Carbyne forms of carbon: continuation of the story
Carbyne forms of carbon: continuation of the story
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DOI：
10.1016/0008-6223(94)90149-x
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发表时间：
1994
期刊：
影响因子：
10.9
通讯作者：
L. Kavan;J. Kastner
中科院分区：
文献类型：
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作者：
L. Kavan;J. Kastner
第一种异构体理论上更稳定III。线性全碳键有时出现在有机分子中。Et-&i-（C= C）i n-SiEt？和HK% C）nH。例如，已在e&y%'s（lo）中进行了syn&esiz&。存在各种其他多炔衍生物[111]，其中一些甚至可经由生物合成获得[12]。多炔氰化物，H-（C= C），，-CN（n= 2-4），据报道出现在星际分子云[131]。小线性全碳分子（C2、C3、.）在彗星、冷星和其他奇异的环境中被发现。在陆地条件下，它们以气态存在，例如，在碳蒸气中，以及在特殊化学或光化学过程的产物中[141]。C4-09的环状形式也可以被认为是1111：下部成员'（e. C6-Cs-“Cracatene”1151具有极高的甲酸热，但大的环状配位数（2Gin）可能不稳定。最终v.形成X。“I Y.*由于富勒烯的发现，C60和其他较大分子的封闭球形结构现在是众所周知的。大环多炔被认为是形成富勒烯的前体[161]。还没有线性全碳分子以宏观量合成，以允许其在凝聚相中表征。鲍曼等人[173已经提出了通过将线性（sp-键合的）连接引入石墨层的假设的碳晶体（“石墨炔”）。类似的推理导致富勒烯炔[18]和层链碳[19]。Diedrich [111]综述了一种针对此类碳链的前瞻性合成方法。鲍曼等人[171怀疑纯线性碳同素异形体（“碳炔”）的存在，因为与例如石墨炔相比，其生成热太高（25.4千卡/摩尔）。自60年代早期以来，关于碳炔存在的有争议的讨论已经出现在文献中（综述参见[3-51]）。这种材料也被称为“白色碳”、“里斯火山口碳”、“chaoite”和“nolvacetvlene”。后者（相当误导）术语有时出现在旧的俄罗斯文件。（Sladkov的术语“carbvne”141，也不是没有矛盾，因为它与IUPAC对某些自由基的编码术语相一致[20]）。
The first isomer is theoretically more stable Ill. Linear all-carbon linkages sometimes occur in organic molecules. Et-&i-(C= C) i n-SiEt? and HK% C) nH. for example, have been syn&esiz&in the e&y%‘s (lo]. There are various other polyyne derivatives [l 11, some of which are even accessible via biosynthesis[12]. Polyynylcyanides, H-(C= C),,-CN (n= 2-4), reportedly appear in interstellar molecular clouds [131. Small linear all-carbon molecules (C2, C3,...) were found in comets, cold stars, and other exotic environments. In terrestrial conditions, they occur in the gaseous state, eg, in carbon vapor, and in products of special chemical or photochemical processes [141. Cvclic forms of C4-09 can also be considered 1111: the lower members’(e. &-Cs-“cracatene” 1151 possess extreme heats of forma&t, but large cyclic &ra@ ements (2 Gin) mieht be stable II 11. Eventuallv. the formation x.“I Y.* 4, of closed spheroidal structures for Ceo and other larger molecules is now well known thanks to the discovery of fullerenes. Macrocyclic polyynes are supposed to be precursors in the formation of fullerenes [161. No linear all-carbon molecule has yet been synthesized in a macroscopic quantity to allow its characterization in a condensed phase. Baughman et al.[173 have suggested hypothethical carbon crystals (“graphynes”) by introducing linear (sp-bonded) links into the graphite layer. Similar reasoning leads to fullereneynes[18] and layer-chain carbons [19]. A prospective synthetic approach toward such carbon skeltons was reviewed by Diedrich [111. Baughman et al.[171 doubt the existence of a purely linear carbon allotrope (“carbyne”), since its heat of formation would be too high (25.4 kcal/mol) as compared, eg, to graphynes.Controversial discussions about the existence of carbyne have appeared in the literature since early 60’s (for reviews see [3-51). Such a material is also called “white carbon”,“Ries crater carbon”,“chaoite” and “nolvacetvlene”. The latter (rather misleading) term appears sometimes in old Russian papers.(Sladkov’s term “carbvne” 141, is not without obiections, either, since it con&ts with the IUPAC-codified term for some free radicals [20]).