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1.
Michael I. Bruce Marcus L. Cole Brian W. Skelton 《Journal of organometallic chemistry》2006,691(22):4601-4614
Complexes M(CCCSiMe3)(CO)2Tp′ (Tp′ = Tp [HB(pz)3], M = Mo 2, W 4; Tp′ = Tp∗ [HB(dmpz)3], M = Mo 3) are obtained from M(CCCSiMe3)(O2CCF3)(CO)2(tmeda) (1) and K[Tp′].Reactions of 2 or 4 with AuCl(PPh3)/K2CO3 in MeOH afforded M{CCCAu(PPh3)}(CO)2Tp′ (M = Mo 5, W 6) containing C3 chains linking the Group 6 metal and gold centres.In turn, the gold complexes react with Co3(μ3-CBr)(μ-dppm)(CO)7 to give the C4-bridged {Tp(OC)2M}CCCC{Co3(μ-dppm)(CO)7} (M = Mo 7, W 8), while Mo(CBr)(CO)2Tp∗ and Co3{μ3-C(CC)2Au(PPh3)}(μ-dppm)(CO)7 give {Tp∗(OC)2Mo}C(CC)2C{Co3(μ-dppm)(CO)7} (9) via a phosphine-gold(I) halide elimination reaction. The C3 complexes Tp′(OC)2MCCCRu(dppe)Cp∗ (Tp′ = Tp, M = Mo 10, W 11; Tp′ = Tp∗, M = Mo 12) were obtained from 2-4 and RuCl(dppe)Cp∗ via KF-induced metalla-desilylation reactions. Reactions between Mo(CBr)(CO)2Tp∗ and Ru{(CC)nAu(PPh3)}(dppe)Cp∗ (n = 2, 3) afforded {Tp∗(OC)2Mo}C(CC)n{Ru(dppe)Cp∗} (n = 2 13, 3 14), containing C5 and C7 chains, respectively. Single-crystal X-ray structure determinations of 1, 2, 7, 8, 9 and 12 are reported. 相似文献
2.
The first luminescent rhenium(I)-gold(I) hetero organometallics, Re{phenAu(PPh3)}(CO)3Cl (3) and Re{(PPh3)AuphenAu(PPh3)}(CO)3Cl (4), have been prepared using the gold(I) complex AuCl(PPh3) (PPh3 = triphenylphosphine) and the novel rhenium(I) complexes Re(phenH)(CO)3Cl (5) (phenH = 3-ethynyl-1,10-phenanthroline) or Re(HphenH)(CO)3Cl (6) (HphenH = 3,8-bis(ethynyl)-1,10-phenanthroline). All the present rhenium(I) complexes 3-6 were revealed to possess a facial configuration (fac-isomer) with respect to the three carbonyl ligands. The main frameworks for these new gold(I) organometallics were constructed by the Au-C σ-bonding (with the η1-type coordination) between the ethynylphenanthrolines and the Au(I) phosphine unit. Re(I)-Au(I) heterometallics 3 and 4 have shown single phosphorescence from the 3MLCT excited state and this observation can be interpreted in terms of the efficient intramolecular energy transfer from the Au(I) unit to the Re(I) unit. 相似文献
3.
Synthesis, structures and some reactions of Ru(CCCCFc)(PP)Cp (PP = dppm, dppe) and related compounds
Michael I. Bruce Frédéric de Montigny Martyn Jevric Brian W. Skelton Allan H. White 《Journal of organometallic chemistry》2004,689(18):2860-2871
The compounds Ru(CCCCFc)(PP)Cp [PP = dppe (1), dppm (2)], have been obtained from reactions between RuCl(PP)Cp and FcCCCCSiMe3 in the presence of KF (1) or HCCCCFc and K[PF6] (2), both with added dbu. The dppe complex reacts with Co2(CO)6(L2) [L2 = (CO)2, dppm] to give 3, 4 in which the Co2(CO)4(L2) group is attached to the outer CC triple bond. The PPh3 analogue of 3 (5) has also been characterised. In contrast, tetracyanoethene reacts to give two isomeric complexes 6 and 7, in which the cyano-olefin has added to either CC triple bond. The reaction of RuCl(dppe)Cp with HCCCCFc, carried out in a thf/NEt3 mixture in the presence of Na[BPh4], gave [Ru{CCC(NEt3)CHFc}(dppe)Cp]BPh4 (8), probably formed by addition of the amine to an (unobserved) intermediate butatrienylidene [Ru(CCCCHFc)(dppe)Cp]+. The reaction of I2 with 8 proceeds via an unusual migration of the alkynyl group to the Cp ring to give [RuI(dppe){η-C5H4CCC(NEt3)CHFc}]I3 (9). Single-crystal X-ray structural determinations of 1, 2 and 4-9 are reported. 相似文献
4.
