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Page 10 of 13 Cheng et al. Chem Synth 2023;3:13 https://dx.doi.org/10.20517/cs.2022.43

a
Table 3. Parameters obtained from the equation determining the Förster radius, R of 3-5
0
Acceptor Donor Φ D b,c R /nm Pt(II)-Polymer Φ lum b,c,d Φ /Φ D
0
lum
2 PF-Br 0.92 4.9 3 1.2 × 10 -3 1.30 × 10 -3
-4 -3
2 PFP-Br 0.90 4.9 4 9.0 × 10 1.00 × 10
2 PFT-Br 0.45 4.5 5 8.4 × 10 -4 1.87 × 10 -3
a 2 -4 1/6 b c
R = 0.211[κ n Φ J(λ)] ; data obtained with an uncertainty of 10 %; the relative luminescence quantum yields were measured at
0
D
d
room temperature using quinine sulfate in 0.5 M H SO as a standard; the luminescence quantum yields of the polymer backbone.
4
2
CONCLUSION
Alkynylplatinum(II) terpyridine complexes (1 and 2) and alkynylplatinum(II) terpyridine-containing
conjugated polymers with different polymer backbones (3-5) have been prepared, and their spectroscopic
properties as well as FRET processes have been studied. The platinum(II)-containing polymers 3-5 are
found to exhibit dual emissive features, in which the two emission bands correspond to IL fluorescence
1
from the polymer backbones and MMLCT emissions from the platinum(II) pendants. Such unique
3
luminescence behavior is attributed to the intramolecular Pt···Pt and/or π-π interactions between the
platinum(II) pendants in the polymer molecules. The FRET processes between the conjugated polymer
backbones and platinum(II) pendants have been studied systemically. It is found that 5 has the lowest
Förster radii (R ) among others, probably due to the lowest emission quantum yield of poly(fluorene-co-
0
thiophene). Distinctive thermo-responsive ratiometric emission changes have been observed for 3 and 4, in
1
which an increase in intensity of the high-energy IL emission originated from the polymer backbones and a
3
decrease in intensity of the low-energy MMLCT emission are found upon heating. The present work has
demonstrated the utilization of “click” reaction for the convenient preparation of platinum(II)-containing
conjugated polymers, which show unique photophysical and spectroscopic properties. Through the
judicious design, ratiometric emission changes upon varying temperatures have been realized in this class of
platinum(II)-containing polymers. This study may provide valuable insights into the preparation of metal-
containing polymeric systems for different applications, such as thermochromic materials. Owing to the
ease of structural modifications, various kinds of polymeric materials could be potentially fabricated, which
could serve as thermochromic sensors for monitoring temperature in real time.

DECLARATIONS
Authors’ contributions
Conducted the synthesis, characterization and photophysical measurements, analyzed the data and
prepared the manuscript: Cheng HK
Initiated and designed the research, analyzed the data and prepared the manuscript: Yam VWW

Availability of data and materials
Not applicable.

Financial support and sponsorship
This work was supported by the Collaborative Research Fund (CRF) (C7075-21G) and the General Research
Fund (GRF) from the Research Grants Council of the Hong Kong Special Administrative Region, People’s
Republic of China (HKU17303421), and the CAS-Croucher Funding Scheme for Joint Laboratory on
Molecular Functional Materials for Electronics, Switching and Sensing. H.-K.C. acknowledges the receipt of
a Postgraduate Studentship.