Lanthanum dibromide complexes of sterically demanding aminopyridinato and amidinate ligands

It is report on synthesis and structure of Ap*LaBr2(THF)(3) and Am*LaBr2(THF)(3) (Ap*-H = {(2,6-diisopropyl-phenyl)-[6-(2,4,6-triisopropyl-phenyl)-pyridin-2-yl]-amine 1, Am*-H = N,N'-bis-(2,6-diisopropylphenyl)benzamidine). X-ray crystal structure analyses of the two seven coordinated complexes were carried out to compare the steric demand of the two amido ligands. A similar overall primary coordination site bulkiness for both ligands and distinct differences regarding this bulkiness for different directions were observed. A better shielding of the second coordination sphere was observed for the aminopyridinate.