Substituted Ferrocenylboranes – Potential Ligand Precursors for ansa‐ Metallocenes, Constrained Geometry Complexes and ansa‐Diamido Complexes

Abstract

Abstract A wide range of potential ligand precursors and related compounds have been synthesized from ferrocenyldibromoborane and ferrocenylenebis(dibromoborane) via salt elimination reactions. These comprise ligand precursors suitable for the preparation of (i) ansa‐metallocenes such as [FcB( η 1 ‐C 5 H 5 ) 2 ] ( 2 ), [FcB(1‐C 9 H 7 ) 2 ] ( 3 ), [FcB(3‐C 9 H 7 ) 2 ] ( 4 ) and [1,1′‐fc{B(3‐C 9 H 7 ) 2 } 2 ] ( 11 ), (ii) constrained geometry complexes such as [FcB(1‐C 9 H 7 )N(H)Ph] ( 7 ) and [FcB(3‐C 9 H 7 )N(H)Ph] ( 8 ), (iii) ansa‐diamido complexes such as [FcB(N(H)Ph) 2 ] ( 9 ) as well as (iv) the related compounds [FcB(Br)N(H) t Bu] ( 5 ), [FcB(Br)N(H)Ph] ( 6 ), [1,1′‐fc{B(Br)N(SiMe 3 ) 2 } 2 ] ( 12 ) and [1,1′‐fc{B(Br)N i Pr 2 } 2 ] ( 13 ) (Fc = ferrocenyl, fc = ferrocenylene, C 5 H 5 = cyclopentadienyl, C 9 H 7 = indenyl). All new compounds have been characterised by multinuclear NMR spectroscopic techniques and in the case of 7 and 12 by X‐ray diffraction methods.