172226-68-5Relevant academic research and scientific papers
Redox Tuning of the Dimolybdenum Compounds at the Ligand Periphery: A Direct Correlation with the Hammett Constant of the Substituents
Lin, Chun,Protasiewicz, John D.,Smith, Eugene T.,Ren, Tong
, p. 2257 - 2258 (1995)
Oxidation potentials of (Ar = aryl), a direct measure of the HOMO (δ orbital) energy, correlate with the Hammett constant of aryl substituents, while both structural and spectroscopic data indicate that the valence structure around the dinuclear core is unperturbed.
Linear Free Energy Relationships in Dinuclear Compounds. 2. Inductive Redox Tuning via Remote Substituents in Quadruply Bonded Dimolybdenum Compounds
Lin, Chun,Protasiewicz, John D.,Smith, Eugene T.,Ren, Tong
, p. 6422 - 6428 (2008/10/09)
Syntheses and characterizations are reported for dimolybdenum(II) compounds supported by the diarylformamidinate (ArNC(H)NAr-) ligand, where Ar is XC6H4-, with X as p-OMe (1), H (2), m-OMe (3), p-Cl (4), m-Cl (5), m-CF3 (6), p-COMe (7), p-CF3 (8), or Ar is 3,4-Cl2C6H3- (9) or 3,5-Cl2C6H3- (10). The (quasi)reversible oxidation potentials measured for the Mo25+/Mo24+ couple were found to correlate with the Hammett constant (ax) of the aryl substituents according to the following equation: ΔE1/2 = E1/2(X) - E1/2(H) = 87(8σx) mV. Molecular structure determinations of compounds 1,2,5, and 10 revealed an invariant core geometry around the Mo2 center, with statistically identical Mo-Mo quadruple bond lengths of 2.0964(5), 2.0949[8], 2.0958(6), and 2.0965(5) A?, respectively. Magnetic anisotropies for compounds 1-10 estimated on the basis of 1H NMR data were similar and unrelated to σx. Similarity in UV-vis spectra was also found within the series, which, in conjunction with the features of both molecular structures and 1H NMR spectra, was interpreted as the existence of a constant upper valence structure across the series. Results of Fenske-Hall calculations performed for several model compounds paralleled the experimental observations.
