The Oxidation of Aroyl Propionic Acids by Sodium Hypochlorite

Author Institution: Department of Chemistry, The College of Wooster, Wooster, Ohi

Synthesis, Characterization, and Computational Study of Three-Coordinate SNS Copper(I) Complexes Based on Bis-Thione Ligand Precursors

A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl2 to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]+. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]+ cation and the [CuCl4]2– counteranion. The [(SNS)Cu]+ complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (g||) and g values consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate in the copper-containing cations and anions. Density functional calculations support the nature of the SNS binding, allowing assignment of a number of features present in the UV–Vis and IR spectra and cyclic voltammograms of these complexes

Synthesis, Spectroscopic Properties, and Photoconductivity of Black Absorbers Consisting of Pt(Bipyridine)(Dithiolate) Charge Transfer Complexes in the Presence and Absence of Nitrofluorenone Acceptors

The diimine–dithiolato ambipolar complexes Pt­(dbbpy)­(tdt) and Pt­(dmecb)­(bdt) (dbbpy = 4,4′-di-<i>tert</i>-butyl-2,2′-bipyridine; tdt^2– = 3,4-toluenedithiolate; dmecb = 4,4′-dimethoxyester-2,2′-bipyridine; bdt^2– = benzene-1,2-dithiolate) are prepared herein. Pt­(dmecb)­(bdt) exhibits photoconductivity that remains constant (photocurrent density of 1.6 mA/cm² from a 20 nm thin film) <i>across the entire visible region of the solar spectrum</i> in a Schottky diode device structure. Pt­(dbbpy)­(tdt) acts as donor when combined with the strong nitrofluorenone acceptors 2,7-dinitro-9-fluorenone (DNF), 2,4,7-trinitro-9-fluorenone (TRNF), or 2,4,5,7-tetranitro-9-fluorenone (TENF). Supramolecular charge transfer stacks form and exhibit various donor–acceptor stacking patterns. The crystalline solids are “black absorbers” that exhibit continuous absorptions spanning the entire visible region and significant ultraviolet and near-infrared wavelengths, the latter including long wavelengths that the donor or acceptor molecules alone do not absorb. Absorption spectra reveal the persistence of donor–acceptor interactions in solution, as characterized by low-energy donor/acceptor charge transfer (DACT) bands. Crystal structures show closely packed stacks with distances that underscore intermolecular DACT. ¹H NMR provides further evidence of DACT, as manifested by upfield shifts of aromatic protons in the binary adducts versus their free components, whereas 2D nuclear Overhauser effect spectroscopy (NOESY) spectra suggest coupling between dithiolate donor protons with nitrofluorenone acceptor protons, in correlation with the solid-state stacking. The NMR spectra also show significant peak broadening, indicating some paramagnetism verified by magnetic susceptibility data. Solid-state absorption spectra reveal further red shifts and increased relative intensities of DACT bands for the solid adducts vs solution, suggesting cooperativity of the DACT phenomenon in the solid state, as further substantiated by ν_C–O and ν_N–O IR bands and solid-state tight-binding computational analysis