Thermally stable rare earth dialkyl complexes supported by a novel bis(phosphinimine)pyrrole ligand

Abstract

A novel bis(phosphinimine)pyrrole based ligand (HL) and its synthesis are reported. Rare earth dialkyl complexes of the ligand, LLn(CH(2)SiMe(3))(2) (Ln = Er, Lu, Sc), have been prepared and found to exhibit high thermal stability in solution. The protio-ligand and dialkyl lanthanide complexes (Ln = Er, Lu) have been characterised by single crystal X-ray diffraction studies.

Insights into the decomposition pathway of a lutetium alkylamido complex via intramolecular C–H bond activation

“…All other geometrical parameters closely match those of dialkyl 1. 10 Interestingly, the Lu-N4 and Lu-N5 bonds lengths of 2.144(4) and 2.143(3) Å, respectively, are similar to other Lu-NHR distances and slightly shorter than the average Lu-NHAr bond length (2.194 Å), 15 which is supportive of our hypothesis that amido ligands bearing aliphatic substituents may form stronger Lu-N bonds than their aromatic counterparts. This difference is even more striking when one considers the great steric demand imparted by the bulky CPh3 groups.…”

“…With this in mind, this work utilizes a nitrogenous ligand bearing an aliphatic CPh3 moiety in lieu of a traditional aromatic substituent. Previously, we reported a thermally stable dialkyl lutetium complex which was supported by a bis(phosphinimine)pyrrole ligand, 10 This complex has been shown to resist thermal decomposition (80 °C) unlike our previously utilized bis(phosphinimine)carbazole framework. 11,12 Rare earth complexes supported by the carbazole scaffold underwent spontaneous self-destructive cyclometalation at the P-and N-bound groups of the phosphinimine donors.…”

Yttrium-Alkyl Complexes Supported by a Ferrocene-Based Phosphinimine Ligand

“…Although a few examples of alkyl yttrium complexes supported by a ligand containing an imine group exist, 53,61 in general, attempts to isolate such complexes resulted in the migration of the alkyl ligand to the imine group. 57,[62][63] We and others [64][65] have reasoned that replacing the imine with a phosphinimine backbone would increase the robustness of the resulting yttrium alkyl complexes. Herein, we report the synthesis, characterization, and reactivity of two yttrium alkyls supported by a ferrocene-based diphosphinimine ligand.…”

X-ray crystal structure of [L 2Ag3]+[OTf]−·5C6D6: a monoanionic bisphosphinimine ligand supported trisilver complex

“…Compared to the neutral, protonated, ligand precursor HL, key bond distances and angles are similar with some slight distortions. The C-N-C bond angle of the pyrrole ring changes from 109.0 (2) (CSD refcode NAYMIL; Johnson et al 2012) to 105.6 (2) , likely as a consequence of coordination to Ag2 and Ag3 (Table 1). Additionally, although the C-P-N bond angles remain significantly different on one side of the ligand to the other, the C-P-N angle of the phosphinimine functionalities coordinated to Ag2 and Ag3 are significantly smaller than that of HL [111.63 (3) from 119.37 (12) ].…”