Di-and triphospha-ferrocenes: Crystal and molecular structures of [Fe(η5-C5Me5)(η5- C3tBu3P2)] and of the adducts

Article abstract of DOI:10.1016/0022-328x(95)05916-d

Synthesis and structural studies of the iron "sandwich" complex [Fe(η⁵-C₅Me₅)(η⁵-C₃^tBu₃P₂)] 1 are described. The lone pair electrons of the two adjacent phosphorus atoms of the C₂^tBu₂P₃ ring in the triphospha-ferrocene complex [Fe(η⁵-C₅Me₅)(η⁵-C₂^tBu₂P₃)] 2 can ligate to other metal centres. The results of single crystal X-ray structural studies of the molybdenum and tungsten pentacarbonyl η¹-complexes [Fe(η⁵-C₅Me₅)(η⁵-C₂^tBu₂P₃)M(CO)₅] (4: M = Mo, 5: M = W) are discussed; they form an isostructural series with the previously reported chromium complex. The starting material 2 reacts with [(C₅H₄Me)(CO)₂Mn(THF)] to form the adduct [Fe(η⁵-C₅Me₅)(η⁵-C₂^tBu₂P₃)Mn(CO)₂(η⁵-C₅H₄Me)] 6. The phenyl-substituted di-and triphosphacyclopentadienides [Na(DME)₃][C₃Ph₃P₂] and [Na(DME)₃][C₂Ph₂P₃] (DME = 1,2-dimethoxyethane) react with ferrous chloride and Li[C₅Me₅] to give the 'sandwich' compounds [Fe(η⁵-C₅Me₅)(η⁵-C₃Ph₃P₂)] 9 and [Fe(η⁵-C₅Me₅)(η⁵-C₂Ph₂P₃)] 10. The latter reacts with W(CO)₅(THF) to yield the η¹-complex [Fe(η⁵-C₅Me₅)(η⁵-C₂Ph₂P₃)W(CO)₅] 11.