Coordination containing transition metal ions

The crystal field spectra and derived A0 and CFSE parameters for several garnets containing octahedrally coordinated trivalent transition metal ions are summarized in table 5.3. The values of A0 and CFSE reflect the variations of metal-oxygen distances in the garnet structures. 

Dendrimer 3 (Fig. 7), which is based on a benzene core branched in the 1, 3, and 5 positions, contains 18 amide groups in its branches and 24 chromophoric dansyl units in the periphery. It is well known that, in sufficiently basic solution, amide groups (25), including the dansylamide units (25) can undergo deprotonation and coordination of transition metal ions. The dansyl units show strong absorption bands in the near UV... 

The majority of electronic transitions in molecules occur in the UV region of the spectrum because the energy separations of electron states typically correspond to the energies of photons in the UV region. However, some molecules have electronic energy separations that correspond to radiation in the visible region (see Fig. 12.3). One such class of compounds includes the coordination compounds that contain transition metal ions (see Section 20.6). 

Most of the coordination compounds we examine in this chapter contain transition-metal ions, although ions of other metals can also form complexes. 

This review is essentially devoted to the coordination polymers which have been synthesized for their potential technologic applications or which could obviously be of interest as far as technological applications are concerned. As a consequence, polymeric complexes based onbenzene-poly-carboxylates ligands and their derivatives will be described in more details. The paragraph dealing with coordination polymers containing transition metal ions is mainly... 

Coordination polymers containing transition metal ions... 

This example emphasizes the potentiality of the benzene polycarboxylate ligands. However some other coordination polymers containing transition metal ions deserve to be highlighted. 

DMPP itself is not a reactive diene in Diels-Alder reactions,but it is activated by coordination to transition metal ions. Complex 198 contains a labile perchlorato ligand that is easily displaced by the dienophile, which possesses a coordinating atom (O, S, As or P) in the group E. The cycloaddition reaction occurs intramolecularly in a highly organised environment, which leads to the coordinated exo cycloadduct 199 exclusively. A standard decoordination step affords the desired enantiopure ligands 200. Only the exo-syn isomers are formed, which bear the lone pair at the phosphorus atom and the dienophile functionalities at the same side of the molecule. ... 

Species such as [Ag(NH3)2] that are assemblies of a central metal ion bonded to a group of surrounding molecules or ions are called metal complexes or merely complexes. If tiie complex carries a net charge, it is generally called a complex ion. (Section 17.5) Compounds that contain complexes are known as coordination compounds. Most of the coordination compounds that we will examine contain transition-metal ions, although ions of otiier metals can form complexes as well. 

Self-assembled coordination poiymers containing transition metal ions and organic bridging ligands have attracted intensive interest because of their potentiai abiiities for selective inclusion and transformation of ions and molecules [I-4]. Construction of a variety of assembled structures plays an important role in designing the size and shape of vacancy. Both the variety of assembled structures and sorption of guest molecules can affect the properties of assembled complexes. 

A very few coordination complexes of tetramethylene sulphone [(CH2)4S02] with transition metal ions have been prepared, and the coordinative ability of sulpholane is generally regarded as quite weak224,225. Sulpholane metal complexes should therefore serve as excellent precursors of the coordination compounds containing other weakly nucleophilic ligands. 

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