Functionalised triazole based pincer and tripodal NHC ligands and their complexes : synthesis, characterization, and catalysis

Abstract

Herein we have synthesized a triazole-based ligand and done the functionalization on triazole ring to a new ligand. We have reported the scope of forming heterometallic complexes using this ligand. N-4 of triazole ring can bind with metal (like Cu) leaving another binding site of NNN- pincer pocket, which will result in heterometallic complexes. These heterometallic complexes using mix 3d metals could be a very good single-molecule magnet (SMM).Functionalize triazole-based ligand L1(I) have the NNN pincer pockets as well as CNHCNCNHC- pincer pocket, herein we have reported a series of complex formation using three different Rumetal precursors and also have shown the X-ray crystal structure of ionic complex formation using 3d metal to NNN pincer pockets as well as CNHCNCNHC- pincer pocket due to presence of electron deficient N atom in the ligand system. Similarly, L2(I) ligand have the NNN Pincer pocket and CNHCNN- pincer pocket, which undergoes metalation to CNHCNN- pincer pocket using 3 different Ru-metal precursors. All the ligands are characterized by ESI-MS, 1H, 13C, 31P NMR, We have also reported the X-ray crystallography data for complex 1a, 1b, 2a and ligand L1(BPh4). Further, we have done the preliminary catalysis using Ru-complex 3b, where C-N bond formation has occurred very efficiently under reaction condition. Which indicates the rather good catalysis reaction using the reported complexes. Triazole based tripodal ligand has been synthesized and metalation has been attempted but no complexes have been isolated so far.