Synthesis and characterisation of magnesium complexes containing sterically demanding N,N'-bis(aryl)amidinate ligands.
Condensation reactions of carboxylic acids and anilines in the presence of polyphosphoric acid trimethylsilyl ester (PPSE) afforded a range of sterically demanding N,N'-bis(aryl)amidines, RN{C(R')}N(H)R [R = Mes (Mes = 2,4,6-trimethylphenyl), R' = Cy (Cy = cyclohexyl) L¹H; R = Dipp (Dipp = 2,6-diisopropylphenyl), R' = Cy L²H; R = Mes, R' = Ph L³H; R = Dipp, R' = Ph L⁴H; R = Mes, R' = Dmp (Dmp = 3,5-dimethylphenyl) L⁵H; R = Dipp, R' = Dmp L⁶H; R = Dmp, R' = Cy L⁷H]. Amidines L¹H-L⁷H have been characterised spectroscopically, and for L⁵H and L⁶H, by X-ray crystallography. Treatment of the amidines with di-n-butylmagnesium in THF solution afforded the monomeric magnesium bis(amidinates) [Mg(L¹)2(THF)] 1, [Mg(L²)2] 2, [Mg(L³)2(THF)] 3, [Mg(L⁵)2(THF)] 5, [Mg(L⁶)2] 6, [Mg(L⁷)2] 7, and the magnesium mono(amidinate) complex [Mg(L⁴)((n)Bu)] 4. These complexes have been characterised spectroscopically, with 1-3, 5 and 6 also being structurally authenticated. Comparison of the magnesium bis(amidinate) complexes reveals that the steric bulk of the amidinate ligand influences both the solid state structure and solution behaviour of these complexes.
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Deborah.Kays@nottingham.ac.uk.
Graeme J
GJ
Moxey
Fabrizio
F
Ortu
Leon
L
Goldney Sidley
Helen N
HN
Strandberg
Alexander J
AJ
Blake
William
W
Lewis
Deborah L
DL
Kays