## 5 Conclusions  
This study assessed the adsorption properties and photocatalytic activity of composite materials created by incorporating Ti(IV)-oxo complexes stabilized with \(\alpha\)-hydroxycarboxylate ligands ((**(1)**-(3)) and Ru(III) complexes ((**(4)** and (5)) into a PMMA matrix. Spectroscopic analyses (Raman and XAS) confirmed that introducing these complexes into the polymer matrix did not lead to significant alterations in their structures. Notably, the absorption maximum of the composites shifted toward the visible light range (from 221 and 281 nm for pure PMMA to 336 and 420 nm in the case of sample PMMA + (**(5)** 20 wt.%), especially in samples containing 10 and 20 wt.% of the complexes, enhancing their potential responsiveness under visible light. The adsorption properties were evaluated using three cationic dyes: methylene blue (MB), crystal violet (CV), and rhodamine B (RhB). The composites demonstrated the highest adsorption with MB (max 37%) and the lowest with RhB (max 5%), with PMMA + (**(3)** exhibiting the greatest adsorption capacity, likely due to the high electron density of complex (**(3)** (Table 1). The photocatalytic activity was assessed under both UV and visible light. The results showed that composites containing titanium complexes had higher photocatalytic activity (58-73% degradation of MB in UV light, 55-71% degradation of CV in UV light, and 55-63% degradation of MB in visible light) than those containing ruthenium complexes (32-33% degradation of MB in UV light, 49-52% degradation of CV in UV light, and 40-45% degradation of MB in visible light). Based on photocatalytic performance, the composites could be classified as (i) UV-active composites ((**(1)** and (2))), (ii) composites active under visible light ((**(4)** and (5))), and (iii) a composite active under both UV and visible light ((3)). The photocatalytic activity was directly influenced by the type of central ion and the stabilizing ligand (Table 1). Ti(IV)-based composites exhibited superior photocatalytic performance due to the ability of Ti(IV) to generate reactive oxygen species (ROS), which are essential for efficient photocatalysis. In contrast, Ru(III)-based complexes rely on redox cycling between Ru(III) and Ru(II) rather than ROS generation, resulting in lower photocatalytic efficiency. Additionally, the stabilizing ligands affected the electronic structure of the complexes, with certain ligands widening the HOMO-LUMO gap and enhancing UV activity, while others extended the activity into the visible range. Therefore, the type of central ion and the stabilizing ligand both play crucial roles in determining the photocatalytic behavior of the composites. Future research should focus on investigating the use of alternative polymer matrices to better understand how the properties of the host material influence photocatalytic \begin{table}
\begin{tabular}{p{85.4 pt} p{85.4 pt} p{85.4 pt} p{85.4 pt} p{85.4 pt}} \hline \hline \multirow{2}{*}{**Composite**} & **Maximum Dye** & \multirow{2}{*}{**Photocatalytic** **Activity MB** (\%)**} & \multirow{2}{*}{**EPR Signals**} & \multirow{2}{*}{**Light** **Activation Range**} \\  & **Absorption (\%)** & & & \\  & **MB** & & & \\ \hline
**TOCs** & & & & \\ PMMA + **(1)** & 2.27–8.99 & 38–69 (UV) & Moderate (O\({}_{2}\)–, Ti\({}^{3+}\)) & UV \\ PMMA + **(2)** & 1.92–8.91 & 45–73 (UV) & Strong (O\({}^{-}\), O\({}_{2}\)–, Ti\({}^{3+}\)) & UV \\ PMMA + **(3)** & 7.48–37.40 & 36–59 (Vis) & Moderate (O\({}^{-}\), O\({}_{2}\)–, Ti\({}^{3+}\)) & UV + Vis \\
**Ru(III) complexes** & & & & \\ PMMA + **(4)** & 2.14–6.62 & 19–33 (UV) & Weak (Ru\({}^{3+}\)) & Vis \\  & & 17–32 (UV) & Weak (Ru\({}^{3+}\)) & Vis \\ PMMA + **(5)** & 5.63–6.69 & 16–41 (Vis) & Weak (Ru\({}^{3+}\)) & Vis \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative table of PMMA composites with Ti(IV) and Ru(III) complexes (the presented data refer to composites containing 2 wt.% and 20 wt.% of the tested complexes). performance.