Thermodynamically stable [4 + 2] cycloadducts of lanthanum-encapsulated endohedral metallofullerenes

• Yuta Takano,
• Yuki Nagashima,
• M. Ángeles Herranz,
• Nazario Martín and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2014, 10, 714–721, doi:10.3762/bjoc.10.65

• slow or fast to allow their observation in an NMR time scale. The signals from the AB-quartet of 4a coalesce at 290 K (= Tc) indicate a dynamic process, which is attributed to the boat-to-boat interconversion of the cyclohexane ring of the addend similarly to the related carbocyclic analogues of C60

Tuning the interactions between electron spins in fullerene-based triad systems

• Maria A. Lebedeva,
• Thomas W. Chamberlain,
• E. Stephen Davies,
• Bradley E. Thomas,
• Martin Schröder and
• Andrei N. Khlobystov

Beilstein J. Org. Chem. 2014, 10, 332–343, doi:10.3762/bjoc.10.31

• 10.3762/bjoc.10.31 Abstract A series of six fullerene–linker–fullerene triads have been prepared by the stepwise addition of the fullerene cages to bridging moieties thus allowing the systematic variation of fullerene cage (C60 or C70) and linker (oxalate, acetate or terephthalate) and enabling precise

• up per molecule in the potential range between −2.3 and 0.2 V (vs Fc+/Fc). No significant electronic interactions between fullerene cages are observed in the ground state indicating that the individual properties of each C60 or C70 cage are retained within the triads. The electron–electron

• materials for the study of polyfunctional materials. For example, significant effort has been directed into incorporating N@C60 molecules into quantum computing devices [2]. Incorporating a second radical centre into these molecules, in addition to the endohedral atom, introduces a mechanism to control the

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• , which are able to solubilize hydrophobic, nearly insoluble guest molecules, such as camptothecin [20], 1,4-dihydroxyanthraquinone [21], betulin [22], benzene and cyclohexane derivatives [23], and even C60 [24] in water. Furthermore, their respective γ-CD thioethers form highly water-soluble 1:2

A study on electrospray mass spectrometry of fullerenol C₆₀(OH)₂₄

• Mihaela Silion,
• Andrei Dascalu,
• Mariana Pinteala,
• Bogdan C. Simionescu and
• Cezar Ungurenasu

Beilstein J. Org. Chem. 2013, 9, 1285–1295, doi:10.3762/bjoc.9.145

• , “Gheorghe Asachi” Technical University of Iasi, 700050 Iasi, Romania 10.3762/bjoc.9.145 Abstract Full characterization of fullerenol C60(OH)24 by HPLC ESI-MS in negative and positive ionization modes was achieved. Fragmentor voltage and capillary voltage were optimized in order to obtain a good signal

• stability and the best peak intensity distribution for the fullerenol C60(OH)24 in both negative and positive modes. While the predominant base peak observed for C60(OH)24 in the negative ionization mode was [M − H]− at m/z 1127, those observed in the positive mode were multiply charged [M − H2O + 4H]4+ at

• m/z 279 and [M − 12H2O + 2NH3 + 6H]6+ at m/z 158. Keywords: electrospray; fullerenol C60(OH)24; mass spectrometry; Introduction Because of their potential for chemical tunability and exciting range of biological activities as glutamate-receptor antagonists [1] and antiproliferative [2][3

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• . Derivative 150 can be desilylated to a C60H36 hydrocarbon, whose C36 backbone represents ca. 60% of the fullerene framework and which can be mapped onto C60 [121]. A pericyclic reaction of conjugated bisallenes which has also been studied extensively over the years involves the Diels–Alder addition with both

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• of C60 in water reaching concentrations of 15 mg/L. Equilibrium state was approached after seven days without the use of organic cosolvents. The 1:2 stoichiometry of the C60/γ-CD thioether complexes was demonstrated by a parabolic phase-solubility diagram. In contrast, native γ-CD forms nanoparticles

• with C60. Particle sizes of C60 were determined by dynamic light scattering. Keywords: C60; cyclodextrins; dynamic light scattering; particle size; solubilization; UV spectrum; Introduction Since the first spectroscopic discovery of buckminsterfullerene, C60, by Kroto, Heath, Curl and Smalley in 1985

• ]. A good solubility of C60 in water is especially required for biological applications; however, this is not the case at all. Solubility of C60 was estimated to be as low as 10−8 ng/L, equivalent to 10 C60 molecules per millilitre of water [10][11]. Therefore, hydrophilic derivatives of C60 have been

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• : A central azobenzene, a rigid frame composed of oligo(phenylacetylenes), which in turn are anchored to azobenzene through para positions, and wheels based on fullerene C60 (azo-14) or p-carboranes (azo-15). Photoisomerization studies suggest that only the azobenzene system with p-carborane wheels

Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

• Katharina C. Kress,
• Martin Kaller,
• Kirill V. Axenov,
• Stefan Tussetschläger and
• Sabine Laschat

Beilstein J. Org. Chem. 2012, 8, 371–378, doi:10.3762/bjoc.8.40

• malonates has been devoted to C60 fullerene dendrimers [27][28][29][30][31]. Only a few liquid crystalline cyanoacetates have been described so far. The first example, a dihydrazide, was reported by Schubert [32]. Furthermore some calamitic and bent-core mesogens derived from α-cyanocinnamic acid were

