Photochemical reaction of dimethylamine in polychloromethanes. Photochemical synthesis of bis(dimethylamino)methane

Abstract

Irradiation of ca. 1.0 M solutions of dimethylamine in carbon tetrachloride at 300 nm and 35°g ave IV.lV.A'.lV'-tetramethylmethanediamine (22 mol %), dimethylamine hydrochloride (32 mol %), and chloroform (25 mol %), plus lesser amounts of methylamine. Quantum yields at zero conversion were 4.7 mol einstein-1 for disappearance of dimethylamine, and 1.2, 1.1, and 1.2 for appearance of diamine, amine hydrochloride, and chloroform, respectively. Similar reactions of dimethylamine were observed in chloroform and , , -trichlorotoluene, but with longer irradiation times. Diamine formed in irradiations of dimethylamine in deuteriochloroform showed no deuterium incorporation. A mechanism involving photodissociation of an amine-halocarbon charge-transfer complex, followed by disproportionation and/or combinations of dimethylamine' radicals, and, finally, by aminal disproportionation is supported by control experiments, quantum yields, and the protochemistry of potential and actual intermediates. The 4:1 reaction stoichiometry of dimethylamine to diamine corresponds to ca. 88% of theoretical yield for production of diamine.

The photochemical reaction of aromatic amines with carbon tetrachloride

“…Sir: The photochemical reaction of amines with halomethanes, especially the reaction of aliphatic amines with CC14, has received considerable attention recently.1 Aromatic amines, as well as aliphatic amines,2 have been shown to form charge-transfer complexes with halomethanes,3 and this complex formation has been considered to play an important role in photochemical reactions. 1,4 Although these complexes in the ground state are so loose as to approach the nature of contact pairs5 when the amines are aromatic and CC14 is the acceptor,3 there is no quantitative estimate of contribution of these complexes to the photochemical reaction.…”

Spring-loaded biradicals. The radical and electron-transfer photochemistry of bridgehead cyclopropyl-substituted 2,3-diazabicyclo[2.2.2]oct-2-enes (DBO's)

“…The second peak was isolated by preparative GC and identified as 4-chloro-1-(3chloropropylidene)cyclohexane (24) by NMR and mass spectral analysis: NMR 1.64-2.72 (m, 10 H), 3.49 (t, 2 H, / = 7.2 Hz), 4.04-4.36 (m, 1 ), 5.16 (t, 1 H). The 500-MHz proton NMR100 and decoupling experiments support the structure: MS, m/e (rel abundance) 41 (52.9), 79 (100.0), 107 (55.0), 143 (4.24), 145 (1.36), 192 (1.45), 194 (0.79), 196 (0.22). A minor peak in the direct photolysate was identified as hexachloroethane by comparing GC retention times and mass spectra with those of an authentic sample.…”

“…Hz), 1.86-2.24 (M, 12 ), 5.15 (t, 2 H, J = 7.1 Hz); 13C NMR 14.88, 20.62, 28.97, 29.78, 37.32, 38.29, 124.25, 124.36, 138.29; MS, m/e (rel abundance) 164 (100), 135 (57.3), 121 (49.3), 107 (48.6), 93 (92.8), 79 (86.1), 67 (32.5), 41 (30.7). Attempted separation of the E and Z isomers failed on a packed TCEP GC column and on SF-96 and SE-54 capillary columns.…”