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1.
Robin Haunschild 《Journal of organometallic chemistry》2008,693(4):737-749
Quantum chemical calculations using density functional theory (B3LYP) were carried out to elucidate the reaction pathways for ethylene addition to the chromium and molybdenum complexes CrO(CH3)2(CH2) (Cr1) and MoO(CH3)2(CH2) (Mo1). The results are compared with previously published results of the analogous tungsten system WO(CH3)2(CH2) (W1). The comparison of the group-6 elements shows that the molybdenum and tungsten compounds Mo1 and W1 have a similar reactivity while the chromium compound has a more complex reactivity pattern. The kinetically most favorable reaction pathway for ethylene addition to Mo1 is the [2+2]Mo,C addition across the MoCH2 double bond which has an activation barrier of only 8.4 kcal/mol. The reaction is slightly exothermic with ΔER = −0.6 kcal/mol. The [2+2]Mo,O addition across the MoO double bond and the [3+2]C,O addition have much higher barriers and are strongly endothermic. The thermodynamically mostly favored reaction is the [1+2]Mo addition of ethylene to the metal atom which takes place after prior rearrangement of the Mo(VI) compound Mo1 to the Mo(IV) isomer Mo1g. The reaction is −19.2 kcal/mol exothermic but it has a large barrier of 34.5 kcal/mol. The kinetically and thermodynamically most favorable reaction pathway for ethylene addition to the chromium homologue Cr1 is the multiple-step process with initial rearrangements Cr1 → Cr1c → Cr1g which are followed by a [1+2]Cr addition yielding an ethylene π complex Cr1g + C2H4 → Cr1g-1. The highest barrier comes from the first step Cr1 → Cr1c which has an activation energy of 14.2 kcal/mol. The overall reaction is exothermic by −26.3 kcal/mol. 相似文献
2.
《Journal of Coordination Chemistry》2012,65(6):993-1009
A series of metal complexes was synthesized using a simple thiourea derivative. The prepared complexes were characterized using different techniques (FTIR, ESR, X-ray diffraction [XRD], TG/DTA, and TEM). The FTIR spectrum of the ligand shows the presence of its tautomer forms (keto–enol). The ligand coordinates as a neutral bidentate in the Pt(IV), Pd(II), and Pt(II) complexes. In the case of Co(II) and Ni(II) complexes, the ligand is mono-negative bidentate. The proposed complexes are four to six coordinate. The geometries are proposed based on electronic spectral data and magnetic measurements and were verified using other tools. The XRD patterns reflect the nanocrystalline structures except for the Cu(II) complex, which is amorphous. The TEM images for platinum complexes show nanosize particles and homogeneous metal ion distribution on the complex surface. The EPR spectrum of Cu(II) complex verified the octahedral geometry of the complex. Molecular modeling was performed to assign the structural formula proposed for the ligand based on the characterization results. 相似文献
3.
《Journal of Coordination Chemistry》2012,65(5):848-860
A new heterocyclic compound N-(5-benzoyl-2-oxo-4-phenyl-2H-pyrimidin-1-yl)-oxalamic acid has been synthesized from N-amino pyrimidine-2-one and oxalylchloride. Bis-chelate complexes of the ligand were prepared from acetate/chloride salts of Cu(II), Co(II), Mn(II), Ni(II), Zn(II), Cd(II), and Pd(II) in methanol. The structures of the ligand and its metal complexes were characterized by microanalyses, IR, AAS, NMR, API-ES, UV-Vis spectroscopy, magnetic susceptibility, and thermogravimetric analyses. An octahedral geometry has been suggested for all the complexes, except for Pd(II) complex, in which the metal center is square planar. Each ligand binds using C(2)=O, HN, and carboxylate. The cyclic voltammograms of the ligand and the complexes are also discussed. The new synthesized compounds were evaluated for antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi using the microdilution procedure. The Cu(II) complex displayed selective and effective antibacterial activity against one Gram-positive spore-forming bacterium (Bacillus cereus ATCC 7064), two Gram-positive bacteria (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) at 40–80 µg mL?1, but poor activity against Candida species. The Cu(II) complex might be a new antibacterial agent against Gram-positive bacteria. 相似文献
4.