The azopyrimidine and azoimidazole ligands (general abbreviations, RL) used in the present work are 2-(p-R-C6H4NN)C4H3N2, RLpm (R=H, Cl) and 2-(p-R-C6H4NN)-1-(Me)C3H2N2, RLim (R=Me, Cl), respectively. The reaction of Re(CO)5Cl with a slight excess of RL in boiling benzene has furnished blue-violet complexes of type Re(CO)3Cl(RL) which have been spectrally characterized. In Re(CO)3Cl(HLpm) and Re(CO)3Cl(ClLim) the Re-Nh, Re-Na distances are 2.173(6), 2.136(6) Å and 2.150(5), 2.166(5) Å, respectively (Nh and Na are heterocyclic and azo N atoms, respectively). Their N-N lengths (1.271(8), 1.281(7) Å) implicate relatively weak Re-azo(π*) back-bonding. In the lattice of Re(CO)3Cl(HLpm), pair-wise C-H?O hydrogen bonding between symmetry related molecules is present (C?O; 3.264(9) Å, H?O; 2.460(10) Å; C-H?O; 130.6(5)°). The lattice of Re(CO)3Cl(ClLim) also consists of centrosymmetric dimers held by aromatic π-π stacking between parallely placed pendant aryl rings (centroid?centroid distance, 3.781(9) Å). Extended Hückel calculations reveal that the LUMO of Re(CO)3Cl(RL) is ∼60% azo in character. One-electron quasireversible electrochemical reduction occurs near −0.1 and −0.4 V vs. SCE in the cases of Re(CO)3Cl(RLpm) and Re(CO)3Cl(RLim), respectively. The redox orbital is believed to be to the above noted LUMO. Electrogenerated Re(CO)3Cl(RL−) underwent spontaneous solvolytic chloride displacement in MeCN furnishing Re(CO)3(MeCN)(RL−) which has been isolated. The latter in turn reacted with imidazole and triphenyl phosphine furnishing Re(CO)3(C3H4N2)(RL−) and Re(CO)3(PPh3)(RL−), respectively. The pattern of carbonyl stretching frequencies of these radical anion complexes is similar to that of Re(CO)3Cl(RL) but for shifts to lower frequencies by 10-40 cm−1. All the three radical anion systems are one-electron paramagnets (1.7-1.8 μB). The unpaired electron is primarily localized in a predominantly azo-π* orbital. A small metal contribution (185, 187Re, I=5/2) is present and both Re(CO)3(MeCN)(RL−) and Re(CO)3(C3H4N2)(RL−) display six-line EPR spectra (A∼28 G). The line shapes and intensities are characteristic of the presence of g-strain. In the case of Re(CO)3(PPh3)(RL−) seven nearly equispaced lines are observed due to virtually equal coupling with metal and 31P (I=1/2) nuclei. The g values of the radical species span the range 2.0033-2.0066. 相似文献
5.
