Towards clustered carbonyl cations [M(3)(CO)(14)](2+) (M = Ru, Os): the need for innocent deelectronation

To access the hitherto almost unknown class of clustered transition metal carbonyl cations, the trimetal dodecacarbonyls M(3)(CO)(12) (M = Ru, Os) were reacted with the oxidant Ag(+)[WCA](−), but yielded the silver complexes [Ag{M(3)(CO)(12)}(2)](+)[WCA](−) (WCA = [Al(OR(F))(4)](−), [F{Al(OR(F))(3)}(2)](−); R(F) = –OC(CF(3))(3)). Addition of further diiodine I(2) to increase the redox potential led for M = Ru non-specifically to divalent mixed iodo-Ru(II)-carbonyl cations. With [NO](+), even the N–O bond was cleaved and led to the butterfly carbonyl complex cation [Ru(4)N(CO)(13)](+) in low yield. Obviously, ionization of M(3)(CO)(12) with retention of its pseudo-binary composition including only M and CO is difficult and the inorganic reagents did react non-innocently. Yet, the radical cation of the commercially available perhalogenated anthracene derivative 9,10-dichlorooctafluoroanthracene (anthracene(Hal)) is a straightforward accessible innocent deelectronator with a half-wave potential E(1/2) of 1.42 V vs. Fc(0/+). It deelectronates M(3)(CO)(12) under a CO atmosphere and leads to the structurally characterized cluster salts [M(3)(CO)(14)](2+)([WCA](−))(2) including a linear M(3) chain. The structural characterization as well as vibrational and NMR spectroscopies indicate the presence of three electronically independent sets of carbonyl ligands, which almost mimic M(CO)(5), free CO and even [M(CO)(6)](2+) in one and the same cation.