Mondal B.Naskar R.Bag J.Garai S.Maity R.2025-01-132025-01-1320242767333https://dl.bhu.ac.in/ir/handle/123456789/1137The novel tetra-triazolium salt 1, featuring a tetrasubstituted central adamantane backbone, is introduced for the synthesis of tetranuclear PdII MIC complexes by quadruple C5-H deprotonation and subsequent addition of the corresponding PdII precursors. The three newly prepared palladium(II) complexes appeared to be stable and have been characterized using standard spectroscopic and HRMS techniques. The molecular structure of the tetranuclear PdII complex bearing a 4-methoxypyridine ligand has been established by using single-crystal XRD. All three newly prepared tetranuclear PdII complexes appeared as active precatalysts for the Sonogashira coupling reaction, which occurred in a homogeneous fashion; however, only the palladium(II) complex bearing a combination of MIC and phosphine ligands was found to be active for the intermolecular ?-arylation of 1-methyl-2-oxindole, as the complexes bearing a pyridine or a 4-methoxypyridine ligand decomposed to Pd0 NPs and appeared to be inactive in the ?-arylation reaction. The ancillary-ligand-dependent (Py vs PPh3) interplay between homogeneous and heterogeneous catalyses has also been correlated with the catalytic outcomes in ?-arylation of 1-methyl-2-oxindole. The electrochemical responses of these complexes have been measured, and the effect of ancillary ligands in both electrochemistry and catalysis has also been examined. � 2024 American Chemical Society.enArticle10.1021/acs.organomet.4c00092