Reactivity of diphosphenes, phospharsenes, and diarsenes toward transition-metal carbonyls

Article abstract of DOI:10.1021/om00085a014

The reactivity of stable diphosphenes, phospharsenes, and diarsenes toward transition-metal carbonyls has been explored. The diphosphene (2,4,6-t-Bu₃C₆H₂)P₂, 2, forms adducts with one Fe(CO)₄ and one Ni(CO)₃ group from reactions with Fe₂(CO)₉ and Ni(CO)₄, respectively. The iron complex (2,4,6-t-Bu₃C₆H₂)₂P ₂Fe(CO)₄, 3, has been structurally characterized by X-ray diffraction. Compound 3 crystallizes in the monoclinic space group P2₁/c, with a = 21.251 (6) ?, b = 9.793 (2) ?, c = 20.99 (2) ?, and β = 108.73 (6)°. The structure reveals that the diphosphene 2 is η¹ bonded to the Fe(CO)₄ group through a phosphorus lone pair. The phospharsene 2,4,6-t-Bu₃C₆H₂As=PCH(SiMe₃) ₂, 8, reacts with Fe₂(CO)₉ to give complexes with an Fe(CO)₄ group attached to As, 9, or P, 10. Treatment of the diarsene 2,4,6-t-Bu₃C₆H₂As= AsCH(SiMe₃)₂, 11, with Cr(CO)₅(THF) affords the complex 2,4,6-t-Bu₃C₆H₂As=AsCH(SiMe₃) ₂Cr(CO)₅, 12, with the Cr(CO)₅ unit η¹ bonded to the (Me₃Si)₂CH-substituted arsenic. This was determined by an X-ray diffraction study. Compound 12 crystallizes in the monoclinic space group P2₁/n with n = 10.710 (3) ?, b = 29.770 (3) ?, c = 11.984 (1) ?, and β = 98.02 (1)°. The structures of and bonding in these complexes are discussed.