How Long Can A C-C σ-Single Bond Be?
Jian-Xiong Yang1, Yan Alexander Wang1
1Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Abstract:
In a specifically designed molecular structure, two sp2-hybridized carbon atoms align their unhybridized 2p orbitals in the same orientation to form an extremely long C2p-C2p σ-single bond that goes beyond 3 Å in length. This new type of C-C σ-bond (coined as a fringe bond) can be made more than 1 Å longer than the current experimental world record (∼1.8 Å) and 300 kJ/mol weaker than the ordinary C-C σ-bond (∼330 kJ/mol). If such molecular monomers are polymerized into infinite chains, the extended long C-C saturated σ-bonding framework manifests band gaps similar to those of some conventional iconic organic-conducting polymers based on conjugated networks of unsaturated bonds.
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