Chemistry remains an experimental science. The theory of chemical bonding leaves much to be desired. Yet, the past 20 years have been marked by a fruitful symbiosis of organic chemistry and molecular orbital theory. Of necessity this has been a marriage of poor theory with good experiment. Tentative conclusions have been arrived a t on the basis of theories which were such a patchwork on approximations that they appeared to have no right to work; yet, in the hands of clever experimentalists, these ideas were transformed into novel molecules with unusual properties. In the same way, by utilizing the most simple but fundamental concepts of molecular orbital theory we have in the past 3 years been able to rationalize and predict the stereochemical course of virtually every concerted organic reaction.' In our work we have relied on the most basic ideas of molecular orbital theory-the concepts of symmetry, overlap, interaction, bonding, and the nodal structure of wave functions. The lack of numbers in our discussion is not a weakness-it is its greatest strength. Precise numerical values would have to result from some specific sequence of approximations. But an argument from first principles or symmetry, of necessity qualitative, is in fact much stronger than the deceptively authoritative numerical result. For, if the simple argument is true, then any approximate method, as well as the now inaccessible exact solution, must obey it. The simplest description of the electronic structure of a stable molecule is that i t is characterized by a finite band of doubly occupied electronic levels, called bonding orbitals, separated by a gap from a corresponding band of unoccupied, antiboding levels as well as a continuum of higher levels. The magnitude of the gap may range from 40 kcal/mole for highly delocalized, large aromatic systems to 250 kcal/mole for saturated hydrocarbons. It should be noted in context that socalled nonbonding electrons of heteroatoms are in fact bonding. Consider a simple reaction of two molecules to give a third species, proceeding in a nonconcerted manner through a diradical intermediate I. A + B + [I] + C

The Conservation of Orbital Symmetry (福井謙一とフロンティア軌導理論) -- (参考論文)

The definitive challenge of forming uncommon pseudo‐π···H–F and C···H–F hydrogen bonds on cyclic and cubic nonpolar hydrocarbons

The review summarizes the data on the synthesis of fullerene C60 and C70 derivatives with various biological activities.

Biologically Active Fullerene Derivatives

Exohedral functionalization of endohedral metallofullerenes: Interplay between inside and outside

Fullerenes, the third allotropic form of carbon, have attracted considerable attention since they were first observed in 1985 and have been widely explored in the past three decades. In this chapter, we review the synthetic methods to prepare empty fullerenes as well as endohedral fullerenes; introduce the structural characteristics of fullerenes, including the isolated pentagon rule, topology, and naming according to the spiral algorithm, Stone-Wales transformations; and describe structures that have been characterized to date. In addition, general remarks about the most important aspects of the chemical reactivity, including hydrogenation, halogenation, oxidation, reduction, cycloaddition reactions, and nucleophilic, electrophilic, and radical additions are presented. Applications, such as in medical treatments and photovoltaic devices, are also systematically described.

Fullerenes and their applications

Epoxide of oestradiol is one of the main risk factors for the genesis and evolution of breast cancer; hence, in recent years there has been considerable interest in the investigation of new inhibitors capable of reducing its carcinogenic activity The aim of this article is to study the [2 + 2] cycloaddition reaction of epoxide of oestradiol in different pristine (C76 and D5h-C80) and endohedral metallofullerene (C72@Sc2C2, C76@Sc2 and C80@Sc2) by means of molecular electrostatic potential (MEP) topological analysis Different from other molecular scalar fields, MEP topology enables to find minima related to lone pairs and π electrons, therefore, this molecular scalar field is appropriate to identify the most reactive sites In consonance with our results, it was found that C80 was the best candidate to carry out the epoxide of oestradiol cycloaddition since more stable adducts were obtained Furthermore, it is expected that more than one oestradiol epoxide molecule will be added to C80, forasmuch as C80 reactivity is enhanced once the adduct is formed The study was carried through DFT framework included in the Gaussian 09 package (MPWB95/6-31G(d,p))

Cycloaddition reactions of pristine and endohedral fullerene molecules: possible anticancer activity

Mexico has a slow development of nanotechnology; however, great efforts have been made to support nanoscience and nanoeducation. The Institute of Scientific and Technological Research of San Luis Potosi created the first specialized graduate program in nanoscience and Nanotechnology in Latin America in 2001, and the first engineering degree in nanotechnology was offered in 2006. Also, the number of researchers, students, networks, clusters and modern equipment for education and researching is growing every year, besides there are 25 degrees of Bachelor of Nanotechnology as well as 87 graduate programs, the country has a great potential for growing in nanoscience and nanotechnology due to its geographic location. Also there are few patents and products based on nanotechnology, despite this, some Mexican researchers have been recognized and honored with awards such as TWAS, and Mexico has created patents as a sanitizer that eliminates the H1N1 virus or anti-graffiti paint. So if the country wants to have a real impact is necessary to make more industry-university links and to promote nanoeducation at all levels focused towards the patents and applications. Research, development and application of standards and regulations for health and environmental protection must not be forgotten.

Nanociencia y nanotecnologia en mexico: origenes, evolucion y progreso

Nanoscience and nanotechnology in mexico: origins, evolution and progress nanociencia y nanotecnologia en mexico: origenes, evolucion y progreso

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Cycloaddition reactions of pristine and endohedral fullerene molecules: possible anticancer activity

Nanociencia y nanotecnologia en mexico: origenes, evolucion y progreso

Nanoscience and nanotechnology in mexico: origins, evolution and progress nanociencia y nanotecnologia en mexico: origenes, evolucion y progreso