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Boltalina, Olga V.; Markov, Vitaliy Yu.; Troshin, Pavel A.; Darwish, Adam D.; Street, Joan M.; Taylor, R. L.

doi:10.1002/1521-3757(20010216)113:4<809::aid-ange8090>3.3.co;2-s

Cited by 13 publications

(24 citation statements)

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“…Even the most stable fullerene, I h (IPR-1)-C 60 (113), forms the polyfluorinated derivative ( #IPR-1 C 60 F 20 , 117) by attaching 20 fluorine atoms to the equatorial belt of the spherical π-system. 153 Figure 40 shows Schlegel diagrams of these three halogenated fullerenes.…”

Section: Aromatic Character Of Fullerenesmentioning

confidence: 99%

Graph Theory of Aromatic Stabilization

Aihara¹

2016

BCSJ

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Aromaticity is very sensitive to the geometry of the π-system. Topological resonance energy (TRE), defined graphtheoretically, represents an aromatic stabilization energy (ASE) arising from cyclic conjugation in the π-system. TRE can be calculated for not only ground-state but also excited-state species. The TRE concept has since been extended analytically to solve many different problems concerning aromaticity and reactivity. Bond resonance energy (BRE), defined in harmony with TRE, is an excellent probe for exploring kinetic stability of cyclic π-systems. It represents the contribution of individual π-bonds to global aromaticity. The well-known isolated pentagon rule (IPR) for fullerenes was verified in terms of BRE. Superaromatic stabilization energy (SSE) defined for macrocyclic π-systems finally confirmed the absence of macrocyclic aromaticity in kekulene. A novel local aromaticity index for polycyclic aromatic hydrocarbons (PAHs) was devised by reinterpreting the definition of SSE. We then found that aromatic properties of some PAHs are not compatible with Clar's aromatic sextet rule. We now feel that many fundamental problems with regard to aromatic stabilization and related phenomena have been solved conceptually.

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Section: Aromatic Character Of Fullerenesmentioning

confidence: 99%

Graph Theory of Aromatic Stabilization

Aihara¹

2016

BCSJ

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“…With the construction of molecular square 2 from 8, the first example of a supramolecular fullerene dimer was obtained. On the other hand, the properties of hexakis-adduct (AE)-1, with six addends in a distinct helical array along an equatorial belt, strongly differ from those of hexakis-adducts featuring a pseudooctahedral addition pattern (for a recent report on another higher adduct of C 60 with all addends placed along an equatorial belt, see [34]). Compound (AE)-1 features an addition pattern (A in Fig.…”

Section: Physical Properties and Chemical Reactivity Of (Ae)-1: Prepamentioning

confidence: 99%

Hexakis-Adducts of [60]Fullerene with Different Addition Patterns: Templated Synthesis, Physical Properties, and Chemical Reactivity

Bourgeois

Woods

Cardullo

et al. 2001

HCA

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Representatives of two classes of hexakis-adducts of C 60 were prepared by templated synthesis strategies. Compound 8 with a dipyridylmethano addend in a pseudo-octahedral addition pattern was obtained by DMAtemplated addition (DMA 9,10-dimethylanthracene; Scheme 1) and served as the starting material for the first supramolecular fullerene dimer 2. Hexakis-adduct 12 also possesses a pseudo-octahedral addition pattern and was obtained by a sequence of tether-directed remote functionalization, tether removal, and regioselective bis-functionalization (Scheme 2). With its two diethynylmethano addends in trans-1 position, it is a precursor for fascinating new oligomers and polymers that feature C 60 moieties as part of the polymeric backbone ( Fig. 1).With the residual fullerene p-electron chromophore reduced to a cubic cyclophane-type sub-structure (Fig. 4), and for steric reasons, 8 and 12 no longer display electrophilic reactivity. As a representative of the second class of hexakis-adducts, (AE)-1, which features six addends in a distinct helical array along an equatorial belt, was prepared by a route that involved two sequential tether-directed remote functionalization steps (Schemes 3 and 5). In compound (AE)-1, p-electron conjugation between the two unsubstituted poles of the carbon sphere is maintained via two (E)-stilbene-like bridges (Fig. 4). As a result, (AE)-1 features very different chemical reactivity and physical properties when compared to hexakis-adducts with a pseudo-octahedral addition pattern. Its reduction under cyclic voltammetric conditions is greatly facilitated (by 570 mV), and it readily undergoes additional, electronically favored Bingel additions at the two sterically well-accessible central polar 6-6 bonds under formation of heptakis-and octakis-adducts, (AE)-30 and (AE)-31, respectively (Scheme 6). The different extent of the residual p-electron delocalization in the fullerene sphere is also reflected in the optical properties of the two types of hexakis-adducts. Whereas 8 and 12 are bright-yellow (end-absorption around 450 nm), compound (AE)-1 is shiny-red, with an end-absorption around 600 nm. This study once more demonstrates the power of templated functionalization strategies in fullerene chemistry, providing addition patterns that are not accessible by stepwise synthetic approaches.1. Introduction. ± Among the higher adducts of buckminsterfullerene (C 60 ; for a recent example, see [1]), hexakis-adducts are increasingly attracting interest as threedimensional scaffolds for advanced materials applications [2] [3]. Among those, derivatives with a pseudo-octahedral (T h ) addition pattern have been the earliest and most widely investigated ones [4 ± 8]. Also known is a hexakis-adduct with a D 3 -symmetrical addition pattern [2]. Both types of hexakis-adducts are accessible by stepwise additions, and their addends are evenly distributed over the entire carbon sphere. In this paper, we describe the synthesis of new hexakis-adducts with the T hsymmetrical addition pattern, which are useful...

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“…It gives a single line in the 19 F NMR spectrum at d À 132.8. [34] The addition pathway for fluorination can occur by two routes, and either C 60 F 18 or C 60 F 20 can be produced. The former is aromatic and is therefore produced in larger quantity.…”

Section: Càcmentioning

confidence: 99%

Fluorinated Fullerenes

Taylor

2001

Chem. Eur. J.

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Recent developments in fluorination of fullerenes coupled with HPLC separation have permitted the isolation and subsequent structural characterisation of many derivatives, a number of which have novel and unexpected structures. The good solubility of fluorofullerenes, high reactivity towards nucleophiles and enhanced dienophilicity of the unsubstituted part of the cage, as a result of electron withdrawal by the fluorines, makes fluorofullerenes promising synthons. In particular that may have enhanced performance in donor-acceptor complexes with respect to bare fullerenes.

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Cited by 13 publications

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Graph Theory of Aromatic Stabilization

Graph Theory of Aromatic Stabilization

Hexakis-Adducts of [60]Fullerene with Different Addition Patterns: Templated Synthesis, Physical Properties, and Chemical Reactivity

Fluorinated Fullerenes

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