Bis(tert-butoxydiphenylsilyl)amide Divalent Lanthanide Complexes.

Area of Science:

• Coordination Chemistry
• Lanthanide Chemistry
• Organometallic Chemistry

Background:

• Stabilizing non-traditional divalent lanthanides is crucial for understanding their unique chemical and physical properties.
• Tuning the electronic structure of lanthanide ions, particularly their 4fⁿ5d¹ ground states, requires novel ligand design.
• Exploring diverse coordination geometries is essential for accessing new lanthanide reactivity.

Purpose of the Study:

• To design and synthesize novel bulky silylamide ligands for stabilizing divalent lanthanides.
• To investigate the coordination chemistry of divalent samarium, europium, and ytterbium with a new ligand system.
• To explore the potential of this ligand framework for stabilizing more reducing divalent lanthanides.

Main Methods:

• Synthesis of bis(tert-butoxydiphenylsilyl)amide ligand.
• Coordination complex formation with Sm(II), Eu(II), and Yb(II).
• Characterization using single-crystal X-ray diffraction, elemental analysis, cyclic voltammetry, magnetometry, and various spectroscopies (IR, NMR, UV-Vis).

Main Results:

• Successful synthesis and characterization of Sm(II), Eu(II), and Yb(II) complexes with pseudo-octahedral geometry.
• Demonstrated the utility of the bulky silylamide ligand in stabilizing these divalent lanthanides.
• Observed complex reactivity with Tm(II), leading to a mixture including a Tm(II) species and a reduced bimetallic Tm(III) complex bridged by a dinitrogen radical.

Conclusions:

• The developed silylamide ligand system effectively stabilizes key divalent lanthanides (Sm, Eu, Yb).
• The ligand framework shows promise but requires further refinement for stabilizing highly reducing divalent lanthanides like Tm(II).
• This work advances the study of non-classical divalent lanthanides and their mixed 4fⁿ5d¹ ground states.