Homoleptic organolanthanide compounds supported by the bis(dimethylsilyl)benzyl ligand.

Kasuni C Boteju,Aaron D Sadow,Arkady Ellern

doi:10.1039/c6cc09304c

Kasuni C Boteju, Aaron D Sadow + Show 1 more

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https://doi.org/10.1039/c6cc09304c

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Abstract

A β-SiH functionalized benzyl anion [C(SiHMe2)2Ph]- is obtained by deprotonation of HC(SiHMe2)2Ph with KCH2Ph or by reaction of KOtBu and (Me2HSi)3CPh; LnI3(THF)n and three equivalents of this carbanion combine to provide homoleptic tris(alkyl)lanthanide compounds Ln{C(SiHMe2)2Ph}3 (Ln = La, Ce, Pr, Nd) containing secondary metal-ligand interactions.

Highlights

A b-SiH functionalized benzyl anion [C(SiHMe2)2Ph]À is obtained by deprotonation of HC(SiHMe2)2Ph with KCH2Ph or by reaction of KOtBu and (Me2HSi)3CPh; LnI3(THF)n and three equivalents of this carbanion combine to provide homoleptic tris(alkyl)lanthanide compounds Ln{C(SiHMe2)2Ph}3 (Ln = La, Ce, Pr, Nd) containing secondary metal–ligand interactions
Synthesis of homoleptic organolanthanide complexes, those of the early trivalent lanthanides (La–Nd), is challenging due to the large radii of these elements, polar bonding, high charge, and high Lewis acidity.[1]. Such homoleptic compounds should be valuable for the synthesis of new catalysts and new materials,[2] yet solvent- or donor-group-free, salt-free, and thermally robust organolanthanide compounds are not readily accessed for the larger metal centers
While donor-free lanthanum and cerium compounds such as Ln{CH(SiMe3)2}3 are known, they are inconveniently accessed through multistep synthesis via Ln{O(2,6-C6H3tBu2)}3.12,13

Summary

Introduction

A b-SiH functionalized benzyl anion [C(SiHMe2)2Ph]À is obtained by deprotonation of HC(SiHMe2)2Ph with KCH2Ph or by reaction of KOtBu and (Me2HSi)3CPh; LnI3(THF)n and three equivalents of this carbanion combine to provide homoleptic tris(alkyl)lanthanide compounds Ln{C(SiHMe2)2Ph}3 (Ln = La, Ce, Pr, Nd) containing secondary metal–ligand interactions. A strategy for stabilizing coordinatively unsaturated rare earth amides has involved the incorporation of SiH groups, which form labile secondary interactions with the lanthanide center.[14] the SiH moiety provides a powerful signature in 1H and 29Si NMR and IR spectra.

Results

Conclusion