Ring slippage in indenyl derivatives of molybdenum and tungsten

Article abstract of DOI:10.1016/0022-328X(95)05859-N

Ring slippage of the indenyl occurs upon dissolution of the complexes [η⁵-IndM(CO)₂L₂]BF₄ (M = Mo or W; L = NCMe or dimethylformamide) in an excess of L, to give [(η³-Ind)M(CO)₂L₃]BF₄. Other ring-slipped complexes synthesized are [η³-Ind)Mo(CO)₂L₃]BF₄ (L₃ = HC(pz)₃, [HB(pz)₃]^-, Me₃tacn or {en(NCMe)}). Addition of NCMe or an excess of L failed to give ring slippage in [η⁵ IndMo(CO)₂L₂]BF₄ (L₂ = bipy, dppe, (PMe₃)₂, {P(OMe)₃}₂ or triphos). NMR and X-ray studies reveal a large folding of the η³-indenyl ring. The structure complex [η³-Ind)W(CO)₂(NCMe)₃]BF₄ (5) was determined by X-ray analysis.