Mechanistic Study of the Diels–Alder Reaction of Paramagnetic Endohedral Metallofullerene: Reaction of La@C₈₂ with 1,2,3,4,5-Pentamethylcyclopentadiene

Abstract

The reaction mechanism of the Diels-Alder reaction of paramagneticendohedral metallofullerene, La@C82, and 1,2,3,4,5-pentamethylcyclopentadiene was studied theoretically and experimentally. Theoretical calculations revealed that this reaction proceeds via a concerted mechanism that includes formation of a stable intermediate. The activation energy of a retro-Diels-Alder reaction was also studied experimentally, which is in good agreement with theoretical results.

Molecular magnetic switch for a metallofullerene

“…For paramagnetic EMFs, the electronic spin resonance (ESR) technique is a powerful tool to detect the spin distributions and spin–nucleus couplings on internal species192021. By means of ESR, it was revealed that the magnetic property of the internal species can be roughly manipulated by changing the dynamic movement of internal species.…”

Emergence of Highly Elaborated π-Space and Extending Its Functionality Based on Nanocarbons: New Vistas in the Fullerene World

“…To explain the selectivity in the DA reaction of La@C 2v (9)-C 82 , DFT calculations were performed. 119 It is noteworthy that La@C 2v (9)-C 82 is a paramagnetic molecule. Recently, DFT studies predicted that the reaction between 1,3-butadiene radical cation with ethylene proceeds via a stepwise path involving an open chain intermediate.…”

“…123 The absorption spectra of the resulting fulleropyrrolidines were similar to that of La@C 2v (9)-C 82 (Cp*), implying that the addition sites were identical to that of La@C 2v (9)-C 82 (Cp*). 119 However, the lack of singlecrystal XRD data has made the structural determination for the La@C 2v (9)-C 82 -based fulleropyrrolidines uncertain to date.…”

A theoretical study of an electronically mismatched Diels–Alder cycloaddition

“…[8][9][10][11][12][13][14][15] Generally, the classic D-A cycloadditions are reacted by electronic-decient diene and electronic-rich dienophile synergetically. [16][17][18][19] However, there are a series of untraditional D-A reactions [20][21][22][23][24][25][26][27][28][29][30][31] between electronically mismatched components, such as the addition between 1,3-butadiene and ethylene (both electron-decient components) or trans-1,3-butadiene and C60 or C70 (both electron-rich components). This novel D-A reaction always exhibits excellent selectivity but also requires stricter conditions than those of the traditional D-A reaction, where the components of dienes and dienophiles generally experience different transformations in order to satisfy the requirement of D-A reaction through the formation of free radical ions, 20,21 molecular electrical reversal [22][23][24][25] and polarity reversal.…”