Why “Effective” Bonds exist when “Real” Bonds are Absent: The Electronic Structure of the (1.1.1.) Propellane
In a recent communication1, Wiberg and Walker reported the synthesis of the presumably “superstrained” (1.1.1.) propellane which, according to previous SCP-MO computations by Newton and Schulman2, has no bond linking the bridgehead carbons, but, nonetheless, it is comparatively very stable1. I now show that MOVB theory3,4 easily accounts for these “strange” observations by comparing the electronic structures of the following three molecules.
KeywordsDouble Occupancy NATO Advance Study Institute Resonance Bond Core Excitation Total Fragment
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- 3.Epiotis, N.D., Larson, J.R., Eaton, H., “Unified Valence Bond Theory of Electronic Structure”, in Lecture Notes in Chemistry, Vol. 29; Springer- Verlag: New York and Berlin, 1982.Google Scholar
- 4.Parts of the MOVB theory of chemistry and illustrative applications have been presented in conferences:Google Scholar
- (a).NATO Advanced Study Institute on Topic in Theoretical Organic Chemistry, Gargnano, Italy, 1979.Google Scholar
- (b).International Symposium on Stereoelectronic Effects in Organic Chemistry, St. Andrews, Scotland, 1980.Google Scholar
- (c).Symposium on Theoretical Aspects of Fluorine Chemistry, 183rd American Chemical Society Meeting, Los Vegas, USA, 1982.Google Scholar
- (d).International Symposium on Theoretical Organic Chemistry, Dubrovnik, Yugoslavia, 1982.Google Scholar
- (a).Epiotis, N.D. Pure Apple. Chem. 1983, 000.Google Scholar
- (b).Epiotis, N.D. Larson, J.R. Israel J. Chem. 1983, 000.Google Scholar
- 5.The compact bond diagrams have been constructed assuming zero nonbonded interactions. The energy ranking of the ligand MO’s is only approximate and the core and ligand orbital stacks are shown without implying that their relative placement is as depicted.Google Scholar
- 6.Epiotis, N.D.; Cherrry, W.R.; Shaik, S.; Yates, R.L.; Bernardi, F. Topics Curr. Chem. 1977, 70, 49–54.Google Scholar
- 7.See p. 266–297 and especially the admonitions on p. 282–284 of Ref. 1.Google Scholar