Liang-Fu Tang Xue-Mei Zhao Zhi-Hong Zou Hai-Bin Song Yu-Ping Zhai 《Journal of organometallic chemistry》2005,690(18):4124-4131
The condensation reaction of CH3COC5H4M(CO)3SnCl3 (M = Mo or W) with PyCONHNH2 (Py = 2,3,4-pyridyl or 2-pyridylmethyl) in mild conditions yields cyclodiazastannoxides fused cyclopentadienyl M-Sn bonded organometallic heterocycle {μ-[C5H4(CH3)CN-NC(O)PyH]M(CO)3SnCl3}. The similar reaction of CH3COC5H4M(CO)3SnCl3 with ArCONHNH2 (Ar = 2-furanyl) gives complexes μ-[C5H4(CH3)CN-NC(O)Ar]M(CO)3SnCl2(H2O), in which the water molecule can be replaced by other N-donor ligands, such as pyridine or 4,4-bipyridine. Arene-bridged organometallic heterocyclic complexes μ-{[C5H4(CH3)CN-NC(O)]2C6H4}{M(CO)3SnCl2(Solvent)}2 have also been prepared by the reaction of CH3COC5H4M(CO)3SnCl3 with terephthaloyl hydrazine. In these new organometallic heterocyclic complexes, it seems that the tin atom prefers to be six-coordinate through absorbing the chloridion or solvent molecules. 相似文献
6.
The paramagnetic complex [Rh(trop2dach)]2 was obtained by reduction of the almost planar 16-electron cationic precursor complex, [Rh(trop2dach)]+1 and characterized by EPR spectroscopy [g11 = 2.069, g22 = 2.014, g33 = 1.964, giso = 2.016; A(Rh) = (<40, 29, 30)]. The unobservable small nitrogen hyperfine coupling and DFT calculations show that most of the spin density is localized on the hydrocarbon ligand framework and only about 35% on the metal center. DFT calculations on various 17 electron rhodium complexes with carbonyl, olefine, or phosphane ligands like [Rh(CO)4], [Rh(cod)2], and [Rh(dppe)2] reveal that in none of these the spin density at the metal center exceeds 45%. That is all formally Rh(0) complexes reported to date are better described as highly delocalized radicals and an assignment of the formal metal oxidation state is not meaningful. 相似文献
7.
Fang Liu 《Journal of organometallic chemistry》2010,695(6):809-3960
A series of heterobinuclear ferrocene-ruthenium complexes Fc(CHCH)nRuCl(CO)(PMe3)3 (n = 1, 3; n = 2, 12), Fc(CHCH)RuCl(CO)(Py)(PPh3)2 (4), and trimetallic Fc(CHCH)RuCl(CO)(PPh3)2(Py-E-(CHCH)Fc) (6) have been prepared. The length of the molecular rods is extended by successive insertion of CHCH spacers in the bridging ligands or the ancillary ligands. The respective products have been fully characterized and the structures of 3 and 12 have been established by X-ray crystallography. Electrochemical studies have revealed that ethenyl heterobimetallic complexes display two successive one-electron processes, and that intermetallic electronic communication between the two endgroups is attenuated with the increase of the length of the conjugated bridge. The electrochemical behavior of the trimetallic complex reveals strong electronic communication between ruthenium and ferrocene transmitted through the ethenyl bridge, however, it also reveals a very weak interaction between ruthenium and ferrocene transmitted through the (E)-CHCH-Py bridge. 相似文献
8.
9.
Jason M. Lynam Tracy D. Nixon Adrian C. Whitwood 《Journal of organometallic chemistry》2008,693(19):3103-3110
Reaction of cis-[RuCl2(dppm)2] (dppm = 1,2-bis(diphenylphosphino)methane) with PhCCH and NaPF6 utilising methanol as solvent results in the formation of the η3-butenynyl complex [Ru(η3-PhCCCCHPh)(dppm)2][PF6] in good yield. Similar reactions with ButCCH and PrnCCH resulted in the corresponding alkyl-substituted complexes and all three of these compounds have been characterised by NMR spectroscopy and X-ray crystallography. The mechanism of this reaction has been probed by employing labelling experiments with both PhCCD and PhC13CH allowing the identity of possible intermediates in the reaction to be determined. Furthermore, [Ru(η3-PhCCCCHPh)(dppm)2][PF6] has been shown to be an effective regio- and stereo-selective catalyst for the dimerisation of PhCCH to Z-PhCCCHCHPh in the absence of solvent. In contrast, no evidence for the formation of alkyne coupling was obtained from the reaction of cis-[RuCl2(dppe)2] (dppe = 1,2-bis(diphenylphosphino)ethane) with PhCCH and NaPF6. 相似文献
10.
