Absence of a magnetic interaction in a dinuclear copper complex? The case of a crossed axial–equatorial oxalate coordination mode
摘要:
A simple and easy preparation of the hydrogen oxalate ligand (HOOCCOO)(-), with only one deprotonated carboxylic function, is described. C-13 NMR spectroscopy furnishes a straightforward characterization of this interesting ligand. This ligand coordinates in its monodeprotonated form to a Cu-II complex with a free coordination position, yielding a complex that presents a very weak antiferromagnetic interaction. In a subsequent step, the second deprotonation allows the isolation of an oxalato-bridged dinuclear Cu-II complex, which is characterized by structural determination, the copper ions being pentacoordinate in an equivalent centrosymmetry-related environment. DFT calculations show that the magnetic interaction through the oxalato bridge is strictly equal to 0 cm(-1), demonstrating that the singlet and triplet states of this oxalato-bridged dinuclear Cu-II complex have the same energy. This dinuclear complex presents a rhombic EPR spectrum, with three well-defined g values, at room temperature as well as at 100 K. (C) 2013 Elsevier Ltd. All rights reserved.
STEREOSELECTIVE SYNTHESIS OF PIPERIDINE DERIVATIVES
申请人:Chou Shan-Yen
公开号:US20100152452A1
公开(公告)日:2010-06-17
This invention relates to dialdehyde or dinitrile compounds, which are useful for stereoselective synthesis of piperidine, pyrrolidine, and azepane derivatives.
这项发明涉及二醛或二腈化合物,可用于对哌啶、吡咯烷和氮杂环庚烷衍生物进行立体选择性合成。
Composition for film formation, method of film formation, and silica-based film
申请人:JSR CORPORATION
公开号:US20030091838A1
公开(公告)日:2003-05-15
A composition for film formation which comprises:
(A) a product of hydrolysis and condensation obtained by hydrolyzing and condensing at least one silane compound selected from the group consisting of compounds represented by the formula (1), compounds represented by the formula (2), and compounds represented by the formula (3) in the presence of water and an ammonium compound, and
(B) an organic solvent.