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1.
Deepika G. Karmalkar Muniyandi Sankaralingam Mi Sook Seo Roman Ezhov Yong‐Min Lee Yulia N. Pushkar Won‐Suk Kim Shunichi Fukuzumi Wonwoo Nam 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16270-16275
A mononuclear nonheme manganese(IV)–oxo complex binding the Ce4+ ion, [(dpaq)MnIV(O)]+–Ce4+ ( 1 ‐Ce4+), was synthesized by reacting [(dpaq)MnIII(OH)]+ ( 2 ) with cerium ammonium nitrate (CAN). 1 ‐Ce4+ was characterized using various spectroscopic techniques, such as UV/Vis, EPR, CSI‐MS, resonance Raman, XANES, and EXAFS, showing an Mn?O bond distance of 1.69 Å with a resonance Raman band at 675 cm?1. Electron‐transfer and oxygen atom transfer reactivities of 1 ‐Ce4+ were found to be greater than those of MnIV(O) intermediates binding redox‐inactive metal ions ( 1 ‐Mn+). This study reports the first example of a redox‐active Ce4+ ion‐bound MnIV‐oxo complex and its spectroscopic characterization and chemical properties. 相似文献
2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(31):9219-9223
Ceric ammonium nitrate (CAN) or CeIV(NH4)2(NO3)6 is often used in artificial water oxidation and generally considered to be an outer‐sphere oxidant. Herein we report the spectroscopic and crystallographic characterization of [(N4Py)FeIII‐O‐CeIV(OH2)(NO3)4]+ ( 3 ), a complex obtained from the reaction of [(N4Py)FeII(NCMe)]2+ with 2 equiv CAN or [(N4Py)FeIV=O]2+ ( 2 ) with CeIII(NO3)3 in MeCN. Surprisingly, the formation of 3 is reversible, the position of the equilibrium being dependent on the MeCN/water ratio of the solvent. These results suggest that the FeIV and CeIV centers have comparable reduction potentials. Moreover, the equilibrium entails a change in iron spin state, from S =1 FeIV in 2 to S =5/2 in 3 , which is found to be facile despite the formal spin‐forbidden nature of this process. This observation suggests that FeIV=O complexes may avail of reaction pathways involving multiple spin states having little or no barrier. 相似文献
3.
Spectroscopic Capture and Reactivity of a Low‐Spin Cobalt(IV)‐Oxo Complex Stabilized by Binding Redox‐Inactive Metal Ions
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Seungwoo Hong Florian F. Pfaff Eunji Kwon Yong Wang Mi‐Sook Seo Eckhard Bill Dr. Kallol Ray Prof. Dr. Wonwoo Nam 《Angewandte Chemie (International ed. in English)》2014,53(39):10403-10407
High‐valent cobalt‐oxo intermediates are proposed as reactive intermediates in a number of cobalt‐complex‐mediated oxidation reactions. Herein we report the spectroscopic capture of low‐spin (S=1/2) CoIV‐oxo species in the presence of redox‐inactive metal ions, such as Sc3+, Ce3+, Y3+, and Zn2+, and the investigation of their reactivity in C? H bond activation and sulfoxidation reactions. Theoretical calculations predict that the binding of Lewis acidic metal ions to the cobalt‐oxo core increases the electrophilicity of the oxygen atom, resulting in the redox tautomerism of a highly unstable [(TAML)CoIII(O.)]2? species to a more stable [(TAML)CoIV(O)(Mn+)] core. The present report supports the proposed role of the redox‐inactive metal ions in facilitating the formation of high‐valent metal–oxo cores as a necessary step for oxygen evolution in chemistry and biology. 相似文献
4.
