## 1 Introduction  
The use of palladium coordination complexes as homogeneous catalysts for a large number of low scale and industrial process is widely known, and in particular for the preparation of various important organic building blocks [1; 2; 3]. Indeed, the formation of new carbon-carbon bonds through the catalyzed carbon-coupling reactions of a large variety of starting materials are key to the area of organic chemistry [4; 5; 6]. Additionally, the requirement of tolerance to almost any unprotected sensitive functional groups [7; 8] increase their recognized importance as some of these C-C coupling reactions, such as the Heck, Suzuki and Negishi reactions, have been recognized with the 2010 Nobel Prize [4; 9]. Even though homogeneous palladium complexes have been reported the most important catalytic systems [5; 6], the major drawback is related with their poor recovered capacity and the difficulty of separating it from the reaction medium, with several environmental consequences. This latter problem, together with the new vision of green chemistry procedures, is the reason of the current efforts to heterogenize homogeneous catalysts [10; 11]. To achieve this challenge, one procedure has been the immobilization of the coordination compounds on insoluble matrixes to obtain heterogeneous catalysts, improving their mechanically stability to be reused [12; 13; 14; 15; 16]. Due to the enhanced stability, the covalent immobilization pathway has therefore proven to be a particularly efficient option for the preparation of heterogeneous metal complex-based catalysts [17]. To date, different insoluble materials have been reported for this purpose, including amorphous or mesostructured silica materials [18], inorganic-organic hybrid materials [19], and polymeric supports [20; 21]. With regard to the polymeric support, the most commonly employed material is the lightly cross-linked Merrifield resin [20; 22; 23], which exhibits a good thermal stability and a surface that acts as a simple anchoring point for metal complex immobilization; however, such systems tend to exhibit a low surface area, which limits their use in heterogeneous systems [24]. To address this issue, a range of methodologies for the preparation of polymeric materials with high surface areas have been reported based on the use of metal chelate monomers (MCM) as co-monomers [25; 26]. For example, porous organic polymers (POPs) [27], polymers synthesized by high internal phase emulsion (Poly-HIPEs) [28; 29], and cross-coupling polymers [30; 31] have been reported. The main disadvantages in using such methodologies to produce immobilized metal-complexes on heterogeneous matrices is the expensive and complex synthetic routes required [21]. Therefore, cross-linked polymers with a high divinylbenzene (DVB) content of DVB open the possibility of providing large surface area materials when it is synthesized by suspension polymerization in presence of a porogen agent allow to obtain materials with tunable properties. Since suspension polymerization allows tuning of the morphology, surface area, and pore size through economical and simple synthetic procedures [21; 32; 33], it is commonly employed in the production of polymer beads with applications in chromatographic separation media (e.g., ion exchange resins) and as supports for enzyme or metal-complex immobilization [34; 35]. The current necessity for new coordination compounds bearing non-expensive and stable ligands as catalysts for carbon coupling reactions has led to the design and synthesis of various nitrogen-based compounds bearing amine [14], oxime [36; 37], quinolone [14], pyridine [38], and imine [14; 39; 40] functional groups. In particular, amines synthesized by the condensation of salic-aldehyde with an aliphatic or an aromatic diamine are commonly known as SALEN or SALOPHEN ligands, respectively, and these ligands can be employed as N\({}_{2}\)O\({}_{2}\) ligands for the preparation of palladium-based catalysts.