Orbital topology

P. Lemmens and P. Millet, in Quantum Magnetism Microscopic Techniques for Novel States of Matter (Springer, Heidelberg, 2004), Chap. Spin - Orbit - Topology, a triptych, and references within. 

RG Pearson (1976) Symmetry Rules for Chemical Reactions Orbital Topology and Elementary Processes. Wiley, New York and references therein... 

R. G. Pearson, Symmetry Rules for Chemical Reactions, Orbital Topology and Elementary Processes, Wiley-Interscience, New York, 1976 R. G. Pearson, Symmetry Rules for Chemical Reactions. In I. Hargittai, ed., Symmetry Unifying Human Understanding, Pergamon Press, Oxford, 1986, pp. 229-236. 

Pearson, Symmetry Rules for Chemical Reactions, Orbital Topology and... 

The predicted band structure, merging considerations of band width and orbital topology, is that of 16. To make a real estimate, one would need an actual calculation of the various overlaps, and these in turn would depend on the Pf Pt separation. 

I.B. Bersuker, The Jahn—Teller effect and vibronic interactions in modem chemistry. Plenum Press, New York, 1984 T.A. Albright, J.K. Burdett and M.W. Whangbo, Orbital interactions in chemistry, Wiley, New York, 1985, pp. 95-100 R.G. Pearson, Symmetry rules for chemical reactions orbital topology and elementary processes, Wiley, New York, 1976, pp. 75-82. 

Pearson RG (1976) Symmetry rules for chemical reactions. Orbital topology and elementary processes. John Wiley, New York... 

Perfluorotetramethylcyclobutadiene oxide (43) rearranges with a half-life of about 20 min at 95°C." As a Dewar furan, it might have been expected to aromatize to perfluorotetramethylfuran (44). That process is orbital topology forbidden," however, and instead 43 is transformed cleanly into cyclopropenyl ketone 45, apparently... 

Instead of undergoing desulfurization with triphenylphosphine and other trivalent phosphorus derivatives, which would yield a cyclobutadiene, Dewar thiophene 99 is aromatized to thiophene 98. ° Thermal aromatization of 99, an orbital topology-forbidden process, has a half-life of 5.1 h at 160°C, but triphenylphosphine brings about this change quite rapidly at RT. 

Keywords Agostic interaction Weak interaction Bond activation Computational studies DFT QM/MM calculations Molecular orbitals Topological analysis Steric effects... 

The molecules examined so far are conjugated in a linear sense, that is, double bonds are added at the ends of a polyene chain or the chains are tied together so that resonance structures can be drawn that propagate along the chain. Suppose, however, that a polyene is joined to the middle of an existing chain. These polyenes are said to be cross-conjugated and can have unusual properties because of their orbital topology. The simplest example is trimethylenemethane, 12.18. The neutral molecule has four it electrons and a resonance structure cannot be written... 

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