Synthesis and thermal behavior of dimethyl scandium complexes featuring anilido-phosphinimine ancillary ligands

A family of N,N donor ligands [1-(NHAr)-2-(PR2double bond; length as m-dashNAr′)C6H4] (1a–d; Ar = 2,6-iPr2-C6H3, R = Me, Ph, Ar′ = 2,4,6-Me3-C6H2, 2-iPr-C6H4, 2,6-iPr2-C6H3) has been prepared and fully characterized by multinuclear NMR spectroscopy and X-ray crystallography. Lithiation of the N–H unit and subsequent salt metathesis protocols with ScCl3THF3 provides an avenue to organometallic scandium complexes. The resultant base-free monomeric dichlorides LScCl2, 3a–d, have been fully characterized by NMR spectroscopy as well as X-ray crystallography (3a,c,d). Alkylation of the dichlorides using LiMe results in clean formation of dialkyl complexes LScMe24a–c. Thermolysis of these materials under argon and hydrogen leads to decomposition products as a result of C–H activation of the ligand. Analysis of these results provides a qualitative assessment of the metalative resistance of each ligand framework.