Molecular orbital theory, applications

The latter results incorporate the very simple ideas of crystal field theory in which the electronic states of a central ion are split by the electric field of surrounding ions or dipoles. Although commonly applied to and configurations, this theory is merely a special case of molecular orbital theory applicable in principle to any system. Of course, the sur-... 

A superb treatment of applied molecular orbital theory and its application to organic, inorganic and solid state chemistry. Perhaps the best source for appreciating the power of the independent-particle approximation and its remarkable ability to account for qualitative behaviour in chemical systems. 

In this section, the conceptual framework of molecular orbital theory is developed. Applications are presented and problems are given and solved within qualitative and semi-empirical models of electronic structure. Ab Initio approaches to these same matters, whose solutions require the use of digital computers, are treated later in Section 6. Semi-empirical methods, most of which also require access to a computer, are treated in this section and in Appendix F. 

Applications of Molecular Orbital Theory in Organic Chemistry I. G. Csizmadia, Ed., Elsevier, Amsterdam (1977). 

Provides a survey of quantum mechanics, semi-empirical computational methods, and the application of molecular orbital theory to organic chemistry. The concepts explored in this book should be easy for most readers to understand. 

Presents the basic theory of quantum mechanics, particularly, semi-empirical molecular orbital theory. The authors detail and justify the approximations inherent in the semi-empirical Hamiltonians. Includes useful discussions of the applications of these methods to specific research problems. 

SECTION 1.5. QUALITATIVE APPLICATION OF MOLECULAR ORBITAL THEORY... 

SECTION 1.6. APPLICATION OF MOLECULAR ORBITAL THEORY TO REACTIVITY... 

Both the language of valence bond theory and of molecular orbital theory are used in discussing structural effects on reactivity and mechanism. Our intent is to illustrate both approaches to interpretation. A decade has passed since the publication of the Third Edition. That decade has seen significant developments in areas covered by the text. Perhaps most noteworthy has been the application of computational methods to a much wider range of problems of structure and mechanism. We have updated the description of computational methods and have included examples throughout the text of application of computational methods to specific reactions. 

McWeeny, R., Proc. Roy. Soc. [London) A237, 355, (ii) "The density matrix in self-consistent field theory. II. Applications in the molecular orbital theory of conjugated systems."... 

Optically active 2-allylpiperidines and -pyrrolidines arc obtained by treating hydroxylactams containing the l-[(S)-l-arylethyl]substituent as an auxiliary (see Appendix) with tin(IV) chloride and trimethyl(2-propenyl)silane46. Interestingly, the moderate diastereoselection when the aryl group is phenyl decreases when 2-chlorophenyl is used, whereas the sense of the stereoselectivity reverses for 2,6-dichlorophenyl or pentachlorophcnyl. These results are rationalized by application of molecular orbital theory and substrate conformational preferences46. 

Application of molecular orbital theory to electron transfer reactions of metal complexes in solution. J. K. Burdett, Comments Inorg. Chem., 1981,1, 85-103 (7). 

Parallel to this use of relatively simple approximations of the molecular orbital theory to the study of complex molecules Berthier has investigated the possible utilization of more refined molecular orbital procedures in the study of necessarily smaller molecules. We owe him the first application of the SCF method to the study of fulvene and azulene and also a pioneering extension, presented in 1953, of the SCF method to the study of molecules with incomplete electronic shells. 

A review of the applications of Htlckel molecular orbital theory to various aspects of phosphazene chemistry, including... 

The limitation of the above analysis to the case of homonuclear diatomic molecules was made by imposing the relation Haa = Hbb> as in this case the two nuclei are identical. More generally, Haa and for heteronuclear diatomic molecules Eq. (134) cannot be simplified (see problem 25). However, the polarity of the bond can be estimated in this case. The reader is referred to specialized texts on molecular orbital theory for a development of this application. 

Houk, K.N. "Application of Frontier Molecular Orbital Theory to Pericyclic Reactions", in "Pericyclic Reactions", A.P. 

Aspects of Homogeneous Catalisis. Applications of Ab Initio Molecular Orbital Theory. 1995 ISBN 0-7923-3107-9... 

A. Streitwieser, Molecular Orbital Theory for Organic Chemists, Wiley, New York, 1961 E. Heilbronner and H. Bock, The HMO Model and Its Applications, Wiley, London, 1968. 

This report begins with a brief review of the electronic and structural features that underlie all of carbene chemistry. Next, we introduce the set of related aromatic carbenes that are the basis for our dissection of the effects of structure on carbene properties. The chemical and spectroscopic techniques and procedures used to probe these carbenes are described and explained briefly in the succeeding section. Then, the results of the application of these probes to the chosen carbenes are presented. Finally, the revealed relation of a carbene s structure to its chemical and physical properties is placed within the predictive framework of molecular orbital theory. Our objective in this report is to present sufficient information to permit us to forecast the properties of an aromatic carbene directly and reliably from its structure. 

Metals conduct electricity through conduction bands. Conduction bands arise from the application of Molecular Orbital theory to multi-atom systems. (See Chapter 10.) The bonding molecular orbitals and, sometimes, other molecular... 

The application of ab initio molecular orbital theory to suitable model systems has led to theoretical scales of substituent parameters, which may be compared with the experimental scales. Calculations (3-21G or 4-31G level) of energies or electron populations were made by Marriott and Topsom in 1984164. The results are well correlated with op (i.e. 07) for a small number of substituents whose op values on the various experimental scales (gas phase, non-polar solvents, polar solvents) are concordant. The nitro group is considered to be one of these, with values 0.65 in the gas phase, 0.65 in non-polar solvents and 0.67 in polar solvents. The regression equations are the basis of theoretical op values for about fifty substituents. The nitro group is well behaved and the derived theoretical value of op is 0.66. 

This theory proves to be remarkably useful in rationalizing the whole set of general rules and mechanistic aspects described in the previous section as characteristic features of the Diels-Alder reaction. The application of perturbation molecular orbital theory as an approximate quantum mechanical method forms the theoretical basis of Fukui s FMO theory. Perturbation theory predicts a net stabilization for the intermolecular interaction between a diene and a dienophile as a consequence of the interaction of an occupied molecular orbital of one reaction partner with an unoccupied molecular orbital of the other reaction partner. 

---