Combustion synthesis and electrochemical properties of the small hydrofullerene C50H10.

The hydrofullerene C(50)H(10) is synthesized by low-pressure benzene-oxygen diffusion combustion. The structure of C(50)H(10) is identified through NMR, mass spectrometry, and IR and Raman spectroscopy as a D(5h) symmetric closed-cage molecule with five pairs of fused pentagons stabilized by ten hydrogen atoms. UV/Vis and fluorescence spectrometric analyses disclose its optical properties as comparable with those of its chloride cousin (C(50)Cl(10)). Cyclic and square-wave voltammograms reveal that the first reduction potential of C(50)H(10) is more negative than that of C(50)Cl(10) as well as C(60), with implications for the utilization of C(50)H(10) as a promising electron acceptor for photovoltaic applications.

4H-Cyclo-penta-[def]phenanthren-4-one.

In the title compound, C(15)H(8)O, the asymmetric unit contains four independent mol-ecules and crystallizes with aromatic π-π stacking inter-actions[centroid-centroid distances = 3.5326 (18) Å].

Chlorination for efficient identification of polycyclic aromatic hydrocarbons by liquid chromatography-mass spectrometry.

Utilizing liquid chromatography-mass spectrometry (LC-MS) for identification of polycyclic aromatic hydrocarbons (PAHs) has long been underrated, as the sensitivity for determination of PAHs directly by MS is very poor. In the present work a chlorination method for high-sensitive determination of PAHs by LC-MS is discussed. This method includes two steps: (1) chlorination of PAHs by the BMC method; (2) determination of the chlorinated PAHs by LC-MS. Interfaced by atmospheric pressure chemical ionization in negative ion mode, five representative perchlorinated PAHs producing from the languidly detectable parent PAHs (naphthalene C(10)H(8), acenaphthene C(12)H(10), phenanthrene C(14)H(10), pyrene C(16)H(10) and fluoranthene C(16)H(10)) have been LC-MS characterized in high sensitivity with determination limits in 10(-9)g/mL level. In addition, molecular compositions and polycyclic carbon-frameworks of unknown PAHs can be identified according to the isotopic pattern of the chloro-derivatives ions in the corresponding mass spectra. Our experiments demonstrate that the proposed chlorination-involving LC-MS method is efficient for the PAHs analysis, for example, in soot and soil samples.

Chlorofullerenes featuring triple sequentially fused pentagons.

The triple sequentially fused pentagons (TSFP) motif is one of the basic subunits that could be used for constructing fullerenes, but it violates the isolated pentagon rule (IPR) and has not been found in carbon cages to date. The properties of TSFP-incorporating fullerenes are thus poorly explored both theoretically and experimentally. Reported herein are four chlorinated derivatives of three different fullerene cages, all with the TSFP motif. X-ray crystallographic analyses indicate that the molecular strain inherent to the pentagon adjacency of a TSFP is significantly relieved upon exohedral chlorination, leaving one of the four pentagon fusion sites unsaturated and rendering the present derivatives chiral. This unique reactivity, in stark contrast to that of previously reported non-IPR fullerenes containing double fused pentagons or triple directly fused pentagons, can be rationalized by density functional theory calculations, and are expected to stimulate further studies of these new members of the fullerene family, both theoretically and experimentally.