Christophe Loup Dr. Ana Tesouro Vallina Dr. Yannick Coppel Dr. Ulla Létinois Prof. Dr. Yasuo Nakabayashi Dr. Bernard Meunier Prof. Dr. Bernhard Lippert Dr. Geneviève Pratviel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(37):11420-11431
Two PtIV and two PtII complexes containing a 2,2′‐bipyridine ligand were treated with a short DNA oligonucleotide under light irradiation at 37 °C or in the dark at 37 and 50 °C. Photolysis and thermolysis of the PtIV complexes led to spontaneous reduction of the PtIV to the corresponding PtII complexes and to binding of PtII 2,2′‐bipyridine complexes to N7 of guanine. When the reduction product was [Pt(bpy)Cl2], formation of bis‐oligonucleotide adducts was observed, whereas [Pt(bpy)(MeNH2)Cl]+ gave monoadducts, with chloride ligands substituted in both cases. Neither in the dark nor under light irradiation was the reductive elimination process of these PtIV complexes accompanied by oxidative DNA damage. This work raises the question of the stability of photoactivatable PtIV complexes toward moderate heating conditions. 相似文献
5.
Cerium(IV) Hexanuclear Clusters from Cerium(III) Precursors: Molecular Models for Oxidative Growth of Ceria Nanoparticles
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Dr. Laurent Mathey Mitali Paul Prof. Dr. Christophe Copéret Prof. Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13454-13461
Reactions of cerium(III) nitrate, Ce(NO3)3?6 H2O, with different carboxylic acids, such as pivalic acid, benzoic acid, and 4‐methoxybenzoic acid, in the presence of a tridentate N,N,N‐donor ligand, diethylenetriamine (L1), under aerobic conditions yielded the corresponding cerium hexamers Ce6O8(O2CtBu)8(L1)4 ( 1 ), Ce6O8(O2CC6H5)8(L1)4 ( 2 ), and Ce6O8(O2CC6H4‐4‐OCH3)8(L1)4 ( 3 ). Hexamers 1 , 2 , and 3 contain the same octahedral CeIV6O8 core, in which all interstitial oxygen atoms are connected by μ3‐oxo bridging ligands. In contrast, treatment of the CeIV precursor (NH4)2Ce(NO3)6 (CAN) with pivalic acid and the ligand L1 under the same conditions afforded Ce6O4(OH)4(O2CtBu)12(L1)2 ( 4 ), exhibiting a deformed octahedral CeIV6O4(OH)4 core containing μ3‐oxo and μ3‐hydroxo moieties in defined positions. In contrast to the formation of 1 – 3 , the use of N‐methyldiethanolamine (L) in the reaction with Ce(NO3)3?6 H2O and pivalic acid afforded a previously reported CeIII dinuclear cluster, Ce2(O2CtBu)6L2, even in the presence of dioxygen. ESI‐MS analysis of the reaction mixture clearly indicated the importance of the ligand L1 in promoting oxidation of the CeIII aggregates, [Cen(O2CtBu)3n(L1)2], which is necessary for the formation of CeIV hexamers. 相似文献
6.
