共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Chien-Hong Cheng 《中国化学会会志》1988,35(4):261-266
Complexes (η4-PhCH=CHCR=NPh)Fe(CO)3, where R=H(1a) and CH3 were synthesized in excellent yield from the reaction of the corresponding α,β-unsaturated ketimines with excess Fe2(CO)9. Reaction of la with (Ph)2CHLi and (CH3)2(NC)CLi at ?78°C or ambient temperature followed by acid quenching gave trans-PhCH=CHCHRNHPh, where R=CHPH2 and C(CH3)2CN, respectively, in good yield. In the presence of 1 atm. of CO the reaction of 1a with (CH3)2(NC)CLi, followed by CuCl2 oxidation resulted in the formation of a carbamyl choride, trans-PhCH=CHCH[C(CH3)2CN]N(Ph)COCl. This species was converted to a carbamate compound trans-PhCH=CHCH[C(CH3)2 - CN]N(Ph)COOCH3 in MeOH in the presence of Ag+. 相似文献
3.
Alain Igau Yannick Miquel Victorio Cadierno Jean-Pierre Majoral 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):585-588
Using the nucleophilic ability of tertiary phosphines we have been able to prepare a large variety of unprecedented stable phosphonium anionic zirconocene(IV) complexes. 相似文献
4.
Dr. Maximilian Joost Dr. Abderrahmane Amgoune Dr. Didier Bourissou 《Angewandte Chemie (International ed. in English)》2015,54(50):15022-15045
For a while, the reactivity of gold complexes was largely dominated by their Lewis acid behavior. In contrast to the other transition metals, the elementary steps of organometallic chemistry—oxidative addition, reductive elimination, transmetallation, migratory insertion—have scarcely been studied in the case of gold or even remained unprecedented until recently. However, within the last few years, the ability of gold complexes to undergo these fundamental reactions has been unambiguously demonstrated, and the reactivity of gold complexes was shown to extend well beyond π‐activation. In this Review, the main achievements described in this area are presented in a historical context. Particular emphasis is set on mechanistic studies and structure determination of key intermediates. The electronic and structural parameters delineating the reactivity of gold complexes are discussed, as well as the remaining challenges. 相似文献
5.
《Analytical letters》2012,45(10):641-654
Abstract The results of polarography and cyclic voltammetry studies of hematoporphyrin IX with eight different added ligands (other than H2O and OH?) in aqueous solvent are reported. Two nitrogenous ligand molecules were found to coordinate with both manganese (III) and manganese(II) hematoporphyrin IX. Oxygenated ligands such as acetate and pyrophosphate showed no tendency to coordinate with either manganese (III) or manganese (II) porphyrin. Porphyrin adsorption on the mercury electrode is quite evident. The adsorption mechanism appears to be complicated. 相似文献
6.
Bianca Seidler Jens H. Tran Julian Hniopek Philipp Traber Dr. Helmar Görls Prof. Dr. Stefanie Gräfe Prof. Dr. Michael Schmitt Prof. Dr. Jürgen Popp Dr. Martin Schulz Prof. Dr. Benjamin Dietzek-Ivanšić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(72):e202202697
In this paper, the photophysical behavior of four panchromatically absorbing, homoleptic bis(4H-imidazolato)CuI complexes, with a systematic variation in the electron-withdrawing properties of the imidazolate ligand, were studied by wavelength-dependent time-resolved femtosecond transient absorption spectroscopy. Excitation at 400, 480, and 630 nm populates metal-to-ligand charge transfer, intraligand charge transfer, and mixed-character singlet states. The pump wavelength-dependent transient absorption data were analyzed by a recently established 2D correlation approach. Data analysis revealed that all excitation conditions yield similar excited-state dynamics. Key to the excited-state relaxation is fast, sub-picosecond pseudo-Jahn-Teller distortion, which is accompanied by the relocalization of electron density onto a single ligand from the initially delocalized state at Franck-Condon geometry. Subsequent intersystem crossing to the triplet manifold is followed by a sub-100 ps decay to the ground state. The fast, nonradiative decay is rationalized by the low triplet-state energy as found by DFT calculations, which suggest perspective treatment at the strong coupling limit of the energy gap law. 相似文献
7.
8.
