Wang Guanjun, Gong Yu, Chen Mohua, Zhou Mingfei
Department of Chemistry & Laser Chemistry Institute, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai 200433, People's Republic of China.
J Am Chem Soc. 2006 May 3;128(17):5974-80. doi: 10.1021/ja0604010.
Reactions of titanium monoxides with methane have been investigated using matrix isolation infrared spectroscopy and theoretical calculations. Titanium derivatives of several simple oxyhydrocarbons have been prepared and identified. The titanium monoxide molecules prepared by laser evaporation of bulk TiO2 target reacted with methane to form the TiO(CH4) complex in solid argon, which was predicted to have C3v symmetry with the oxygen atom coordinated to one hydrogen atom of the methane molecule. The complex rearranged to the CH3Ti(O)H titano-acetaldehyde molecule upon visible (lambda > 500 nm) irradiation. The titano-acetaldehyde molecule sustained further photochemical rearrangement to the CH2Ti(H)OH titano-vinyl alcohol molecule, which was characterized to be a simple carbene complex involving agostic bonding. The CH2Ti(H)OH molecule reacted with a second methane to form the (CH3)2Ti(H)OH titano-isopropyl alcohol molecule spontaneously on annealing. The (CH3)2Ti(H)OH molecule also can be produced via UV photon-induced rearrangement of the CH3Ti(O)H(CH4) complex.
利用基质隔离红外光谱和理论计算研究了一氧化钛与甲烷的反应。制备并鉴定了几种简单含氧烃的钛衍生物。通过对块状TiO₂靶进行激光蒸发制备的一氧化钛分子与甲烷反应，在固体氩中形成TiO(CH₄)络合物，预计该络合物具有C₃v对称性，其中氧原子与甲烷分子的一个氢原子配位。在可见光（λ>500 nm）照射下，该络合物重排为CH₃Ti(O)H钛代乙醛分子。钛代乙醛分子持续发生光化学重排，生成CH₂Ti(H)OH钛代乙烯醇分子，其特征为涉及agostic键的简单卡宾络合物。CH₂Ti(H)OH分子与第二个甲烷反应，在退火时自发形成(CH₃)₂Ti(H)OH钛代异丙醇分子。(CH₃)₂Ti(H)OH分子也可通过CH₃Ti(O)H(CH₄)络合物的紫外光子诱导重排产生。
