Nitrogen-tailored quasiparticle energy gaps of polyynes

Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.

Large-scale synthesis of polyynes with commercial laser marking technology

The space-confined synthesis method has been an efficient way for the preparation of linear carbon chains.However,the large-scale preparation of linear carbon chains still faces many challenges due to the lack of methods for the large-scale synthesis of precursors,such as short carbon chains(polyynes),and regulation technology for the transport of reactants in one-dimensional space.Here,we report a facile method for the rapid preparation of polyynes in large quantities using a commercial laser marking machine.Spectroscopic characterizations show that a large number of polyynes,such as C_(8)H_(2),C_(10)H_(2),C_(12)H_(2),and C_(14)H_(2),can be produced by ablating the graphite plate immersed in the organic liquid using a laser marking machine.The results of in situ Raman spectroscopy investigation of C_(2n)H_(2)-filled single-walled carbon nanotubes further confirm that a variety of polyyne molecules are synthesized.Meanwhile,in situ Raman spectroscopy also shows that the local heating treatment can accelerate the filling process of C_(2n)H_(2)into one-dimensional channels.This work provides new insights into the study of linear carbon chains and space-confined synthesis methods.

Pharmacokinetic profiles of falcarindiol and oplopandiol in rats after oral administration of polyynes extract of Oplopanax elatus

Polyynes, such as facarindiol(FAD) and oplopandiol(OPD), are responsible for anticancer activities of Oplopanax elatus(O. elatus). A novel approach to pharmacokinetics determination of the two natural polyynes in rats was developed and validated using a liquid chromatography-electrospray ionization-mass spectrometry(LC-MS) method. Biosamples were prepared by liquid-liquid extraction using ethyl acetate/n-hexane(V : V = 9 : 1) and the analytes were eluted on an Agilent ZORBAX Eclipse Plus C18 threaded column(4.6 mm × 50 mm, 1.8 μm) with the mobile phase of acetonitrile-0.1% aqueous formic acid at a flow-rate of 0.5 m L·min–1 within a total run time of 11 min. All analytes were simultaneously monitored in a single-quadrupole mass spectrometer in the selected ion monitoring(SIM) mode using electrospray source in positive mode. The method was demonstrated to be rapid, sensitive, and reliable, and it was successfully applied to the pharmacokinetic studies of the two polyynes in rat plasma after oral administration of polyynes extract of O. elatus.

HYPERBRANCHED CONJUGATIVE MACROMOLECULES CONSTRUCTED FROM TRIPLE-BOND BUILDING BLOCKS

Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polymers possess low intrinsic viscosities and high thermal stabilities, losing little of their weights when heated to 〉 400℃. Upon pyrolysis at 〉 800℃, the polymers graphitize with high char yields （up to 86%）. Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60, a well-known optical limiter. Poly（alkenephenylenes）, poly（aroylarylenes） and polyynes are readily cross-linkable by UV irradiation, serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes （n up to 1.86）. The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls, which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities （Ms up to ca. 118 emu/g） and near-zero magnetic losses.

One-dimensional sp carbon:Synthesis,properties,and modifications

Carbyne,as the truly one-dimensional carbon allotrope with sp-hybridization,has attracted significant interest in recent years,showing potential applications in next-generation molecular devices due to its ultimate one-atom thinness.Various excellent properties of carbyne have been predicted,however,free-standing carbyne sample is extremely unstable and the corresponding experimental researches and modifications are under-developed compared to other known carbon allotropes.The synthesis of carbyne has been slowly developed for the past decades.Recently,there have been several breakthroughs in in-situ synthesis and measurement of carbyne related materials,as well as the preparation of ultra-long carbon chains toward infinite carbyne.These progresses have aroused widespread discussion in the academic community.In this review,the latest approaches in the synthesis of sp carbon are summarized.We then discuss its extraordinary properties,including mechanical,electronic,magnetic,and optical properties,especially focusing on the regulations of these properties.Finally,we provide a perspective on the development of carbyne.

A review of linear carbon chains

Linear carbon chains(LCCs)are a one-dimensional sp1-hybridized allo trope of ca rbon.LCCs are extre mely unstable:The longer the LCCs,the less stable the materials.Thus,it is a big challenge to synthesize long LCCs.Although the research on the short LCCs,e.g.,polyynes,can be traced back to the 18th,LCCs are still not well-known compared to other allotropes of carbon,e.g.,fullerenes,carbon nanotubes and graphene.Therefore,introducing recent progress on LCCs is of great significance to draw more attention in the community of nanocarbons as well as nanomaterials in general.Theoretically,various excellent properties have been predicted.Experimentally,LCCs with different length in many kinds of forms have been successfully synthesized.In this review,we summarized recent studies of polyynic LCCs from both theoretical and experimental aspects.Also,perspectives are highlighted to point out the further investigations of the materials.