Synthesis and photoluminescence of manganese() naphtylphosphonic diamide complexes

Manganese( ii ) halide complexes with N , N , N ′, N ′-tetramethyl- P -naphtalen-2-ylphosphonic diamide were synthesized from anhydrous MnX 2 salts (X = Cl, Br, I) and characterized. Single-crystal X-ray diffraction revealed in all the cases slightly distorted tetrahedral geometry of the coordination sphere. The photoluminescence spectra showed the superimposition of a green emission, related to the 4 T 1 ( 4 G) → 6 A 1 ( 6 S) transition of Mn( ii ), with a band in the red range. Different possible attributions to the lowest-energy emission were taken into account. The emission spectra of the isolated products are dependent upon the nature of the halide and, in the case of X = Br, also upon the excitation wavelength. X-ray diffraction revealed tetrahedral geometry for manganese( ii ) halide complexes with napthylphosphonic diamide ligands. The photoluminescence spectra showed the superimposition of green Mn( ii ) emission with a band in the red range.