Spiroconjugation in 1-, 2-, and 3-Dimensions: The Foundations of a Spiro Quantum Chemistry

A recent paper has described the structure of a hypothetical 3-,4-connected net termed glitter. This is a model of an allotrope of carbon in the form of a synthetic metal. That paper pointed to the importance of through-space pσ interactions of adjacent olefin units in the net in understanding the electronic structure at the Fermi level. The present communication elucidates the role of spiroconjugation in understanding features of the electronic band structure and density of states of glitter. With this analysis of spiroconjugation in the 1-dimensional polyspiroquinoid polymer and the 3-dimensional glitter lattice, the foundations have been laid for a new type of quantum chemistry herein called spiro quantum chemistry. Spiro quantum chemistry complements traditional quantum chemistry which is focused on linear polyenes, circular annulenes, polyhexes, 2-dimensional graphene sheets and related structures including fullerenes, by focusing on spiroconjugated hydrocarbon structures in 1-, 2- and 3-D, including linear spiro[n]quinoids and polyspiroquinoid in 1-D, circular cyclospiro[n]quinoids, spiro[m,n]graphene fragments and spirographene in 2-D and [m,n,o]glitter fragments and glitter in 3-D.