Valeriu Mereacre Ayuk M. Ako Muhammad Nadeem Akhtar Anja Lindemann Christopher E. Anson Annie K. Powell 《Helvetica chimica acta》2009,92(11):2507-2524
Reactions of CeIII(NO3)3?6 H2O or (NH4)2[CeIV(NO3)6] with Mn‐containing starting materials result in seven novel polynuclear Ce or Ce/Mn complexes with pivalato (tBuCO ) and, in most cases, auxiliary N,O‐ or N,O,O‐donor ligands. With nuclearities ranging from 6–14, the compounds present aesthetically pleasing structures. Complexes [CeIV6(μ3‐O)4(μ3‐OH)4(μ‐O2CtBu)12] ( 1 ), [CeIV6MnIII4(μ4‐O)4(μ3‐O)4(O2CtBu)12(ea)4(OAc)4]?4 H2O?4 MeCN (ea?=2‐aminoethanolato; 2 ), [CeIV6MnIII8(μ4‐O)4(μ3‐O)8(pye)4(O2CtBu)18]2[CeIV6(μ3‐O)4(μ3‐OH)4(O2CtBu)10(NO3)4] [CeIII(NO3)5(H2O)]?21 MeCN (pye?=pyridine‐2‐ethanolato; 3 ), and [CeIV6CeIII2MnIII2(μ4‐O)4(μ3‐O)4(tbdea)2(O2CtBu)12(NO3)2(OAc)2]?4 CH2Cl2 (tbdea2?=2,2′‐(tert‐butylimino]bis[ethanolato]; 4 ) all contain structures based on an octahedral {CeIV6(μ3‐O)8} core, in which many of the O‐atoms are either protonated to give (μ3‐OH)? hydroxo ligands or coordinate to further metal centers (MnIII or CeIII) to give interstitial (μ4‐O)2? oxo bridges. The decanuclear complex [CeIV8CeIIIMnIII(μ4‐O)3(μ3‐O)3(μ3‐OH)2(μ‐OH)(bdea)4(O2CtBu)9.5(NO3)3.5(OAc)2]?1.5 MeCN (bdea2?=2,2′‐(butylimino]bis[ethanolato]; 5 ) contains a rather compact CeIV7 core with the CeIII and MnIII centers well‐separated from each other on the periphery. The aggregate in [CeIV4MnIV2(μ3‐O)4(bdea)2(O2CtBu)10(NO3)2]?4 MeCN ( 6 ) is based on a quasi‐planar {MnIV2CeIV4(μ3‐O)4} core made up of four edge‐sharing {MnIVCeIV2(μ3‐O)} or {CeIV3(μ3‐O)} triangles. The structure of [CeIV3MnIV4MnIII(μ4‐O)2(μ3‐O)7(O2CtBu)12(NO3)(furan)]?6 H2O ( 7 ?6 H2O) can be considered as {MnIV2CeIV2O4} and distorted {MnIV2MnIIICeIVO4} cubane units linked through a central (μ4‐O) bridge. The Ce6Mn8 equals the highest nuclearity yet reported for a heterometallic Ce/Mn aggregate. In contrast to most of the previously reported heterometallic Ce/Mn systems, which contain only CeIV and either MnIV or MnIII, some of the aggregates presented here show mixed valency, either MnIV/MnIII (see 7 ) or CeIV/CeIII (see 4 and 5 ). Interestingly, some of the compounds, including the heterovalent CeIV/CeIII 4 , could be obtained from either CeIII(NO3)3?6 H2O or (NH4)2[CeIV(NO3)6] as starting material. 相似文献
7.
Catalytic Water Oxidation by Ruthenium(II) Quaterpyridine (qpy) Complexes: Evidence for Ruthenium(III) qpy‐N,N′′′‐dioxide as the Real Catalysts
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Yingying Liu Dr. Siu‐Mui Ng Dr. Shek‐Man Yiu Dr. William W. Y. Lam Xi‐Guang Wei Dr. Kai‐Chung Lau Prof. Tai‐Chu Lau 《Angewandte Chemie (International ed. in English)》2014,53(52):14468-14471
Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation‐resistant and can stabilize high‐oxidation‐state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2]2+ (qpy=2,2′:6′,2′′:6′′,2′′′‐quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze CeIV‐driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy‐N,N′′′‐dioxide (ONNO) complexes [Ru(ONNO)(L)2]3+ which are the real catalysts for water oxidation. 相似文献
8.
Prof. Jesper Bendix Dr. Kensha Marie Clark 《Angewandte Chemie (International ed. in English)》2016,55(8):2748-2752
To survey the noninnocence of bis(arylimino) acenaphthene (BIAN) ligands (L) in complexes with early metals, the homoleptic vanadium complex, [V(L)3] ( 1 ), and its monocation, [V(L)3]PF6 ( 2 ), were synthesized. These complexes were found to have a very rich electronic behavior, whereby 1 displays strong electronic delocalization and 2 can be observed in unprecedented valence tautomeric forms. The oxidation states of the metal and ligand components in these complexes were assigned by using spectroscopic, crystallographic, and magnetic analyses. Complex 1 was identified as [VIV(Lred)(L.)2] (Lred=N,N′‐bis(3,5‐dimethylphenylamido)acenaphthylene; L.=N,N′‐bis(3,5‐dimethylphenylimino)acenaphthenesemiquinonate). Complex 2 was determined to be [VV(Lred)(L.)2]+ at T<150 K and [VIV(L.)3]+ at T>150 K. Cyclic voltammetry experiments reveal six quasi‐reversible processes, thus indicating the potential of this metal–ligand combination in catalysis or materials applications. 相似文献
9.
