Nitrogen Directs Multiple Radical Additions to the 9,9′‐Bi‐1‐aza(C₆₀‐I_h)[5,6]fullerene: X‐ray Structure of 6,9,12,15,18‐C₅₉N(CF₃)₅

Abstract

Gestapelt wie Pappbecher: Moleküle des ersten strukturell aufgeklärten (C59N)2‐Derivats, das Trifluormethyl‐Gruppen trägt, stapeln mit einem Abstand von 10.179 Å senkrecht aufeinander und bilden so eine seltene, nicht dicht gepackte Anordnung (AAA…︁; siehe Bild). Die Gegenwart von Stickstoff im Fulleren‐Grundgerüst führt zu einzigartigen Additionsmustern in C59N(CF3)7/9/11.

Pentaarylazafullerenes and their Triaryldihydro and Tetraarylmonohydro Precursors

“…The N atom is disordered over the five equivalent positions of the isolated pentagon owing to the overlap of five molecules rotated by 72° relative to each other. The same feature was observed in the single‐crystal structure of C 59 N(CF 3 ) 5 3d. The average bond lengths within the pyrrole ring, at 1.40 Å, are comparable to the average bond length of 1.38 Å in pyrrole 13.…”

“…through a complex sequence of reactions and rearrangements starting from a cage‐opened oxafulleroid prepared from C 60 3c. More recently, this pentaaddition pattern was obtained upon reaction of (C 59 N) 2 with trifluoromethyl iodide where C 59 N(CF 3 ) 5 was formed among other higher adducts and characterized by X‐ray single‐crystal analysis 3d…”

Crystal‐Packing Trends for a Series of 6,9,12,15,18‐Pentaaryl‐1‐hydro[60]fullerenes

“…Interestingly, the groups of Sokolov, as well as Matsuo and Nakamura, have reported the crystal structure of 6,9,12,15,18‐pentamethyl‐1‐hydro‐[60]fullerene ( 1 , R=CH 3 ) as an example of one of the smallest stacking fullerenes (Figure 1a) 19. Sokolov suggested that the formation of columnar stacks is general and independent of the nature of the addend 20. However, we have found that a number of pentaarylfullerenes form nonstacked motifs (Scheme , Table 2), which indicates that stacking is far from general in these compounds.…”

“…Accordingly, phenyl groups with relatively large and spheroidal substituents at the 4‐position are the best suited to promote stacking, as determined experimentally from their crystal structures (vide infra), whereas small addends (e.g., 1 , R=CH 3 or Ph, Figure 2a, b) give sockets with a cavity that can be too shallow for efficient stacking 19. 20…”

Formation of Heterofullerenes by Direct Exposure of C60 to Boron Vapor

“…The resulting molecule, a heterofullerene, acquires electronic structure that is distinct from its all‐carbon precursor. Therefore, modification of electronic and optical properties by heteroatom doping is a promising route toward devising, for example, fullerene‐based molecular electronics, solar cells, and hydrogen‐storage technologies, as well as exploring new fullerene chemistry 7–14. Preferred elements for fullerene doping are trivalent heteroatoms that most closely resemble carbon in size and electronegativity, because such elements are most likely to exhibit covalent bonding in a fullerene.…”