スキップしてメイン コンテンツに移動

投稿

4月, 2015の投稿を表示しています

Reactions of Co(III)–Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

Pankaj Kumar   † ,  Yong-Min Lee   † ,  Young Jun Park   † ,  Maxime A. Siegler   ‡ ,  Kenneth D. Karlin   * ‡ , and  Wonwoo Nam   * † †  Department of Chemistry and Nano Science,  Ewha Womans University , Seoul 120-750,  Korea ‡  Department of Chemistry,  The Johns Hopkins University , Baltimore, Maryland 21218,  United States J. Am. Chem. Soc. ,  2015 ,  137  (13), pp 4284–4287 DOI:  10.1021/ja513234b Publication Date (Web): March 20, 2015 Copyright © 2015 American Chemical Society * karlin@jhu.edu , * wwnam@ewha.ac.kr Abstract New Co III –nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)Co III (NO)] 2+  ( 1 ) and [(13-TMC)Co III (NO)] 2+  ( 2 ), were synthesized via [(TMC)Co II (CH 3 CN)] 2+  + NO(g) reactions. Spectroscopic and structural characterization showed that these compounds bind the nitrosyl moiety in a bent end-on fashion. Complexes  1  and  2 reacted with KO 2 /2.2.2-cryptand to produce [(12-TMC)Co II (NO 2 )] +  (

構造生物学:超原子分解能の結晶構造解析で、[NiFe]ヒドロゲナーゼの水素原子を検出

ヒドロゲナーゼの活性種の結晶構造です。FeとNiを架橋するヒドリドがきっちり見える分解能も驚きですが、水素分子からヒドリドを取った時にのこるプロトンが、ニッケルに配位するシステイン上に乗っていると いうことまで見えているのが驚きです。配位子上でのプロトンのやり取りは、よりフォーカスされて行く事と思います。 Hideaki Ogata , Koji Nishikawa &  Wolfgang Lubitz Affiliations Contributions Corresponding authors Nature   520 ,   571–574   (23 April 2015)   doi:10.1038/nature14110 Received   18 August 2014  Accepted   20 November 2014  Published online   26 January 2015 Article tools Full text PDF Citation Reprints Rights & permissions Article metrics ヒドロゲナーゼは、金属触媒部位で水素分子をプロトンと電子へと可逆的に変換する酵素である。この酵素の構造と機能を理解するには、豊富に含まれる水素の位置の検出が極めて重要だが、タンパク質のX線結晶構造解析では、水素原子の検出は重大な問題の1つである。水素原子は回折への寄与が非常に弱い上に、単結晶の品質ではサブオングストロームの分解能を得るには不十分な場合が多いからである。今回我々は、標準型の[NiFe]ヒドロゲナーゼ(分子量約91.3 kDa)の結晶構造を、分解能0.89 Åで決定した。厳密に嫌気的に単離することにより、ヒドロゲナーゼを特定の分光学的状態、すなわち活性な還元型Ni-R(亜型のNi-R1)の状態で得ることができた。高分解能、適切な精密化法、入念なモデル作成によって、水素原子の大部分について、構造内での位置を明らかにできた。これによって、水素分子がヘテロリティックに開裂して生じた産物が直接検出され、ヒドリド(H  −  )はNiとFeを架橋しており、プロトン(H  +  )はシステ

Tris(8-methoxy-2-quinolylmethyl)amine (8-MeOTQA) as a highly fluorescent Zn2+ probe prepared by convenient C3-symmetric tripodal amine synthesis

TPAが、二時間で収率98%で合成できるそうです。 だれか試してみてはいかがでしょう? Yuji Mikata , * a b      Yuki Nodomi , b      Risa Ohnishi , b      Asako Kizu b  and   Hideo Konno c    Show Affiliations Dalton Trans. , 2015, Advance Article DOI:  10.1039/C5DT00514K Received 04 Feb 2015, Accepted 23 Mar 2015 First published online 23 Mar 2015 |  | Share on citeulike | Share on facebook | Share on twitter | |  More PDF Rich HTML    Send PDF to Kindle Download Citation BibTex   EndNote   MEDLINE   ProCite   ReferenceManager   RefWorks   RIS   Request Permissions Abstract Cited by Related Content Metrics   A convenient synthesis of  C 3 -symmetric tribenzylamine (TBA) derivatives has been investigated. The reaction of benzyl chlorides with acetaldehyde ammonia trimer ( 1 ) in the presence of base afforded tribenzylamines in high yields. This efficient method allows the diverse synthesis of TPA (tris(2-pyridylmethyl)amine) and TQA (tris(2-qui

Magnetic superexchange interactions: trinuclear bis(oxamidato) versus bis(oxamato) type complexes

