Electronic Theories Of Organic Chemistry

This volume focuses on the use of quantum theory to understand and explain experiments in organic chemistry. High level ab initio calculations, when properly performed, are useful in making quantitative distinctions between various possible interpretations of structures, reactions and spectra. Chemical reasoning based on simpler quantum models is, however, essential to enumerating the likely possibilities. The simpler models also often suggest the type of wave function likely to be involved in ground and excited states at various points along reaction paths. This preliminary understanding is needed in order to select the appropriate higher level approach since most higher level models are designed to describe improvements to some reasonable zeroth order wave function. Consequently, most of the chapters in this volume begin with experimental facts and model functions and then progress to higher level theory only when quantitative results are required.In the first chapter, Zimmerman discusses a wide variety of thermal and photochemical reactions of organic molecules. Gronert discusses the use of ab initio calculations and experimental facts in deciphering the mechanism of β-elimination reactions in the gas phase. Bettinger et al focus on carbene structures and reactions with comparison of the triplet and singlet states. Next, Hrovat and Borden discuss more general molecules with competitive triplet and singlet contenders for the ground state structure. Cave explains the difficulties and considerations involved with many of the methods and illustrates the difficulties by comparing with the UV spectra of short polyenes. Jordan et al discuss long-range electron transfer using model compounds and model Hamiltonians. Finally, Hiberty discusses the breathing orbital valence bond model as a different approach to introducing the crucial σπ correlation that is known to be important in organic reactions.

Electronic Charges of Bonds in Organic Compounds presents simple and diverse methods for calculating the electronic charges of bonds from the results of physical methods of investigation. This book is composed of 10 chapters that consider the concept of electronic charges of bonds, which opened up possibilities for the study of the chemical and physical properties of organic compounds. Chapter I deals with the history of the structural theory of organic compounds, demonstrating the development of the idea of electronic bond charges and showing the close analogy between the methods of studying them. Chapters II to VI discuss the results of a study of the relationship of the electronic charges of bonds to the physical and physicochemical characteristics of molecules and their structural elements. Chapters VII to X highlight the relationship between the electronic charges of bonds and chemical properties. This book will be of value to organic chemists.

Many organic chemists will agree with me that the old "electronic theory" has for a long time been inadequate for the interpretation of various new findings in chemistry, particularly for those of reactivity. Considering the outstanding progress which has been made during the past 20 years in the interpretation of these facts, aided by the molecular orbital theory, the time has finally come for a new book showing what is within and what is beyond the reach of quantum-chemical methods. It was therefore highly suitable that Dr. F. L. Boschke of the Springer Verlag suggested to me to make a contribution to a volume in the series "Topics in Current Chemistry" in February 1969. The article was published as Vol. 15, No 1 in June 1970. This new book is an expanded version of the article written in 1970. In this present volume several of the most up-to-date findings which have been gained in organic chemistry since then have been added. It is highly probable that a certain "theoretical" design in the experimenta lists' mind may have been the reason for these developments, whether they themselves are aware of it or not. Theory produces new experimental ideas and conversely, a host of experimental data add another vista to new theories. Due to the mutual beneficial effect of theory and experiment this book will always retain its value, although the quantum-chemical approach to the theory of reactivity is, of course, still in the develop mental stage.

PREFACE. THE Author of this very practical treatise on Scotch Loch - Fishing desires clearly that it may be of use to all who had it. He does not pretend to have written anything new, but to have attempted to put what he has to say in as readable a form as possible. Everything in the way of the history and habits of fish has been studiously avoided, and technicalities have been used as sparingly as possible. The writing of this book has afforded him pleasure in his leisure moments, and that pleasure would be much increased if he knew that the perusal of it would create any bond of sympathy between himself and the angling community in general. This section is interleaved with blank shects for the readers notes. The Author need hardly say that any suggestions addressed to the case of the publishers, will meet with consideration in a future edition. We do not pretend to write or enlarge upon a new subject. Much has been said and written-and well said and written too on the art of fishing but loch-fishing has been rather looked upon as a second-rate performance, and to dispel this idea is one of the objects for which this present treatise has been written. Far be it from us to say anything against fishing, lawfully practised in any form but many pent up in our large towns will bear us out when me say that, on the whole, a days loch-fishing is the most convenient. One great matter is, that the loch-fisher is depend- ent on nothing but enough wind to curl the water, -and on a large loch it is very seldom that a dead calm prevails all day, -and can make his arrangements for a day, weeks beforehand whereas the stream- fisher is dependent for a good take on the state of the water and however pleasant and easy it may be for one living near the banks of a good trout stream or river, it is quite another matter to arrange for a days river-fishing, if one is looking forward to a holiday at a date some weeks ahead. Providence may favour the expectant angler with a good day, and the water in order but experience has taught most of us that the good days are in the minority, and that, as is the case with our rapid running streams, -such as many of our northern streams are, -the water is either too large or too small, unless, as previously remarked, you live near at hand, and can catch it at its best. A common belief in regard to loch-fishing is, that the tyro and the experienced angler have nearly the same chance in fishing, -the one from the stern and the other from the bow of the same boat. Of all the absurd beliefs as to loch-fishing, this is one of the most absurd. Try it. Give the tyro either end of the boat he likes give him a cast of ally flies he may fancy, or even a cast similar to those which a crack may be using and if he catches one for every three the other has, he may consider himself very lucky. Of course there are lochs where the fish are not abundant, and a beginner may come across as many as an older fisher but we speak of lochs where there are fish to be caught, and where each has a fair chance. Again, it is said that the boatman has as much to do with catching trout in a loch as the angler. Well, we dont deny that. In an untried loch it is necessary to have the guidance of a good boatman but the same argument holds good as to stream-fishing...