Why Cyclodecapentaene is Not an Aromatic Hydrocarbon

[caption id="attachment_16073" align="alignright" width="440"] Fig 1. Cyclodecapentaene - all cis form.[/caption] There are aromatic hydrocarbons and there are non-aromatic hydrocarbons. For basic mono-ring structures that have alternating carbon-carbon double bonds, there is a rule called Hückel’s rule that defines whether a given hydrocarbon can be aromatic or not. It might seem, at first that cyclodecapentaene (C10H10 or [10]-annulene) should be aromatic. Yet, cyclodecapentaene is not an aromatic hydrocarbon. Let’s find out why not. A Few Simple Rules for Aromatic Behavior  The double bonds in the ring must be conjugated (alternating). This allows for the electrons to be delocalized [in conceptualization be flipped in either a clockwise or counterclockwise direction]. This allows for the presence of what is called a ring current.  The ring must be flat.  The mono-ring must feature…
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Polyacetylene Conductive Polymer

Chemistry, Technology
[caption id="attachment_12124" align="alignleft" width="440"] Acetylene Welding - NASA[/caption] Metals are electrically conductive, yes. But is there such a thing as a polyacetylene conductive polymer? In a sense, a plastic that is not electrically insulative, but electrically conductive, and a top-notch conductor at that? Ethyne (AKA acetylene) polymerizes to polyethyne (polyacetylene) in the presence of copper catalysts. When prepared in an alternate way, polyacetylene (CH)2 exhibits moderate electric conductivity. Oxidation with iodine increases conductivity of the polymer by several powers of ten. In fact, it approaches the specific electrical resistance of silver. In 2000, Shirakawa, Heeger and McDiarmid received the Nobel Price for this discovery. How is the reaction written? And what is so special about polyacetylene conductive polymer? General Schematic Preparation of Polyacetylene The simple saturated molecule ethane is written…
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