Coordinated Universal Time compounds

Even so great an admirer of Werner as Paul Pfeiffer (1875-1951),93 Werner s former student and one-time chief of staff at the University of Zurich and the man who first applied Werner s theory to crystal structures (see Section 1.1.5.4), proposed modifications of the coordination theory. He applied what he called the principle of affinity adjustment of the valencies to overcome certain shortcomings of Werner s theory.94 He considered the ionizable radicals or atoms in the outer sphere to be combined with the complex radical as a whole and not attached definitely to the central atom or to any of its associated molecules. He also applied this idea to complex organic molecular compounds. However, Pfeiffer s modifications should not be interpreted as attacks on Werner s ideas. 

The metalloporphyrins as macrocyclic compounds have a few sites for specific and universal solvation and are able to axial coordination of some ligands. At the present time chemical modification of macrocycle is a main way of increasing of selectivity of molecular complex formation. The data obtained earlier [1,2] show that the selectivity may be increased due to specific %-% interactions of the metalloporphyrins with aromatic molecules. Aromatic molecules coplanar to the macrocycle will rise geometrical requirements to axial coordinating ligands. In particular, the results of the thermodynamic study of the axial coordination of n-propylamine by zinc(II) porphyrins in benzene have demonstrated the formation of the complexes of the metalloporphyrin containing both w-propylamine and benzene [2], The aim of this work is to study the molecular complexes of zinc (II) porphyrins prepared by slow crystallization from saturated solutions in benzene, w-propylamine and mixed solvent benzene - -propylamine. 

Alfred Werner s first paper on the coordination theory (7) was published in 1893 and was introduced to Japan in an abridged form in 1897 by Riko Majima (1874-1962), who was a postgraduate student in the College of Science, Tokyo Imperial University. Majima, who later became the father of organic chemistry in Japan, introduced this paper and three subsequent papers of Werner s in the Tokyo Kagaku Kaishi (Journal of the Tokyo Chemical Society) under the title of "Theory of Molecular Compounds" (2). If read today, Majima s articles are difficult to understand even for us who know the coordination theory, indicating that Werner s ideas were not easily understandable at that time. 

University of Florence and then the Laboratory CNR (National Research Council) Institute for the Study of Energy and Stereochemistry of Coordination Compounds, whose scientific development coincided with development of coordination chemistry to which Sacconi greatly contributed by S3mthesizing a large class of new compounds with unusual geometries [16, 17] and new electronic properties [18]. He was before his time in his use of physical methods in the study of modem chemistry and pursued this track in particular in magnetochemistry [19], in X-ray diffractometry [20], in calorimetry, in visible and IR spectroscopy [21] and nuclear magnetic resonance [22, 23] techniques. 

Werner has been claimed as a national by the Germans, French and Swiss. He was born in Mulhouse while Alsace was still part of France, remained there after it was seized in the Franco-Prussian War of 1870 (and even served in the German army) but he spent most of his career as an independent researcher in Zurich, coming to the University of Zurich (initially as an organic chemist ) in 1893. By then he had already taken an interest in coordination compounds, which at the time were poorly (if at aU) understood, especially with regard to constitution and structure [11]. The existence of a number of series of species, each containing a metal in combination with the same constituents but in varying numbers, was very hard to reconcile with well-established laws of proportions and valency. 

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