絞り込み

16644

広告

【動画】点滴をします。 (日経BP)

診察室やカンファレンスなどでよく使う医療英語のエッセンスを、今日も楽しく学んでいきましょう。 今日のトレーニングも「最初の3単語」です。診察室でよく使うこのフレ...

  1. 渦巻く銀河の形成プロセス、空飛ぶ天文台が...
  2. COP、排出削減強化で隔たり (デイリー...
  3. [医学] 胚の原腸陥入期の三胚葉のエピゲ...
  4. [医学] 癌532例を蛋白質の特徴から1...

ニュース一覧

Emergence of comparable covalency in isostructural cerium(iv)- and uranium(iv)-carbon multiple bonds.

著者 Gregson M , Lu E , Tuna F , McInnes EJL , Hennig C , Scheinost AC , McMaster J , Lewis W , Blake AJ , Kerridge A , Liddle ST
Chem Sci.2016 May 01 ; 7(5):3286-3297.
この記事をPubMed上で見るPubMedで表示
この記事をGoogle翻訳上で見る Google翻訳で開く

スターを付ける スターを付ける     (3view , 0users)

Full Text Sources

We report comparable levels of covalency in cerium- and uranium-carbon multiple bonds in the iso-structural carbene complexes [M(BIPM)(ODipp)] [M = Ce (), U (), Th (); BIPM = C(PPhNSiMe); Dipp = CH-2,6-Pr] whereas for M = Th the M[double bond, length as m-dash]C bond interaction is much more ionic. On the basis of single crystal X-ray diffraction, NMR, IR, EPR, and XANES spectroscopies, and SQUID magnetometry complexes are confirmed formally as metal(iv) complexes. In order to avoid the deficiencies of orbital-based theoretical analysis approaches we probed the bonding of analysis of RASSCF- and CASSCF-derived densities that explicitly treats the orbital energy near-degeneracy and overlap contributions to covalency. For these complexes similar levels of covalency are found for cerium(iv) and uranium(iv), whereas thorium(iv) is found to be more ionic, and this trend is independently found in all computational methods employed. The computationally determined trends in covalency of these systems of Ce ∼ U > Th are also reproduced in experimental exchange reactions of with MCl salts where and do not exchange with ThCl, but does exchange with MCl (M = Ce, U) and and react with UCl and CeCl, respectively, to establish equilibria. This study therefore provides complementary theoretical and experimental evidence that contrasts to the accepted description that generally lanthanide-ligand bonding in non-zero oxidation state complexes is overwhelmingly ionic but that of uranium is more covalent.
PMID: 29997821 [PubMed]
印刷用ページを開く Endnote用テキストダウンロード