Synthesis and Reactivity of a Bio‐inspired Dithiolene Ligand and its Mo Oxo Complex

An original synthesis of the fused pyranoquinoxaline dithiolene ligand qpdt^2? is discussed in detail. The most intriguing step is the introduction of the dithiolene moiety by Pd‐catalyzed carbon–sulfur coupling. The corresponding Mo^IVO complex (Bu₄N)₂[MoO(qpdt)₂] ( 2 ) underwent reversible protonation in a strongly acidic medium and remained stable under anaerobic conditions. Besides, 2 was found to be very sensitive towards oxygen, as upon oxidation it formed a planar dithiin derivative. Moreover, the qpdt^2? ligand in the presence of [MoCl₄(tBuNC)₂] formed a tetracyclic structure. The products resulting from the unique reactivity of qpdt^2? were characterized by X‐ray diffraction, mass spectrometry, NMR spectroscopy, UV/Vis spectroscopy, and electrochemistry. Plausible mechanisms for the formation of these products are also proposed.     

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Energy levels calculation for Er3+: LiYF4

The complete configuration 4f¹¹ of Er³⁺ was diagonalized with a Hamiltonian containing electrostatic, two-body and three-body configuration interaction, spin-orbit and crystal field parameters of LiYP₄. A set of 18 parameters was adjusted to fit the experimental energy levels as given by Petrov and Tkachuk.     

连续波锁模P_r~（3＋）：YLF激光器

本文报导了采用氩离子激光器来泵浦Ｒｒ￣（３＋）：ＹＬＦ晶体，应用声光调制器实现了主动锁模；同时应用振动─高反射平面镜也实现了被动锁模，两种锁模均得到了ｐｓ光脉冲。据作者了解这是这种晶体材料的第一次锁模运转。     

Spectroscopic properties of Ln2MoO6:Eu3+

The spectroscopic properties of Ln₂MoO₆:Eu³⁺ (Ln = La, Gd, Y) compounds were investigated. The differences in the recorded fluorescence spectra are in accord with the different structures. For the La₂MoO₆:Eu³⁺ case, the spectrum is compatible with a C₂ point site symmetry. It appears that the energy level scheme is connected with the rare earth oxychloride one, so it is possible to determine accurately sets of crystal field parameters simulating the spectrum. For the other compounds, the Eu³⁺ ions occupy three different point sites. By using the site-selective excitation on the ⁵D₀ level it is possible to identify the energy level scheme characterizing each point site.