Suresh M. Tuwar Vidyavati A. Morab Sharanappa T. Nandibewoor Javali R. Raju 《Transition Metal Chemistry》1991,16(4):430-434
Summary Catalysis of the CeIV-allyl alcohol (AA) reaction in acid solution depends both on the of rate enhancement and product distribution on the catalyst used: OsVIII results mainly in acrolein, whereas PdII gives acrylic acid. The rate laws in the two cases also differ:viz., Equations 1 and 2K1 is the equilibrium constant of formation of the OsVIII-allyl alcohol complex and k1 is the rate constant of its oxidation by CeIV; K2 is the equilibrium constant for the formation of the CeIV-PdII-allyl alcohol complex and k2 is its rate constant of decomposition. Rate = K1k1[CeIV][AA][OsVIII]/(1+K1[AA]) (1) Rate = K1k1[CeIV][PdII]/(1+K2[CeIV]) (2)While OsVIII is effective in H2SO4 solution, aqueous HClO4 is needed for PdII. Both reactions proceed through formation of catalyst-allyl alcohol complexes with participation of free radicals. The details of these observations are discussed. 相似文献
10.
Laila H. Abdel‐Rahman Rafat M. El‐Khatib Shimaa M. Abdel‐Fatah H. Moustafa Ali M. Alsalme Ayman Nafady 《应用有机金属化学》2019,33(11)
In this study, three novel complexes comprising trivalent Cr (III), Fe (III) and Ru (III) with imine ligand derived from 2‐amino‐3‐hydroxypyridine and o‐vanillin (H2L) have been synthesized and characterized via wide range of spectroscopic and analytical tools such as 1H NMR and 13C NMR, infrared (IR) and UV–Vis spectrophotometry, conductivity and magnetic measurements. The obtained results along with DFT data confirmed a 1:1 (metal: ligand) stoichiometry with non‐planner geometries for the three complexes. The binding action and the docking study of the prepared metal‐complexes to calf thymus DNA was also studied by absorption spectra and viscosity technique, which revealed that the three complexes interact strongly with DNA through intercalative binding mode. Significantly, these metal‐imine complexes showed strong and efficient anti‐inflammatory and antimicrobial activities against various gram‐positive (Microccus luteus), gram‐negative (Escherichia coli and Serratia marcescence) bacteria, and three strains of fungus. Moreover, all complexes exhibited more potent cytotoxicity effect on the outgrowth of different types of carcinoma cells, including human colon (HCT‐116 cell line), breast (MCF‐7 cell line), and hepatic cellular (HepG‐2), than the clinically‐proven Vinblastine standard. 相似文献
11.
