Synthesis and reactivity of rare-earth-N,N'-(diphenyl)formamidinate and rare-earth-N,N'-bis(2,4-dimethylphenyl)formamidinate complexes.

Redox transmetallation/protolysis reactions were employed to synthesize a series of the rare earth bis(aryl)formamidinate complexes. Trivalent complexes were synthesized with three chelating formamidinate ligands about the metal centers. A study of the reactivity towards the Tishchenko reaction shows the compounds catalyse the Tishchenko reaction in the formation of esters from aldehydes. [Display omitted] • The chemistry we present here extends our studies of rare earth formamidinato chemistry and their applicability in Tishchenko catalysis. • The chemistry presented should be of great interest to inorganic and organometallic chemists, and more specifically to those with interests in f-block chemistry. Furthermore, due to the great interest in cyclopentadienyl replacement chemistry in rare earth studies more broadly, this chemistry will appeal to most synthetic and structural chemists. • We therefore think that Inorganica Chmica Acta is the right platform to publish our results to rapidly spread our findings to the inorganic chemical community. • We look forward to hearing from you soon regarding this submission. Redox transmetallation/protolysis reactions of rare earth metals, Hg(C 6 F 5) 2 and a formamidine (PhFormH = N , N '-(diphenyl)formamidine or DMFormH = N , N ' -bis(2,4-dimethylphenyl)formamidine) in tetrahydrofuran (thf) or 1,2-dimethoxyethane (dme) were employed to synthesize a series of the rare earth N,N' -bis(aryl)formamidinate complexes. Accordingly, trivalent complexes with the composition [Ln(PhForm) 3 (thf) n ]⋅(solv.) m [n = 2, m = 0, Ln = La (1), Pr (2); n = 2, m = 0.5, solv = thf, Sm (3); n = 2, m = 1.5, solv. = PhMe, Ln = Nd (4); n = 2, m = 1.5, solv. = thf, Ln = Gd (5); n = 2, m = 3, solv. = thf, Ln = Tb (6), Dy (7), and Y (8); n = 1; m = 0, Ln = Ho (9), Er (10) and Lu (11)] or [Ln(DMForm) 3 (solv.)] [Ln = Sm (12), Gd (13), solv. = dme; Ln = Pr (14), Ho (15), solv. = DMFormH; Ln = Y (16), Lu (17), solv. = thf; Ln = Er (18), solv. = dmf; dmf = N,N -dimethylformamide] were synthesized and characterized by X-ray crystallography. Complexes 1 – 8 have eight coordinate Ln metals with three chelating PhForm and two transoid thf ligands, whilst 9 – 11 are seven coordinate with a single thf ligand. Thus, there are three structural discontinuities, namely at Ho, Y, Er, the second of which occurs in defiance of a decrease in ion size. An investigation of catalytic reactivity of representative Ln complexes in the conversion of aldehydes into esters (Tishchenko reaction) revealed most have modest catalytic properties. [Y(PhForm) 3 (thf) 2 ]⋅3thf 7 and [Y(DMForm) 3 (thf)] 16 had the highest reactivity for their respective ligands, with 16 by far the most effective catalyst. [ABSTRACT FROM AUTHOR]