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Cheng et al. Chem Synth 2023;3:13 https://dx.doi.org/10.20517/cs.2022.43 Page 9 of 13

Figure 9. Ratiometric emission intensity plots of the high-energy (HE) and low-energy (LE) bands of 3-5 in acetonitrile with increasing
temperature. I /I of 3 = I 413nm /I 673nm ; I /I of 4 = I 413nm /I 673nm ; I /I of 5 = I 465nm /I 673nm .
LE
HE
HE
LE
HE
LE

t
Figure 10. Normalized UV-vis absorption of [Pt( Bu tpy)(C≡CC H -C HN C H )]OTf (2) and emission spectra of PF-Br, PFP-Br and
13
3
4
6
3
2
6
PFT-Br showing the spectral overlap between the emission spectra of the polymer energy donors and the UV-vis absorption spectrum
of the platinum(II) complex 2 energy acceptor.
from the polymer backbone of 5 is found to be less effectively quenched when compared to that of 3 and 4.
The related parameters have been obtained and are summarized in Table 3. Since the platinum(II)-
containing conjugated polymers 3-5 share similar molecular structures except for the polymer backbone, it
is believed that the values of the relative orientation of the transition dipoles of the chromophores (κ) and
the distance between the donor and the acceptor (r) should be almost the same. Therefore, the FRET
efficiency is mainly governed by the emission quantum yield of the donor (Φ ) and the spectral overlap
D
integral of the absorption spectrum of the acceptor and emission spectrum of the donor (J(λ)), which are
related to the Förster radius (R ). It is found that the calculated R value of 5 is the lowest, indicating that the
0
0
FRET in 5 should be the least efficient, as reflected by the smallest decrease in emission quantum yield of
the polymer backbone.