Jesús Ma Martínez-Snchez Rufina Bastida de la Calle Alejandro Macías Paulo Prez-Lourido Laura Valencia Matarranz 《Polyhedron》2006,25(18):3495-3500
Hydrated nitrate and perchlorate salts of the transitional metal ions Co2+, Ni2+ and Cu2+ have been used to investigate the coordination capability of the octaaza macrocycle L derived from 2,6-diformylpyridine and diethylenetriamine. The synthesis of the metal complexes was carried out in 1:1 and 2:1 metal:ligand molar ratios, but dinuclear complexes were obtained in all cases due to the size of the 24-membered ligand. The complexes have been characterized by elemental analysis, molar conductivity, mass spectrometry, IR spectroscopy, diffuse reflectance and magnetic measurements. The dinuclear nature of the compounds was confirmed by X-ray diffraction. The crystal structures of [Ni2L(NO3)2](NO3)2, [Cu2L(NO3)4] and [Cu2L(ClO4)4], were determined. 相似文献
5.
The feasibility of a novel and simple layer-by-layer chemical deposition method for the preparation of nano-sized metal 8-hydroxyquinolate complexes has been investigated and reported. Uniform nanocrystalline films have been synthesized via dipping a substrate alternately in metal ion solution followed by ligand solution. The stoichiometry of the as-grown anhydrous Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complex crystals were confirmed from the metal analysis and molar stoichiometric ratio of metal ion to 8-hydroxyquinoline. This was characterized as 1:2 for the Co(II), Ni(II), Cu(II) and Zn(II)–quinolate complexes. The Fe(III)–quinolate thin film was found to exhibit a 1:3 ratio. Electron impact-mass spectra (EI-MS) of all the synthesized thin film metal quinolate complexes were recorded and the results refer to the existence of the molecular ion peak at the corresponding m/z values. Confirmation of such stoichiometric 1:2 and 1:3 ratios were also evident from the (EI-MS) study. The deposited thin films were also subjected to analysis by a scanning electron microscope (SEM) and a particle size ?50 nm was detected. FT-IR and UV–Vis spectroscopy were further used to confirm the structure of the metal 8-hydroxyquinolate complexes. Thermal gravimetric analysis (TGA) was also used to follow up the possible thermal decomposition steps and to calculate the thermodynamic parameters of the nano-sized metal complexes. 相似文献
6.
The kinetics and mechanism of processes of reduction of Pd(II) complexes with a number of inorganic (NH3 , Cl– , etc.) and organic (ethylenediamine, glycine, -alanine, etc.) ligands on a dropping-mercury electrode and a Pd electrode in solutions with various concentrations of ligands, hydrogen ions, and supporting electrolytes are reviewed. The nature of electrochemical and chemical steps of processes of reduction of various complexes of Pd(II) is discussed.Translated from Elektrokhimiya, Vol. 40, No. 12, 2004, pp. 1494–1502.Original Russian Text Copyright © 2004 by Kravtsov. 相似文献
7.
The [Co(HOr)(H2O)2(im)2] (1), [Ni(HOr)(H2O)2(im)2] (2), [Zn(H2O)2(im)4](H2Or)2 (3) and [Cd(HOr)(H2O)(im)3] (4) complexes (H3Or: orotic acid, im: imidazole) were synthesized and characterized by elemental analysis, magnetic and conductance measurements,
UV-vis and IR spectra. The thermal behaviour of the complexes was also studied by simultaneous thermal analysis techniques
(TG, DTG and DTA). The orotate ligand (HOr2−) coordinated to the Co(II), Ni(II) and Cd(II) ions are chelated to the deprotonated pyrimidine nitrogen (N(3)) and the carboxylate oxygen, while do not coordinate to the Zn(II) ion is present as a counter-ion (H2Or−). The first thermal decomposition process of all the complexes is endothermic deaquation. This stage is followed by partially
(or completely) decomposition of the imidazole and orotate ligands. In the later stage, the remained organic residue exothermically
burns. On the basis of the first DTGmax, the thermal stability of the complexes follows order: 2, 176°C>1, 162°C>4, 155°C>3, 117°C in static air atmosphere. The final decomposition products which identified by IR spectroscopy were the corresponding
metal oxides. 相似文献
8.
