Bonding of ligands

The method of catalyst immobilisation appeared to affect its performance in catalysis. Catalyst obtained by method II showed a low selectivity in the hydroformylation of 1-octene (l b aldehyde ratio was even lower than 2) at a very high rate and high yields of isomerised alkenes (Table 3.2, entry 2), whereas procedure IV resulted in a catalyst that was highly selective for the linear aldehyde (with a l b ratio of 37) (entry 5). In accordance with examples from literature it is likely that procedure II gave rise to the ionic bonding of ligand-free rhodium cations on the slightly acidic silica surface [29],... 

FIGURE 3 Chemical pathway for covalent bonding of ligand exchanges with silica gel. 

Bonding of ligands to alkali, alkaline earth and rare earth metal ions is mainly electrostatic. Consequently, these bonds can be described as a combination of electrostatic and van der Waals terms (see Chapter 14). 

The oxidative addition of C H bonds of ligands is very common and this reaction forms metal alkyl or metal aryl complexes. In osmium triarylphosphine complexes, orthomet-allation gives four-membered metaUocycles. When the ortho... 

The orbital interaction scheme that describes bonding of ligands as CO, but also of other ligands, in terms of the sum of donative and backdonative interactions is called the Chatt-Dewar-Duncanson picture of the chemical bond. Historically it was first used to describe bonding of ethylene. As we will see later, bonding to surfaces (Section 4.4.1.2) is quite analogous and there it is called the Blyholder model. 

The development of methodologies for the covalent bonding of ligands to polymeric supports is important for the preparation of novel reagents to be used in ionic and molecular separations which are important to the environment and for the preparation of chemical sensors which can be used in the monitoring of environmentally sensitive areas. Our research focuses on identifying the mechanisms by which immobilized ligands... 

It therefore seems appropriate to collect together the different types of evidence for out-of-the-plane bonding of ligands in axial copper-(II) complexes and to assess the different methods available for satisfying the out-of-the-plane bonding potential of a strictly square coplanar CuL4 chromophore. 

When metals come together and bond in conjunction with bonding of ligands, they look like a cluster of metal atoms in the center with the ligand dangling around them. For this reason, they re known as cluster compounds. 

In this complex, the molecule of coordinated ethylene occupies a single coordination site and is oriented perpendicularly to the plane of the square anion. In both complexes mentioned above (i.e., the complexes with two-center ligands and the olefin rr complexes), the bonding of ligands to the central atom occurs via the dihapto type. Moreover, the rotation of olefin about the metal-ligand bond was observed both in Zeise s salt and in some other ir complexes. Thus, the free energies for the activation of olefin (L) rotation in complexes (PR3)PtCl2 -L and PtCl(acac) - L depend on the nature of R and L, and vary within 44.4-67 kJ mol (10.6 16 kcal mol ) [80]. 

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