A New Approach to Functionalize an Organic Compound through the Influence of Metal Bis(dithiolene) Complexes Leading to Ion-Pair Compounds Exhibiting Strong Emission at Room Temperature in the Visible Region

The facile oxidation of 6,12-dihydrodipyrido [1,2-α;1‘,2‘-d] pyrazidinium (DDP2+ = [C12H12N2]2+) chloride to cyclic quaternary
ammonium monocation, 12-oxo-9H-dipyrido[1,2-α;1‘,2‘-d]pyrazin-5-ium (ODP1+ = [C12H9N2O]1+) is achieved when it reacts with
[M(mnt)2]2- (MNi2+ and Cu2+) resulting in the formation of the
ion pair compounds [ODP]2[Ni(mnt)2] (1) and [ODP]2[Cu(mnt)2] (2),
respectively (see Scheme for the structures of [ODP]1+ and
[DDP]2+). The nickel complex 1 exhibits intense emission at room
temperature in the visible region, whereas, in the case of copper
analogue 2, the emission gets quenched. The oxo cation ODP
(known to be an unstable species and never characterized
unequivocally before) is stabilized in 1 and 2 by cation−anion
interactions.