Tetramethylethylenediamine(dimethyl)nickel(II) is the organonickel complex with the formula (Me2NCH2CH2NMe2)NiMe2 (Me = CH3).

This yellow-brown, air-sensitive compound is popular precursor to diverse organonickel complexes.

It is prepared from the tmeda adduct of nickel(II) acetylacetonate by reaction with methyl lithium.

[1][2] The tmeda ligand is easily displaced by bases such as bipyridine and diphosphines.

Treatment of the complex with electrophilic alkenes results in elimination of ethylene, giving alkene complexes.