Chemistry Reference
In-Depth Information
O
R
O
R
O
R
H
N
H
N
HO
NH
2
O
R
O
R
OH
H
2
N
OH
NH
O
amino acid
dipeptide
tripeptide
NH
2
-H
+
+M
n+
-2H
+
+M
n+
-3H
+
+M
n+
R
O
R
O
R
O
R
R
O
O
O
-
O
-
N
-
N
-
N
-
NH
2
M
M
M
O
-
X
N
H
2
N
H
2
X
X
O
R
R
Figure 8.1
Examples of amino acid and peptide coordination to a metal ion. Deprotonation of carboxylic acid
and amide groups is required for efficient coordination; potential donor groups are highlighted in the
free ligands.
Nucleotide 'building blocks' of DNA/RNA polymers contain a phosphate ester, a sugar
ring and an aromatic nitrogen base, and thus contain a number of potential O- and N-donor
groups (Figure 8.2). RNA single chains and DNA duplex chains consist of a backbone of
linked phosphate diesters R O PO(O
−
) O R, that each offer an oxygen anion suitable
for complexation or at least ion-pair binding. Moreover, the array of aromatic nitrogen bases
that branch from the backbone offer nitrogen donors that have the potential to participate
R
ribonucleotide
(with adenine
base)
O
-
O
P
O
H
2
N
N
H
O
O
X
X
H
OH
X
X
M
M
N
P
O
X
X
O
-
N
R'
O
H
H
O
N
N
N
H
R''
R
H
2
N
N
coordination as a
N-donor ligand
coordination as a
phosphate diester
N
Figure 8.2
Examples of potential nucleotide coordination to a metal ion. Both oxygen and nitrogen donors
(examples circled) have the ability to bind to metal ions.
