Addition of borohydride ion to coordinated isocyanides: the structure of π-C5H5Fe(CO)[(CHNCH3)2BH2]

The structure of π-C₅H₅Fe(CO)(CHNCH₃)₂BH₂] has been determined from three dimensional X-ray diffractometer data collected by counter methods. The compound crystallizes in the space group P2₁/a with four molecules in a cell of dimensions a = 12.33(3), b = 6.14(2) and c = 16.21(7)Å with β = 105.0(2)°. The observed and calculated densities are 1.37(2) and 1.379(6) g/cm³ respectively. Full-matrix least-squares refinement has resulted in R = 0.113 for the 1238 data with F²_o ? σ (F²_o). The structure results from a BH^?₄ anion adding across two coordinated isocyanide ligands to form a six-membered heterocyclic ring containing BN bonds.