Alejandro Portugués Inmaculada López-García Javier Jiménez-Bernad Dr. Delia Bautista Dr. Juan Gil-Rubio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(68):15535-15547
The study of perfluoroalkyl metal complexes is key to understand and improve metal-promoted perfluoroalkylation reactions. Herein, we report the synthesis of the first gold complexes with primary or secondary perfluoroalkyl ligands by photoinitiated reactions between AuI organometallic complexes and iodoperfluoroalkanes. Complexes of the types LAuRF (L=PPh3 or N,N-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; RF=n-C4F9, n-C6F13, i-C3F7, c-C6F11) and [Au(RF)(Ar)I(PPh3)] (Ar=2,4,6-trimethylphenyl) have been isolated and characterized. Alkynes RFC≡CR were formed by reaction of Ph3PAuC≡CR (R=Ph, nHex) with IRF (RF=n-C4F9, i-C3F7). According to the evidences obtained, this transformation undergoes through a photoinitiated radical mechanism. AuIII complexes [Au(n-C4F9)(X)(Y)L] (X=Y=Cl, Br, I, Me; X=Me, Y=I) have been prepared or in situ generated, and their thermal or photochemical decomposition reactions have been studied. 相似文献
9.
E. İspir 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):3160-3174
Two novel Schiff base ligands, 4-((3-(trimethoxysilyl)propylimino)methyl)benzene– 1,2,3-triol (L1H) and 4-((3-(triethoxysilyl)propylimino)methyl)benzene–1,2,3-triol (L2H), have been synthesized by the reaction of 2,3,4-trihydroxybenzaldehyde with 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane, respectively. The mononuclear CoII and CuII complexes of these Schiff bases were prepared. The complexes of the Schiff bases are formed by coordination of N, O atoms of the ligands. The proposed structures were confirmed by elemental analyses, FT-IR, and UV-visible spectroscopy, magnetic susceptibility, and conductance measurements; the 1H NMR spectra of the ligands were also recorded. The analytical data show that the metal to ligand ratio in the complexes containing silicon is 1:2. The electrochemical properties of the complexes have been investigated at 100 mVs?1 scan rate in DMSO. In addition, the antimicrobial activity of L1H and L2H Schiff ligands, and their [M(L1)2] and [M(L2)2] type coordination compounds, were investigated. 相似文献
10.
11.
《Electroanalysis》2017,29(2):538-547
A few novel metal complexes of chelidonic acid (chelH2), namely [Ca(chel)(H2O)3] ( 1 ), [Cu(chel)(H2O)5] ⋅ 2H2O ( 2 ) and [VO(chel)(H2O)3] ⋅ 2H2O ( 3 ) were prepared, identified by elemental analysis and characterized by electrochemical methods. IR‐spectra and thermal stability in solid state are discussed as well. The electrochemical characteristics of the free chelidonic acid and its complexes 1 – 3 were studied by (cyclic) square‐wave voltammetry, on static mercury drop electrode (SMDE) and paraffin‐impregnated graphite electrode (PIGE), in aqueous media over a wide pH range. The reduction of chelidonic acid on SMDE is a kinetically controlled electrode reaction, occurring with the transfer of one electron and two protons for 1<pH<6, whereas in very alkaline media the electron transfer is pH independent, i.e . the mechanism of electro‐reduction of chelH2 is proposed. The experimental parameters of the electroanalytical procedure were optimized and the method was applied for the investigation of the metal ion coordination preferences toward chelidonic acid. For the direct determination of solid complexes 1 – 3 , SW voltammetry of microparticles was used. 相似文献
12.
