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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.

Tetrakis(dimethylamino)diborane(4) reacts photochemically at 300 nm in carbon tetrachloride to give chlorotris(dimethylamino)diborane(4) in 74% yield at 95 % conversion, as well as smaller amounts of bis(dimethylamino)methane, tris(dimethylamino)borane, and chloroform. Irradiation of tetrakis(dimethylamino)diborane(4) in chloroform gave chlorotris(dimethylamino)diborane(4) in 58 % yield at 93 % conversion, plus smaller amounts of tris(dimethylamino)borane, bis(dimethy!amino)borane, and methylene chloride. In methylene chloride, tris(dimethylamino)borane was the major product, and chlorotris(dimethylamino)diborane(4), bis(dimethylamino)borane, and methyl chloride were formed in lesser yields. Reaction was most efficient in carbon tetrachloride, least efficient in dichloromethane. The products were shown to arise by competing boron-boron and boronnitrogen homolyses, of which only the latter was visible in carbon tetrachloride at ambient temperatures. Lowtemperature irradiations in carbon tetrachloride revealed transient formation of bis(dimethylamino)chloroborane as an important photoproduct. Rapid dark reaction between bis(dimethylamino)chloroborane and tetrakis(dimethylamino)diborane(4) at room temperature gave tris(dimethylamino)borane and chlorotris(dimethylamino)-( 50) C.

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