Exploring Excited‐State Tunability in Luminescent Tris‐cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations
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Fabio Juliá Dr. Gabriel Aullón Dr. Delia Bautista Dr. Pablo González‐Herrero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17346-17359
The synthesis, structure, electrochemistry, and photophysical properties of a series of heteroleptic tris‐ cyclometalated PtIV complexes are reported. The complexes mer‐[Pt(C^N)2(C′^N′)]OTf, with C^N=C‐deprotonated 2‐(2,4‐difluorophenyl)pyridine (dfppy) or 2‐phenylpyridine (ppy), and C′^N′=C‐deprotonated 2‐(2‐thienyl)pyridine (thpy) or 1‐phenylisoquinoline (piq), were obtained by reacting bis‐ cyclometalated precursors [Pt(C^N)2Cl2] with AgOTf (2 equiv) and an excess of the N′^C′H pro‐ligand. The complex mer‐[Pt(dfppy)2(ppy)]OTf was obtained analogously and photoisomerized to its fac counterpart. The new complexes display long‐lived luminescence at room temperature in the blue to orange color range. The emitting states involve electronic transitions almost exclusively localized on the ligand with the lowest π–π* energy gap and have very little metal character. DFT and time‐dependent DFT (TD‐DFT) calculations on mer‐[Pt(ppy)2(C′^N′)]+ (C′^N′=thpy, piq) and mer/fac‐[Pt(ppy)3]+ support this assignment and provide a basis for the understanding of the luminescence of tris‐cyclometalated PtIV complexes. Excited states of LMCT character may become thermally accessible from the emitting state in the mer isomers containing dfppy or ppy as chromophoric ligands, leading to strong nonradiative deactivation. This effect does not operate in the fac isomers or the mer complexes containing thpy or piq, for which nonradiative deactivation originates mainly from vibrational coupling to the ground state. 相似文献
12.
A publication by Alexander P. Smirnoff in Helvetica Chimica Acta in 1920 [6] describes the first synthesis of a coordination species, i.e., of tris(propane‐1,2‐diamine‐κN1,κN2)platinum(4+) ([PtIV(pn)3]4+), where it was shown that the configuration of a chiral center in the ligand can influence the configuration at the metal. The present investigation of [PtIV(pn)3]4+ was carried out by NMR spectroscopy, where all nuclei in the metal complex were used as sources of information, i.e., 1H, 13C, 15N, and 195Pt. 13C‐NMR and 15N‐NMR spectroscopy (of isotopically enriched complex) were especially informative for the analysis of isomer distribution. Stereoselectivity in the formation reaction of the complexes is rather modest, whereas Δ‐, and Λ‐isomers can be separated efficiently by crystallization. A mixture of [Pt{(S)‐pn}3]4+ and [Pt{(R)‐pn}3]4+ shows no scrambling of the enantiomeric ligands, thus proving the inertness of the complexes. 相似文献
13.
3‐3′‐Benzylidenebis[4‐hydroxycoumarin] or 4‐nitro,3‐3′‐benzylidenebis[4‐hydroxycoumarin] or 4‐methoxy,3‐3′‐benzylidenebis[4‐hydroxycoumarin] and their complexes with Cu(II), Fe(II) and Fe(III) were synthesized and characterized using 1H‐NMR, 13C‐NMR, IR spectra, electronic spectra, magnetic measurements and elemental analyses. The ligands, metal salts, complexes, control and standard drug were tested for their in‐vitro antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Salmonella typhi, and Serratia marcescens. The metal complexes exhibit good activity against bacterial strains compared with parental compounds and moderate compared with the standard drug (ciprofloxacin). In‐vitro DNA‐binding activity was carried out using agarose gel electrophoresis. The synthesized compounds show effective DNA‐binding activity. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
14.
Polly L. Arnold Ian J. Casely Sergey Zlatogorsky Claire Wilson 《Helvetica chimica acta》2009,92(11):2291-2303
The use of tetravalent cerium alkoxides, nitrates, and triflates was studied as a direct route to [CeIV(carbene)] complexes. Protonolysis reactions between 1H‐imidazolium‐ or imidazoline (=4,5‐dihydro‐1H‐imidazole)‐containing alkoxide proligands HL (L=OCMe2CH2[1‐C(NCHCHNiPr)]) and HLS (LS=OCMe2CH2[1‐C(NCH2CH2NiPr)]) and CeIV tert‐butoxide, triflate, and nitrate compounds were studied to target [CeIV(N‐heterocyclic carbene)] complexes (of unsaturated and saturated carbenes, resp.). Instead, tetravalent cerium imidazolium [(OtBu)3Ce(μ‐OtBu)2(μ‐HL)Ce(OtBu)3], or imidazolinium adducts [(OtBu)3Ce(μ‐OtBu)2(μ‐HLS)Ce(OtBu)3] were isolated. However, the salt metathesis of cerium triflate with KL provided a simple route to [CeL4], which was significantly improved if an external oxidant, benzoquinone, was included in the mixture to maintain oxidation‐state integrity. Likewise, the salt metathesis of cerium triiodide with KL and added benzoquinone provided a straightforward route to [CeL4]. 相似文献
15.
