Neutralization reactions between (NBu
4)
2[
trans-Pt(C
6F
5)
2(CN)
2]
1 and (NBu
4)
2[
cis-Pt(C
6F
5)
2(CN)
2]
2 with TlPF
6 have been carried out, and the resulting structures of [
trans,trans,trans-Tl
2{Pt(C
6F
5)
2(CN)
2}·(CH
3COCH
3)
2]
n [
4·(CH
3COCH
3)
2]
n and {Tl[Tl{
cis-Pt(C
6F
5)
2(CN)
2}]·(H
2O)}
n [
5·(H
2O)]
n have been determined by X-ray crystallography. Remarkably, the change from
trans to
cis geometry on the platinum substrate causes a significant decrease in the Pt
II···Tl
I metallophilic interaction. Thus, the platinum center in the
trans fragment easily connects with two Tl
I ions forming a distorted pseudo-octahedron PtTl
2, which generates a final two-dimensional layered structure by secondary additional intermolecular Tl
I···N(CN) interactions. However, the [
cis-Pt(C
6F
5)
2(CN)
2]
2− fragment interacts strongly with just one Tl center leading to an extended helical [−Pt−Tl−Pt−Tl−]
nn− chain. In this case, the second thallium center neutralizes the anionic chain mainly through Tl···N(CN) (
intra) and Tl···F(C
6F
5) (
intra and
inter)teractions. The reaction of TlPF
6 with the monoanionic fragment (NBu
4)[
cis-Pt(C
6F
5)
2(CN)(PPh
2C
![](http://pubs.acs.org/images/entities/tbd1.gif)
CPh)]
3 yields the discrete associated dimer [Tl{
cis-Pt(C
6F
5)
2(CN)(PPh
2C
![](http://pubs.acs.org/images/entities/tbd1.gif)
CPh)}]
2 [
6]
2. Dimer [
6]
2 could be described as two square pyramids with the thallium atoms in the apical positions, connected through Tl···N(cyano) interactions. The final heteropolynuclear Pt−Tl complexes, except
4 at room temperature, show bright emission in the solid state when irradiated with
UV–vis radiation, in contrast to the precursors
1 and
3, which are not luminescent. This difference indicates that the emissions in
4−
6 are presumably related to the interaction between the metal centers. The Pt−Tl bonding interactions and, consequently, the emissive properties are lost in solution at room temperature, as shown by the conductivity and NMR measurements. However, variable-concentration luminescence measurements in glassy acetonitrile solutions indicate the formation of different aggregates with different degrees of Pt···Tl interactions for
4 and
5 and a dimeric structure similar to that observed in solid state for
6.