Nitrogen-based tetradentate ligands such as tris[2-(dimethylamino)ethyl]amine (Me6TREN), 1,4,8,11-tetraaza-1,4,8,11-tetramethyl-cyclotetradecane (ME6CYCLAM), and tris[(2-pyridyl) methyl]amine (TPMA) are currently some of the most active multi-dentate ligand structures used in atom transfer radical reactions. In this study, we explore the synthesis and characterization of tris-(2-aminoethyl)amine ligand derivatives incorporating increasing electron-withdrawing para substituent functional groups (CH3, H, Cl, CF3, CN, NO2) along with their corresponding copper complexes. This ligand design slowed down the activity of analogous complexes, providing an opportunity to conduct activation rate (kact) kinetic studies on atom transfer radical addition (ATRA) reactions using UV-Vis spectroscopy. Ligands were synthesized utilizing the Mannich reaction scheme, incorporating a tris[2-(amino)ethyl]amine precursor and the following para-substituted precursors; 4-methylbenzaldehyde, benzaldehyde, 4-chlorobenzaldehyde, 4-trifluoromethylbenzaldehyde, 4-cyanobenzaldehyde, and 4-nitrobenzaldehyde. Metalation reactions were subsequently carried out with copper(I) and copper(II) chloride salts to generate respective complexes. Characterization techniques utilized and presented in this study include nuclear magnetic resonance (1H, 13C, COSY, HSQC, VT-NMR), ESI-TOF mass spectrometry, IR spectroscopy, UV-Vis spectroscopy, and x-ray crystallography.

Synthesis and characterization of tris-(2-aminoethyl)amine copper complexes ncorporating para-substituted electron withdrawing functional groups

249th National Meeting (2015)

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