Chemistry Reference
In-Depth Information
Figure 4.14
Structural representation of the [(PMe
3
)
2
Pt(9-MeG))]
6
(NO
3
)
6
molecular
hexagon
4.14 ).
14
The platinum atoms lie in two parallel planes separated by 0.34 Å, and these
planes make an angle of 50 ° with the plane of the nucleobases. The distance between
two adjacent metal atoms is 6.5 Å , and the longest Pt · · · Pt distance is 12.9 Å . Hydro-
gen bonding plays an important role in stabilizing the hexanuclear cation and the
crystal lattice, which is destroyed in absence of the mother liquor.
Although it is not comprised of hexagons, there is another example of a com-
plex based on a windmill-shaped hexanuclear copper(II) cluster {(H
2
O)
2
Cu
2
( m
3
- (A)
4
[Cu(oda)(H
2
O)]
4
} · 6H
2
O
(oda = oxydiacetato),
in
which
a
dinuclear
' core '
[
]
II
2
(
) (
)
is connected to four peripheral Cu(oda)(H
2
O) units
(Figure 4.15 ).
15
The dimeric fragment is centrosymmetric and is made of two Cu
II
atoms bridged by four m -
N3
,
N9
-adeninate anions in a windmill-shaped arrangement
with a Cu · · · Cu distance of 2.94
Å
′
Cu
µ
-
NN
39
,
-A
H O
2
4
2
. This structural subunit was previously reported
for some dimeric compounds.
16
Pyrimidines
Rauterkus
et al.
, have synthesized the fi rst pentanuclear metallomacrocycles with
pyrimidines (thymine (T) and uracil (U)).
17
The reaction between 2,2
- dipyridylket -
onedichloridoplatinum(II) with an excess of uracil or thymine affords three penta-
nuclear platinum(II) macrocyclic compounds. Three different Pt(II) entities are
found in these structures in which the uracil or thymine ligands are coordinated to
platinum through the endocyclic nitrogens (N1,N3) and also by means of the exo-
cylic oxygens (O2 and/or O4) (Figure 4.16). The compounds have the ability to
capture different anions (nitrate, perchlorate, tetrafl uoroborate and hexafl uoro-
′
