Tetra-Tert-Butyl Methane – The Acyclic Alkane That Seemingly Should Exist

Chemistry, Education
The smallest non-cyclic alkane that theoretically should exist, but to date has never successfully been prepared, is tetra-tert-butyl methane. The reason it is so elusive is crowding or steric hindrance. Introducing TTBM Tetra-tert-butyl methane is the common name of 3,3-ditert-butyl-2,2,4,4-tetramethylpentane. A glimpse at the structure reveals the overcrowding. Despite the overcrowding, according to energy calculations, the molecule (we’ll call it TTBM) should be capable of existence. Assembling the Model Even building the model from its component parts presented a measure of difficulty. The 17 carbon atoms (black spheres) and 36 hydrogen atoms (smaller white spheres) required some effort to assemble into TTBM. Still, it was accomplished with all the component atoms not touching one another. What is the problem or problems? [caption id="attachment_16028" align="alignleft" width="405"] Molecular Model TTBM[/caption] Synthesis While…
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Organic Chemistry: What is Ring Strain?

[caption id="attachment_16313" align="alignright" width="440"] Cyclopropane suffers from ring strain.[/caption] Carbon ring strain? What is that? Let's begin at the beginning. The element carbon is one of a small number of elements that can bond to itself repeatedly. Compare gases such as oxygen (O2), called diatomic gases because generally only two atoms unite. Oxygen is exceptional in that it does form the triatomic molecule, ozone (O3). However, carbon can form even lengthy chains. Thus, carbon can form, not only methane (CH4), but ethane (H3C-CH3), propane (H3C-CH2-CH3), butane (H3C-CH2-CH2-CH3), pentane (H3C-CH2-CH2-CH2-CH3), and so on. Curiously, carbon can also close those chains to form rings, much as a woman can close a string of pearls about her neck using a clasp. [sc name="MidArticleAdsense"] Cyclization Although methane cannot so close, nor can ethane, the…
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