Editing Cubane (section)

===Cubenes and ''poly''-cubylcubane===
Despite their orbital strain, two cubenes have been synthesized, and a third analyzed [[computational chemistry|computationally]]. ''ortho''-{{chem name|Cubene}}, produced via [[lithium-halogen exchange]] followed by elimination,<ref name=MMisc>{{cite website|website=Cubane|first=B.|last=Muir|publisher=[[Imperial College London]]|title=Further topics|url=https://www.ch.ic.ac.uk/local/projects/b_muir/Cubane/Cubanepro/FurtherTopics.html|access-date=22 May 2025|url-status=live|archive-url=http://web.archive.org/web/20240119125713/https://www.ch.ic.ac.uk/local/projects/b_muir/Cubane/Cubanepro/FurtherTopics.html|archive-date=19 Jan 2024}}</ref> was the most pyramidalized alkene ever made at the time of its synthesis;<ref>{{cite journal |title= Cubene (1,2-dehydrocubane) |first1= Philip E. |last1= Eaton |first2= Michele |last2= Maggini |journal= J. Am. Chem. Soc. |year= 1988 |volume= 110 |issue= 21 |pages= 7230–7232 |doi= 10.1021/ja00229a057 |bibcode= 1988JAChS.110.7230E }}</ref> ''meta''-{{chem name|cubene}} is even less stable, and ''para''-{{chem name|cubene}} probably only exists as a [[diradical]] rather than an actual diagonal bond.<ref>{{cite book |title= Strained Hydrocarbons |url= https://archive.org/details/strainedhydrocar00hypo_746 |url-access= limited |editor-first= Helena |editor-last= Dodziuk |chapter= 2.3 A Theoretical Approach to the Study and Design of Prismane Systems |first1= Ruslan M. |last1= Minyaev |first2= Vladimir I. |last2= Minkin |first3= Tatyana N. |last3= Gribanova |publisher= Wiley |year= 2009 |isbn= 9783527627141 |page=55}}</ref>   They rapidly undergo [[nucleophilic addition]].<ref name=Cubenes/>  

Decomposition of cubenes has enabled chemists to synthesize cubylcubane, as well as higher oligomers.<ref name=Cubenes>{{cite journal |last1=Eaton |first1=Philip E. |title=Cubanes: Starting Materials for the Chemistry of the 1990s and the New Century |journal=Angewandte Chemie International Edition in English |date=1992 |volume=31 |issue=11 |pages=1421–1436 |doi=10.1002/anie.199214211 |language=en |issn=1521-3773}}</ref> Per [[X-ray diffraction]], the central cubane-cubane bond is exceedingly short (1.458 Å), much shorter than the typical C-C single bond (1.578 Å). This is attributed to the fact that the exocyclic orbitals of cubane are [[s orbital|''s''-rich]] and close to the nucleus.<ref>{{cite journal |last1=Gilardi |first1=Richard. |last2=Maggini |first2=Michele. |last3=Eaton |first3=Philip E. |title=X-ray structures of cubylcubane and 2-tert-butylcubylcubane: short cage-cage bonds |journal=Journal of the American Chemical Society |date=1 October 1988 |volume=110 |issue=21 |pages=7232–7234 |doi=10.1021/ja00229a058 |bibcode=1988JAChS.110.7232G |issn=0002-7863}}</ref> 

The ''oligo''-cubylcubanes are rigid molecular rods considered for [[liquid crystal]] design, but scarcely accessible through conventional [[organic synthesis]].  Absent solubizing groups on the cubane [[monomer]], oligomers with at least 4 units are essentially insoluble.<ref>{{cite website|website=Cubane|first=B.|last=Muir|publisher=[[Imperial College London]]|title=Applications|at=Polymers|url=https://www.ch.ic.ac.uk/local/projects/b_muir/Cubane/Cubanepro/Applications.html|access-date=22 May 2025|url-status=live|archive-url=https://web.archive.org/web/20240508043615/https://www.ch.ic.ac.uk/local/projects/b_muir/Cubane/Cubanepro/Applications.html|archive-date=8 May 2024}}</ref>  Poly-cubylcubane is, however, synthesizable via high pressure, solid-state polymerization.  It exhibits exceptionally high [[refractive index]].<ref>{{cite journal |last1=Huang |first1=Haw-Tyng |last2=Zhu |first2=Li |last3=Ward |first3=Matthew D. |last4=Wang |first4=Tao |last5=Chen |first5=Bo |last6=Chaloux |first6=Brian L. |last7=Wang |first7=Qianqian |last8=Biswas |first8=Arani |last9=Gray |first9=Jennifer L. |last10=Kuei |first10=Brooke |last11=Cody |first11=George D. |last12=Epshteyn |first12=Albert |last13=Crespi |first13=Vincent H. |last14=Badding |first14=John V. |last15=Strobel |first15=Timothy A. |title=Nanoarchitecture through Strained Molecules: Cubane-Derived Scaffolds and the Smallest Carbon Nanothreads |journal=Journal of the American Chemical Society |date=21 January 2020 |volume=142 |issue=42 |pages=17944–17955 |doi=10.1021/jacs.9b12352 |pmid=31961671 |bibcode=2020JAChS.14217944H |s2cid=210870993 |issn=0002-7863|url=https://par.nsf.gov/servlets/purl/10210835}}</ref>