Yttrium and scandium complexes of a bulky bis(phosphinimine)carbazole ligand

• Published in: Inorganica Chimica Acta Vol. 422; pp. 209 - 217
• Main Authors: Johnson, Kevin R.D., Hayes, Paul G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014
• Subjects: Cyclometalation; Ligand design; Phosphinimine; Rare earth; Scandium; Yttrium; Ligand design; Rare earth; Cyclometalation; Yttrium; Phosphinimine; Scandium
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2014.05.045

A new, bulky mesityl-substituted bis(phosphinimine)carbazole ligand has been prepared. It has been used to support a variety of scandium and yttrium complexes, prepared by both alkane elimination and salt metathesis routes. [Display omitted] •A new bulky mesityl-substituted bis(phosphinimine)carbazole ligand.•Organometallic yttrium complex prepared by protonolysis.•Double cyclometalation.•Monomeric and Lewis-base free Sc and Y dichloride complexes.•Ligand reactivity and ability to support rare earth metal complexes examined. The synthesis and reactivity of a bulky bis(phosphinimine)carbazole pincer ligand (HL) bearing mesityl N-aryl groups is described. Reaction of HL with Y(CH2SiMe3)3(THF)2 afforded a doubly cyclometalated organoyttrium complex, whereby the ligand was κ3N, κ2C coordinated to the metal via three nitrogen atoms and two ortho-metalated P-phenyl rings. Deprotonation of (HL) with nBuLi liberated a monomeric and thermally stable lithium salt of the ligand (LLi). Salt metathesis reactions of LLi with ScCl3(THF)3 and YCl3(THF)3.5 generated the corresponding rare earth dichloro complexes, which were found to be monomeric and Lewis-base free.