Facile Access to Functional Building Blocks of C₆₀ Involving C₃‐Symmetrical Addition Patterns

Abstract

A new class of C3‐symmetrical fullerene building blocks with a well‐defined spatial arrangement of addends has been developed. They comprise compounds with a e,e,e‐trisaddition pattern and a mixed octahedral hexakisaddition pattern. Fullerenophosphates with a e,e,e‐addition pattern were used for the spatial preorganization of the addends. After deprotection seven different trisbromides (12–16, 15a, 16a) with varying chain lengths and orientation of the functional groups were obtained. Acetylenes could be coupled to these compounds by click chemistry through an intermediate trisazide. For the synthesis of mixed hexakisadducts 19–21 a template system based on a central benzyl moiety was attached to the free hemisphere of the trisadduct fullerenophosphates. It was shown that the phosphate and the benzyl template can be removed independently. Fully deprotected building block 24 bearing both terminal bromide and hydroxy moieties was prepared. In addition, rather complex hybrid architecture 29 bearing three porphyrin units in the polar addend zone was successfully synthesized.

A study towards the regioselective synthesis of the e,e,e trisadduct of C60 via the [4+2] Diels-Alder reaction with tethers bearing ortho-quinodimethane precursors

“…The tether-directed remote functionalization method has been successfully applied for the synthesis of C 3 -symmetrical trisadducts of C 60 by the groups of Diederich, 6 Hirsch, [7][8][9][10][11][12] Nierengarten 13-15 and ours. [16][17][18] Opened-and closed-structure tethers equipped with three malonate groups were utilized for this purpose and all possible C 3 -symmetrical addition patterns have been accessed except the cis-1,cis-1,cis-1 (all-cis-1) which is not energetically favored owing to the steric hindrance of the addends.…”

“…The reports of Hirsch [9][10][11][12] and Nierengarten 13,14 on the synthesis of e,e,e trisadducts of C 60 with tripodal tethers equipped with malonate moieties, prompted us to design opened-structure tether 10 bearing ortho-quinodimethane precursors covalently connected to the phloroglucinol focal point via two-carbon alkyl chains (Scheme 3). Bromoethanol was firstly protected as a THP ether 33 followed by a three-fold Williamson etherification with phloroglucinol to afford tripodal protected alcohol 7.…”

Efficient Photoinduced Energy and Electron Transfer in ZnII–Porphyrin/Fullerene Dyads with Interchromophoric Distances up to 2.6 nm and No Wire‐like Connectivity

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Their photophysical properties have been investigated in details, revealing that the deactivation scenario can be affectedb ys everal parameters, such as the polarity of the solvent [15][16][17][18][19][20][21][22][23] or the interchromophoric distance. [29,[33][34][35][36][37][38][39][40][41][42][43] For example, we have reported the synthesis of the hybrid system fullerene-porphyrin-fullerene( F-P-F,s ee the structure below).T his compoundwas prepared by the reactiono faC 60 derivative bearing an azide functional group [34,35] with aZ n II -porphyrin bearing two terminal alkyne groupsu nder the copper-mediated Huisgen 1,3-dipolar cycloaddition conditions. [29,[33][34][35][36][37][38][39]…”

“…[24][25][26][27][28][29][30][31][32] As part of this research, it has been shown that the fullerene-porphyrin conjugation can be convenientlya chieved by using copper-catalyzed alkyne-azide cycloaddition (CuAAC) reactions. [29,[33][34][35][36][37][38][39][40][41][42][43] For example, we have reported the synthesis of the hybrid system fullerene-porphyrin-fullerene( F-P-F,s ee the structure below).T his compoundwas prepared by the reactiono faC 60 derivative bearing an azide functional group [34,35] with aZ n II -porphyrin bearing two terminal alkyne groupsu nder the copper-mediated Huisgen 1,3-dipolar cycloaddition conditions. [44][45][46][47][48] Detailed photophysical studies revealed strong excited-state interactions between the different components in the conjugate F-P-F. [34,49] In particular,a ne fficient photoinduced electron transfer from both fullerenea nd porphyrin triplet levels has been evidenced in benzonitrile.…”

Mono‐ und ditope Bisfunktionalisierung von Graphen

“…Dadurch lassen sich vielversprechende praktische Anwendungen im Bereich der Sensorik, [1] des Nanokompositaufbaus [2] und biomedizinischer Produkte [3] verwirklichen. Die Synthese derartiger molekularer Architekturen, bestehend aus einem Kohlenstoffallotrop-Kern und zwei oder mehreren unterschiedlichen kovalent gebundenen Funktionalitäten, konnte im Bereich der Fulleren- [4][5][6][7][8][9][10] und der Kohlenstoffnanorçhrenchemie [11][12][13][14][15] bereits realisiert werden. Demgegenüber erschien der zielgerichtete Aufbau von gemischtfunktionalen Graphenderivaten nur schwer umsetzbar.E ine der effizientesten Methoden der Graphenfunktionalisierung basiert auf der Reduktion/Exfolierung von Graphit mit Alkalimetallen in inerten Lçsungsmitteln und nachfolgendem Abfangen der intermediär gebildeten Graphenide mit geeigneten Elektrophilen (Schema 1a).…”