Metal ions structures

Centi, G., Wichterlova, B. and Bell, A.T. (2001) Catalysis by Unique Metal Ion Structures in Solid Matrices. Kluwer Academic, Dordrecht. 

Recently, West and coworkers (275) prepared the complex of SONO with lanthanum perchlorate which has a L M of 4 1. Lanthanum in this complex attains a coordination number of eight due to the coordination of both S-0 and N—0 groups to the metal ion (Structure VI). 

Centi, G. Perathoner, S. Vazzana, F., Catalysis using guest single and mixed oxides in host zeolite matrices, in Catalysis by Unique Metal Ion Structures in Solid Matrices, Centi, G. Bell, A.T. Wichterlova, B. (eds.), Springer-Verlag. Dordrecht (The Netherlands), 2001,165-186. 

It would be highly desirable to be able to correlate metal ion structure as well as the individual steric requirements of the specific substituents Ri, R2, and Ra with the equilibration studies cited above. Because of the numerous uncertainties associated with the data, however, only qualitative generalizations can be made. The higher-valent metal aldolate complexes (M = ZnL, MgL, AIL2), upon equilibration, appear to favor the threo diastereomer to a greater extent than the monovalent metal aldolates (M = Li, Na). With regard to... 

Scheme 8), which also control the enolate stereochemistry in amide systems. The influence of metal ion structure on the stereochemical outcome of the aldol process again underscores the importance of metal ligand effects in the enhancement of aldol stereoselection. 

Esters. The hydrolysis of a number of esters has been shown to be subject to catalysis by metal ions. Structurally these esters are similar they contain a secondary functional group which can serve as a ligand for a metal ion. 

Complexes of 2,2 -Dialkyl( ethanediylidenedinitrilo )diethanethiols. The previously unknown Schiff base derivatives of a-diketones with -mercaptoalkyl-amines should be ideally suited to form metal complexes in which the ligand is coordinated in a planar tetradentate manner. Further, the mercaptide functions should occupy cis positions in the coordination sphere of the metal ion. Structure V illustrates the structure expected for such substances. Three products might... 

Matsuoka, M., and Anpo, M., in "Catalysis by Unique Metal Ion Structures in Solid Matrices", (G. Centi, B. Wichterlova and A.T. Bell, Eds.), p. 249. Kluwer Academic Publishers, 2001. 

Perovskite-related oxides of the K2MF4 (A2BO4+J B-transition metal ion) structure (Figure 16) have been investigated by several groups as alternative mixed conductors for SOFC. 

Transition metal complexes of the larger polyaza macrocyclic ligands have been less extensively studied than for the smaller ring systems. For the pentaaza macrocycles, [ISJaneNs with ethylene bridges appears to form the most stable complexes with most metal ions. Structural data for a variety of pentaaza macrocyclic complexes have been reviewed. The N-H bonds as well as the different sized chelate rings must be considered in calculating the... 

As there is usually more than one way of arranging two or more ligands about a central metal ion, structural isomers, that is, two complexes of the same formula but different chemical and physical properties, are possible. 

BeU AT (2001) Siting and stabUity of metal cations in zeoUtes for catalysis. In Centi G, Wichterlova B, BeU AT (eds) Catalysis by unique metal ion structures in soUd matrices, vol 13, NATO science series 11. Kluwer, Dordrecht, pp 55—73... 

Panov Gl, Dubkov KA, Paukshtis EA (2001) Identification of active oxygen species over Fe complexes in zeolites. In Centi G et al (eds) Catalysis by unique metal Ion structures in solid matrices, vol 13. Kluwer, Dordrecht, p 149... 

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