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• [19]. As noted below, this extended aromatic surface is oriented perfectly for C60 inclusion [23]. 2 Conformational properties Oxacalix[3]arenes have received significant attention as receptors, mainly due to their structural features: A cavity formed by a 18-membered ring, only two basic

• function as a molecular recognition centre. The cavity created by the lipophilic phenolic units, particularly when held in place through allosteric effects of lower-rim substituents bound to metals, can accommodate a number of quaternary ammonium ions or buckminsterfullerene, C60. Consequently, the ability

• guests and immediately suggests binding to fullerenes. Furthermore, the macrocyclic bowl is the perfect size for C60 and has a complementary threefold-symmetry element. Based on the knowledge that p-tert-butylcalix[8]arene was able to complex C60 [72][73] Shinkai investigated the interaction of C60 with

Reciprocal polyhedra and the Euler relationship: cage hydrocarbons, C_nH_n and closo-boranes [B_xH_x]²⁻

• Michael J. McGlinchey and
• Henning Hopf

Beilstein J. Org. Chem. 2011, 7, 222–233, doi:10.3762/bjoc.7.30

• and will remain at the forefront of alicyclic chemistry until a stepwise synthesis of C60 is achieved. However, we note en passant that Scott, de Meijere and their colleagues have devised a rational route to C60 from a chlorinated precursor, C60H27Cl3, in which only the final ring closures were

• original concept and propose that other highly symmetrical cage hydrocarbons of the CnHn type might have closo-borane counterparts. Indeed, Lipscomb and Massa have discussed the structures of borane analogues of fullerenes [52][53] and even of nanotubes [54]. In particular, they proposed that C60 (V, E, F

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• molecular building blocks, it is possible to modulate the interactions necessary for organization of single molecules in to supramolecular architectures to give rise to the desired metallomesogenic material. Moreover, preliminary measurements of photoconductivity on these complexes doped with C60 to

Synthesis of mesogenic phthalocyanine-C₆₀ donor–acceptor dyads designed for molecular heterojunction photovoltaic devices

• Yves Henri Geerts,
• Olivier Debever,
• Claire Amato and
• Sergey Sergeyev

Beilstein J. Org. Chem. 2009, 5, No. 49, doi:10.3762/bjoc.5.49

• /bjoc.5.49 Abstract A series of phthalocyanine-C60 dyads 2a–d was synthesized. Key steps in their synthesis are preparation of the low symmetry phthalocyanine intermediate by the statistical condensation of two phthalonitriles, and the final esterification of the fullerene derivative bearing a free COOH

• example of LC phthalocyanine-C60 dyads. Keywords: donor–acceptor dyad; fullerene; liquid crystals; phthalocyanine; phthalonitrile; Introduction Among sustainable energy technologies, photovoltaic (PV) conversion of solar energy is considered as a promising solution. Although currently the market is

• expect that for such high order of self-organization, liquid crystalline (LC) materials will be beneficial, because they combine order and fluidity, which allows the self-healing of structural defects [8]. One of the most widely used molecules in the bulk heterojunction PV devices is fullerene C60

New diarylmethanofullerene derivatives and their properties for organic thin- film solar cells

• Daisuke Sukeguchi,
• Surya Prakash Singh,
• Mamidi Ramesh Reddy,
• Hideyuki Yoshiyama,
• Rakesh A. Afre,
• Yasuhiko Hayashi,
• Hiroki Inukai,
• Tetsuo Soga,
• Shuichi Nakamura,
• Norio Shibata and
• Takeshi Toru

Beilstein J. Org. Chem. 2009, 5, No. 7, doi:10.3762/bjoc.5.7

• , thermal treatment under reflux in toluene gave diarylmethanofullerenes 1a–k in good yields. The C70 derivative 2, a mixture of isomers, was prepared from 16a by a procedure similar to those of C60 derivatives 1a–k using C70 instead of C60. As expected, all the compounds were soluble in all organic

• ; 7.88, N; 4.21. Found: C; 68.92, H; 8.19, N; 4.21. Methyl 4-{[6,6]-1-[3,4-bis(octyloxy)phenyl]C61}benzoate (1a) To a solution of 16a (613 mg, 0.92 mmol) in dry pyridine (5.0 mL) was added sodium methoxide (50 mg, 0.92 mmol). After stirring for 30 min at room temperature, a solution of C60 (398 mg, 0.55

• ; toluene). First fraction was unreacted C60. Fractions containing brown color were collected and the solvent was evaporated to leave a solid. This compound was dissolved in toluene and refluxed for 24 h to complete the isomerisation. The isomerisation was confirmed by HPLC (Develosil ODS-HG-5, MeOH/CHCl3

Synthesis of thienyl analogues of PCBM and investigation of morphology of mixtures in P3HT

• Fukashi Matsumoto,
• Kazuyuki Moriwaki,
• Yuko Takao and
• Toshinobu Ohno

Beilstein J. Org. Chem. 2008, 4, No. 33, doi:10.3762/bjoc.4.33

• methanofullerenes were prepared from p-tosylhydrazones (2) by a one-pot method. A slight excess of p-tosylhydrazone (1.2 equiv) was mixed and heated with C60 in the presence of sodium methoxide. The reaction was monitored by TLC and stopped within 3 to 4 h. As expected, the compound 3d exhibited an extremely low Rf