TRIPLEDECKER COMPLEXES .8. ELECTROPHILIC STACKING REACTIONS OF BORATAFERROCENE AND BIS(BOROLE)COBALTATE IONS WITH TRICARBONYLMETAL FRAGMENTS OF CHROMIUM AND MANGANESE GROUP-METALS

Bis(borole)cobaltate ions [CoL2]- (1-) and borataferrocene ions [CpFeL]- (2-) (a: L = C4H4BMe; b: L = C4H4BPh) readily undergo stacking reactions. When treated with sources of chromium group M(CO)3 fragments, 1b- and 2b- form 30-e tripledecked anions [mu-L(CoL){M(CO)3}]- (M = Cr, Mo, W) (3- -5-) and [mu-L(FeCp){M(CO)3}]- (M = Cr, Mo, W) (6- -8-). These 30-e anions are very sensitive to nucleophilic degradation by e.g. water, acetonitrile and to a lesser extent acetone. Cyclic voltammetry reveals a reversible oxidation of 6- to give the 29-e neutral tripledecker complex mu-L(FeCp)[Cr(CO)3] (6), while the oxidation of the higher homologues is fully irreversible. Protonation of 6- -8- affords hydrido complexes mu-L(FeCp)MH(CO)3] (M = Cr, Mo, W) (9-11), and, with PhCH2Br, the benzyl derivate mu-L(FeCp)[W(CO)3(CH2Ph)] (12) is produced. Similar stacking reactions with manganese group M(CO)3 fragments produce neutral tripledecked complexes as e.g. mu-L(CoL)Re(CO)3] (14) (L = C4H4BPh). In the case of the reaction of [CpFeL]- (2-) with [Mn(CO)3(NCMe)3]PF6 symmetric tripledecker compounds mu-L[Mn(CO)3]2 (15a,b) and mu-L(FeCp)2 (16a,b) are formed in a novel dismutation reaction (a: L = C4H4BMe; b: L = C4H4BPh).