Synthesis, Characterization and Quantum Chemical Study of New Biaryl Backbone Ligands in Bis (Oxamato) Type Compounds

Abstract

A straightforward consecutive synthesis methodology for the preparation of two derivatives of bis (oxamato) type based on biarylbackbone compounds 2-4 is presented. All compounds were isolated and tested to be soluble in common organic solvents. Compound 2 was readily converted into its saponified form (namely 3) when treated with four equivalents of [ⁿBu₄N]OH and the subsequent addition of Pd (OAc)₂. Compound 3 could be isolated smoothly from the reaction mixture as a fine brown solid. Treatment of 2 with an excess amount of methylamine in dry ethanol gave compound 4 as crystalline colorless material. The synthesized compounds 2 and 4 were characterized by IR-, NMR-spectroscopy, elemental analysis, mass spectroscopy and melting point. Density functional theory (DFT) calculations were carried out to correlate the structural features of compound 2