced fluorine chemical shifts through two bonds

“…This isotopeinduced chemical shift was 2.3 times less important than that observed for 2-fluorothiophene. 10 The large effect in the aromatic thiophene 15 could be related to the shortening of the carbon-sulfur bond. On the other hand, 1  19 F 13/12 C is larger for sulfides than for oxidized sulfur derivatives.…”

“…In a pioneering study, a very large 2  19 F 34/32 S effect was observed in the 2-fluorothiophene spectrum. 10 …”