Robin Haunschild 《Journal of organometallic chemistry》2008,693(24):3627-3637
Quantum chemical calculations using DFT at the B3LYP level have been carried out for the reaction of ethylene with the group-7 compounds ReO2(CH3)(CH2) (Re1), TcO2(CH3)(CH2) (Tc1) and MnO2(CH3)(CH2) (Mn1). The calculations suggest rather complex scenarios with numerous pathways, where the initial compounds Re1-Mn1 may either engage in cycloaddition reactions or numerous addition reactions with concomitant hydrogen migration. There are also energetically low-lying rearrangements of the starting compounds to isomers which may react with ethylene yielding further products. The [2 + 2]Re,C cycloaddition reaction of the starting molecule Re1 is kinetically and thermodynamically favored over the [3 + 2]C,O and [3 + 2]O,O cycloadditions. However, the reaction which leads to the most stable product takes place with initial rearrangement to the dioxohydridometallacyclopropane isomer Re1a that adds ethylene with concomitant hydrogen migration yielding Re1a-1. The latter reaction has a slightly higher barrier than the [2 + 2]Re,C cycloaddition reaction. The direct [3 + 2]C,O cycloaddition becomes more favorable than the [2 + 2]M,C reaction for the starting compounds Tc1 and Mn1 of the lighter metals technetium and manganese but the calculations predict that other reactions are kinetically and thermodynamically more favorable than the cycloadditions. The reactions with the lowest activation barriers lead after rearrangement to the ethyl substituted dioxometallacyclopropanes Tc1a-1 and Mn1a-1. The manganese compound exhibits an even more complex reaction scenario than the technetium compounds. The thermodynamically most stable final product of ethylene addition to Mn1 is the ethoxy substituted metallacyclopropane Mn1a-2 which has, however, a high activation barrier. 相似文献
9.
Sensuke Ogoshi Takuma Nishida Yoshiaki Fukunishi Ken Tsutsumi Hideo Kurosawa 《Journal of organometallic chemistry》2001,620(1-2):190-193
Isomerization of phenyl-substituted propargylplatinum(II) complex, trans-Pt(CH2CCPh)(Cl)(PPh3)2 (1) to allenyl complex, trans-Pt(CPh=C=CH2)(Cl)(PPh3)2 (2) was found to be catalyzed by zerovalent complex Pd(PPh3)4. The reaction was proposed to proceed through the transfer of the propargyl/allenyl ligand both from Pt(II) to Pd(0) and Pd(II) to Pt(0). The former transfer, which seemingly has a thermodynamic disadvantage, has unambiguously been confirmed to take place; treatment of 1 with Pd(PPh3)4 or a mixture of Pd2(dba)3 and PPh3 resulted in the formation of Pd(I) complex, Pd2(μ-PhCCCH2)(μ-Cl)(PPh3)2 which lies in equilibrium with a mixture of propargyl/allenylpalladium(II) and Pd(0) complexes. 相似文献
10.
Yan-Bing Wang Yan-Xiao Liu Zhi-Hui Zhu Xue-Mei Zhao Bing Song Xinju Zhu Xin-Qi Hao 《Journal of Saudi Chemical Society》2019,23(1):104-110
A series of platinum and palladium pincer complexes supported by achiral 1,3-bis(2′-imidazolinyl)benzene-based NCN ligands have been prepared via direct C2 metalation. Meanwhile, ligand precursor 3b and Pt(II) complex 4b were characterized by crystallographic studies, which reveals that the platinum atom in 4b adopts a distorted-square-planar geometry. The Pd(II) pincer complexes 5b was found to be an efficient catalyst for Suzuki cross-coupling reaction of aryl bromides and phenylboronic acid under air. In the presence of 0.5?mol% of Pd(II) 5b in DMF/K3PO4·3H2O for 8?h, the corresponding biaryl products could be obtained in 24–99% yields. 相似文献
11.
