Beryllium(II) complexes with (R 2N) 2P(O)F (R = Me or Et): Synthesis and characterisation by multinuclear ( 31P, 19F and 9Be) NMR in solution

Abstract

Two beryllium complexes Be[(R 2N) 2P(O)F] 4(ClO 4) 2 (R = Me ( 1) and R = Et ( 2)) were synthesised and characterised by multinuclear ( 31P, 19F and 9Be) NMR, IR and elemental analyses. Solution 9Be NMR spectra of the two complexes show sharp quintuplets due to coupling with four equivalent phosphorus atoms, indicative of highly symmetric environment for the beryllium centre and consistent with a tetrahedral geometry in solution. Density functional theory (DFT) calculations, carried out at the B3LYP level, have been used to support the interpretations of NMR data for the two complexes prepared. A comparison of the results obtained for the bound and free ligands is discussed.