Synthesis, characterization, and crystal structure of novel bulky phenyl-bridged -diimine binucleating ligands

A series of sterically and electronically modulated phenyl-bridged -diimine ligands L1-L6 of the general formula Ar-N=C(Me)-C(Me)=N-C6H4-N=C(Me)-C(Me)=N-Ar have been synthesized (L1 : Ar=2,6-iPr(2)-C6H3; L2: Ar=2,6-Me-2-C6H3; L3: 4-Me-C6H4; L4: Ar=4-Et-C6H4; L5: Ar=2,4,6-Cl-3-C6H2; L6: Ar=4-Cl-C6H4). All of which have been characterized by H-1 NMR, C-13 NMR, IR, and elemental analysis. In addition, the effect of the electronic modification was studied by UV-Vis spectroscopy, and the structure of a representative ligand was confirmed by single-crystal X-ray diffraction. Moreover, a DFT electronic structure of the same ligand has been determined.