Htickel molecular orbitals

For excellent discussions of this method see Woodward, R.B. Hoffmann, R. Ref. 1256 Jones, R.A.Y. Physical and Mechanistic Organic Chemistry, 2nd ed. Cambridge University Press Cambridge, 1984, p. 352 Klumpp, G.W. Reactivity in Organic Chemistry, Wiley NY, 1982, p. 378 Yates, K. Htickel Molecular Orbital Theory, Academic Press NY, 1978, p. 263. 

Use of Htickel Molecular Orbital Theory in Interpreting the Visible Spectra of Polymethine Dyes 172... 

In Chapter 5, conventional simple Htickel molecular orbital (SHMO) theory is introduced. The Htickel a is suggested as a reference energy, and use of / as a unit of energy is advocated. Parameters for heteroatoms and hybridized orbitals are given. An interactive computer program, SHMO, which uses the conventions introduced in this chapter, is available on the Web [12]. 

Htickel molecular orbital calculations have been performed for anthranil the n electron densities and mobile bond orders of Del Re80 and Berthier and Del Re81 are given in Fig. 2. 

Ac = Acetyl acac = Acetylacetonate bda = Benzylidene-acetone BINOL = l,l -bi-2-naphthol Bn = Benzyl brsm = Yield based on recovered starting material Bu = Bntyl CAN = Ceric anunonium nitrate CBS = Corey/Bakshi/Shibata catalyst [(+) or (—)-(S)-2-methyl-oxazaborolidine] COD = Cyclo-l,5-octadiene COT = Cyclooctatetraene Cp = Cyclopentadienyl Cp = Penta-methylcyclopentadienyl Cy = Cyclohexyl DCC = Dicy-clohexylcarbodiimde DMF = Ai,A-dimethylformainide DMPU = l,3-dunethyl-3,4,5,6-tetrahydro-2(lH)-pyrimidin-one DMSO = Dimethylsnlfoxide dppe = Diphenylphosp-hinoethane dr = Diastereomer ratio dppm = Diphenylphos-phinomethane E = Electrophile ee = Enantiomeric excess EHMO = Extended htickel molecular orbital Et =... 

HUckel (p. 328) was a pioneer in the field of molecular orbital theory. He developed the LCAO method in its simplest form, yet Htickel molecular orbitals have proved enormously successful in dealing with organic molecules. Htickel proposed the 4/i + 2 rule in 1931. It has been tested in many ways since then, and it works. Now, what is the theoretical basis for this rule ... 

Hess Jr., B.A. and Schaad, L.J. (1971a). Htickel Molecular Orbital Ji Resonance Energies. A New Approach. JAm.Chem.Soc., 93, 305-310. 

McClelland, B.J. (1974). Graphical Method for Factorizing Secular Determinants of Htickel Molecular Orbital Theory. J.Chem.Soc. Faraday Trans II, 70,1453-1456. 

Extensive research activities have been directed towards elucidating the actual site of activation and reduction of dinitrogen. Extended Htickel molecular orbital calculations carried out on idealised models (Figure 4.28, 45a) of the cofactors FeMco (M = Mo, V, Fe) of the three nitrogenases suggest, based on the similarity of the electronic structures. 

Figure 1. Contour diagram in the plane of the three most important extended Htickel molecular orbitals of the generic bent metallocene CpzMt. Solid and dashed lines correspond to positive and negative contour of the wave function. ...

E. Heilbronner, Htickel molecular orbitals of Mobius-type conformations of annulenes,... 

TABLE P13-9 Extended Htickel Molecular Orbitals for Allene... 

Obtain access to any of the common computer programs that will solve the Htickel molecular orbital problem for various molecules. You will have to find out how the necessary information is put into the computer. 

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