Prof. Dr. Holger Braunschweig Marco Fuß Dr. Swagat K. Mohapatra Katharina Kraft Dr. Thomas Kupfer Melanie Lang Dr. Krzysztof Radacki Dr. Constantin G. Daniliuc Prof. Dr. Peter G. Jones Prof. Dr. Matthias Tamm 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(38):11732-11743
A novel one‐pot method was developed for the preparation of [Ti(η5‐C5H5)(η7‐C7H7)] (troticene, 1 ) by reaction of sodium cyclopentadienide (NaCp) with [TiCl4(thf)2], followed by reduction of the intermediate [(η5‐C5H5)2TiCl2] with magnesium in the presence of cycloheptatriene (C7H8). The [n]troticenophanes 3 (n=1), 4 , 8 , 10 (n=2), and 11 (n=3) were synthesized by salt elimination reactions between dilithiated troticene, [Ti(η5‐C5H4Li)(η7‐C7H6Li)] ? pmdta ( 2 ) (pmdta=N,N′,N′,N′′,N′′‐pentamethyldiethylenetriamine), and the appropriate organoelement dichlorides Cl2Sn(Mes)2 (Mes=2,4,6‐trimethylphenyl), Cl2Sn2(tBu)4, Cl2B2(NMe2)2, Cl2Si2Me4, and (ClSiMe2)2CH2, respectively. Their structural characterization was carried out by single‐crystal X‐ray diffraction and multinuclear NMR spectroscopy. The stanna[1]‐ and stanna[2]troticenophanes 3 and 4 represent the first heteroleptic sandwich complexes bearing Sn atoms in the ansa bridge. The reaction of 3 with [Pt(PEt3)3] resulted in regioselective insertion of the [Pt(PEt3)2] fragment into the Sn? Cipso bond between the tin atom and the seven‐membered ring, which afforded the platinastanna[2]troticenophane 5 . Oxidative addition was also observed upon treatment of 4 with elemental sulfur or selenium, to produce the [3]troticenophanes [Ti(η5‐C5H4SntBu2)(η7‐C7H6SntBu2)E] ( 6 : E=S; 7 : E=Se). The B? B bond of the bora[2]troticenophane 8 was readily cleaved by reaction with [Pt(PEt3)3] to form the corresponding oxidative addition product [Ti(η5‐C5H4BNMe2)(η7‐C7H6BNMe2)Pt(PEt3)2] ( 9 ). The solid‐state structures of compounds 5 , 6 , and 9 were also determined by single‐crystal X‐ray diffraction. 相似文献
13.
Daniel Eppel Philipp Penert Johanna Stemmer Christina Bauer Dr. Matthias Rudolph Margit Brückner Dr. Frank Rominger Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(34):8673-8677
Starting from commercially available DMSAuCl and diazonium salts, cationic [ ]AuIII complexes were synthesized in a selective, photosensitizer-free, photochemical reaction by irradiation with blue LED light. This new protocol represents the first easy synthesis of these types of pincer complexes in moderate to excellent yield starting from a readily available gold(I) precursor with nitrogen as the only by-product. Owing to the disadvantages of known protocols, especially the toxicity in the case of a transmetalation with mercury or the necessity for a mostly twofold excess of a gold precursor, this method offers an attractive alternative towards this kind of gold(III) complexes. In addition, the first arylated [ ]Au(III) pincer complex was synthesized by using this technology. 相似文献
14.
15.
4-Morpholinoacetophenone thiosemicarbazone, MAPT, and its nickel(Ⅱ) and copper(Ⅱ) complexes have been prepared and characterized by elemental analysis, magnetic susceptibility, spectral methods (FT-IR, ^1H NMR) and cyclic voltammetry. Electrochemical behaviors of the complexes have been studied by cyclic voltammetry in DMF media showing metal centered reduction processes for both of them. The redox properties, nature of the electrode processes and the stability of the complexes were discussed. [Cu(MAPT)2]Cl2 complex shows Cu(Ⅱ)/Cu(Ⅰ) couple and quasi-reversible wave associated with the Cu(Ⅲ)/Cu(Ⅱ) process. The reduction/oxidation potential values depend on the structures of complexes. Also, the antimicrobial activities of these complexes were determined against S. aureus, E. coli and B. subtilis. 相似文献
16.
用密度泛函计算和循环伏安法研究了锰在金和铅表面的欠电位沉积(UPD)行为. 理论计算, 假设生成紧密的二维相(2D)欠电位沉积层, 用基于密度泛函理论的DMol3软件计算在金与铅表面生成2D相锰层的欠电位偏移值8710;fE2DMe, 证明锰在金表面可发生欠电位沉积, 而在铅表面不能发生欠电位沉积. 循环伏安实验结果与理论计算不一致: 金电极析氢电位高不利于研究锰的还原沉积反应, 没有发现锰的欠电位沉积现象; 铅电极在MnCl2溶液中有锰的欠电位沉积现象. 这种理论计算与电化学实验结果的差异, 主要是因为理论计算没有考虑溶剂与阴离子特性吸附作用的影响, 理论计算模型是电化学实验体系的一种理想模型. 相似文献
17.
