Piperazine Functionalization of C₇₀ for Incorporation into Supramolecular Assemblies

Abstract

The photochemical reaction of piperazine with C produces a mono-adduct (N(CH CH ) NC ) 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 I N(CH CH ) NI C that was formed by reaction of N(CH CH ) NC with I . Crystals of polymeric {Rh (O CCF ) N(CH CH ) NC } ⋅nC H that formed from reaction of the mono-adduct with Rh (O CCF ) contain a sinusoidal strand of alternating molecules of N(CH CH ) NC and Rh (O CCF ) connected through Rh-N bonds. Silver nitrate reacts with N(CH CH ) NC to form black crystals of {(Ag(NO )) (N(CH CH ) NC ) } ⋅7nCH Cl that contain parallel, nearly linear chains of alternating (N(CH CH ) NC molecules and silver ions. Four of these {Ag(NO )N(CH CH ) NC } chains adopt a structure that resembles a columnar micelle with the ionic silver nitrate portion in the center and the nearly non-polar C cages encircling that core. Of the three bis-adducts, one was definitively identified through crystallization in the presence of I as {N(CH CH ) N} C with addends on opposite poles of the C cage and a structure with C symmetry. In {I N(CH CH ) N} C , individual {I N(CH CH ) N} C 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 I is suggested as a method to produce ordered crystals with complex supramolecular structures from substances that are otherwise difficult to crystallize.

Discovery of a Fullerene–Polyoxometalate Hybrid Exhibiting Enhanced Photocurrent Response

“…In recent years, photoelectrochemicals have attracted much attention because of their advantages of environmental protection, rapid response, and high sensitivity. Lately, studies of photoelectric materials have mainly been focused on the molecule level. , Compared to traditional materials, molecular materials, such as fullerenes and polyoxometalates (POMs), have specific structures, which make them the perfect models to study the synthesis, electron conduction, and modification of materials. − Also, it is easier to tune the properties of molecular materials by altering the chemical bonds. − Fullerenes are traditional organic functional molecules and are widely used in many aspects, such as electrocatalysis, encompass atoms, etc. − The most widely used field is photoelectric conversion because of its electronic storage capacity. , However, its inherent low conductivity and difficulty in characterization limited its development. Similar to fullerenes, as a kind of classical inorganic compounds, POMs also have good abilities to store electrons because of the abundance of metal ions. − Differently, POMs showed better conductivity than fullerenes, while poor acid–base resistance and difficult derivatization are obstacles to their application .…”