Reactions of Ring-Slipped Iron Complexes Derived from P(S)Ph-Bridged [1]Ferrocenophane: Synthesis of Bis(half-sandwich) Heterodinuclear Complexes

P(S)Ph-bridged [1]ferrocenophane, [Fe{(η5-C5H4)2P(S)Ph}] (1), reacted under UV−vis photoirradiation with P(OMe)3, P(OMe)2Ph, or PMe3 to give respective ring-slipped products. The reaction with
P(OMe)3 afforded [Fe{(η5-C5H4)(η1-C5H4)P(S)Ph}{P(OMe)3}2] (2a), while the bulkier P(OMe)2Ph gave
initially the similar complex 2b, but gradual dissociation of the η1-C5H4 moiety took place from the iron
center in THF to form [Fe{η5-C5H4P(S)Ph(C5H4)-κS}{P(OMe)2Ph}2] (4b), in which the η5-C5H4 ring
bearing a PS pendant group adopted an unprecedented η5-κS coordination mode and the other C5H4
group left the coordination sphere of the iron atom. The reaction with PMe3 gave directly the corresponding
η5-κS product 4c in ether, but its PS group was replaced in THF with the remaining PMe3 to give
[Fe{(η5-C5H4)P(S)Ph(C5H4)}(PMe3)3] (3c) with the P(S)Ph(C5H4) group dangling from the η5-C5H4
ring. When 2a having an η1-C5H4 group was allowed to react with [M(CO)3(NCMe)3] (M = Mo, W), the
iron−molybdenum and −tungsten heterodinuclear complexes {μ-η5:η5-(C5H4)2P(S)Ph-κS}[Fe{P(OMe)3}2][M(CO)3] (M = Mo (5-Mo), W (5-W)) were obtained, in which the two metal fragments were linked
with an η5-C5H4P(S)Ph(η5-C5H4)-κS bridge. In addition, 5-Mo and 5-W were readily converted in
acetonitrile to the respective acetonitrile complexes {μ-η5:η5-(C5H4)2P(S)Ph}[Fe(NCMe){P(OMe)3}2][M(CO)3], with the PS group giving up coordination to the iron center. A variety of these reaction
patterns observed were discussed in terms of steric bulkiness and basicity of the phosphorus ligands
concerned.