Carbyne: The Molecular Approach

Abstract

For the last 60+ years, the synthesis and study of cumulenes and polyynes have been the focus of a small, but dedicated, group of researchers. Many of the remarkable electronic, optical, and structural properties of cumulenes and polyynes had already been identified in the earliest reports. The molecular lengths achievable by the initial syntheses were, unfortunately, somewhat limited by synthetic methods available. For the past 15 years, we have worked toward expanding on the synthesis of cumulenes and polyynes through the development of new methods and stabilization motifs. As new compounds have become available, homologous series of cumulenes and polyynes have then been examined as a function of molecular length. While we are not yet there, we would like to eventually provide a general description of the sp-carbon allotrope carbyne, and this account presents some of our efforts toward this goal.

How to Bend a Cumulene

“…These linear molecules have several interesting properties. For example, they can be used as molecular wires [31][32][33][34] as their conductivity is significantly better than the other possible form of linear carbon chains,p olyynes. [32,35,36] Strong s donors as end-capping groups of the cumulene chain give their radical speciesaremarkable stability, [26,32,[37][38][39][40] with someo ft hese radicals stable even to air.…”

Mono‐ and Bis(imidazolidinium ethynyl) Cations and Reduction of the Latter To Give an Extended Bis‐1,4‐([3]Cumulene)‐p‐carboquinoid System

“…Mono-and bis(imidazolidinium ethynyl) cations have also been synthesized from the reaction of an NHC with phenylethynyl bromide or 1,4-bis(bromoethynyl)benzene.C yclic voltammetry coupled with synthetic and structural studies showed that the dication is readily reduced to aneutral, singlet bis-1,4-([3]cumulene)-p-carboquinoid as ar esult of the paccepting properties of the capping NHCs.Extended cumulenes and polyynes have received much attention. Fore xample,T ykwinski and co-workers [1,2] and others [3] have used them as molecular wires and as linkers between the end caps of rotaxanes. [4] These extended linear carbon-atom chains are conjugated p-systems,w hich allows for communication across their length.…”

“…Extended cumulenes and polyynes have received much attention. Fore xample,T ykwinski and co-workers [1,2] and others [3] have used them as molecular wires and as linkers between the end caps of rotaxanes. [4] These extended linear carbon-atom chains are conjugated p-systems,w hich allows for communication across their length.…”

Структурные Свойства Тонких Пленок, Полученных Магнетронным Распылением Полидиацетилена

“…В работе [29] серия линий с волновыми числами в диапазоне 1700−2200 cm −1 приписывается колебаниям sp-гибридизованных цепочек в структуре углеродсеребряных композитов. В то же время, данная линия не встречается в спектрах углеродных цепочек с sp-гибридизацией, находящихся в растворе [30,31], и не предсказывается моделями, в которых рассчитывается спектр идеальных цепочечных структур, стабилизированных различными радикалами [32]. Все это позволяет предположить ее связь с деформацией структуры цепочек.…”