Chelating agent Complexing ligand that forms more

Charles s and Gay-Lussac s law Relation stating that at constant P and n, the volume of a gas is directly proportional to its absolute temperature, 106-107, 111 Chelating agent Complexing ligand that forms more than one bond with a central metal atom the complex formed is called a chelate, 411-412 natural, 424-425 synthetic, 424-425 Chemical equation Expression that describes the nature and relative amounts of reactants and products in a reaction, 60-61. See also Equation, net ionic. 

It is also observed that chelating agents (polydentate ligands) form more stable complexes than a comparable number of donor atoms in monodentate ligands. Consider the following example of Ni+ complexes with four ammonia molecules (each monodentate) and two ethylenediamine... 

All Gd(III) chelates approved for contrast agent application have one inner sphere water molecule. The inner sphere proton relaxivity is linearly proportional to the hydration number q (Eq. (5)), thus a higher q would result in increased relaxivities. However, ligands that leave space for more than one water molecule in the first coordination sphere form complexes of reduced stability,... 

Reagents formed with chiral /3 -diketonate ligands such as Lnftfcfs and Ln(hfc)3 in the presence of Ag(fod) or other silver /3-diketonates are effective for chiral discrimination . Lanthanide chelates with dcm are ineffective in the binuclear complexes, presumably because the dcm ligand is so sterically hindered that it prevents the formation of the quadruple chelate anion. Silver complexes besides Ag(fod) actually form more effective chiral discriminating agents with Pr(tfc)3, Yb(tfc)3 and Yb(hfc)3, but these complexes are not commercially available so have not been used beyond exploratory studies . ... 

Finally, we also observe that the kinetics of dissociation at any pH are independent of added metal ions and other ligands, even though they may form more stable complexes with the [15]aneNj macrocycle or with Mn(II), respectively. This has the consequence that in vivo kinetic stability will not be at risk in the presence of any potential biological chelating agent or in the presence of other endogenous free metal ions. 

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