Chemistry Reference
In-Depth Information
HH1
∆
HT1
HH2
platinum
nitrogen
carbonium
oxygen
phosphorus
Figure 5.13
(Plate 8)
Minimum energy models (from NMR-restrained MMD calculations) of
the
anti
/
anti
HH1 L (top) and
anti
/
syn
D
HT1 L (centre) forms of (
S
,
R
,
R
,
S
)-bip-Pt(d(GpG))
and the
anti
/
anti
HH2 R (bottom) form of (
R
,
S
,
S
,
R
)-bip-Pt(d(GpG)) (the conformation of the
5
-G; only the chelate-ring atoms of the bip ligand are shown).
Based on data from Refs 101 and 106 (See colour plate section)
′
-G is given fi rst, then that of 3
′
Pt(d(GpG)) and (
S,R,R,S
) - bip - Pt(GpG) both favoured two variants,
anti
/
anti
HH1
L (with N and S puckers for the 5
-G residues, respectively) and
anti
/
syn
DHT1 L (both sugars having mainly N puckers, top and centre molecular models in
Figure 5.13 ).
103,106
When these complexes were kept at pH 10 for several days, the
DHT1 L variant became favoured over the HH1 L variant, demonstrating that D HT1
L is more favourable when N1 is deprotonated.
103,131
For (
R,S,S,R
) - bip - Pt(d(GpG))
′
and 3
′
