Behavior of Supramolecular Polymerization of Alkynylplatinum(II) Complex in Different Compositions of DMSO and Water

The self-assembly of R-L-Pt-BP in DMSO/H₂O showed solvent-dependent CD and photoluminescence (PL). A cooperative mechanism with red-shifted emission and higher ΔG appeared in 2:8 mixtures; whereas 5:5 and 8:2 followed an isodesmic model with opposite CD signals.

Abstract

We report the self-assembling behavior of a terpyridine-based alkyne platinum(II) complex (R-L-Pt-BP) under varying composition ratios of DMSO and H₂O. The resulting self-assemblies exhibited distinct photoluminescence and circular dichroism (CD) properties depending on the solvent conditions. Notably, strong positive CD signals were observed for the self-assembled R-L-Pt-BP in DMSO and H₂O (2:8 v/v), accompanied by a red-shift in emission wavelength. In contrast, a negative CD signal was observed for the self-assembled R-L-Pt-BP in DMSO and H₂O (5:5 v/v), along with a blue shift in photoluminescence (PL). The self-assembly formed in DMSO and H₂O (2:8 v/v) followed a cooperative model characterized by a nucleation–elongation mechanism, whereas those formed in DMSO and H₂O (5:5 and 8:2 v/v) adhered to an isodesmic model. Thermodynamic parameters were determined using EQ model of the heating curves. The Gibbs free energy (ΔG) of the self-assemblies formed in DMSO and H₂O (5:5 and 2:8 v/v) was found to be higher than that formed in DMSO and H₂O (8:2 v/v).

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