# Synthetic Routes to Silsesquioxane-Based Systems as Photoactive Materials and Their Precursors
## 1 Introduction
### Heck Coupling for Obtaining Silylakenyl Units Anchored at the Si-O-Si Core
The products were compared, their thermal resistance was verified and they exhibited \(T_{\mathrm{d}}\)5\({}^{\mathrm{\%}}\) up to 445 \({}^{\mathrm{\circ}}\)C. The UV-vis and PL spectra in THF were analyzed and, in general, were similar to those obtained for T\({}_{8}\) analogues. Interestingly, the UV-vis absorption maxima of products obtained via Heck and double Heck coupling were almost the same (in the range 254-374 nm), while the emission of double-functionalized compounds was a bit red-shifted (310-465 nm), as should be expected for the slightly extended, excited state of conjugation. The p-substituted stilbene-based T\({}_{10}\) and T\({}_{12}\) exhibited emission maxima dependent on the electronic properties on the substituents (e.g., the largest red shift of \(\lambda_{\mathrm{em}}\) for the = -NH\({}_{2}\) group, that results from a charge transfer). For this derivative, a solvatochromism was also observed for MeCN (acetonitrile), THF and cyclohexane solvents used. Additionally, the dependence of emission spectra shapes (maxima)  
Figure 14: T\({}_{10}\) and T\({}_{12}\) stilbene derivatives obtained by Heck coupling and cross-metathesis. Figure 13: T\({}_{10}\) and T\({}_{12}\) areen derivatives obtained by Heck Coupling and Cross-Metathesis. and their intensity on the solvent used (MeCN:THF, hexane:THF) and the spectra collected for various compound concentration suggested their aggregation. This possible aggregation may be responsible for the exciplex formation and seems to differ significantly from the one known for traditional organic molecules. These findings might suggest smaller band gaps, meaning a possible use of these systems in 3D hole/electron transport devices. The research connected with the use of T\({}_{10}\) and T\({}_{12}\) cages was carried on for copolymeric systems. Again, [PERSON] et al. performed experiments using octa(vinyl)silsesquioxane T\({}_{8}\) (OVS) and octa(p-iodophenyl)silsesquioxane T\({}_{8}\) to obtain a mixture of T\({}_{10}\) and T\({}_{12}\) with mixed vinyl- and p-iodophenyl-substituent placement (with a 90% yield) along with an analogous reaction for vinyl and phenyl-substituted T\({}_{10}\) and T\({}_{12}\) cages [63]. The vinyl/phenyl-mixed T\({}_{10}\) and T\({}_{12}\) systems were substrates for the following:  
* Heck Coupling reaction (analogous catalytic conditions described in [61]) with 1,4-dibromobenzene and 4,4'-dibromostilbene, resulting in lightly branched non-linear copolymeric systems with a 83-86% yield. This is the fastest way to obtain the desired copolymeric compounds.Cross-metathesis (described in detail in Section 3.3) reaction, using [PERSON] first generation catalyst with 1,4-dibromobenzene to obtain (again) slightly branched non-linear copolymeric system with a 89% yield.The vinyl/(p-iodo)phenyl-mixed T\({}_{10}\) and T\({}_{12}\) cages were substrates for the reverse synthetic path (i.e., cross-metathesis reaction, using [PERSON] first generation catalyst with 1,4-dibromobenzene to obtain a slightly branched non-linear copolymeric system with a 95% yield).The abovementioned copolymer (i.e., its p-iodophenyl substituents) was post-modified via a Heck coupling reaction using R-styrenes (H-styrene, OMe-styrene) to obtain R-styrene functionalized copolymer with a 67% yield. All these six types of copolymers were tested in terms of their photophysical properties, with results collated for those with bis(vinyltriethoxysilyl)benzene and 4,4'-bis(vinyltriethoxysilyl)stilbene used as models. All copolymers exhibited a red shifted emission spectra that were strongest for the copolymers obtained via Heck Coupling (described in the first point) at ca. 20-60 nm for the DVB derivative when compared with the model compounds. This is attributed to shorter conjugated linkers, enabling Si-O-Si cage participation in the 3D excited states. The compounds were obtained in particular because of their 3D interaction in the excited state that corresponds with their application in OLEDs devices.