共查询到20条相似文献,搜索用时 472 毫秒
1.
M. Sc. Christoph Schiwek Dr. Jenni Meiners M. Sc. Moritz Förster Dr. Christian Würtele Dr. Martin Diefenbach Prof. Dr. Max C. Holthausen Prof. Dr. Sven Schneider 《Angewandte Chemie (International ed. in English)》2015,54(50):15271-15275
The iridium dihydride [Ir(H)2(HPNP)]+ (PNP=N(CH2CH2PtBu2)2) reacts with O2 to give the unusual, square‐planar iridium(III) hydroxide [Ir(OH)(PNP)]+ and water. Regeneration of the dihydride with H2 closes a quasi‐catalytic synthetic oxygen‐reduction reaction (ORR) cycle that can be run several times. Experimental and computational examinations are in agreement with an oxygenation mechanism via rate‐limiting O2 coordination followed by H‐transfer at a single metal site, facilitated by the cooperating pincer ligand. Hence, the four electrons required for the ORR are stored within the two covalent M? H bonds of a mononuclear metal complex. 相似文献
2.
Dr. Masahiro Kamitani Balazs Pinter Dr. Chun‐Hsing Chen Dr. Maren Pink Prof. Dr. Daniel J. Mindiola 《Angewandte Chemie (International ed. in English)》2014,53(41):10913-10915
The dimethyl aryloxide complexes [(PNP)M(CH3)2(OAr)] (M=Zr or Hf; PNP?=N[2‐P(CHMe2)2‐4‐methylphenyl]2); Ar=2,6‐iPr2C6H3), which were readily prepared from [(PNP)M(CH3)3] by alcoholysis with HOAr, undergo photolytically induced α‐hydrogen abstraction to cleanly produce complexes [(PNP)M=CH2(OAr)] with terminal methylidene ligands. These unique systems have been fully characterized, including the determination of a solid‐state structure in the case of M=Zr. 相似文献
3.
Pak-Ho Chan Sheng-Pei Chen Kin-Wai Yeung Kwong-Chak Cheung Shuangjin Hong Shi-Gang Sun Kwok-Yin Wong 《Electrochemistry communications》2005,7(12):1244-1248
The osmium nitride complex [OsVI(NH3)4N]3+ undergoes a one-electron reduction in acetonitrile to give [OsV(N)(NH3)4]2+, which further reacts by nitride coupling to give the μ-dinitrogen osmium complex [(CH3CN)(NH3)4OsII(N2)OsII(NH3)4(CH3CN)]4+. The formation of the μ-dinitrogen osmium complex is promoted by the presence of perchlorate anion, which causes the deposition of [(CH3CN)(NH3)4OsII(N2)OsII(NH3)4(CH3CN)](ClO4)4 on the electrode surface upon repetitive voltammetric scans. 相似文献
4.
Marta Falcone Lok Nga Poon Dr. Farzaneh Fadaei Tirani Prof. Marinella Mazzanti 《Angewandte Chemie (International ed. in English)》2018,57(14):3697-3700
Cleavage of dihydrogen is an important step in the industrial and enzymatic transformation of N2 into ammonia. The reversible cleavage of dihydrogen was achieved under mild conditions (room temperature and 1 atmosphere of H2) by the molecular uranium nitride complex, [Cs{U(OSi(OtBu)3)3}2(μ‐N)] 1, leading to a rare hydride–imide bridged diuranium(IV) complex, [Cs{U(OSi(OtBu)3)3}2(μ‐H)(μ‐NH)], 2 that slowly releases H2 under vacuum. This complex is highly reactive and quickly transfers hydride to acetonitrile and carbon dioxide at room temperature, affording the ketimide‐ and formate‐bridged UIV species [Cs{U(OSi(OtBu)3)3}2(μ‐NH)(μ‐CH3CHN)], 3 and [Cs{U(OSi(OtBu)3)3}2(μ‐HCOO)(μ‐NHCOO)], 4 . 相似文献
5.
