New [2]Boraferrocenophane and Diferrocenyldiborane(4) Derivatives

The new [2]boraferrocenophane derivative [Fe(eta(5)-C5H4)-B(Mes)-B(Mes)-(eta(5)-C5H4)] (2) was prepared by reaction of 1,1'-dilithioferrocene with B-2(Mes)(2)Cl-2. In addition, the diborane(4) B-2(NMe2)(2)Fc(2) (3) was isolated from the reaction of B-2(NMe2)(2)Cl-2 and monolithioferrocene. Both species were fully characterized including X-ray diffraction analyses. While B-2(NMe2)(2)Fc(2) (3) adopts an unstrained geometry, [2]boraferrocenophane 2 features notable molecular ring strain manifested in the tilt-angle a = 10.5(2)degrees.