Magnesiation of Isodicyclopentadiene. Formation of Sandwich and Monomeric Complexes and the Stereoselectivity of Their Reactions with Transition Metal Halides

Abstract

The exo,exo-bis(isodicyclopentadienyl)magnesium sandwich and the monomeric exo-(isodicyclopentadienyl)butylmagnesium TMEDA complex have been synthesized and characterized by 1H and 13C NMR spectroscopy in C6D6 solution. The solid-state structures were determined by X-ray crystallography. The stereoselectivity with which both moisture-sensitive compounds react with TiCl3·3THF and ZrCl4 was assessed and suitably compared to related observations recorded for alkali metal (Li+, Na+, and K+) complexes of isodicyclopentadiene.

Control of N- or C-Bridging Mode in Dimeric Butylmagnesium Silylamides

“…Considering dibutylmagnesium as a deprotonation reagent for these silazanes, either just one or both butyl groups are expected to be substituted by the ligand. Until now, only a few small intermediates with similar bidentate nitrogen ligands still bearing a butyl group and thereby maintaining one functionality are known. , As shown by Chong and co-workers these intermediates possess interesting applicabilities, e.g., as enantioselective alkylation reagents for aldehydes . The deprotonation of two amines containing an additional side arm with another coordinating amine function yields small four-coordinate magnesium compounds, which are potential CVD precursors. , Starting from the same ligand, the selective synthesis of either an intermediate still bearing one functionality or the 2-fold deprotonation product would be desirable.…”

Cyclopentadienyl Complexes of the Alkaline Earths in Light of the Periodic Trends

“…However, [Cp Me4{(CH2)2CH=CH2} 2 Mg] (Cp Me4{(CH2)2CH=CH2} =C 5 Me 4 {(CH 2 ) 2 CH=CH 2 }) is linear [36] . [Cp CH(Cyp)2 2 Mg] [14a] (Cp CH(cyp)2 =C 5 {CH(cyclo‐C 3 H 5 ) 2 }H 4 ) and [ isodi Cp 2 Mg] [37] ( isodi Cp=isodicyclopentadienyl; C 10 H 11 ) are also bent for similar steric reasons. The [bis(fulvene)Mg 2 ] complex with eight t Bu groups consists of two tethered metallocene fragments twisted with respect to each other to minimize the steric repulsion while the Mg centers are bent away from each other [14b] …”

“…The molecules are typically monomeric or dimeric depending on the sterics, while a few polymeric barium iodides are known [33b,81] . Figure 7 shows a consolidated list ordered in a Cp’ ring‐wise manner, [14a,20b,29a,33b,35,37,41,44–45,51b,53,81–82] but a detailed case to case comparison could be complicated and ineffective as four different variables (Cp’, M, X, and the co‐donors) are involved. However, a gross periodic pattern is still apparent where the smaller Mg has more examples with the sterically less bulky or less substituted Cp’ rings, while it is opposite for the larger Ca to Ba.…”

Alkaline Earth Organometallics

“…From the amine adducts Me 2 Mg(tmeda) (L ¼ tmeda, The exo,exo-bis(isodicyclopentadienyl)magnesium sandwich and the monomeric exo-(isodicyclopentadienyl)butylmagnesium tmeda complex 74 ( Figure 40) have been synthesized and characterized by 1 H and 13 C NMR spectroscopy and X-ray crystallography. 258 Heterocyclic derivatives Heterocyclic derivatives of the cyclopentadienyl ligand have been incorporated in organomagnesium species. 258 Heterocyclic derivatives Heterocyclic derivatives of the cyclopentadienyl ligand have been incorporated in organomagnesium species.…”