Monodentate ligand complexed inorganic

TABLE 1.3 Colors of Select Aqueous (Uncomplexed) and Other Simple Monodentate" Ligand-Complexed Inorganic Ions. Note How Color Changes with Ligand... 

Simple inorganic ions and molecules like NH3, CN , Cl-, H20 form monodentate ligands, that is one ion or molecule occupies one of the spaces available around the central ion in the coordination sphere, but bidentate (like the dipyridyl ion), tridentate, and also tetradentate ligands are known. Complexes made of polydentate ligands are often called chelates, the name originating from the Greek word for the claw of the crab, which bites into an object like the polydentate ligand catches the central ion. The formation of chelate complexes is used extensively in quantitative chemical analysis (complexometric titrations). ... 

Studies with platinum(IV) complexes are complicated by platinum(II) catalysis 18). Some of the recent Russian work has considered this aspect 44) i but correlations are still being made without consideration of the catalytic problem 104)- The recent isolation of several optically active platinum(IV) complexes with all inorganic, monodentate ligands 35) should allow substantiation for older work which has always suggested retention, in agreement with the high A values for platinum(IV). 

Note Inorganic ligands are chiefly monodentate, whereas organic ligands are most often multi-dentate in complexes. 

The bulk of the work has been carried out using complexes of the type [M(bidentate)2X2] where bidentate is a bidentate ligand and X is monodentate. Anotha important area deals with the loss of optical activity of resolved octahedral complices. These reactions can be very fast or very slow and have long scinated inorganic chemists. In a number of cases the loss of optical activity (racemisation) is rdated to cis treats isomerisation. For example, in the [M(bidentate)2X2] complexes, the enantiomaic cis-isomer may lose its optical activity by isomeri g to the optical inactive ti-ans-isomer. Early and subsequent work on cis treats isomerisation and racemisation of octahedral metal complexes has been summarised and detailed in various books and reviews [ 1-6]. 

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