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oe1(光电查) - 科学论文

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  • Time-Resolved Spectroscopic Study of N,N-Di(4-bromo)nitrenium Ions in Selected Solutions

    摘要： Nitrenium ions are important reactive intermediates in chemistry and biology. In this work, femtosecond and nanosecond transient absorption (fs-TA and ns-TA) along with nanosecond time-resolved resonance Raman (ns-TR3) experiments were employed to examine the photochemical pathways of N-(4,4′-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF4? (salt (DN) from just absorption of a photon of light to the production of the important N,N-di(4-bromophenyl)nitrenium ion 2. In acetonitrile (MeCN), the formation of halogenated diarylnitrenium ion 2 was observed within 4 ps, showing the vibrational spectra with strong intensity. The nucleophilic adduct reaction of ion 2 with H2O was also examined in aqueous solutions. The direct detection of the unique ortho adduct intermediate 3 shows that there is an efficient and exclusive reaction pathway for 2 with H2O. The results shown in this paper give new characterization of 2, which can be used to design time-resolved spectroscopy investigations of covalent addition reactions of nitrenium ions with other molecules in future studies.

    关键词： transient absorption,reactive intermediate,resonance Raman,nitrenium ion

    更新于2025-09-23 15:22:29

  • Photosensitive Tin Sulfur Dioxide Complexes with Unexpected Bonding Modes

    摘要： Infrared spectra of the matrix isolated Sn(η2-O2S), Sn(η2-OSO), Sn(η2-O2S)(η1-OSO), Sn(η2-O2S)2, OSn2(η2-SO) and Sn(μ2-O2)SnS molecules were observed following laser-ablated Sn atoms reactions with SO2 during condensation in solid argon. The assignments for the major vibrational modes were confirmed by appropriate S18O2 and 34SO2 isotopic shifts, and density functional vibrational frequency calculations (B3LYP and BPW91). Interestingly, the mononuclear complexes are interconvertible; that is, irradiation induces the isomerization of Sn(η2-O2S) and Sn(η2-O2S)(η1-OSO) to Sn(η2-OSO) and Sn(η2-O2S)2, respectively, and vice versa on annealing. However, there is no evidence of isomerization reaction in between the binuclear molecules OSn2(η2-SO) and Sn(μ2-O2)SnS. Bonding in these products is discussed, and the electronic structures change associated with different bonding types are revealed which is crucial for the observed photochemical reactions.

    关键词： Quantum chemical calculation,Matrix-isolation,Reactive intermediate,Infrared spectra,Reaction mechanism

    更新于2025-09-19 17:15:36