Synthesis and Crystal Structures of [Fe(bpe6)2Cl2] and [Fe(bpe6)2Cl2]+ [FeCl4]¿ (bpe6 = 1,2-Bis(phosphorinan-1-yl)ethane)

Abstract

The bidentate ligand 1,2-bis(phosphorinan-1-yl)ethane (bpe6) reacts with iron(II) chloride to form a 2 : 1 complex trans-[Fe(bpe6)₂Cl₂] (2) which has been characterized crystallographically. Photochemically induced oxidation of trans-[Fe(bpe6)₂Cl₂] in chloroform solution affords [Fe(bpe6)₂Cl₂] ⁺ [FeCl₄] ^– (9) which was also characterized crystallographically. Competitive ligand substitution reactions with Fe(PP)₂Cl₂ complexes [PP = 1,2-bis(phosphorinan-1-yl)ethane (bpe6), 1,2-bis(dimethylphosphino)ethane (dmpe), 1,2-bis(diethylphosphino)ethane (depe) and 1,2-bis(dipropylphosphino)ethane (dprpe)] show the relative qualitative chelation strengths to be dmpe > bpe6 > depe > dprpe.

Crystal data for the bis-chloroform solvate of trans-[Fe(bpe6)₂Cl₂] (2) C₂₆H₅₀Cl₈FeP₄ at 21 ˚ C: space group Pbca (No. 61), a 16.988(3), b 11.102(2), c19.617(2) Å, V 3699.8(8) Å ³ , Z 4, N_o 1322, N_var 178, R(F) 0.0560, R_w(F) 0.0450. Crystal data for [Fe(bpe6)₂Cl₂] ⁺ [FeCl₄] ^– (9) C₂₄H₄₈Cl₆Fe₂P₄ at 21 ˚ C: space group Pbcn (No. 60), a 10.649(6), b 20.02(2), c 16.34(1) Å, V 3484(4) Å ³ , Z 4, N_o 861, N_var 165, R(F) 0.0540, R_w(F) 0.0380.