Tuning Reactivity of Platinum(II) Complexes

H 3 N
Cl
Pt
NH 3
H 3 N NH 2 (CH 2 )nH 2 N
Cl
Cl
H 3 N
Pt
Cl
Cl
Pt
NH 3
NH 3
Pt
Cl
NH 3
NH 3
H 3 N NH 2 (CH 2 )nH 2 N
Pt
N S N Pt
HH 3
H 3 N
15
Pt
Cl
Cl
H 3 N NH 2 (CH 2 )nH 2 N
1,1/t,t 1,1/c.c
Pt
H3N Pt
N
N
HN NH
6
4
Cl
Cl
2+
NH 3
Cl
NH 2 (CH 2 )nH 2 N
NH 3
BBR3464
NH 3
2+
Cl
H 3 N
O
Pt
O
Pt
O
O
N
NH 3
Cl
H 3 N
H 3 N
Pt
H 3 N
NH 3
Cl
Pt
NH 3
NH 3
2+
N N
Pt Pt
OH
NH 3
Pt
Cl
O
O
N Pt
Figure 1.9: Selected multinuclear platinum(II) complexes with flexible amino- and rigid
azine and azoles ligands. 77,78
1.3.5.1 Amino Linkers
The complexes with flexible linkers, for instance, aliphatic diamines developed by
Farrell and co-workers (1,1/t,t and 1,1/c,c in Figure 1.9) were designed to form long-
range cross-links to DNA. 79,80 In contrast with the mononuclear complexes, such as
antitumor cisplatin and clinically ineffective transplatin, both the cis and trans-isomers
in the dinuclear platinum complexes are antitumor active, 81 although their efficiencies
are affected by geometry. 82,83 The dinuclear cis isomer [{cis-PtCl(NH3)2}2(H2N-(CH2)6-
NH2] +2 (1,1/c,c) is kinetically more inert in its reactions with DNA and in double-
stranded DNA produces more interstrand cross-links than its trans counterpart. 83 Also,
for the 1,1/c,c complex, the chloro ligand is less sterically accessible than the chloro
ligand on the 1,1/t,t complex, and this is reflected in slower reaction rates. 84 Similarly, a
2+
5
7
3
O
O
2+
NH 3
Cl
3+
NH 3
NH 3
2-