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

Two molecular pairs [Mo-2(DAniF)(3)](2)[N, N'-diethylterephthalamidate] (1) and [Mo-2(DAniF)(3)](2){1,3- C6H4[C(O)NPh](2)}(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 Mo-2( 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 [Mo-2] 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.