Four-dimensional chemistry

Asymmetric catalysis is four-dimensional chemistry as stated by Noyori,6 because high efficiency can only be achieved through the coordination of both an ideal three-dimensional structure x, y, z) and suitable kinetics (/). Recently developed metal-ligand difunctional catalysts really provide a new basis for developing efficient catalytic reactions. 

The notion of the Valence State of an atom is based on that of Pauling [35] and Van Vleck [36] called atom in molecule . When considering only integral chemistry , where the multiplicity of bonds is represented by positive integers, and moreover, postulating that the highest multiplicity of the chemical bond considered is three1, the valence state of the atom can be described as a four-dimensional vector VVS [27, 37, 28, 38] ... 

Madronich S, Flocke S (1998) The role of solar radiation in atmospheric chemistry. In Boule P (ed) Handbook of environmental chemistry. Springer, Heidelberg, pp 1-26 Mahfouf IF, Rabier F (2000) The ECMWF operational implementation of four-dimensional variational assimilation. Part I experimental results with improved physics. Q J R Meteorol Soc 126 1171-1190... 

Z. B. Stoynov and B. S. Savova-Stoynov, "Impedance Study of Non-Stationary Systems Four-Dimensional Analysis," Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 183 (1985) 133-144. 

Four photographs of molecular models illustrate the shapes of specific molecules and highlight the concept of three dimensional chemistry. 

Bottegoni, G., Kufareva, I.,Totrov, M., and Abagyan, R. (2009) Four-dimensional docking a fast and accurate account of discrete receptor flexibility in ligand docking. Journal of Medicinal Chemistry, 52, 397 06. 

Mehdaoui, L, Krdner, D., Pykavy, M., Freund, H. J., Kltiner, T. (2005). Photo-induced desorption of NO from NiO (100) calculation of the four-dimensional potential energy surfaces and systematic wave packet studies. Physical Chemistry Chemical Physics, 8, 1584-1592. http //dx.doi.org/10.1039/b512778e. 

Chemical theory, if anything, is distorted even more than physics on projection from four-dimensional space-time. In electromagnetic and other field theories, gauge particles have mathematically assigned phase factors, which in chemistry are simulated as probability density. Whereas the purely mathematical symbolism suffices as working models in particle physics, chemistry has the more stringent demand to deal with extended three-dimensional entities. Even at its lowest level, the known chemical function of an electron, defined as a structureless point particle, becomes incomprehensible. 

The true meaning of both quantum and relativity theories, which has been demonstrated [1] to emerge only in four-dimensional formalism, has serious implications for the three-dimensional theories of atomic and molecular structure. Nonclassical attributes of atomic matter, such as electron spin, are associated with four-dimensional hypercomplex functions, known as quaternions, and cannot be accounted for by classical three-dimensional models, which include wave mechanics as traditionally formulated. The notorious failure of quantum chemistry to model the structure of non-hydrogen atoms and molecules is a manifestation of the same problem. The awareness that atomic and molecular structures are classical three-dimensional concepts dictates the use of classical rather than four-dimensional quantum models for their characterization. 

Although Kekule and Couper were correct in describing the tetravalent nature of carbon, chemistry was still viewed in a two-dimensional way until 1874. In that year, Jacobus van t Hoff and Joseph Le Bel added a third dimension to our ideas about organic compounds when they proposed that the four bonds of carbon are not oriented randomly but have specific spatial directions. Van t Hoff went even further and suggested that the four atoms to... 

This book is divided into four parts. Part I provides a theoretical derivation of the bond valence model. The concept of a localized ionic bond appears naturally in this development which can be used to derive many of its properties. The remaining properties, those dependent on quantum mechanics, are, as in the traditional ionic model, fitted empirically. Part II describes how the model provides a natural approach to understanding inorganic chemistry while Part 111 shows how the limitations of three-dimensional space lead to new and unexpected properties appearing in the inorganic chemistry of solids. Finally, Part IV explores applications of the model in disciplines as different as condensed matter physics and biology. The final chapter examines the relationship between the bond valence model and other models of chemical bonding. 

Although coordination number 8 cannot be regurded as common, the number of known compounds has Increased rapidly in recent years, so thai it is now exceeded only by four- and six-coordiration. The factors important in this increase can be traced largely to improved three-dimensional X-ray lechniques and to increased interest in ihe coordination chemistry oflanthanide and actinide elements (see Chapter 14). 

The shapes of covalent molecules are determined by the number of valence electrons and orbitals available, giving H2, BF3, CH4, NH3, PH3, H20, HF, C1F, PF5, SF6, and IF7. Carbon has four valence electrons and four orbitals, so tetrahedral sp3 bonding dominates the chemistry of carbon. This matches the three-dimensional bonding in zinc blende (3 2PT), and it is the structure of diamond with carbon in P and T layers. 

Figure 8.28 Schematic diagram showing (a) diffraction from a single crystal, (b) from four crystals at different orientations with respect to the incident beam and (c) from a polycrystalline powder giving rise to a pattern of concentric cones of diffraction, often presented as a one-dimensional plot of intensity vs diffraction angle (reproduced by permission of The Royal Society of Chemistry).

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