Group 3 complexes incorporating (furyl)-substituted disilazide ligands
摘要:
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}Cl-2 (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}(2)Cl (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-O-furyl bonds are present. Preliminary investigation in two areas of catalysis are presented. (C) 2009 Elsevier B. V. All rights reserved.