The synthesis, derivatization and coordination behavior of a new aminobis(diphosphonite), PhN{P(OC6H4OMe-o)2}2 (1) is described. The ligand 1 reacts with H2O2, elemental sulfur or selenium to give the corresponding dichalcogenides PhN{P(E)(OC6H4OMe-o)2}2 (E = O, 2; S, 3; Se, 4) in good yield. Reactions of 1 with Mo(CO)6, Pd(NCCH3)2Cl2 and Pt(COD)Cl2 resulted in the formation of the chelate complexes, Mo(CO)4[PhN{P(OC6H4OMe-o)2}2] (5) and MCl2[PhN{P(OC6H4OMe-o)2}2] (M = Pd,7; M = Pt, 8) whereas in the reaction of 1 with [CpFe(CO)2]2, one of the P-N bonds cleaves due to the metal assisted hydrolysis to give a mononuclear complex, [CpFe(CO){P(O)(OC6H4OMe-o)2}{PhN(H)(P(OC6H4OMe-o)2)}] (6). The molecular structures of 1, 4, 5 and 6 are determined by X-ray studies. 相似文献
12.
Alasdair J. RobbieAndrew R. Cowley Michael W. Jones Jonathan R. Dilworth 《Polyhedron》2011,30(11):1849-1856
Two new sterically demanding diaminophosphinothiolate ligands (HL1 and HL2) have been prepared and the X-ray crystal structure of the Li salt of HL2 has been determined. The complex [Pd(L1)2] was fully characterized, but in contrast to other phosphinothiolates, complexes with the M(L)3 stoichiometry could not be prepared. Reaction of LH1 with Ni(II) led to cleavage of the arythiolate group and isolation of a thiolate bridged dimer, confirmed by an X-ray crystal structure. The Rh(I) complexes [Rh(nbd)L] (L = L1, L2) were characterized including an X-ray structure. 相似文献
13.
Conclusion Heating of a solution of the PtCl6
2– ion and an arylmercury compound containing a substituent in the ortho position to mercury leads to the formation of a diaryl (in the case of -naphthylmercury) or arene (in the case of the mesityl or pentamethylphenyl mercury derivatives).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2374–2376, October, 1986.The authors express their gratitude to A. E. Shilov and A. K. Yatsimirskii for a useful discussion of these results. 相似文献
14.
《Journal of Coordination Chemistry》2012,65(14):2274-2287
New Schiff bases have been synthesized from benzofuran-2-carbohydrazide and benzaldehyde, [BPMC] or 3,4-dimethoxybenzaldehyde, [BDMeOPMC]; complexes of the type MLX2, where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II), L = BPMC or BDMeOPMC and X = Cl, have been prepared. Structures have been elucidated on the basis of elemental analysis, conductance measurements, magnetic properties, spectral studies i.e., 1H NMR, electronic, ESR and IR studies show that the Schiff bases are bidentate through the azomethine nitrogen and oxygen of the carbonyl. We propose tentative structures for all of these complexes. The antifungal and antibacterial activities of the ligands and their metal complexes have been screened against fungi Aspergillus niger and Aspergillus fumigatus and against bacteria Escherichia coli and S. aurious. 相似文献
15.
B. A. Arbuzov A. A. Karasik G. N. Nikonov E. V. Malova R. Sh. Khadiullin A. Kh. Plyamovatyi K. M. Enikeev 《Russian Chemical Bulletin》1992,41(2):253-259
1,3,5-Diazaphosphorinanes and 1,5,3,7-diazadiphosphacyclooctanes form complexes with Pt(II), Pd(II), Cu(I), and Ag(I) salts. Platinum and palladium are coordinated through phosphorous atoms. In the case of 1,3-diphenyl-5-p-toluidenomethyl-1,3,5-diazaphosphorinane complex formation with platinum and palladium is accompanied by formation of a new polydentate ligand, p-tolylbis-(1,3-di-p-tolyl-1,3,5-diazaphosphorinane-5-yl)methylamine, where the metal is also bonded to phosphorus atoms.DeceasedA. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 335–342, February, 1992. 相似文献
16.
