# Naphthalene-Based Polymers as Catalytic Supports for Suzuki Cross-Coupling
It was shown that the porous structure and the SSA of the resulting polymers can be regulated by changing the molar ratio of the crosslinking agent to monomers. Overall, the use of catalytic materials based on HAPs in the processes of fine organic synthesis is promising [18]. However, weak interactions between metal NPs and non-functionalized aromatic supports often lead to leaching and aggregation/sintering of NPs during catalytic reactions. The introduction of functional groups or heteroatoms into the support significantly improves the metal-support interaction and, as a consequence, the dispersion of metal NPs [22]. A number of porous aromatic polymers consisting of nitrogen-rich building blocks (i.e., triazine, carbazole, imine, and amide blocks) were synthesized and used as catalytic supports [23]. One of the ways to obtain functionalized polymers is by using monomers with functional groups. [PERSON] et al. [24] synthesized a series of polymers based on benzyl alcohol via Friedel-Crafts alkylation reaction using methylal as a crosslinking agent and anhydrous ferric chloride as a catalyst. Using phenol as a monomer, hyper-crosslinked polymeric materials were synthesized for CO\({}_{2}\) adsorption [13]. Another approach to the functionalization of HAPs is the introduction of substituents in phenyl rings after the polymer synthesis. The sulfonation reaction serves as an effective method for obtaining new solid acid catalysts. [PERSON] et al. [25] synthesized polymers functionalized by sulfonate groups, which allowed the creation of new heterogeneous acid catalysts. [PERSON] et al. [26] synthesized an efficient solid acid catalyst based on a sulfonated polymer for the conversion of monosaccharides to 5-hydroxymethylfurfural. Thus, mono-functional acid or base catalysts can be synthesized via introduction of acid (-SO\({}_{3}\)H) or basic (-NH\({}_{2}\)) groups into the HAPs' structure, allowing high stability of the resulting functionalized microporous materials [18]. Naphthalene (NA)-based polymers have been known for more than 50 years. As compared with other monomers (benzene, toluene, and xylene), NA gives a higher polymer yield in the presence of aluminum chloride [27]. [PERSON] et al. [28] developed microporous networks based on NA, 1-naphthol (NL), and 1-methylnaphthalene using the external crosslinker knitting method, the solvent knitting method, and the Scholl coupling reaction. The sample synthesized via Friedel-Crafts reaction while using methylal as a crosslinking agent revealed the highest SSA of 2870 m\({}^{2}\)/g [28]. Thus, NA-based polymers are promising since they possess high SSA, a narrow pore size distribution, and stability. The characteristics of such polymers can be influenced by choosing a monomer, varying the amount of crosslinking agent, and introducing functional groups. However, to our knowledge, the application of NA-based HAPs in catalysis is poorly studied. There is no data on the use of NA-based polymers in the Suzuki cross-coupling process. Moreover, there is no data on the formation of Pd NPs in the environment of NA-based polymers. Herein, we report for the first time the application of NA-based polymers for the Pd-catalyzed model reaction of Suzuki cross-coupling between 4-bromoanisole (BrAN) and phenylboronic acid (PBA). Several types of polymers were synthesized via Friedel-Crafts alkylation (Figure 1) with NA or NL as monomers at varying levels of methylal content. In addition, one of the NA-based polymers underwent either sulfonation or nitration to find out how the polymer functionalization influences the porosity and hydrophilicity, which is expected to affect the catalytic properties. Thus, the aim of this work is to show if such properties of NA-based polymers as porosity and hydrophilicity will affect the processes of Pd NPs formation, both during the reduction and in situ during the Suzuki reaction, and also the behavior of the developed catalysts in the Suzuki cross-coupling.