Iodination of cyclo-E5 -Complexes (E=P, As).

In a high-yield one-pot synthesis, the reactions of [Cp*M(η5 -P5 )] (M=Fe (1), Ru (2)) with I2 resulted in the selective formation of [Cp*MP6 I6 ]+ salts (3, 4). The products comprise unprecedented all-cis tripodal triphosphino-cyclotriphosphine ligands. The iodination of [Cp*Fe(η5 -As5 )] (6) gave, in addition to [Fe(CH3 CN)6 ]2+ salts of the rare [As6 I8 ]2- (in 7) and [As4 I14 ]2- (in 8) anions, the first di-cationic Fe-As triple decker complex [(Cp*Fe)2 (μ,η5:5 -As5 )][As6 I8 ] (9). In contrast, the iodination of [Cp*Ru(η5 -As5 )] (10) did not result in the full cleavage of the M-As bonds. Instead, a number of dinuclear complexes were obtained: [(Cp*Ru)2 (μ,η5:5 -As5 )][As6 I8 ]0.5 (11) represents the first Ru-As5 triple decker complex, thus completing the series of monocationic complexes [(CpR M)2 (μ,η5:5 -E5 )]+ (M=Fe, Ru; E=P, As). [(Cp*Ru)2 As8 I6 ] (12) crystallizes as a racemic mixture of both enantiomers, while [(Cp*Ru)2 As4 I4 ] (13) crystallizes as a symmetric and an asymmetric isomer and features a unique tetramer of {AsI} arsinidene units as a middle deck.