《Comptes Rendus Chimie》2016,19(8):909-920
The interactions of methylxanthine bases with metal ions are of major biological interest and are important in bioinorganic chemistry. One of these bases is 8-chlorotheophylline (Ctp), which exhibits high stimulant action. Here, the metal complexation reactions of Ctp with Cr(III), Mn(II), Co(II), Ni(II), and Cu(II) ions were investigated, in a 1:2 molar ratio and in basic media. All of the prepared complexes were confirmed using elemental analysis, magnetic moment measurements, molar conductance, thermal analysis, and UV–Vis., IR, and Raman spectroscopies. Spectroscopic results revealed direct cation interactions for all of the metal ions via the deprotonated N7 atom of Ctp. The biological activity of the complexes was examined to determine the effect of chelation on the bioactivity of Ctp. It was observed that free Ctp possesses very low inhibitory activity towards several bacteria and fungi. However, the potency of its Cr(III)-complex exceeded that of the standard drug Ciprofloxacin against all of the tested bacterial strains, and the potency of this complex was 28% and 11% higher than those of the standard drug Fluconazole against the Aspergillus flavus and Penicillium Sp fungal strains, respectively. 相似文献
17.
Uzelmeier CE Smucker BW Reinheimer EW Shatruk M O'Neal AW Fourmigué M Dunbar KR 《Dalton transactions (Cambridge, England : 2003)》2006,(44):5259-5268
Reactions of 3,4-dimethyl-3',4'-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF(4)](-) salts of Fe(ii), Co(ii), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)(2)][BF(4)](2). Similar reactions between o-P2 and AgSbF(6) or AgPF(6) produced the salts [Ag(o-P2)(2)][X] where X = [SbF(6)](-) or [PF(6)](-). The resulting compounds were fully characterized by (1)H and (31)P{(1)H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin-orbit coupling contribution at higher temperatures and an effective S' = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers. 相似文献
18.
Yahya Nural Rafet Kilincarslan H. Ali Dondas Bekir Cetinkaya Mehmet Sami Serin Ronald Grigg Tuncay Ince Colin Kilner 《Polyhedron》2009,28(14):2847-2854
A series of Ni(II), Pd(II) and Cu(II) metal complexes of highly functionalized aroylaminocarbo-N-thioyl pyrrolidines were prepared and characterized by microanalysis, spectroscopic methods, magnetic susceptibility measurements and single crystal X-ray diffraction studies. The antifungal activity of the metal complexes against the yeast Saccharomyces cerevisae and against the fungus Penicillium digitatum was studied. 相似文献
19.
Vesna Radulović Alessia Bacchi Giancarlo Pelizzi Dušan Sladić Ilija Brčeski Katarina Andjelković 《Monatshefte für Chemie / Chemical Monthly》2006,137(6):681-691
Summary. Complexes of Pt(II), Pd(II), and Ni(II) with the condensation derivative of 2-(diphenylphosphino)benzaldehyde and semioxamazide
were synthesized, characterized, and their antimicrobial activity was evaluated. The ligand and the complexes were characterized
by spectroscopic methods with the particular accent on NMR spectral analysis. For the palladium(II) complex, the crystal structure
was determined by X-ray analysis. In all the complexes the ligand is coordinated as a tridentate via a P, N, O donor set. The Pd(II) and Pt(II) complexes have a square planar geometry, whereas the geometry of the Ni(II) complex
is tetrahedral. The ligand showed antibacterial and antifungal activity, which was enhanced upon complexation. 相似文献
20.
Complexes of Pd(II) with aminobutyric acid AmH = NH2CH(CH2CH3)COOH, namely, trans-[Pd(AmH)2Cl2] with monodentate (via the NH2 group) AmH ligands and cis-, trans-Pd(Am)2 with bidentate (via NH2 and COO groups) ligands have been synthesized for the first time. Elemental analysis and IR and NMR spectroscopy were used to identify the synthesized compounds. The NMR spectra of the Pd(II) complexes were interpreted by comparing them with the NMR spectra of the analogous complexes of Pt(II). For Pt(II) and Pd(II) complexes with aminobutyric acid used as examples, an approach to identification of diastereomer bis-aminoacid complexes in specimens with racemic aminoacids by NMR spectroscopy is demonstrated. 相似文献