Synthesis of homoazafullerene [C59N(CH2)]R and azahomoazafullerene [C59N(NH)]R

The selective insertion of a CH₂ or NH group is achieved through the PCl₅ induced reaction of a CH₂OH or NHOH group, respectively.

Piperazine Functionalization of C70 for Incorporation into Supramolecular Assemblies

The photochemical reaction of piperazine with C₇₀ produces a mono-adduct (N(CH₂ CH₂ )₂ NC₇₀ ) in high yield (67 %) along with three bis-adducts. These piperazine adducts can combine with various Lewis acids to form crystalline supramolecular aggregates suitable for X-ray diffraction. The structure of the mono-adduct was determined from examination of the adduct I₂ N(CH₂ CH₂ )₂ NI₂ C₇₀ that was formed by reaction of N(CH₂ CH₂ )₂ NC₇₀ with I₂ . Crystals of polymeric {Rh₂ (O₂ CCF₃ )₄ N(CH₂ CH₂ )₂ NC₇₀ }_n ⋅nC₆ H₆ that formed from reaction of the mono-adduct with Rh₂ (O₂ CCF₃ )₄ contain a sinusoidal strand of alternating molecules of N(CH₂ CH₂ )₂ NC₇₀ and Rh₂ (O₂ CCF₃ )₄ connected through Rh-N bonds. Silver nitrate reacts with N(CH₂ CH₂ )₂ NC₇₀ to form black crystals of {(Ag(NO₃ ))₄ (N(CH₂ CH₂ )₂ NC₇₀ )₄ }_n ⋅7nCH₂ Cl₂ that contain parallel, nearly linear chains of alternating (N(CH₂ CH₂ )₂ NC₇₀ molecules and silver ions. Four of these {Ag(NO₃ )N(CH₂ CH₂ )₂ NC₇₀ }_n chains adopt a structure that resembles a columnar micelle with the ionic silver nitrate portion in the center and the nearly non-polar C₇₀ cages encircling that core. Of the three bis-adducts, one was definitively identified through crystallization in the presence of I₂ as ¹² {N(CH₂ CH₂ )₂ N}₂ C₇₀ with addends on opposite poles of the C₇₀ cage and a structure with C_2v symmetry. In ¹² {I₂ N(CH₂ CH₂ )₂ N}₂ C₇₀ , individual ¹² {I₂ N(CH₂ CH₂ )₂ N}₂ C₇₀ units are further connected by secondary I2⋅⋅⋅N2 interactions to form chains that occur in layers within the crystal. Halogen bond formation between a Lewis base such as a tertiary amine and I₂ is suggested as a method to produce ordered crystals with complex supramolecular structures from substances that are otherwise difficult to crystallize.

Selective formation and structural properties of rhombic dodecahedral [70]fullerene microparticles formed by reaction with aliphatic diamines

We have accomplished the selective formation of rhombic dodecahedral microparticles on the submicrometer to micrometer scale by the reaction of [70]fullerene (C(70)) with primary aliphatic diamines. The morphology of the resultant microparticles was analyzed by scanning electron microscopy, powder X-ray diffraction, and other spectroscopic methods, demonstrating that the resultant particles held a rhombic dodecahedral shape having a simple cubic lattice structure and that primary aliphatic amines were mostly trapped inside the particles through electronic interaction between C(70) and amines. Furthermore, we have discovered interesting structural characteristics in which the incorporated amines could be removed from the C(70) microparticles or exchanged with other primary aliphatic diamines.