Untersuchungen über einen mikrobiologisch feststellbaren Serumfaktor nach Gelbsucht

Electrophoretic Determination of Lactococcus lactis Modified by Zinc Ions

“…Zinc is one of the most essential microelements and is crucial for the proper function of a large number of macromolecules and enzymes as far it participates in bone mineralization, healing wounds and is responsible for the proper functioning of the immune system or insulin secretion [25]. In 1956, G. Schwarzenbach and Ahrland Chatt and Davis [26,27] classified the metal ions into two classes called a and b types. Those two research groups have explained that the class a t of metals prefer to bind with class a of donors and accordingly class b of metals prefer to interact with class b of donors.…”

Dielectric relaxation studies of ion motions in electrolyte-containing perfluorosulfonate ionomers. 3. Zinc sulfate and calcium chloride systems

“…We have begun to extend our work, originally involving alkali-metal cations, to other metal cation species within the Schwarzenbach classification according to their complex-forming characteristics, based on either mainly electrostatic or mainly covalent forces. 7 In this study, we present results for a divalent cation, Ca2+, in aqueous CaCl2 solutions over a broad concentration range. Purely electrostatic bonding is believed to dominate as its hydration number of ca.…”

The Principle of Hard and Soft Acids and Bases and the Problem of Competitive Coordination in Complex Compounds

“…1)4 ' 5 The reactivities of the intermediate acids (IA) and bases (IB) require a specific consideration. The above postulates, combined in the HSAB principle, are not new to chemists, since (1) the possibility of assigning chemical reactions to the acid-base category follows directly from the Usanovich theory 26 , as rightly pointed out by Yatsimirskii 13 , Day and Selbin 27 , Evans 18 , and Denes 28 ; (2) the classification of acids which follows from the HSAB principle is identical with the classification of metal ions into classes A and Β (Schwarzenbach 29 ) or a and b (Ahrland, Chatt, and Davies 30 ), as was emphasised by Pearson himself 4 ' and also in monographs 31 ' and reviews 10 ' 33 ; an approach to the estimation of softness and hardness of bases was suggested by Schwarzenbach 34 ' 35 ; (3) the preferential coordination of hard acids to hard bases and of soft acids to soft bases has long been known to chemists as the postulate of the predominance of electrostatic or covalent interaction in individual acid-base reactions (including donor-acceptor reactions 13 ). This fact, which follows from classical polarisation concepts of coordination chemistry, has been pointed out in monographs 36 " 38 and original papers 13 ' 39 .…”