PdII‐bis(triazolyl)phenylmethanol complexes bearing different groups (i. e., H, OMe, OH, COOH) directly attached to the benzyl rings were explored as precatalysts for copper‐free Sonogashira and Suzuki–Miyaura coupling reactions in water. Crystal structures reveal a bidentate N,N binding mode of the bis(triazolyl) ligands affording a distorted square planar PdII complexes. With the exception of the phenol‐substituted bis(triazolyl) ligands, the other three Pd complexes exhibited high activities toward Suzuki–Miyaura coupling reactions. Transmission electron microscopy (TEM) study and PPh3 poisoning experiments confirm that bis(triazoly)‐stabilized Pd nanoparticles (Pd NPs) were generated in situ during the catalytic reactions and involved as one of the active catalytic species in the Suzuki–Miyaura cross coupling.

Triazole-based ligands, tris (triazolyl)methanol (Htbtm), bis (triazolyl)phenylmethanol (Hbtm), and phenyl (pyridin-2-yl)(triazolyl)methanol (Hpytm), with differences in ligand denticity (i.e., bidentate and tridentate) and type of N donors (i.e., triazole and pyridine) were functionalized onto a silica support to produce the corresponding SiO 2 -L (L = tbtm, btm, pytm). Subsequent reactions with Pd (CH 3 COO) 2 in CH 2 Cl 2 yielded Pd/SiO 2 -L. ICP-MS reveals that Pd loadings are higher with increased N loadings, resulting in the following trend: Pd/SiO 2 -tbtm (0.83 mmol Pd g −1 ) > Pd/SiO 2 -btm (0.65 mmol Pd g −1 )~Pd/SiO 2 -pytm (0.63 mmol Pd g −1 ). Meanwhile, TEM images of the used Pd/SiO 2 -L catalysts after the first catalytic cycle show that the mean size of Pd NPs is highest with Pd/SiO 2 -pytm (8.5 ± 1.5 nm), followed by Pd/SiO 2 -tbtm (6.4 ± 1.6 nm) and Pd/SiO 2 -btm (4.8 ± 1.3 nm). Based on TONs, catalytic studies toward aerobic oxidation of benzyl alcohol to benzaldehyde at 60°C in EtOH showed that Pd/SiO 2 -pytm possessed the most active surface Pd(0) atoms, most likely as a result of more labile properties of the pyridine-triazole ligand compared to tris-and bis (triazolyl) analogs. ICP-MS and TEM analysis of Pd/SiO 2 -btm indicate minimal Pd leaching and similar average Pd NPs sizes after 1 st and 5 th catalytic runs, respectively, confirming that SiO 2 -btm is an efficient Pd NPs stabilizer. The Pd/SiO 2 -btm catalyst was also active toward aerobic oxidation of various benzyl alcohol derivatives in EtOH and could be reused for at least 7 reaction cycles without a significant activity loss.