2,2-[60]Fullerenoalkanoyl chlorides (1a-d) were easily and securely prepared from the corresponding 2,2-[60]fullerenoalkanoic acids (2a-d) by the reaction with thionyl chloride in an unusual mixed solvent, CH2Cl2/dioxane. The characterization of 1a-d by 1H and 13C NMR, FT-IR, and MALDI-TOF-MASS was conducted for the first time. The 2,2-[60]fullerenoalkanoyl chlorides thus obtained were readily converted to the corresponding amides and esters in moderate to excellent yields by the condensation with amines and alcohols, respectively. Upon applying the condensation, [60]fullerene-biomolecule hybrids were easily prepared.
[reaction: see text] [60]Fullerenoacetyl chloride, one of the reactive derivatives of [60]fullerenoacetic acid, was isolated and identified for the first time. This acid chloride was easily synthesized in good yield from tert-butyl [60]fullerenoacetate through two steps. In the presence of 4-(dimethylamino)pyridine as a base, the acid chloride smoothly reacted with various alcohols under mild conditions to give the corresponding esters including [60]fullerene-biomolecule hybrids in moderate to high yields.
After optimization of the preparation procedure and the alloy composition of a PtCo catalyst, we found that MEA of the PtCo catalyst could show better I-V performance than that of a Pt catalyst. To improve the stability of a carbon support, we have evaluated various types of carbon, and we found a graphitized carbon could show better stability than a normal carbon. We also evaluated the PtCo catalyst on the graphitized carbon to achieve both better ORR activity and better stability of carbon, but the PtCo catalyst on the graphitized carbon could not show any ORR activity improvement due to the larger particle size of PtCo. After exploring new carbons, we could find a unique carbon which has higher surface area and better stability than a normal carbon. We prepared the PtCo catalyst on the carbon, and this catalyst could show good balance between the ORR activity and the carbon stability.
A series of novel transformations of [60]fullerene derivatives were found, starting from methano[60]fullerenes with an electron-donating group on the methano-bridge carbon. Aminomethano[60]fullerenes, in situ generated by the treatment of their trifluoromethanesulfonic acid salts with a base, were readily converted into 1-acyl-1,2-dihydro[60]fullerenes via the ring opening of the cyclopropane moiety. The aldehyde/ketones thus obtained were easily hydrolyzed to give 1,2-dihydro[60]fullerene in the presence of hydroxide anions.
[reaction: see text] Aminomethano[60]fullerene was synthesized for the first time as a trifluoromethanesulfonic acid salt by applying the Curtius rearrangement of azidocarbonylmethano[60]fullerene as the key reaction. Aminomethano[60]fullerene thus obtained was found to be able to react with various acyl chlorides to afford the corresponding amides.
Ethylene/norbornene copolymerizations were conducted with [Ph2C(Flu)(3‐RCp)]ZrCl2 [R: Me (1) or Me3Si (2)], which give alternating EN copolymers. The activity of 1 in the absence of R3Al was approximately twice that of 2 and increased further upon addition of R3Al. Et3Al increased the activity most effectively, and the $\overline {M} _{{\rm n}} $ of the produced polymer decreased from 100 000 to 25 000 g · mol−1. On the other hand, the $\overline {M} _{{\rm n}} $ value increased upon addition of iBu3Al from 100 000 to 209 000 g · mol−1 accompanied by an ≈2.5‐fold increase of activity. Consequently, 1 was found to be one of the most promising complexes for the synthesis of alternating EN copolymers, of which $\overline {M} _{{\rm n}} $ value was efficiently controlled by the kind and the amount of R3Al added.magnified image
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