Synthesis of η-arene derivatives of chromium and molybdenum containing Lewis-acid boron substituents

Abstract

The compounds Ph(CH₂)₃B(OH)₂I, [Ph(CH₂)₃BO]₃II, Ph(CH₂)₃B(1,2-O₂C₆H₄)III, Ph(CH₂)₃BC₈H₁₄IV(BC₈H₁₄= 9-borabicyclo[3.3.1]nonan-9-yl), [Cr{η-Ph(CH₂)₃B(1,2-O₂C₆H₄)}(CO)₃]1, [Cr{η-Ph(CH₂)₃BC₈H₁₄}(CO)₃]2, [Cr{η-Ph(CH₂)₃BBr₂·SMe₂}(CO)₃]3, [Cr{η-Ph(CH₂)₄BC₈H₁₄}(CO)₃]4, [Cr(η-Ph(CH₂)₄BC₈H₁₄}(CO)₂(PPh₃)]5, [Cr{η-PhCH₂CHCH₂}(CO)₃]6, [Cr{η-Ph(CH₂)₂CHCH₂}(CO)₃]7, [Cr{η-Ph(CH₂)₂η-CHCH₂}(CO)₂]8, [Cr{η-Ph(CH₂)₂CHCH₂}(CO)₂(PPh₃)]9, [Li(Et₂O)_n][Cr{η-PhCH₂CHCH₂}(CO)₂{C(O)Ph}]10, [Li(Et₂O)_n][Cr{η-Ph(CH₂)₂CHCH₂}(CO)₂{C(O)Ph}]11, [Mo{η-Ph(CH₂)₃BC₈H₁₄}₂]12 and [Cr{η-Ph(CH₂)₃BOC₈H₁₄}(CO)₃]13, have been prepared and characterised. Compounds 1–5, 12 and 13 have π-donor η-arene ligands which also bear a Lewis-acid σ-acceptor boron group. There was no evidence that these boron groups formed ground-state intra- or inter-molecular interactions with the Lewis base functions of the carbonyl oxygen atoms.