Sandwich and Half-Sandwich Ln(II) (Ln = Sm, Yb) Complexes with Bulky Fluorenyl Ligands. Competitive Abstraction of H or SiMe₃ from 2,7-tBu₂-9-SiMe₃-Fluorene by an Amido Anion

Abstract

The half-sandwich fluorenyl-amido complex [2,7-tBu 2 -9-SiMe 3 C 13 H 6 ]Yb[N(SiMe 3 ) 2 ](DME) was synthesized by the reaction of [(Me 3 Si) 2 N] 2 Yb(THF) 2 with 2,7-tBu 2 -9-SiMe 3 C 13 H 7 (1:1 molar ratio) in 83% yield. The analogous reaction of [(Me 3 Si) 2 N] 2 Sm(THF) 2 affords a mixture of equimolar amounts of the half-sandwich complexes [2,7-tBu 2 -9-SiMe 3) was synthesized in 60% yield by reacting [(Me 3 Si) 2 N] 2 Sm(THF) 2 with 2 equiv of 2,7-tBu 2 -9-SiMe 3 C 13 H 7 . Complexes 2b and 3 result from competitive abstraction of H or SiMe 3 from 2,7-tBu 2 -9-SiMe 3 -fluorene by an amido group. In contrast, the homoligand sandwich complex [2,7-tBu 2 -9-SiMe 3 C 13 H 6 ] 2 Sm(DME) (5) could be synthesized in 80% yield when [(p-tBuC 6 H 4 ) 2 CH] 2 Sm(DME) 2 was used as a precursor. The complex (2,7-tBu 2 C 13 H 7 ) 2 Sm(THF) 2 (6) was synthesized by the reaction of 2,7-tBu 2 C 13 H 8 with [(Me 3 Si) 2 N] 2 Sm(THF) 2 (2:1) in 65% yields. The crystal structures of complexes 1, 2a,b, 3, 5, and 6 were established by X-ray analyses.

Thermally Stable Cationic Bis(benzhydryl) Complexes of Early Lanthanides (La, Ce, Nd)

“…A benzhydryl anion, due to the delocalization of a negative charge within the conjugated π-system, easily modifiable steric demand, and variable and flexible bonding modes, seems to be a promising and cheap candidate for the synthesis of isolable hydrocarbyl lanthanide complexes. Recently, we successfully introduced new bulky benzhydryl ligand [( p - t Bu-C 6 H 4 ) 2 CH] − to organolanthanide chemistry, which proved to be suitable for the synthesis of isolable thermally stable neutral (for Ln II,III and Ca) and cationic alkyl complexes (for Ln III ) as well as their half-sandwich alkyl derivatives . The reactivity and catalytic performance of complexes were explored .…”

“…Recently, we successfully introduced new bulky benzhydryl ligand [( p - t Bu-C 6 H 4 ) 2 CH] − to organolanthanide chemistry, which proved to be suitable for the synthesis of isolable thermally stable neutral (for Ln II,III and Ca) and cationic alkyl complexes (for Ln III ) as well as their half-sandwich alkyl derivatives . The reactivity and catalytic performance of complexes were explored . In this work, we report on the synthesis of cationic benzhydryl complexes of La, Ce, and Nd in the form of separated and contact ionic pairs.…”

Solid-state and solution-phase characterization of SmII-aza[2.2.2]cryptate and its methylated analogue

“…Complexes of divalent lanthanide (Ln II ) ions have attracted attention in recent years owing to their interesting luminescence, magnetic, and electrochemical properties. 1–25 One such group of Ln II complexes that have been the subject of extensive investigation with regard to their structural, photophysical, and electrochemical properties is the Ln II -cryptates. 2,26–42 In many studies, cryptands such as 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (222) and 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacos-5-ene are used to encapsulate Ln II ions, 26–32,37–42 and reported Ln II -cryptates have luminescence and electrochemical properties that are useful in applications including light-emitting diodes, imaging, and catalysis.…”