Yong Zhao Yong Cun Yang Hao Shi Hong You Zhu Rong Huang Chao Ming Chi Yan Zhao 《Helvetica chimica acta》2010,93(6):1136-1148
Three novel bis(β‐cyclodextrin (CD))s with flexible glycol linkers, i.e., ethylene glycol‐bridged bis(6‐hydroxy‐6‐deoxy‐β‐CD) ( 2 ), diethylene glycol‐bridged bis(6‐hydroxy‐6‐deoxy‐β‐CD) ( 3 ), and triethylene glycol‐bridged bis(6‐hydroxy‐6‐deoxy‐β‐CD) ( 4 ) have been synthesized by the reaction of mono[6‐O‐(p‐toluenesulfonyl)]‐β‐CD with corresponding materials. The inclusion complexation behaviors of these compounds 2 – 4 with organic dyes; that is, acridine red (=N‐[(3Z)‐6‐(methylamino)‐3H‐xanthen‐3‐ylidene]methanaminium chloride; AR), neutral red (=N8,N8,3‐trimethylphenazine‐2,8‐diamine hydrochloride; NR), ammonium 8‐anilinonaphthalene‐1‐sulfonate (ANS), sodium 6‐(p‐toluidinyl)‐naphthalene‐2‐sulfonate (TNS), rhodamine B (RhB) and brilliant green (=N‐(4‐{[4‐(diethylamino)cyclohexa‐2,5‐dien‐1‐yl](phenyl)methyl}cyclohex‐2‐en‐1‐ylidene)‐N‐ethyl‐ethanaminium hydrogen sulfate; BG), have been investigated at 25° in phosphate buffer (pH 7.20) by ultraviolet, fluorescence, and 2D‐NMR spectroscopy. The results indicate that the two linked CD units may cooperatively bind a guest, and the molecular binding ability toward dye guests, especially bent ANS, T‐shaped RhB, and triangular BG, can be extended. This cooperative binding mode is confirmed by Job's experiments and 2D‐NMR investigations. Furthermore, the complex stability depends greatly on the linker length of these glycol‐bridged bis(β‐CD)s and the size and shape of guest. The higher binding ability and selectivity of dye molecules by bis(β‐CD)s 2 – 4 are discussed from the viewpoint of size/shape‐fit concept and multiple recognition mechanism. 相似文献
16.
Uwe Bayer Daniel Werner Ccilia Maichle‐Mssmer Reiner Anwander 《Angewandte Chemie (International ed. in English)》2020,59(14):5830-5836
The homoleptic pyrazolate complexes [CeIII4(Me2pz)12] and [CeIV(Me2pz)4]2 quantitatively insert CO2 to give [CeIII4(Me2pz?CO2)12] and [CeIV(Me2pz?CO2)4], respectively (Me2pz=3,5‐dimethylpyrazolato). This process is reversible for both complexes, as observed by in situ IR and NMR spectroscopy in solution and by TGA in the solid state. By adjusting the molar ratio, one molecule of CO2 per [CeIV(Me2pz)4] complex could be inserted to give trimetallic [Ce3(Me2pz)9(Me2pz?CO2)3(thf)]. Both the cerous and ceric insertion products catalyze the formation of cyclic carbonates from epoxides and CO2 under mild conditions. In the absence of epoxide, the ceric catalyst is prone to reduction by the co‐catalyst tetra‐n‐butylammonium bromide (TBAB). 相似文献
17.
