Group 3 complexes incorporating (furyl)-substituted disilazide ligands

A series of mono- and bis-amide scandium and yttrium compounds incorporating the furyl-substituted disilazide ligand, [N{SiMe2R}2]− {i} (where R = 2-methylfuryl) have been synthesized. The compounds Sc{i}Cl2 (1), Sc{i}(CH2SiMe3)2 (2) and Sc{i}(OAr)2 (3) were made from suitable scandium starting materials employing either a salt metathesis protocol with Li{i} or via protonolysis of Sc–C bonds by the neutral amine H{i}. The thermally unstable bis-alkyl yttrium compound, ‘Y{i}(CH2SiMe3)2’ was isolated as the bis-THF adduct (4) and the bis-aryloxide Y{i}(OAr)2 (5) was synthesized by elimination of LiOAr from Y(OAr)3. The bis-amide complex Y{i}2Cl (6) and conversion to a rare example of an yttrium benzyl compound Y{i}2(CH2Ph) (7) are described. The yttrium cation, [Y{i}2]+, was synthesized by benzyl abstraction from 7 using B(C6F5)3. Structural characterization of representative examples show variation in the coordination modes for amide ligand {i}, differing primarily in the number of furyl groups that coordinate to the metal, with examples in which zero, one or two M–Ofuryl bonds are present. Preliminary investigation in two areas of catalysis are presented.