Group 3 and Lanthanide Boryl Compounds: Syntheses, Structures, and Bonding Analyses of Sc−B, Y−B, and Lu−B σ-Coordinated NHC Analogues

Reaction of [Ln(CH2SiMe3)2(THF)n][BPh4] (Ln = Sc, Y, Lu ; n = 3, 4) with Li{B(NArCH)2}(THF)2 (Ar = 2,6-C6H3iPr2) formed the first group 3 and lanthanide boryl compounds, Sc{B(NArCH)2}(CH2SiMe3)2(THF) and Ln{B(NArCH)2}(CH2SiMe3)2(THF)2 (Ln = Y, Lu), which contain two-center, two-electron Ln−B σ bonds. All of these systems were crystallographically characterized. Density functional theory analysis of the Ln−B bonding found it to be predominantly ionic, with covalent character in the σ-bonding Ln−B HOMO.