Synthesis, Reactivity, and Structure of Mixed-Ligand Ytterbium Complexes Supported by β-Diketiminate

The preparation and reaction chemistry of β-diketiminate ytterbium complexes is described. Reaction of [(DIPPh) 2 nacnac]Li ((DIPPh) 2 nacnac = N, N -diisopropylphenyl-2,4-pentanediimine anion) with 1 equiv of anhydrous YbCl 3 in THF, followed by crystallization from toluene, affords the monomeric complex [(DIPPh) 2 nacnac]YbCl 2 (THF) 2 ( 1 ) in high yield. Recrystallization of complex 1 from toluene gives an unexpected dimeric complex, {[(DIPPh) 2 nacnac]YbCl(μ-Cl) 3 Yb[(DIPPh) 2 nacnac](THF)}·1/2MePh ( 2 ), which has a rare triple chloride bridge. Reaction of complex 1 with CH 3 C 5 H 4 Na in 1:1 molar ratio in THF gives the mixed-ligand ytterbium chloride (CH 3 C 5 H 4 )[(DIPPh) 2 nacnac]YbCl ( 3 ). Complex 3 readily undergoes metathesis reactions with 1 equiv of LiNPh 2 or LiNPr i 2 in THF to form the compounds (CH 3 C 5 H 4 )[(DIPPh) 2 nacnac]YbNPh 2 ( 4 ) and (CH 3 C 5 H 4 )[(DIPPh) 2 nacnac]YbNPr i 2 ( 5 ), respectively. The complexes 2, 3, and 4 have been characterized by an X-ray diffraction structure determination.