Zur Elektrochemie von Metall(O)-Verbindungen, V [1] Reaktionen von Diazadien-Metall(VIb)-carbonylkationen und -anionen / Electrochemistry of Metal(O) Compounds, V [1] Reactions of Diazadiene Metal(VIb) Carbonyl Cations and Anions

Abstract

<jats:title>Abstract</jats:title><jats:p> Carbonyl complexes of chromium, molybdenum and tungsten of the type DAD M(CO)<jats:sub>4</jats:sub> with DAD - diazadiene (R-N=CR′-CR′=NR) are shown by cyclic voltammetry to undergo electron transfer reactions to [DAD M(CO)<jats:sub>4</jats:sub>]<jats:sup>+</jats:sup> and [DAD M(CO)4]<jats:sup>-</jats:sup>. The rate of subsequent chemical reactions with nucleophiles or by loss of ligands depend on the sol-vent, the metal and the ligands' electronic and steric properties. Chromium(+I) is more readily stabilized than Mo(+I) or W(-I) while the opposite is true for the stability of the anions formed. The dimerisation of a low-coordinate species DAD Mo(CO)<jats:sub>3</jats:sub> from the reduction of DAD Mo(CO)<jats:sub>3</jats:sub>(CH<jats:sub>3</jats:sub>CN) is detected electrochemically. The stabilization of oxidation states +1 and -I is briefly discussed in view of the DAD ligand properties.</jats:p>

FT-EPR Study of Methyl Radicals Photogenerated from [Ru(Me)(SnPh3)(CO)2(iPr-DAB)] and [Pt(Me)4(iPr-DAB)]: An Example of a Strong Excitation Wavelength Dependent CIDEP Effect

“…This prevents detection of FT-EPR spectra because of the instrument dead time. The g values of the [M(CO) 3 (tBu-DAB)] • (M = Mn, Re) radicals were found at values (2.0043 and 2.0059, respectively) similar to that of the radical anion of the free ligand (2.0034) …”