Synthesis & complexation of tripodal tris (1,2,3-triazol-5-ylidene) mesoionic carbene ligands

• Main Author: Laxmi, Shoba
• Other Authors: Jason England
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Science::Chemistry::Inorganic chemistry::Metals; DRNTU::Science::Chemistry::Inorganic chemistry::Synthesis
• Online Access: http://hdl.handle.net/10356/76187
• Institution: Nanyang Technological University

Herein, the synthesis and coordination of a new 1,2,3-triazol-5-ylidene ligand system using cobalt salts to form an imido cobalt complex. 1,2,3-triazol-5-ylidenes are a special class of mesoionic carbenes (MICs) synthesised from triazoles, which are conveniently obtained through [2+3] “click” cycloaddition reactions. Isolation of the target tris[(1,2,3-triazol-5-ylidene)methyl] amine ligand precursors, H3Ln(X)3, in high yield has proven to be difficult. The free carbene, Ln formed was found to be stable at -80°C based on low temperature 1H NMR studies done. Two different complexation routes, silver transmetalation and direct metalation were explored. Sufficient quantities of cobalt(II) complex, [CoL1(CH3CN)][OTf]2 was successfully synthesised via the direct metalation. [CoL1(CH3CN)][OTf]2 synthesised was characterised using 1H NMR, cyclic voltammetry and X-Ray crystallography.