Protonation of the lithio derivatives of the 1,2,4-tri-phosphaferrocenes, [LiFe(η4-P2C2tBu2PBu)(η5-C5R5)] (R = H, Me): Crystal and molecular structure of [Fe(η4-P3C2tBu2BuH)(η5-C5Me5)]

A new synthetic route is described to generate the 4-centre-5 electron donor ring system (P3C2tBu2BuH), via protonation of the lithium salts [LiFe(η4-P2C2tBu2PBu)(η5-C5R5)] (R = H, Me). The molecular structure of [Fe(η4-P3C2tBu2BuH)(η5-C5R5)] (R = Me) has been determined by a single crystal X-ray study.