636
Bioinorganic Chemistry
11
pH-dependent Stabilities
649
12
Cooperativity
651
13
Metal Ion Binding Characteristics
651
13.1
Amino Acids
651
13.2
Peptides
651
13.3
Proteins
652
13.4
Nucleosides
652
13.5
Nucleic Acids
653
14
Dioxygen
653
15
Metal Ion Complexation Kinetics
654
15.1
Substitution Reactions
654
15.2
Ligand Exchange
655
Bibliography
656
Books and Reviews
656
Primary Literature
657
Keywords
Chelate (from Greek claw)
Multiple bonding of two or more atoms of a single molecule to a metal ion, often to
form Fve- or six-membered rings.
Ligand
A molecule or ion with a donor atom possessing a lone pair of electrons that interacts
with a metal ion.
pH
=−
log(H
+
)
The negative decade logarithm of the hydrogen ion activity or concentration. Almost all
chemists and biochemists calibrate a pH meter with buffers that yield a pH scale based
closely on hydrogen ion activity. Many coordination chemists calibrate a pH meter
using known concentrations of hydrogen ion. In the region of 0.1 to 0.2 ionic strength,
the concentration scale yields acidity constant logarithms (p
K
a
values) about 0.12 log
unit lower than those on the more common activity-based scale. Stability constants of
metal ions with ligands are unaffected by the choice of pH scale.
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