Ansa‐Complexes of [Mn(η⁵‐C₅H₅)(η⁶‐C₆H₆)]: Preparation, Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3)

Abstract

We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa-bridging elements. Their preparation was achieved by salt-elimination reactions of the dilithiated precursor [Mn(η(5) -C5 H4 Li)(η(6) -C6 H5 Li)]⋅pmdta (pmdta=N,N,N',N',N''-pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single-atom-bridged derivatives, [Mn(η(5) -C5 H4 )(η(6) -C6 H5 )SntBu2 ] and [Mn(η(5) -C5 H4 )(η(6) -C6 H5 )SiPh2 ], could also be determined by X-ray structural analysis. We investigated for the first time the reactivity of these ansa-cyclopentadienyl-benzene manganese compounds. The reaction of the distannyl-bridged complex [Mn(η(5) -C5 H4 )(η(6) -C6 H5 )Sn2 tBu4 ] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn-Sn bond to give a triatomic ansa-bridge. The investigation of the ring-opening polymerization (ROP) capability of [Mn(η(5) -C5 H4 )(η(6) -C6 H5 )SntBu2 ] with [Pt(PEt3 )3 ] showed that an unexpected, unselective insertion into the Cipso -Sn bonds of [Mn(η(5) -C5 H4 )(η(6) -C6 H5 )SntBu2 ] had occurred.

η6‐Metalated Aryl Iodides in Diels‐Alder Cycloaddition Reactions: Mode of Activation and Catalysis

“…First, we modified the nature of the transition metal and found that no change in the barrier is observed when using the group 8 [CpM II (PhI)] + analogues (M=Fe, Os) as catalysts. At variance, the barrier is significantly reduced for the cycloaddition mediated by the isoelectronic d 6 ‐neutral [CpMn I (PhI)] complex [33] cat1‐Mn (ΔΔE=1.5 kcal/mol with respect to cat1 ), whereas the activity of its heavier group 7 counterparts ( cat1‐Tc and cat1‐Re ) is comparatively lower. A similar reduction in the barrier is found for the isolectronic‐d 6 group 9 [CpM III (PhI)] 2+ complexes cat1‐Co (M=Co) and cat1‐Rh (M=Rh) [34] .…”

An isoindoline bridged [M(η6-arene)2]+ (M = Re, 99mTc) ansa-arenophane and its dinuclear macrocycles with axial chirality

“…1–4 There is a plethora of literature precedence for late transition metal ansa -complexes 5 including group 7 elements. 6 Ansa -rhenocene complexes with Re III were reported by Heinekey et al 7 and Conway and coworkers. 8 They reported the synthesis of C(CH 3 ) 2 and Si(CH 3 ) 2 bridged rhenocenes respectively.…”