Reactivity of Scandium Terminal Imido Complex toward Boranes: C(sp³)–H Bond Borylation and B–O Bond Cleavage

Scandium terminal imido complex [(NNNN)­ScNDIPP] (2; NNNN = [MeC­(N­(DIPP))­CHC­(Me)­(NCH₂CH₂NMeCH₂CH₂NMe₂)]⁻, DIPP = 2,6-ⁱPr₂C₆H₃) reacts with 9-borabicyclononane (9-BBN) to give scandium borohydride [(NNNN­(B)­H)­Sc­(N­(H)­DIPP)] (3; NNNN­(B)H = [MeC­(N­(DIPP))­CHC­(Me)­(NCH₂CH₂NMeCH₂CH₂N­(Me)­CH₂(BBN)]^2–), and C­(sp³)–H bond borylation of the NNNN ligand occurs during this reaction. In contrast, the reaction between complex 2 and catecholborane (CatBH) gives scandium catecholate [(NNNN)­Sc­(Cat)] (4), and B–O bond cleavage happens during this reaction. Both 3 and 4 have been well-characterized including the single-crystal X-ray diffraction analysis. Reaction of 2 with bis­(catecholato)­diboron (CatB–BCat) also gives a B–O bond cleavage product.