Crystal and molecular structures of some phosphane-substituted cymantrenes [(C5H4X)Mn(CO)LL'] (X = H or Cl, L = CO, L' = PPh3 or PCy3, and LL' = Ph2PCH2CH2PPh2)

Abstract

UV irradiation of tetrahydrofuran solutions of [CpMn(CO)₃] (Cp = π-C₅H₅ or π-C₅H₄Cl) in the presence of the phosphanes PPh₃ or PCy₃ (Cy = cyclohexyl) and Ph₂PCH₂CH₂PPh₂ yields the substitution products [CpMn(CO)₂PR₃] (R = Ph or Cy) and [CpMn(CO)(Ph₂PCH₂CH₂PPh₂)], namely, dicarbonyl(η⁵-cyclopentadienyl)(triphenylphosphane-κP)manganese(I), [Mn(C₅H₅)(C₁₈H₁₅P)(CO)₂], 1a, dicarbonyl(η⁵-1-chlorocyclopentadienyl)(triphenylphosphane-κP)manganese(I), [Mn(C₅H₄Cl)(C₁₈H₁₅P)(CO)₂], 1b, dicarbonyl(η⁵-cyclopentadienyl)(tricyclohexylphosphane-κP)manganese(I), [Mn(C₅H₅)(C₁₈H₃₃P)(CO)₂], 2a, dicarbonyl(η⁵-1-chlorocyclopentadienyl)(tricyclohexylphosphane-κP)manganese(I), [Mn(C₅H₄Cl)(C₁₈H₃₃P)(CO)₂], 2b, carbonyl(η⁵-cyclopentadienyl)[1,2-bis(diphenylphosphanyl)ethane-κ²P,P']manganese(I), [Mn(C₅H₅)(C₂₆H₂₄P₂)(CO)], 3a, and carbonyl(η⁵-1-chlorocyclopentadienyl)[1,2-bis(diphenylphosphanyl)ethane-κ²P,P']manganese(I), [Mn(C₅H₄Cl)(C₂₆H₂₄P₂)(CO)], 3b, The crystal structure determinations show a very small influence of the chlorine substitution and a moderate influence of the phosphane substitution on the bond lengths. The PR₃ groups avoid being eclipsed with the C-Cl bonds. All the compounds employ weak C-H...O interactions for intermolecular association, which are enhanced by C-H...Cl contacts in the chlorinated products.

Keywords: crystal structure; cymantrene; irradiation; phosphane complexes; weak interactions.