Intramolecularly Coordinated Gallium Sulfides: Suitable Single Source Precursors for GaS Thin Films 下载免费PDF全文
Tomáš Řičica Tomáš Světlík Dr. Libor Dostál Prof. Aleš Růžička Dr. Květoslav Růžička Dr. Ludvík Beneš Prof. Petr Němec Dr. Marek Bouška Dr. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18817-18823
Our studies have been focused on the synthesis of N→Ga coordinated organogallium sulfides [L1Ga(μ‐S)]3 ( 1 ) and [L2Ga(μ‐S)]2 ( 2 ) containing either N,C,N‐ or C,N‐chelating ligands L1 or L2 (L1 is {2,6‐(Me2NCH2)2C6H3}? and L2 is {2‐(Et2NCH2)‐4,6‐tBu2‐C6H2}?). As the result of the different ligands, compounds 1 and 2 differ mutually in their structure. To change the Ga/S ratio, unusually N→Ga coordinated organogallium tetrasulfide L1Ga(κ2‐S4) ( 3 ) was prepared and the unprecedented complex [{2‐[CH{(CH2)3CH3}(μ‐OH)]‐6‐CH2NMe2}C6H3]GaS ( 4 ) was also isolated as the minor by‐product of the reaction. Compounds 1 – 3 were further studied as potential single‐source precursors for amorphous GaS thin film deposition by spin‐coating. 相似文献
6.
Two‐Electron Reductive Carbonylation of Terminal Uranium(V) and Uranium(VI) Nitrides to Cyanate by Carbon Monoxide 下载免费PDF全文
Peter A. Cleaves Dr. David M. King Dr. Christos E. Kefalidis Prof. Laurent Maron Dr. Floriana Tuna Prof. Eric J. L. McInnes Dr. Jonathan McMaster Dr. William Lewis Prof. Alexander J. Blake Prof. Stephen T. Liddle 《Angewandte Chemie (International ed. in English)》2014,53(39):10412-10415
Two‐electron reductive carbonylation of the uranium(VI) nitride [U(TrenTIPS)(N)] ( 2 , TrenTIPS=N(CH2CH2NSiiPr3)3) with CO gave the uranium(IV) cyanate [U(TrenTIPS)(NCO)] ( 3 ). KC8 reduction of 3 resulted in cyanate dissociation to give [U(TrenTIPS)] ( 4 ) and KNCO, or cyanate retention in [U(TrenTIPS)(NCO)][K(B15C5)2] ( 5 , B15C5=benzo‐15‐crown‐5 ether) with B15C5. Complexes 5 and 4 and KNCO were also prepared from CO and the uranium(V) nitride [{U(TrenTIPS)(N)K}2] ( 6 ), with or without B15C5, respectively. Complex 5 can be prepared directly from CO and [U(TrenTIPS)(N)][K(B15C5)2] ( 7 ). Notably, 7 reacts with CO much faster than 2 . This unprecedented f‐block reactivity was modeled theoretically, revealing nucleophilic attack of the π* orbital of CO by the nitride with activation energy barriers of 24.7 and 11.3 kcal mol?1 for uranium(VI) and uranium(V), respectively. A remarkably simple two‐step, two‐electron cycle for the conversion of azide to nitride to cyanate using 4 , NaN3 and CO is presented. 相似文献
7.
Dr. Salvador B. Muñoz III Dr. Wei‐Tsung Lee Dr. Diane A. Dickie Dr. Jeremiah J. Scepaniak Deepak Subedi Dr. Maren Pink Prof. Michael D. Johnson Prof. Jeremy M. Smith 《Angewandte Chemie (International ed. in English)》2015,54(36):10600-10603
Thermolysis of the iron(IV) nitride complex [PhB(tBuIm)3Fe?N] with styrene leads to formation of the high‐spin iron(II) aziridino complex [PhB(tBuIm)3Fe‐N(CH2CHPh)]. Similar aziridination occurs with both electron‐rich and electron‐poor styrenes, while bulky styrenes hinder the reaction. The aziridino complex [PhB(tBuIm)3Fe‐N(CH2CHPh)] acts as a nitride synthon, reacting with electron‐poor styrenes to generate their corresponding aziridino complexes, that is, aziridine cross‐metathesis. Reaction of [PhB(tBuIm)3Fe‐N(CH2CHPh)] with Me3SiCl releases the N‐functionalized aziridine Me3SiN(CH2CHPh) while simultaneously generating [PhB(tBuIm)3FeCl]. This closes a synthetic cycle for styrene azirdination by a nitride complex. While the less hindered iron(IV) nitride complex [PhB(MesIm)3Fe?N] reacts with styrenes below room temperature, only bulky styrenes lead to tractable aziridino products. 相似文献
8.
