Unique Double and Triple Decker Arrangements of Rare‐Earth 9,10‐Diborataanthracene Complexes Featuring Single‐Molecule Magnet Characteristics

Abstract

Abstract Herein, we present the first report on the synthesis of rare‐earth complexes featuring a 9,10‐diborataanthracene ligand. This 14‐π‐electron ligand is highly reductive and was previously used in small‐molecule activation. Salt elimination reactions between dipotassium 9,10‐diethyl‐9,10‐diborataanthracene [K 2 (DEDBA)] and [Ln III (η 8 ‐Cot TIPS )(BH 4 )(thf) x ] (Cot TIPS =1,4‐( i Pr 3 Si) 2 C 8 H 6 ) in a 1 : 1 ratio yielded heteroleptic sandwich complexes [K(η 8 ‐Cot TIPS )Ln III (η 6 ‐DEDBA)] (Ln=Y, Dy, Er). These compounds form Lewis‐base‐free one‐dimensional coordination polymers when crystallised from toluene. In contrast, reaction of [K 2 (DEDBA)] and [Ln III (η 8 ‐Cot TIPS )(BH 4 )(thf) x ] in a 1 : 2 ratio led to the formation of heteroleptic triple‐decker complexes [(η 8 ‐Cot TIPS )Ln III ( μ ‐η 6 :η 6 ‐DEDBA)Ln III (η 8 ‐Cot TIPS )] (Ln=Y, Dy, Er). Notably, these are not only the first lanthanide triple‐decker compounds featuring a six‐membered ring as a deck but also the first trivalent lanthanide triple‐decker featuring a heterocycle in the coordination sphere. Magnetic investigations reveal that [K(η 8 ‐Cot TIPS )Ln III (η 6 ‐DEDBA)] (Ln=Dy, Er) and [(η 8 ‐Cot TIPS )Er III ( μ ‐η 6 :η 6 ‐DEDBA)Er III (η 8 ‐Cot TIPS )] exhibit Single‐Molecule Magnet (SMM) behaviour. In the case of [(η 8 ‐Cot TIPS )Ln III ( μ ‐η 6 :η 6 ‐DEDBA)Ln III (η 8 ‐Cot TIPS )] (Ln=Dy, Er), the introduction of a second near lanthanide ion results in strong antiferromagnetic interactions, allowing the enhancement of the magnetic characteristic of the system, compared to the quasi isolated counterpart. This research renews the overlooked coordination chemistry of the DBA ligand and expands it to encompass rare‐earth elements.

Topics & Concepts