12087-58-0Relevant academic research and scientific papers
DFT-Supported Threshold Ionization Study of Chromium Biphenyl Complexes: Unveiling the Mechanisms of Substituent Influence on Redox Properties of Sandwich Compounds
Ketkov, Sergey Yu.,Tzeng, Sheng-Yuan,Wu, Pei-Ying,Markin, Gennady V.,Tzeng, Wen-Bih
, p. 13669 - 13675 (2017)
High-resolution mass-analyzed threshold ionization (MATI) spectra of (η6-Ph2)2Cr and (η6-Ph2)(η6-PhMe)Cr demonstrate that the Ph groups work as electron donors, decreasing the ionization energy of the gas-phase bisarene complexes. In contrast to electrochemical data, a close similarity of the Ph and Me group effects on the oxidation of free sandwich molecules has been revealed. However, DFT calculations testify for the opposite shifts of the electron density caused by the Me and Ph substituents in the neutral complexes, the latter behaving as an electron-accepting fragment. On the contrary, in the bisarene cations, the Ph group becomes a stronger donor than methyl. This change provides the similar substituent effects observed with the MATI experiment. On the other hand, the well-documented opposite influence of the Me and Ph fragments on the redox potential of the (η6-arene)2Cr+/0 couple in solution appears to be a result of solvation effects but not intramolecular interactions as shown for the first time in this work.
η6-ARENE METAL COMPLEXES. SYNTHESIS, REACTIVITY AND CRYSTAL AND MOLECULAR STRUCTURE OF 6-1,3,5-Me3C6H3)2>AlCl4 AND THE ONE-POT SYNTHESIS OF V(η6-1,3,5-Me3C6H3)2, Cr(η6-MeC6H5)2 AND Mo(η6-MeC6H5)2
Calderazzo, Fausto,Invernizzi, Renzo,Marchetti, Fabio,Masi, Francesco,Moalli, Angelo,et al.
, p. 53 - 60 (2007/10/02)
The products of the reduction of VX3 by the Al/AlX3 (X=Cl, Br, I) system in 1,3,5-Me3C6H3 (mes), AlX4, have been isolated and structurally characterized for X=Cl.Crystal data: C18H24AlCl4V; M=460.1; orthorhombic, space group Pnnm, a=15.078(5); b=14.391(3); c=10.481(3) Angstroem; U=2274(1) Angstroem3; Z=4; Dc=1.344 Mg m-3; ??(Mo-Kα1)=0.70930 Angstroem; μ=0.93 mm-1; F(000)=944; T=294 K.The structure consists of the discrete VMes2+ and AlCl4- ions, the former containing sandwiched, eclipsed arene ligands.In the parent hydrocarbon as medium, no further reduction of the vanadium(I) complex occurred even over long reaction times: in the presence of tetrahydrofuran, the crude primary product of the reaction was further reduced by the excess of aluminium affording bismesitylenevanadium(0), Vmes2, in good yields.The slight solubility of AlCl4 in mesitylene has been found to increase enormously by addition of the equivalent of AlCl3: this adduct clathrates additional mesitylene up to a critical ratio of the mesitylene/vanadium molar value, further addition of mesitylene giving a biphasic system.The new synthetic method used for Vmes2 has been extended to the preparation of the chromium(0) and molybdenum(0) complexes, Cr(η6-MeC6H5)2 and Mo(η6-MeC6H5)2, respectively.
