Transformation of the Cyclo-P5 Middle Deck in [(Cp*Fe)(Cp'''Co)(µ,η5:η4-P5)] upon Functionalization - A Comprehensive Study of Reactivity.

Abstract

[(Cp*Fe)(Cp'''Co)(µ,η 5 :η 4 -P5)](1) was functionalized by main group nucleophiles and subsequently electrophilically quenched or oxidized. Reacting 1 with group 14 nucleophiles revealed different organo-substituted P5R middle-decks depending on the steric and electronic effects of the used alkali metal organyls (2: R = tBu; 3: R = Me). With group 15 nucleophiles, first isolatable monosubstituted complexes with phosphanides could be obtained as P5 ligands containing exocyclic {PR2} units (4: R = Cy, H; 5: R = Ph). These monoanionic complexes 2-5 were isolated and electrophilic quenching revealed novel types of neutral functionalized polyphosphorus complexes. These complexes bear formal chains of P5R'R'' (6: R' = tBu, R' = Me) in a 1,3-disubstitution pattern or P6R'R''R''' units (7: R' = Cy, R'' = H, R''' = Me; 8: R' = Me, R'' = Ph, R''' = Me) in a 1,1,3-substitution as middle-decks stabilized by one {Cp'''Co} and one {Cp*Fe} fragment. One-electron oxidation of 2, 3 or 5 by AgBF4 gave access to paramagnetic triple-decker complexes bearing P5R middle-decks in various coordination fashions (R = tBu (10), R = PPh2 (12)). For R = Me (11) a dimerization is observed revealing a diamagnetic tetranuclear cluster containing a unique dihydrofulvalene-type P10R2 ligand.