Synthesis and alkylation of an iron phosphane complex. Crystal and molecular structure determinations for CpFe(CO)2{P(C6H5){N[Si(CH3) 3]2}} and CpFe(CO)2{P(CH3)(C6H5){N[Si(CH 3)3]2+}}(O3SCF 3-)

Article abstract of DOI:10.1021/om00096a013

The reactions of NaFe(C₅H₅)(CO)₂ and NaFe[(CH₃)₅C₅](CO)₂ with (C₆H₅)P(Cl){N[Si(CH₃)₃]₂} form iron phosphane compounds (C₅H₅)Fe(CO)₂{P(C₆H ₅){N[Si(CH₃)₃]₂}} (1) and [(CH₃)₅C₅]Fe(CO)₂{P(C ₆H₅){N[Si-(CH₃)₃]₂}} (2) which have been characterized by spectroscopic methods, and the crystal and molecular structure of 1 has been determined by single-crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁/n with a = 10.871 (2) ?, b = 18.231 (4) ?, c = 11.561 (2) ?, β = 95.89 (2)°, Z = 4, V = 2279.1 (7) ?³, and ρ = 1.30 g cm^-3. Least-squares refinement gave R_F = 5.5% and R_wF = 5.2% on 2894 unique data with F > 5σ(F). The molecular structure contains a CpFe(CO)₂ unit bonded to a pyramidal P(C₆H₅){N[Si(CH₃)₃]₂} fragment through a long Fe-P bond distance, 2.338 (1) ?. Reactions of 1 with (CH₃)₃OBF₄ and CH₃O₃SCF₃ result in methylation of the phosphorus center, and the products have been characterized by spectroscopic methods. The crystal and molecular structure of (C₅H₅)Fe-(CO)₂{P(CH₃)(C ₆H₅){N[Si(CH₃)₃]₂}} ⁺(O₃SCF₃^-) has been determined by single-crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁/n with a = 11.571 (4) ?, b = 17.590 (5) ?, c = 14.200 (3) ?, β = 104.91 (2)°, Z = 4, V = 2792 (1) ?³, and ρ = 1.45 g cm^-3. Least-squares refinement gave R_F = 9.4% and R_wF = 9.7% on 2966 unique reflections with F > 5σ(F). The molecular structure is related to the structure of 1 with the addition of a methyl group on the pyramidal phosphorus center. The addition results in a shorter Fe-P bond distance, Fe-P = 2.263 (3) ?, and P-CH₃ = 1.82 (1) ?.