Half-pseudoferrocene cations from nucleophilic addition of o-carboranyl anions to the [(eta(6)-mesitylene)(2)Fe](2+) dication

0382801 - ÚACH 2013 RIV GB eng J - Článek v odborném periodiku
Bakardjiev, Mario - Štíbr, Bohumil - Holub, Josef - Růžička, A. - Padělková, Z.
Half-pseudoferrocene cations from nucleophilic addition of o-carboranyl anions to the [(eta(6)-mesitylene)(2)Fe](2+) dication.
Dalton Transactions. Roč. 41, č. 23 (2012), s. 7151-7155. ISSN 1477-9226. E-ISSN 1477-9234
Grant CEP: GA ČR(CZ) GAP207/11/0705
Klíčová slova: trialkylaluminum reagens * Iron complexes * reduction * biscarborane * B10C2H12
Kód oboru RIV: CA - Anorganická chemie
Impakt faktor: 3.806, rok: 2012

Reactions between the mesitylene (mes) dication [(eta(6)-mes)(2)Fe](2+) (1a) [(PF6-)(2) salt] and lithium o-carboranes Li[1-R-1,2-C2B10H11] (2) (R = H, 2a; Me, 2b; Ph, 2c) at low temperature (-60 degrees 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 [(eta(5)-mes-exo-6-{2-R-1,2-C2B10H11})Fe(eta(6)-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(PF6)(2) with a reverse order of addition of the reaction components yielded an orange salt [(eta(5)-mes-exo-6-{1,2-C2B10H11}) Fe(eta(6)-mes)](+)[closo-nido-H11B10C2-C2B10H12](-) (3acCA) (cCA = conjucto-carborane anion = [closo-nido-H11B10C2-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)(2)Fe+]. radical cation. The structures of both 3PF(6) 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.
Trvalý link: http://hdl.handle.net/11104/0212921