Johan Vibenholt Magnus Magnussen Christian Anthon Jesper Bendix 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(7):m177-m179
Five‐coordinate Cr(N)(salen) {salen is 2,2′‐[ethane‐1,2‐diylbis(nitrilomethylidyne)]diphenolate} reacts with [RhCl(COD)]2 (COD is 1,5‐cyclooctadiene) to yield the heterobimetallic nitride‐bridged title compound, namely chlorido‐2κCl‐[2(η4)‐1,5‐cyclooctadiene]{2,2′‐[ethane‐1,2‐diylbis(nitrilomethylidyne)]diphenolato‐1κ4O,N,N′,O′}‐μ‐nitrido‐1:2κ2N:N‐chromium(V)rhodium(I), [CrRh(C16H14N2O2)ClN(C8H12)]. The Cr—N bond of 1.5936 (14) Å is elongated by only 0.035 Å compared to the terminal Cr—N bond in the precursor. The nitride bridge is close to being linear [173.03 (9)°] and the Rh—N bond of 1.9594 (14) Å is very short for a monodentate nitrogen‐donor ligand, indicating significant π‐acceptor character of the Cr[triple‐bond]N group. 相似文献
9.
Highly Active,Low‐Valence Molybdenum‐ and Tungsten‐Amide Catalysts for Bifunctional Imine‐Hydrogenation Reactions 下载免费PDF全文
Dr. Subrata Chakraborty Dr. Olivier Blacque Dr. Thomas Fox Prof. Heinz Berke 《化学:亚洲杂志》2014,9(1):328-337
The reactions of [M(NO)(CO)4(ClAlCl3)] (M=Mo, W) with (iPr2PCH2CH2)2NH, (PNHP) at 90 °C afforded [M(NO)(CO)(PNHP)Cl] complexes (M=Mo, 1a ; W, 1b ). The treatment of compound 1a with KOtBu as a base at room temperature yielded the alkoxide complex [Mo(NO)(CO)(PNHP)(OtBu)] ( 2a ). In contrast, with the amide base Na[N(SiMe3)2], the PNHP ligand moieties in compounds 1a and 1b could be deprotonated at room temperature, thereby inducing dehydrochlorination into amido complexes [M(NO)(CO)(PNP)] (M=Mo, 3a ; W, 3b ; PNP=(iPr2PCH2CH2)2N)). Compounds 3a and 3b have pseudo‐trigonal‐bipyramidal geometries, in which the amido nitrogen atom is in the equatorial plane. At room temperature, compounds 3a and 3b were capable of adding dihydrogen, with heterolytic splitting, thereby forming pairs of isomeric amine‐hydride complexes [Mo(NO)(CO)H(PNHP)] ( 4a(cis) and 4a(trans) ) and [W(NO)(CO)H(PNHP)] ( 4b(cis) and 4b(trans) ; cis and trans correspond to the position of the H and NO groups). H2 approaches the Mo/W?N bond in compounds 3a , 3b from either the CO‐ligand side or from the NO‐ligand side. Compounds 4a(cis) and 4a(trans) were only found to be stable under a H2 atmosphere and could not be isolated. At 140 °C and 60 bar H2, compounds 3a and 3b catalyzed the hydrogenation of imines, thereby showing maximum turnover frequencies (TOFs) of 2912 and 1120 h?1, respectively, for the hydrogenation of N‐(4 ‐ methoxybenzylidene)aniline. A Hammett plot for various para‐substituted imines revealed linear correlations with a negative slope of ?3.69 for para substitution on the benzylidene side and a positive slope of 0.68 for para substitution on the aniline side. Kinetics analysis revealed the initial rate of the hydrogenation reactions to be first order in c(cat.) and zeroth order in c(imine). Deuterium kinetic isotope effect (DKIE) experiments furnished a low kH/kD value (1.28), which supported a Noyori‐type metal–ligand bifunctional mechanism with H2 addition as the rate‐limiting step. 相似文献
10.
