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)(THP)(n)][BPh4] (Ln = Sc,y, Lu; n = 3,4) with Li{B(NArCH)(2)}(THF)(2) (Ar = 2,6-(C6H3Pr2)-Pr-i) 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 sigma 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 a-bonding Ln-B HOMO.