Unexpected Reactivity of [(η5-1,2,4-tBu3C5H2)Ni(η3-P3)] towards Main Group Nucleophiles and by Reduction

The reduction of [Cp'''Ni(eta(3)-P-3)](1; Cp''' = eta(5)-1,2,4-tBu(3)C(5)H(2)) with potassium produces the complex anion [(Cp'''Ni)(2)(mu,eta(2:2)-P-8)](2-) (2), which contains a realgar-like P-8 unit. The anionic triple-decker sandwich complex [(Cp'''Ni)(2)(mu,eta(3:3)-P-3)](-) (3) with a cyclo-P-3 middle deck is obtained when 1 is treated with NaNH2 as a nucleophile. Na[3] can subsequently be oxidized with AgOTf to the neutral triple-decker complex [(Cp'''Ni)(2)(mu,eta(3:3)-P-3)] (4). In contrast, 1 reacts with LiPPh2 to give the anionic compound [(Cp'''Ni)(2)(mu,eta(2:2)-P6PPh2)](-) (5), a complex containing a bicyclic P-7 fragment capped by two Cp'''Ni units. Protonation of Li[5] with HBF4 leads to the neutral complex [(Cp'''Ni)(2)(mu,eta(2:2)-HP6PPh2)] (6). Adding LiNMe2 to 1 results in [Cp'''Ni(eta(2)-P3NMe2)](-) (7) becoming accessible, a complex which forms as a result of nucleophilic attack at the cyclo-P3 ring of 1. The complexes K-2[2], Na[3], 4, 6, and Li[7] were fully characterized and their structures determined by single-crystal X-ray diffraction. The stoichiometric and catalytic reactivity of organometallic