Reactivity of TpMe2‐Supported Yttrium Alkyl Complexes toward Aromatic N‐Heterocycles: Ring‐Opening or CC Bond Formation Directed by CH Activation 下载免费PDF全文
Dr. Weiyin Yi Prof. Dr. Jie Zhang Shujian Huang Prof. Dr. Linhong Weng Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):867-876
Unusual chemical transformations such as three‐component combination and ring‐opening of N‐heterocycles or formation of a carbon–carbon double bond through multiple C–H activation were observed in the reactions of TpMe2‐supported yttrium alkyl complexes with aromatic N‐heterocycles. The scorpionate‐anchored yttrium dialkyl complex [TpMe2Y(CH2Ph)2(THF)] reacted with 1‐methylimidazole in 1:2 molar ratio to give a rare hexanuclear 24‐membered rare‐earth metallomacrocyclic compound [TpMe2Y(μ‐N,C‐Im)(η2‐N,C‐Im)]6 ( 1 ; Im=1‐methylimidazolyl) through two kinds of C–H activations at the C2‐ and C5‐positions of the imidazole ring. However, [TpMe2Y(CH2Ph)2(THF)] reacted with two equivalents of 1‐methylbenzimidazole to afford a C–C coupling/ring‐opening/C–C coupling product [TpMe2Y{η3‐(N,N,N)‐N(CH3)C6H4NHCH?C(Ph)CN(CH3)C6H4NH}] ( 2 ). Further investigations indicated that [TpMe2Y(CH2Ph)2(THF)] reacted with benzothiazole in 1:1 or 1:2 molar ratio to produce a C–C coupling/ring‐opening product {(TpMe2)Y[μ‐η2:η1‐SC6H4N(CH?CHPh)](THF)}2 ( 3 ). Moreover, the mixed TpMe2/Cp yttrium monoalkyl complex [(TpMe2)CpYCH2Ph(THF)] reacted with two equivalents of 1‐methylimidazole in THF at room temperature to afford a trinuclear yttrium complex [TpMe2CpY(μ‐N,C‐Im)]3 ( 5 ), whereas when the above reaction was carried out at 55 °C for two days, two structurally characterized metal complexes [TpMe2Y(Im‐TpMe2)] ( 7 ; Im‐TpMe2=1‐methyl‐imidazolyl‐TpMe2) and [Cp3Y(HIm)] ( 8 ; HIm=1‐methylimidazole) were obtained in 26 and 17 % isolated yields, respectively, accompanied by some unidentified materials. The formation of 7 reveals an uncommon example of construction of a C?C bond through multiple C–H activations. 相似文献
11.
Josh Abbenseth Daniel Delony Marc C. Neben Christian Würtele Bas deBruin Sven Schneider 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6404-6407
The isolable complex [Os(PHMes*)H(PNP)] (Mes*=2,4,6‐tBu3C6H3; PNP=N{CHCHPtBu2}2) exhibits high phosphinyl radical character. This compound offers access to the phosphinidene complex [Os(PMes*)H(PNP)] by P?H proton coupled electron transfer (PCET). The P?H bond dissociation energy (BDE) was determined by isothermal titration calorimetry and supporting DFT computations. The phosphinidene product exhibits electrophilic reactivity as demonstrated by intramolecular C?H activation. 相似文献
12.
Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization 下载免费PDF全文
Dr. Bjorn Askevold Dr. Marat M. Khusniyarov Dr. Wolfgang Kroener Dr. Klaus Gieb Prof. Paul Müller Dr. Eberhardt Herdtweck Dr. Frank W. Heinemann Dr. Martin Diefenbach Prof. Max C. Holthausen Veacheslav Vieru Prof. Liviu F. Chibotaru Prof. Sven Schneider 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):579-589
Functionalization of the PNP pincer ligand backbone allows for a comparison of the dialkyl amido, vinyl alkyl amido, and divinyl amido ruthenium(II) pincer complex series [RuCl{N(CH2CH2PtBu2)2}], [RuCl{N(CHCHPtBu2)(CH2CH2PtBu2)}], and [RuCl{N(CHCHPtBu2)2}], in which the ruthenium(II) ions are in the extremely rare square‐planar coordination geometry. Whereas the dialkylamido complex adopts an electronic singlet (S=0) ground state and energetically low‐lying triplet (S=1) state, the vinyl alkyl amido and the divinyl amido complexes exhibit unusual triplet (S=1) ground states as confirmed by experimental and computational examination. However, essentially non‐magnetic ground states arise for the two intermediate‐spin complexes owing to unusually large zero‐field splitting (D>+200 cm?1). The change in ground state electronic configuration is attributed to tailored pincer ligand‐to‐metal π‐donation within the PNP ligand series. 相似文献
13.
Synthesis and Reactivity of Mononuclear Iron Models of [Fe]‐Hydrogenase that Contain an Acylmethylpyridinol Ligand 下载免费PDF全文
Dr. Bowen Hu Prof. Dr. Dafa Chen Prof. Dr. Xile Hu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1677-1682
[Fe]‐hydrogenase has a single iron‐containing active site that features an acylmethylpyridinol ligand. This unique ligand environment had yet to be reproduced in synthetic models; however the synthesis and reactivity of a new class of small molecule mimics of [Fe]‐hydrogenase in which a mono‐iron center is ligated by an acylmethylpyridinol ligand has now been achieved. Key to the preparation of these model compounds is the successful C?O cleavage of an alkyl ether moiety to form the desired pyridinol ligand. Reaction of solvated complex [(2‐CH2CO‐6‐HOC5H3N)Fe(CO)2(CH3CN)2]+(BF4)? with thiols or thiophenols in the presence of NEt3 yielded 5‐coordinate iron thiolate complexes. Further derivation produced complexes [(2‐CH2CO‐6‐HOC5H3N)Fe(CO)2(SCH2CH2OH)] and [(2‐CH2CO‐6‐HOC5H3N)Fe(CO)2(CH3COO)], which can be regarded as models of FeGP cofactors of [Fe]‐hydrogenase extracted by 2‐mercaptoethanol and acetic acid, respectively. When the derivative complexes were treated with HBF4?Et2O, the solvated complex was regenerated by protonation of the thiolate ligands. The reactivity of several models with CO, isocyanide, cyanide, and H2 was also investigated. 相似文献
14.
Synthesis of Mixed Silylene–Carbene Chelate Ligands from N‐Heterocyclic Silylcarbenes Mediated by Nickel 下载免费PDF全文
Gengwen Tan Dr. Stephan Enthaler Prof. Dr. Shigeyoshi Inoue Dr. Burgert Blom Prof. Dr. Matthias Driess 《Angewandte Chemie (International ed. in English)》2015,54(7):2214-2218
The NiII‐mediated tautomerization of the N‐heterocyclic hydrosilylcarbene L2Si(H)(CH2)NHC 1 , where L2=CH(C?CH2)(CMe)(NAr)2, Ar=2,6‐iPr2C6H3; NHC=3,4,5‐trimethylimidazol‐2‐yliden‐6‐yl, leads to the first N‐heterocyclic silylene (NHSi)–carbene (NHC) chelate ligand in the dibromo nickel(II) complex [L1Si:(CH2)(NHC)NiBr2] 2 (L1=CH(MeC?NAr)2). Reduction of 2 with KC8 in the presence of PMe3 as an auxiliary ligand afforded, depending on the reaction time, the N‐heterocyclic silyl–NHC bromo NiII complex [L2Si(CH2)NHCNiBr(PMe3)] 3 and the unique Ni0 complex [η2(Si‐H){L2Si(H)(CH2)NHC}Ni(PMe3)2] 4 featuring an agostic Si? H→Ni bonding interaction. When 1,2‐bis(dimethylphosphino)ethane (DMPE) was employed as an exogenous ligand, the first NHSi–NHC chelate‐ligand‐stabilized Ni0 complex [L1Si:(CH2)NHCNi(dmpe)] 5 could be isolated. Moreover, the dicarbonyl Ni0 complex 6 , [L1Si:(CH2)NHCNi(CO)2], is easily accessible by the reduction of 2 with K(BHEt3) under a CO atmosphere. The complexes were spectroscopically and structurally characterized. Furthermore, complex 2 can serve as an efficient precatalyst for Kumada–Corriu‐type cross‐coupling reactions. 相似文献
15.
