Derivate des Borols, XVII {η 5 ‐[1‐(Diisopropylamino)borol]}metall‐Komplexe: Synthesen, Protonierung, interne Rotation

Derivatives of Borole, XVII 1) . – {η 5 ‐[1‐(Diisopropylamino)borole]}metal Complexes: Syntheses, Protonation, Internal Rotation New complexes M(CO) 4 L (M = Cr, W), cis ‐M(CO) 2 L 2 [M = Mo, W (not isolated)], and (COD)NiL have been prepared from the Diels‐Alder dimer L 2 , where L is 1‐(diisopropylamino)borole, C 4 H 4 BNiPr 2 . Complexes of L can be protonated at the nitrogen atom to give stable salts such as [Cr(CO) 4 (LH)]BF 4 , [Fe(CO) 3 (LH)]BF 4 , [(C 6 Me 6 )Ru(LH)]BF 4 , and [CpCo(LH)]BF 4 ; B — N bond dissociation is not observed. Barriers to internal rotation have been determined by variable temperature NMR spectroscopy for Cr(CO) 4 L, (COD)NiL, and NiL 2 . Three processes have been identified: rotation of the NiPr 2 group around the B — N bond, gear‐mesh rotation of the isopropyl groups around the C — N bonds, and rotation of L with respect to the counter ligands.