Thermodynamic and kinetic stability of magnesium dication solvated by tetramethylethylenediamine

Stability of the Mg2+TMEDA complex (tetramethylethylenediamine ((CH3)2NCH2CH2N(CH3)2,TMEDA) has been studied using density functional theory at BMK/6-311G(2d,2p)//BMK/6-31G(d). The results indicated that the Mg2+TMEDA complex is thermodynamically unstable toward loss of (CH3)2N(CH2)+ fragment. However, the presence of a higher energy barrier of 68 kcal/mol hinders this exothermic process. Formation of MgH+ is thermoneutral with 55 kcal/mol barrier. The dissociation of the complex to produce C2H4, C 2 H 6 + , CH3CH2N(CH3)2, Mg(N(CH3)2)2+, N(CH3)2, C2H4, C2H6, CH3, CH4, H2, H, CH 3 + , and CH 4 + is endothermic. The last four channels gain further kinetic stability due to the presence of sizable energy barriers. These findings show that the Mg2+TMEDA complex can be observed under appropriate experimental conditions.