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Download fileSubstituent-Dependent Optical and Electrochemical Properties of Triarylformazanate Boron Difluoride Complexes
dataset
posted on 2014-10-06, 00:00 authored by Stephanie M. Barbon, Jacquelyn
T. Price, Pauline A. Reinkeluers, Joe B. GilroyThe
straightforward synthesis and detailed characterization of nine substituted
triarylformazanate boron difluoride complexes is reported. The effect
of electron-donating (p-anisole) and electron-withdrawing
(p-benzonitrile) substituents on optical and electrochemical
properties, relative to phenyl substituents, was studied at two different
positions within the formazanate ligand framework. Each of the BF2 complexes was characterized by 1H, 13C, 11B, and 19F NMR spectroscopy, cyclic voltammetry,
infrared spectroscopy, UV–vis absorption and emission spectroscopy,
mass spectrometry, and elemental analysis. Select examples were studied
by X-ray crystallography, revealing highly delocalized structures
in the solid state. The complexes were reversibly reduced in two steps
electrochemically to their radical anion and dianion forms. The complexes
also exhibited substituent-dependent absorption and emission properties,
accompanied by significant Stokes shifts, with the aryl substituents
at the 1,5-positions of the formazanate backbone having a greater
influence on these properties than aryl substituents at the 3-position.
Breaking the symmetry in three different complexes resulted in a modest
increase in emission intensity relative to that of symmetrically substituted
derivatives.