1380441-86-0Relevant academic research and scientific papers
Half-pseudoferrocene cations from nucleophilic addition of o-carboranyl anions to the [(η6-mesitylene)2Fe]2+ dication
Bakardjiev, Mario,Stibr, Bohumil,Holub, Josef,Ruzicka, Ales,Padelkova, Zdenka
, p. 7151 - 7155 (2012)
Reactions between the mesitylene (mes) dication [(η6-mes) 2Fe]2+ (1a) [(PF6-)2 salt] and lithium o-carboranes Li[1-R-1,2-C2B10H 11] (2) (R = H, 2a; Me, 2b; Ph, 2c) at low temperature (-60 °C, 1 h, followed by stirring for 2 h at r.t.) in THF resulted in a clean addition of the corresponding carborane anions to one of the unsubstituted arene sites in 1a, forming a series of orange monocations of general structure [(η5-mes-exo-6-{2-R-1,2-C2B10H 11})Fe(η6-mes)]+ (3) (R = H, 3a; Me, 3b; Ph, 3c) which were isolated as PF6- salts (3PF 6) in yields ranging 50-75%. Individual complexes were obtained on purification by LC or preparative TLC on a silica gel substrate, using MeCN-CH2Cl2 mixtures as the mobile phase. Interestingly, the room-temperature reaction between 2a (threefold excess) and 1a(PF 6)2 with a reverse order of addition of the reaction components yielded an orange salt [(η5-mes-exo-6-{1,2-C 2B10H11})Fe(η6-mes)] +[closo-nido-H11B10C2-C 2B10H12]- (3acCA) (cCA = conjucto-carborane anion = [closo-nido-H11B10C 2-C2B10H12]-) as a sole product in 71% yield. The formation of this conjucto anion can be taken as a strong support for the participation of a radical-chain mechanism in the ostensible nucleophilic addition which we suppose to be initiated by the formation of the [(mes)2Fe+] radical cation. The structures of both 3PF6 and 3acCA have been established by X-ray diffraction and the constitution of all compounds isolated is in agreement with elemental analyses, multinuclear NMR data, and MS spectra.