The Cerium(IV) complexes [{N[CH2CH2N=CH(2‐O‐3,5‐tBu2C6H2)]3}CeCl] ( 1 ) and [{N[CH2CH2N=CH(2‐O‐3,5‐tBu2C6H2)]3}Ce(NO3)] ( 2 ) were derived from the condensation of tris(2‐aminoethyl)amine and 3,5‐di‐tert‐butylsalicylaldehyde and the appropriate Ce starting material CeCl3(H2O)6 and (NH4)2[Ce(NO3)6], respectively. Single crystal X‐ray diffraction studies reveal monomeric complexes. 相似文献
16.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(35):10631-10636
Reaction of [U(TrenTIPS)(PH2)] ( 1 , TrenTIPS=N(CH2CH2NSiPri3)3) with C6H5CH2K and [U(TrenTIPS)(THF)][BPh4] ( 2 ) afforded a rare diuranium parent phosphinidiide complex [{U(TrenTIPS)}2(μ‐PH)] ( 3 ). Treatment of 3 with C6H5CH2K and two equivalents of benzo‐15‐crown‐5 ether (B15C5) gave the diuranium μ‐phosphido complex [{U(TrenTIPS)}2(μ‐P)][K(B15C5)2] ( 4 ). Alternatively, reaction of [U(TrenTIPS)(PH)][Na(12C4)2] ( 5 , 12C4=12‐crown‐4 ether) with [U{N(CH2CH2NSiMe2But)2CH2CH2NSi(Me)(CH2)(But)}] ( 6 ) produced the diuranium μ‐phosphido complex [{U(TrenTIPS)}(μ‐P){U(TrenDMBS)}][Na(12C4)2] [ 7 , TrenDMBS=N(CH2CH2NSiMe2But)3]. Compounds 4 and 7 are unprecedented examples of uranium phosphido complexes outside of matrix isolation studies, and they rapidly decompose in solution underscoring the paucity of uranium phosphido complexes. Interestingly, 4 and 7 feature symmetric and asymmetric UPU cores, respectively, reflecting their differing steric profiles. 相似文献
17.
Prof. Dr. Axel Schulz Dr. Alexander Villinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3649-3663
Following our interest in binary element–nitrogen compounds we report here on the synthesis and comprehensive characterization (M.p., IR/Raman, elemental analysis, 14N/133Cd/199Hg NMR) of tri‐ and tetraazido cadmate and mercurate anions [E(N3)(2+n)]n? (E=Cd, Hg; n=1, 2) in a series of [Ph4P]+ and [PNP]+ ([PNP]+=bis(triphenylphosphine)iminium) salts. The azide/chloride exchange in CH2Cl2 as well as the formation of tetrazolate salts in CH3CN solutions of the polyazido mercurates were investigated. Single crystal X‐ray structures of all new compounds, and for comparison [Ph4P][Cd2(N3)5(H2O)], were determined. Moreover, the synthesis of anhydrous cadmium(II) azide and its DMSO adduct is presented for the first time. For a better understanding of structure and bonding in E(N3)2, [E(N3)3]? and [E(N3)4]2?, theoretical calculations at the M06‐2X/aug‐cc‐pVDZ level were carried out. 相似文献
18.
