η⁶‐Bonded Alkylbenzenes as Novel Bridging Ligands in Dinuclear Complexes of Iron and Cobalt

Abstract

leads to formation of the I-(arylcarbony1oxy)aIkyltriphenylphosphonium salts 5[21, which can be converted by reaction with strong bases [sodium bis(trimethylsily1)amide 6a[3a1, lithium diisopropylamide 6b[3b1] into the corresponding 1-(arylcarbony1oxy)alkylidenetriphenylphosphoranes 7. The highly reactive ylides 7 (they undergo Wittig reactions even at -5OoC) have surprising properties: when their solutions are heated from -60°C to room temperature, the unsymmetrically substituted 1,2-diketones 9 and triphenylphosphane 4 are obtained.We presume that the carbanionic center initially reacts

A π-Stacked Organometallic Propeller: Experimental and Theoretical Studies on Reactivity and Bonding in the π-Arene-Bridged Nickel Triple-Decker [{(η5-Me4EtC5)Ni}2(μ-η3:η3-decacyclene)]

“…The 1 H NMR spectroscopic data are in close agreement to the related cationic Co III complex [(η 5 -C 5 H 5 )Co(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 3 CH 2 NMe 2 )(PMe 3 )] ϩ PF 6 Ϫ reported recently. [30] X-ray Analysis of 16 Figure 11 depicts the molecular structure of 16 as a result of a single-crystal X-ray diffraction study.…”

“…This exceeds the modest twist disposed on the naphthalene moieties of the free ligand by almost 100% (9.3°and 7.7°) and gives 3 a distinct propeller-like shape when compared to free decacyclene (see Figure 2). [ (6); C 1 ϪC 6 ϪC 2 119.5(4), C 3 ϪC 4 ϪC 2 120.4(4), C 4 ϪC 5 ϪC 3 118.6(4), C 5 ϪC 6 ϪC 4 112.6(4), C 6 ϪC 5 ϪC 1 121.3(4) Figure 2. Overlay of the molecular structure of uncomplexed decacyclene 1 and the dinickel triple-decker 3 showing the propeller-like arrangement of the naphthalene units of uncomplexed 1 and the bridging decacyclene ligand of 3; atom numbering scheme according to Figure 1 …”

“…[44] Geometrical parameters were taken from X-ray structural studies of the parent compounds [3,23,31,33,35] and averaged. For comparison, the same structural parameters were employed for the different metals in the model compounds [(η 5 -C 5 H 5 )M(µ-η 6 :η 6 [a] As given in parameter file of the CACAO program; standard EH parameters.…”

Triple-decker transition metal complexes bridged by a single carbocyclic ring

“…16(a)) appear to be similar based on their formulae, the only true common feature is the bonding of all the benzene ring carbons to an M 2 unit. All the C-C bond distances within the benzene ring of 24 are equal, but the C-C double bonds that are coordinated to only one iron atom are significantly shorter than the other C-C bonds in the hexamethylbenzene ring of 25a [83]. Thus, it is proposed that the vanadium atoms (bridged by two hydride ligands) in 24 are bonded to ''aromatic'' benzene, while a localised dienediyl structure is postulated for 25 [75].…”

Reversible Halide‐Modulated Nickel–Nickel Bond Cleavage: Metal–Metal Bonds as Design Elements for Molecular Devices

“…Bifacial η 3 ,η 3 -bridging of an arene between two metal centers has been previously observed in dinuclear Ni, [10a, 18] Pt, [19] and Co complexes. [20] In contrast, in compound 2 , the arene bridges in η 3 ,η 1 –fashion, probably due to the steric constraints of the triphosphine.…”