RSC - Dalton Trans. latest articles  by Mohammad A. Abdulmalic  /   28d   //   keep unread   //   hide   //   preview Dalton Trans. , 2015, Advance Article DOI : 10.1039/C4DT03579H, Paper Mohammad A. Abdulmalic, Azar Aliabadi, Andreas Petr, Yulia Krupskaya, Vladislav Kataev, Bernd Buchner, Ruslan Zaripov, Evgeniya Vavilova, Violeta Voronkova, Kev Salikov, Torsten Hahn, Jens Kortus, Francois Eya'ane Meva, Dieter Schaarschmidt, Tobias Ruffer The origin of larger  J  values of trinuclear bis(oxamidato)  versus  bis(oxamato) type complexes is explained by an interplay with the spin densities of their mononuclear precursors. To cite this article before page numbers are assigned, use the DOI form of citation above. The content of this RSS Feed (c) The Royal Society of Chemistry

Synthesis and characterization of copper(II) complexes with multidentate ligands as catalysts for the direct hydroxylation of benzene to phenol

RSC - Dalton Trans. latest articles  by Li Wu  /   28d   //   keep unread   //   hide   //   preview Dalton Trans. , 2015, Advance Article DOI : 10.1039/C5DT00575B, Paper Li Wu, Wei Zhong, Beibei Xu, Zhenhong Wei, Xiaoming Liu Like iron( III ) complexes, copper( II ) complexes catalyse the direct hydroxylation of benzene to phenol with H 2 O 2  as the oxidant and their catalytic efficiency correlates with the reduction potentials of the copper( II ) complexes. To cite this article before page numbers are assigned, use the DOI form of citation above. The content of this RSS Feed (c) The Royal Society of Chemistry PDF Rich HTML

Defining the Role of Tyrosine and Rational Tuning of Oxidase Activity by Genetic Incorporation of Unnatural Tyrosine Analogs

Yang Yu   † ,  Xiaoxuan Lv   ‡ ¶ ,  Jiasong Li   ‡ ¶ ,  Qing Zhou   ‡ ¶ ,  Chang Cui   ∥ ,  Parisa Hosseinzadeh   § ,  Arnab Mukherjee   ∥ ,  Mark J. Nilges   ⊥ ,  Jiangyun Wang   * ‡ ¶ , and  Yi Lu   * † ∥ § ‡  Laboratory of Non-Coding RNA, Institute of Biophysics,  Chinese Academy of Sciences , Chaoyang District, Beijing, 100101,  P. R. China ¶  University of Chinese Academy of Sciences, Beijing 100049,  P. R. China † Center of Biophysics and Computational Biology,  ∥ Department of Chemistry,  § Department of Biochemistry, ⊥ Illinois EPR Research Center,  University of Illinois at Urbana−Champaign , Urbana, Illinois 61801,  United States J. Am. Chem. Soc. ,  2015 ,  137  (14), pp 4594–4597 DOI:  10.1021/ja5109936 Publication Date (Web): February 11, 2015 Abstract While a conserved tyrosine (Tyr) is found in oxidases, the roles of phenol ring p K a  and reduction potential in O 2  reduction have not been defined despite many years of research on numerous oxida

Manganese-Catalyzed Late-Stage Aliphatic C–H Azidation

Xiongyi Huang , Tova M. Bergsten , and John T. Groves * Department of Chemistry, Princeton University , Princeton, New Jersey 08544 United States J. Am. Chem. Soc. , Article ASAP DOI: 10.1021/jacs.5b01983 Publication Date (Web): April 14, 2015 Copyright © 2015 American Chemical Society Abstract We report a manganese-catalyzed aliphatic C–H azidation reaction that can efficiently convert secondary, tertiary, and benzylic C–H bonds to the corresponding azides. The method utilizes aqueous sodium azide solution as the azide source and can be performed under air. Besides its operational simplicity, the potential of this method for late-stage functionalization has been demonstrated by successful azidation of various bioactive molecules with yields up to 74%, including the important drugs pregabalin, memantine, and the antimalarial artemisinin. Azidation of celestolide with a chiral manganese salen catalyst afforded the azide product in 70% ee, represent

Heme-thiolate ferryl of aromatic peroxygenase is basic and reactive

P450の、APO-II (Fe(IV)-OH:たぶんCompound IIと呼んでも差し支えない)の活性に関する論文です。Fe(IV)–OHのpKaは10だそうです。ヒドロキソにも関わらず、この錯体はC–HやO–HからのH•引き抜きを行います。 Compound Iとの活性比較も行っており、Compound Iのほうが活性は高いのですが、Compound Iによるアルカンの酸化より、Compound IIによるアルカンの酸化の速度の方が、より大きな BDE依存性が出ているところが興味深いです。なんでなんでしょう? Xiaoshi Wang a ,  René Ullrich b ,  Martin Hofrichter b , and  John T. Groves a , 1 Author Affiliations Contributed by John T. Groves, February 19, 2015 (sent for review January 6, 2015; reviewed by John H. Dawson Abstract Full Text Authors & Info Figures SI Metrics Related Content PDF PDF + SI Significance The heme-thiolate peroxygenase of  Agrocybe aegerita  is a remarkably capable biocatalyst and a mechanistic analog of cytochrome P450. The stability of this fungal protein has provided a rare opportunity to study P450-like C−H hydroxylation in a novel and unrelated enzyme. Both APO-I and APO-II have been generated, and their redox potentials have been determined. The ferryl species Cy