NH3 Synthesis in the N2/H2 Reaction System using Cooperative Molecular Tungsten/Rhodium Catalysis in Ionic Hydrogenation: A DFT Study 下载免费PDF全文
Dr. Verena Moha Prof. Dr. Walter Leitner Dr. Markus Hölscher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2624-2628
The ionic hydrogenation of N2 with H2 to give NH3 is investigated by means of density functional theory (DFT) computations using a cooperatively acting catalyst system. In this system, N2 binds to a neutral tungsten pincer complex of the type [(PNP)W(N2)3] (PNP=pincer ligand) and is reduced to NH3. The protons and hydride centers necessary for the reduction are delivered by heterolytic cleavage of H2 between the N2–tungsten complex and the cationic rhodium complex [Cp*Rh{2‐(2‐pyridyl)phenyl}(CH3CN)]+. Successive transfer of protons and hydrides to the bound N2, as well as all NxHy units that occur during the reaction, enable the computation of closed catalytic cycles in the gas and in the solvent phase. By optimizing the pincer ligands of the tungsten complex, energy spans as low as 39.3 kcal mol?1 could be obtained, which is unprecedented in molecular catalysis for the N2/H2 reaction system. 相似文献
19.
《中国化学快报》2023,34(10):108153
Glutathione depletion provides a promising strategy for the design of non-platinum anticancer drugs. Here we report a series of electrophilic (salen)osmium(VI) nitrides that react with glutathione to generate (salen)osmium(III) ammine compounds. In vitro studies indicate that these osmium(VI) nitrides show comparable cytotoxicity to cisplatin against various carcinoma. Mechanistic studies with the representative compound [OsVI(N)(LH)(OH2)](PF6) (1, LH = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) suggest that 1 induces glutathione depletion, reactive oxygen species generation, endoplasmic reticulum stress, and in turn triggers death receptor-mediated apoptosis and autophagy in lung cancer cells. In vivo evaluations show that 1 can inhibit tumor xenograft growth effectively with no body weight drop. 相似文献
20.
Cerium‐Complex‐Catalyzed Oxidation of Arylmethanols under Atmospheric Pressure of Dioxygen and Its Mechanism through a Side‐On μ‐Peroxo Dicerium(IV) Complex 下载免费PDF全文
Mitali Paul Satoru Shirase Dr. Yuma Morimoto Dr. Laurent Mathey Dr. Balasubramanian Murugesapandian Dr. Shinji Tanaka Prof. Dr. Shinobu Itoh Prof. Dr. Hayato Tsurugi Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4008-4014
A new CeIV complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)2] ( 1 ), bearing a dianionic pentadentate ligand with an N3O2 donor set, has been prepared by treating (NH4)2Ce(NO3)6 with the sodium salt of ligand L1 . Complex 1 in the presence of TEMPO and 4 Å molecular sieves (MS4 A) has been found to serve as a catalyst for the oxidation of arylmethanols using dioxygen as an oxidant. We propose an oxidation mechanism based on the isolation and reactivity study of a trivalent cerium complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)(THF)] ( 2 ), its side‐on μ‐O2 adduct [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)]2(μ‐η2:η2‐O2) ( 3 ), and the hydroxo‐bridged CeIV complex [Ce{NH(CH2CH2N=CHC6H2‐3,5‐(tBu)2‐2‐O)2}(NO3)]2(μ‐OH)2 ( 4 ) as key intermediates during the catalytic cycle. Complex 2 was synthesized by reduction of 1 with 2,5‐dimethyl‐1,4‐bis(trimethylsilyl)‐1,4‐diazacyclohexadiene. Bubbling O2 into a solution of 2 resulted in formation of the peroxo complex 3 . This provides the first direct evidence for cerium‐catalyzed oxidation of alcohols under an O2 atmosphere. 相似文献