The imination of a cage-opened C60 derivative was performed by the use of N,N-dimethyl-1,4-phenylenediamine, giving a imine derivative in addition to two reduced compounds bearing an amine or methylene group instead of the imine unit, in which the diamine is considered to work as reductants. The imine and amine derivatives showed near-infrared absorption tailing to 1050 and 1200 nm, respectively.
The imination of a cage-opened fullerene C60 derivative was examined using N,N-dimethyl-1,4-phenylenediamine. The desired imine derivative showed a remarkably intense near-infrared (NIR) absorption band (λ
edge=1050 nm). According to theoretical calculations, the longest wavelength absorption is assignable to the HOMO→LUMO transition with a strong charge-transfer character, in which the HOMO localizes on the introduced imine moiety while the high LUMO coefficients can be seen over the entire C60 skeleton. It should be noted that the two reduced compounds bearing an amine or methylene group were also formed in the reaction producing the imine derivative, the former of which again showed NIR absorption tailing to 1200 nm. In this reduction, the hydride source is considered to be α-hydrogen of the diamine so that the use of N,N,N’,N’-tetramethyl-1,4-phenylenediamine increased the yield of the methylene derivative up to 20%.Zum Volltext