Synthesis and Catalytic Water Oxidation Activities of Ruthenium Complexes Containing Neutral Ligands
Dr. Yunhua Xu Lele Duan Dr. Torbjörn Åkermark Lianpeng Tong Bao‐Lin Lee Dr. Rong Zhang Prof. Björn Åkermark Prof. Licheng Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(34):9520-9528
Two dinuclear and one mononuclear ruthenium complexes containing neutral polypyridyl ligands have been synthesised as pre‐water oxidation catalysts and characterised by 1H and 13C NMR spectroscopy and ESI‐MS. Their catalytic water oxidation properties in the presence of [Ce(NH4)2(NO3)6] (CeIV) as oxidant at pH 1.0 have been investigated. At low concentrations of CeIV (5 mM ), high turnover numbers of up to 4500 have been achieved. An 18O‐labelling experiment established that both O atoms in the evolved O2 originate from water. Combined electrochemical study and electrospray ionisation mass spectrometric analysis suggest that ligand exchange between coordinated 4‐picoline and free water produces Ru aquo species as the real water oxidation catalysts. 相似文献
18.
By means of spectrophotometric methods the interaction of CeIV in sulphate and nitrate containing solutions with diethylenetriaminepentaacetic acid (DTPE, H5L), ethylenetriaminetetraacetic acid (ÄDTE, H4A), nitrilotriacetic acid (NTE, H3X), iminodiacetic acid (IMDE, H2Z), acids, and glycine (HGL) has been investigated. In weakly acidic acid redox-stable CeIV complexomates are formed with DTPE, ÄDTE and NTE; CeIV reduction proceeds the more slowly, the more stable the complexonate is. The reverse holds for strongly acidic solutions. Inorganic anions in the solutions display a strong influence on composition and redoxactivity of the CeIV complexonates. The stability of CeIV in its complexonates depends on the type of metal-ligand bonding. 相似文献
19.
Jing‐Yuan Xu He‐Dong Bian Qing‐Lun Wang Wen Gu Shi‐Ping Yan Dai‐Zheng Liao Peng Cheng Zong‐Hui Jiang Pan‐Wen Shen 《无机化学与普通化学杂志》2003,629(6):1063-1067
Two new transition metal(II) complexes [M(hdpa)2(N(CN)2)2] (M = Mn ( 1 ), Co ( 2 ); hdpa = 2, 2'‐dipyridylamine) have been prepared and characterized structurally and magnetically. Both compounds crystallize in the monoclinic space group C2/c. 1 and 2 are isotypic with the unit cell parameters a = 8.634(9), b = 13.541(14), c = 21.99(2) Å, β = 94.806(18)°, and V = 2562(5) Å3 for 1 , a = 8.617(3) Å, b = 13.629(5)Å, c = 21.598(8)Å, β = 94.593(6)°, and V = 2528.4(15)Å3 for 2 , and Z = 4 for both. According to X‐ray crystallographic studies, each metal(II) ion was six‐coordinated with four nitrogen atoms from two bidentate hdpa ligand and two nitrogen atoms from two N(CN)— anions to form slightly distorted octahedrons. Adjacent complex molecules are connected by hydrogen bonds or π···π interactions to form three‐dimensional network. The IR and UV spectroscopy were measured and the magnetic behaviors were investigated. 相似文献
20.
The synthesis of [Ce(Salen′)2] ( 1 ) (H2Salen′ = N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)ethylenediamine) was performed using two different approaches. CeCl3 reacts with two equivalents of K2Salen′ in THF under the formation of [(THF)2KCe(Salen′)2] ( 2 ). Complex 2 could be converted to the CeIV complex 1 via oxidation with p‐benzoquinone and air, respectively. The reversible reduction process was realized using elemental potassium in boiling THF. Furthermore, the reaction of the CeIV starting material [(tBuO)4Ce(THF)2] with the “free” ligand H2Salen′ in boiling toluene lead in the formation of 1 as well. 相似文献