Synthesis, Isomer Count, and Nuclear Spin Relaxation of H₂O@Open-C₆₀ Nitroxide Derivatives

Abstract

H(2)O@C(60) derivatives covalently linked to a nitroxide radical were synthesized. The (1)H NMR of the guest H(2)O revealed the formation of many isomers with broad signals. Reduction to the diamagnetic hydroxylamines sharpened the (1)H NMR signals considerably and allowed for an "isomer count" based on the number of observed distinct signals. For H(2)O@K-8, 17 positional isomeric nitroxides are predicted, not including additional numbers of regioisomers; indeed, 17 signals are observed in the (1)H NMR spectrum.

Synthesis of Isoselenocyanates

“…The 1 H and 13 C NMR spectra of nitroxyl isocyanides 3a-c were recorded in the presence of a drop of a reducing agent [in fact the spectra of the corresponding hydroxylamines 3a(OH)-c(OH) were recorded]. In this research phenylhydrazine was used, 48 however, sometimes the use of hydrazobenzene 49,50 and pentafluorophenylhydrazine 51 have also been reported.…”

Molecular magnetic switch for a metallofullerene

“…Recently, Turro et al . chemically modified the H 2 @C 60 with a nitroxide radical, and observed an indirect but strong magnetic communication between the electron spin of nitroxide paramagnet and the nuclear spin of encaged H 2 (refs 23, 24, 25, 26, 27, 28). This finding provides a valuable clue for us on manipulating the magnetic property of paramagnetic EMFs via a foreign paramagnet29.…”

Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

“…This was achieved by adding a drop of a reducing agent – in fact the spectra of the corresponding hydroxylamines were recorded. In this research phenylhydrazine has been used [ 49 – 50 ], however, sometimes using of hydrazobenzene [ 51 – 52 ] or pentafluorophenyl hydrazine [ 35 ] as reducing agents have been reported, as well.…”