Molecular pairs and a propeller containing quadruply bonded dimolybdenum units linked by polyamidate ligands

Two molecular pairs [Mo2(DAniF)3]2[N,N'-diethylterephthalamidate] (1) and [Mo2(DAniF)3]2{1,3-C6H4[C(O)NP]} (2) where DAniF = N,N'-di-p-anisylformamidinate) and the propeller ([Mo2(DAniF)3]3{1,3,5-C6H3[C(O)NPh]3} (3)) have been prepared in good yield and high purity by directly combining Mo2(DAniF)3(O2CCH3) with the corresponding polyamidates. Electrochemical measurements of these complexes show unresolved redox waves, which indicate that the dimetal centers are only electronically weakly coupled. Compound 1 was chemically oxidized by ferrocenium tetrafluoroborate to the two-electron oxidation product 4, where one electron was removed from each of the [Mo2] units. The hyperfine coupling in the EPR spectrum (A = 22 x 10-4 cm-1 ) suggests that 4 is an electron-trapped species with one electron residing on each of the two dimolybdenum units, as suggested also by electrochemical measurements.