Reactivity of Polyynes: Complex Molecules from Simple Carbon Rods

Abstract

Polyynes are linear carbon rods that may be regarded as models of carbyne – still elusive linear allotropic form of carbon. This microreview addresses the use of polyynes as synthetic precursors of complex organic and organometallic compounds. Application of such unusual molecules as starting materials for various chemical transformations leads to products which often are not easily accessible using “traditional“ approaches. Polyynes may for instance be used in the synthesis of molecular wires, materials possessing high nonlinear optical response, complex donor–acceptor systems, solvatochromic fluorescent dyes or natural products. The most significant challenge here is to control the regioselectivity of a transformation of such linear sp‐hybridized carbon chains. The impact of steric and electronic properties of reagents on the reaction pattern is hence highly important and will be discussed. Moreover, the transformations of end‐groups will also be addressed since their reactivity might very often be different than that of acetylenes.

A Series of Mono- and Bis-Alkynyl Co(III) Complexes Supported by a Tetra-imine Macrocyclic Ligand (TIM)

“…Metal alkynyl complexes have been an attractive target for both synthetic and material chemists since the pioneering work of Nast and subsequent development in polymerization by Hagihara . Exploration of novel alkynyl complexes based on transition metals has remained topical as evidenced by many comprehensive reviews that have appeared during the ensuing decades. − Both the extended conjugation and structural rigidity of metal-oligoynes render them appealing candidates for opto-electronic materials, − molecular wires, − and active species for molecular devices. − It is noteworthy that many of the efforts mentioned above have been based on 4 d and 5 d metals such as Ru, Re, Ir, and Pt, which are rare and precious metals. To transform these interesting properties and functions into technological applications, surrogates based on earth abundant elements are desired.…”

Nano-Hybrid Au@LCCs Systems Displaying Anti-Inflammatory Activity

“…Moreover, the Au@LCCs 2.6:1 showed a significantly higher anti-inflammatory activity than the 1:1 dispersion ( Figure 10 ). Although not well characterized and understood at the cellular and molecular level, the biological activity of Au NPs has been reported by several authors [ 74 ], conversely, there is no evidence of potential bioproperties of inorganic graphene-derived LCCs [ 75 ]. So the observed anti-inflammatory effects need to be ascribed to Au NPs contained in the hybrid Au@LCC colloid.…”

Linear Relationship between 13C NMR Chemical Shifts and the Bending of sp‐Carbon Chains

“…They are also used intensively as building blocks for materials and in supramolecular chemistry . Investigations of the stability of polyynes reveal that the reactivity regarding their dimerization and decomposition increases with growing chain length . Therefore, it is necessary for the synthesis of higher polyynes to attach large, sterically demanding end‐capping groups in order to prevent decomposition of the polyyne .…”

“…The energy,w hich is necessary to bend the acetylenic chain, decreases with the increasing number of acetylene units. [4] Therefore, it is necessary for the synthesis of higherp olyynest oa ttach large, sterically demanding end-capping groups in order to preventd ecomposition of the polyyne. However,t here is still no possibility to measure the extent of the nonlinearity in solution.…”

“…[1] They are also used intensively as building blocks for materials and in supramolecular chemistry. [4] Therefore, it is necessary for the synthesis of higherp olyynest oa ttach large, sterically demanding end-capping groups in order to preventd ecomposition of the polyyne. [4] Therefore, it is necessary for the synthesis of higherp olyynest oa ttach large, sterically demanding end-capping groups in order to preventd ecomposition of the polyyne.…”