title: Experimental and computational studies of intracomplex reactions in Mg+(primary, secondary alkylamine) complexes induced by photoexcitation of Mg+.
abstract: We report herein a comprehensive study of photoinduced reactions in complexes of Mg+ with primary (n-propyl- and isopropylamine) and secondary amines (dipropyl- and diisopropylamine) in the spectral range of 230-440 nm. Similar to the methyl- and ethylamine complexes studied previously, N-H bond activation of these complexes is very unfavorable. Instead, the C(alpha)-C, C-N, and C(alpha)-H bond-cleavage photoproducts are observed after photoexcitation of the Mg+ complexes (3(2)P<--3(2)S). For Mg+(primary amine) complexes, for example, Mg+-NH2CH2CH2CH3, and Mg+-NH2CH(CH3)2, the photoproducts resulting from C(alpha)--C rupture prevail after P(z) and charge-transfer excitations, whereas the Mg+ photofragment is predominant upon P(x,y) excitation. However, with further N-alkyl substitution, as in Mg+(secondary amine) complexes, for example, Mg+-NH(CH2CH2CH3)2 and Mg+-NH[CH(CH3)2]2, a novel intracomplex C-C coupling photoreaction dominates on P(x,y) excitation of Mg+, which is believed to arise from Mg+* insertion into the C-N bond. With P(z) and charge-transfer excitation, the Mg-R elimination photoproducts, arising from C(alpha)-C bond cleavage, predominate. The energetics and possible mechanisms of the intracomplex photoreactions are analyzed in detail with the help of extensive quantum mechanics calculations.
authors.affiliation: Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, PR China.
authors.forename: Haichuan
authors.initials: H
authors.lastname: Liu
authors.forename: Yihua
authors.initials: Y
authors.lastname: Hu
authors.forename: Shihe
authors.initials: S
authors.lastname: Yang
authors.forename: Wenyue
authors.initials: W
authors.lastname: Guo
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Lu
authors.forename: Lianming
authors.initials: L
authors.lastname: Zhao