Shun-Liu Deng

Outer Wall Selectively Oxidized, Water-Soluble Double-Walled Carbon Nanotubes

The outer walls of double-walled carbon nanotubes (DWNTs) were selectively oxidized using a combination of oleum and nitric acid. Intercalation of oleum between bundled DWNTs enabled a homogeneous reaction by equally exposing all outer wall surfaces to the oxidants. At optimized reaction conditions, this double-wall chemistry enabled high water solubility through carboxylic acid functional groups introduced to the outer wall, while leaving the inner tube intact, as shown by Raman scattering and high resolution TEM. These outer wall selectively oxidized DWNTs retained electrical conductivity up to 65% better than thin films of similarly functionalized single-walled carbon nanotubes, which can be attributed to enhanced electrical percolation via the nonoxidized inner tubes.

Separation and identification of perchlorinated polycyclic aromatic hydrocarbons and fullerenes (C60, C70) by coupling high-performance liquid chromatography with ultraviolet absorption spectroscopy and atmospheric pressure chemical ionization mass spectrometry

Simultaneous separation and identification of perchlorinated polycyclic aromatic hydrocarbons (PCPAHs) and fullerenes is of practical interest due to the growth mechanism of fullerenes involved with PCPAHs. Non-aqueous reversed-phase high-performance liquid chromatography (HPLC), with an ODS column and a gradient mobile phase of methanol-ethanol-cyclohexane mixtures, was combined with both rapid-scan ultraviolet spectrometry (UV) and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) for the separation and identification of over 80 PCPAHs as well as fullerenes C60 and C70, that were synthesized in the discharge reaction of chloroform. PCPAH retention was found to depend on the number of aromatic rings and the degree of non-planarity of PCPAH structure. Based on the isotopic pattern of molecular ion or/and quasi-molecular ion peaks in corresponding mass spectra, molecular compositions of the PCPAH products were unambiguously determined. The results obtained from the HPLC-UV-MS analysis not only are helpful for the understanding of the fullerenes formation mechanism, but also contribute to the analytical technique capable of separating and identifying the complicated mixture of PCPAHs and fullerenes.

Five isomers of C60 generated in microwave plasma of chloroform

Abstract In addition to I h symmetry buckminsterfullerene, four other isomers of C 60 were generated in a microwave plasma of chloroform. The newly observed isomers, separated and identified by a high performance liquid chromatography coupled with mass spectrometry (HPLC–MS), were found to be stable at room temperature but transform to buckminsterfullerene when heated. With regards to the generation of various fully chlorinated carbon clusters as well as the C 60 isomers, which may be attributed to the rapidly cooling of the synthetic reaction, a modified Pentagon Road scheme is suggested for fullerene formation.

Outerwall selective alkylcarboxylation and enrichment of double-walled carbon nanotubes

Double-walled carbon nanotubes were enriched from their single- and few-walled counterparts as well as other carbonaceous byproducts coexisting in as-synthesized materials using Billups–Birch reductive alkylcarboxylation chemistry. The enrichment was made possible due to high selectivity of the reaction towards smaller diameter, single-walled carbon nanotubes and more defective carbonaceous structures. Raman resonant scattering studies suggest that alkylcarboxylation selectively occurred on the outerwalls while the inner-tubes remained unaffected. The separated double-walled carbon nanotubes were water soluble due to outerwall alkylcarboxylation, but the Raman modes and part of the optical properties of the inner-tubes were preserved.

Synthesis, structural characterization and ab initio calculation of dipyridyltetraazathiapentalene: a highly conjugative polycyclic molecule with hypervalent N-S-N bond

通讯作者地址: Zheng, LS (通讯作者), Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China

Capillary electrophoresis of covalently functionalized single-chirality carbon nanotubes: Nanoanalysis

We demonstrate the separation of chirality‐enriched single‐walled carbon nanotubes (SWCNTs) by degree of surface functionalization using high‐performance CE. Controlled amounts of negatively charged and positively charged functional groups were attached to the sidewall of chirality‐enriched SWCNTs through covalent functionalization using 4‐carboxybenzenediazonium tetrafluoroborate or 4‐diazo‐N,N‐diethylaniline tetrafluoroborate, respectively. Surfactant‐ and pH‐dependent studies confirmed that under conditions that minimized ionic screening effects, separation of these functionalized SWCNTs was strongly dependent on the surface charge density introduced through covalent surface chemistry. For both heterogeneous mixtures and single‐chirality‐enriched samples, covalently functionalized SWCNTs showed substantially increased peak width in electropherogram spectra compared to nonfunctionalized SWCNTs, which can be attributed to a distribution of surface charges along the functionalized nanotubes. Successful separation of functionalized single‐chirality SWCNTs by functional density was confirmed with UV‐Vis‐NIR absorption and Raman scattering spectroscopies of fraction collected samples. These results suggest a high degree of structural heterogeneity in covalently functionalized SWCNTs, even for chirality‐enriched samples, and show the feasibility of applying CE for high‐performance separation of nanomaterials based on differences in surface functional density.

The formation mechanism of fullerene

Although tremendous advances in fullerene sciences have been achieved since the first discovery of fullerene in the middle of 1980’, the formation of these all-carbon cages still remains a mystery. Based on available experimental and computational evidences, some interpretations responsible for fullerene formation have been suggested in literatures. Most of them can be classified as bottom-up, top-down or size-up/size-down models. Suffering from limitation of powerful evidences, however, most of them still require validation. Herein we review the most important hypothetic fullerene formation models that have been proposed to date.

Bis(pentachlorophenyl) disulfide

通讯作者地址: Zheng, LS (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Univ Malaya, Dept Chem, Kuala Lumpur 50603, Malaysia

1,2,3,5,6,7,8,9-octachlorocyclopenta[def]phenanthren-4-one

通讯作者地址: Huang, RB (通讯作者), Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Dept Chem, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 电子邮件地址: rbhuang@xmu.edu.cn