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.
One abiding surprise in fullerene science is that I(h)-symmetric buckminsterfullerene C(60) (ref. 1) (I(h)-C(60) or (#1,812)C(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm) remains the sole C(60) species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule, which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected, synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C(2v)- and C(s)-symmetric C(60) cages. These chlorinated species, (#1,809)C(60)Cl(8)(1) and (#1,804)C(60)Cl(12)(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C(60) isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme.
The hen egg shells (HES) from EnShi, HuBei Province, China, which contain selenium, are used as adsorbent for the adsorption of lead ion from its aqueous solutions. The selenium in the HES could help to remove lead from its aqueous solution. The HES had been found to be the more efficient in the experiment and removed about 95% of lead from its aqueous solution. The final concentration of lead ion was found lower than the waste water quality standards from the initial concentration of lead ion 100.0 mg/L through these two steps of adsorptions. One gram of the HES can adsorb nearly 31.71±0.040 mg of lead ions. The adsorption kinetics was fitted by first-order model throughout the period. The present adsorption process is spontaneous, indicating HES can be availably used for the removal of lead ions from its aqueous solution.
In this paper, we collected 108 soil samples from four representative mining areas based on the selenium resources distribution in Enshi City. The contents of eight heavy metal elements including Pb, Cd, Hg, As, Cr, Cu, Zn and Ni were detected by inductively coupled plasma mass spectrometry (ICP-MS). The compositive pollution effects in the four mining areas of the heavy metals were evaluated through the single factor index method and the Nemero synthesis index evaluation method. The accumulation characteristics of heavy metals in the vegetable soils were also analyzed in the four mining areas. The results shown that the pollution of the vegetable soils in the four mining areas were attributed to a multi-metals pollution mainly by the V, Cd, Hg and Ni. The vegetable soils in Enshi City have been polluted by heavy metals based on the results of the ayalasis of the single factor index method and the Nemero synthesis index evaluation method. The influence of the heavy metals to the pollution in Enshi City is Cd>Ni>Cr>Cu>Hg>As>Zn>Pb.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.