To a solution of 1-bromododecane (0.39 mL, 1.6 mmol) in acetonitrile (0.12 mL) was added N,N,N',N'-tetramethylethylenediamine (0.080 mL, 0.53 mmol). The resulting clarified solution was heated to reflux and stirred for 2 h. The formation of a light yellow solid was observed during the reaction. Cold acetone (~9 mL) was added to the warm reaction mixture and the mixture was subsequently cooled to 0 °C, precipitating a white precipitate. The white powder was collected by filtration through a Büchner funnel and washed sequentially with cold acetone (ca. 4 mL) and hexane (ca. 4 mL) to afford N,N'-bis(dodecyldimethyl)ethylenediammonium bromide (306 mg, 94% yield) as a white powder: the melting point was 189.0-194.0 °C; 1H NMR (300 MHz, CDCl3) δ 4.79 (s, 4H), and 3.74-3.69 (m, 4H), 3.50 (s, 12H), 1.79 (br s, 4H), 1.38-1.25 (m, 36H), 0.88 (t, J = 6.3 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ 65.87, 56.75, 51.28, 31.99, 29.78, 29.75, 29.69, 29.65, 29.46, 26.36, 23.16, 22.76, 14.21; low resolution mass spectrometry (ESI) m/z 227.5 [M2+; calculated value for C30H66N2: 227.26].
