The reaction of [Pt(Me)2( 2 -TMEDA)] with excess [2]2 in C6H6 at 25 °C for 4 days, yielded Pt-Mg•TMEDA as the major reaction product (Scheme 2). DOSY studies on Pt-Mg•TMEDA suggest that coordination of TMEDA to Mg is fast and reversible, with Pt-Mg being generated in C6H6 solution at 298 K. Consistent with this argument, the Pt NMR spectrum shows a characteristic quintet resonance at  = -5851 ppm ( 1 J195Pt-1H = 836 Hz) due to the coupling of the Pt centre to four equivalent hydride ligands. The corresponding hydride resonance appears at  = -7.24 ppm in the 1 H NMR spectrum. The presence of four hydride ligands rather than two in this complex likely arises from reaction of intermediate species with the solvent (C6H6).