Yu Xuan Hu Dr. Jing Zhang Fangfang Zhang Xiaoyan Wang Prof. Dr. Jun Yin Prof. Dr. František Hartl Prof. Dr. Sheng Hua Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4567-4575
Four cyclometalated diiridium complexes, with IrCp*Cl (Cp*=η5-C5Me5−) termini bridged by 1,4- and 1,3-bis(p-tolyliminoethyl)benzene ( 1 , 2 ), or 1,4- and 1,3-bis(2-pyridyl)benzene ( 3 , 4 ), were prepared and characterized by nuclear magnetic resonance (NMR) spectroscopy and single-crystal X-ray diffraction (complexes 1 , 2 , and 4 ). The two iridium centers in complexes 1 and 3 are thus bound at the central benzene ring in the para-position (trans-Ir2), whereas those in complexes 2 and 4 are in the meta-position (cis-Ir2). Cyclic voltammograms of all four complexes show two consecutive one-electron oxidations. The potential difference between the two anodic steps in 1 and 3 is distinctly larger than that for 2 and 4 . The visible–near-infrared (NIR)–short-wave infrared (SWIR) absorption spectra of trans-Ir2 monocations 1 + and 3 + are markedly different from those of cis-Ir2 monocations 2 + and 4 +. Notably, strong near-infrared electronic absorption appears only in the spectra of 1 + and 3 + whereas 2 + and 4 + absorb only weakly in the NIR-SWIR region. Combined DFT and TD-DFT calculations have revealed that (a) 1 + and 3 + (the diiridium-benzene trans-isomers) display the highest occupied spin-orbitals (HOSO) and the lowest unoccupied spin-orbital (LUSO) evenly delocalized over both molecule halves, and (b) their electronic absorptions in the NIR-SWIR region are attributed to mixed metal-to-ligand and ligand-to-ligand charge transfers (MLCT and LLCT). In contrast, cis-isomers 2 + and 4 + do not feature this stabilizing π-delocalization but a localized mixed-valence state showing a weak intervalence charge-transfer (IVCT) absorption in the SWIR region. 相似文献
18.
19.
Laura Nunes dos Santos Comprido Dr. Johannes E. M. N. Klein Prof. Dr. Gerald Knizia Prof. Dr. Johannes Kästner Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):2892-2895
We herein report a computational study of the bonding in gold(I) vinylidene complexes and compare them to their carbene and CO analogues. The relevance of these intermediates is analysed for the intramolecular cyclisation leading to vinyl sulfonates. 相似文献
20.
Dr. Jinxiang Chen Zi‐Ao Huang Zhengyu Lu Dr. Hong Zhang Prof. Dr. Haiping Xia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5363-5375
Reactions of the hydrido‐butenylcarbyne complex [OsHCl2(≡CC(PPh3)=CHEt)(PPh3)2]BF4 ( 1 ) with nitriles RC≡N (R=2‐cyclopropyl‐2‐oxopropyl, 3‐amino‐2‐oxobutyl) lead to six‐membered cyclic vinylidene complexes 3 and azavinylidene complexes 4 , that is, iso‐osmapyridiniums. Treatment of 1 with excess 2‐formylbenzonitrile at reflux temperature in CHCl3 in the presence of air produces a fused osmapyridinium 8 , which is first oxidized to the tricyclic iso‐osmapyridinium derivative 7 , then to iso‐osmapyridinium 9 , which contains a fused naphthalenone fragment. The conversion of iso‐osmapyridinium 9 (with a vinylidene segment) to the iso‐osmapyridinium compounds 10 and 11 (with azavinylidene segments) was achieved in the presence of a hydrogen halide, such as HCl or HI. The molecular structures of the complexes synthesized were confirmed by X‐ray studies. Moreover, the aromatic stabilization energy and nucleus‐independent chemical‐shift values of the osmapyridiniums and the strain in the iso‐osmapyridinium rings were investigated by DFT calculations. 相似文献