Reaction of [Pt()Cl]+ ( = 4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine) with 5-ethynyl-2,2′-bipyridine (HCCbpy) or 5,5′-bis(trimethylsilylethynyl)-2,2′-bipyridine (Me3SiCCbpyCCSiMe3) in the presence of cuprous iodide gives [Pt(tBu3tpy)(CCbpy)]+ (1) or [{Pt()}2(CCbpyCC)]2+ (2) through Pt-acetylide σ-coordination, respectively. Incorporating 1 or 2 with Ln(hfac)3(H2O)2 through 2,2′-bipyridyl chelating the LnIII (Ln = Nd, Eu, and Yb) centers induces formation of a series of [Pt()(CCbpy){Ln(hfac)3}]+ (PtLn) or [{Pt()}2(CCbpyCC){Ln(hfac)3}]2+ (Pt2Ln) complexes, respectively. The structures of binuclear platinum(II) complex 2(PF6)2 and heterobinuclear PtNd complex 3(CF3COO) were determined by single crystal X-ray diffraction. Both 1 and 2 exhibit typical low-energy absorption bands in near UV-Vis region, ascribed to dπ(Pt) → π∗() MLCT and π(CCbpy/CCbpyCC) → π∗() LLCT transitions. Upon formation of the PtLn or PtLn2 complexes, the low-energy absorption bands are obviously blue-shifted (15-20 nm) compared with those in the PtII precursor 1 or 2. With excitation at 350 nm < λ < 550 nm which is the absorption region of MLCT and LLCT transitions, sensitized luminescence that is characteristic of the corresponding lanthanide(III) ions occurs in both PtLn and Pt2Ln complexes. In contrast, Pt-based luminescence from the MLCT and LLCT states are mostly quenched in these Pt-Ln heteronuclear complexes, revealing that quite effective Pt → Ln energy transfer is operating from the Pt()(acetylide) chromophore to the lanthanide(III) centers. 相似文献
11.
12.
The Ru(II) phenyl complex TpRu(PMe3)(NCMe)Ph {Tp = hydridotris(pyrazolyl)borate} reacts with isonitriles to form complexes of the type TpRu(PMe3)(CNR)Ph (R = tBu, CH2Ph, CH2CH2Ph). Neither thermal nor photolytic reactions of these systems with excess isonitrile and benzene resulted in the production of corresponding imines. DFT studies that probed the energetics of the desired catalytic transformations revealed that (Tab)Ru(PH3)(CNCH2CH2Ph)Ph {Tab = tris(azo)borate} is the most stable species in a proposed catalytic cycle. Exclusive of calculated transition states, the highest points on the calculated free energy surface are 34 kcal/mol, for (Tab)Ru(PH3)(o,η2-C,C-CNCH2CH2Ph)Ph {relative to the starting material (Tab)Ru(PH3)(CNCH2CH2Ph)Ph}, and 27 kcal/mol for the C-H activation product (Tab)Ru(PH3)(o-C6H4CH2CH2NC) and benzene. The substantial increases in free energy result primarily from the loss of the stable ruthenium-η1-isonitrile interaction. 相似文献
13.
Within the framework of polarizable continuum model with integral equation formalism (IEF-PCM), an argon matrix effect on the geometry and infrared frequencies of the agostic H2CMH2 (M = Ti, Zr, Hf) methylidene complexes was investigated at B3LYP level of theory with the 6-311++G(3df,3pd) basis set for C, H, and Ti atoms and Stuttgart/Dresden ECPs MWB28 and MWB60 for the Zr and Hf atoms. At the B3LYP/IEF-PCM level of theory, H2CTiH2 was optimized to an energy minimum having a pyramidal structure. The calculated dipole moment of this structure is 3.06 D. The B3LYP/IEF-PCM simulations gave the three complexes’ agostic angle ∠HCM (°), distance r(H?M) (Å), and CM bond length r(CM) (Å) as follows: ∠HCTi = 87.4, r(H?Ti) = 2.079, r(CTi) = 1.803; ∠HCZr = 89.3, r(H?Zr) = 2.243, r(CZr) = 1.956; ∠HCHf = 94.7, r(H?Hf) = 2.343, r(CHf) = 1.972. As a comparison, the B3LYP simulations gave the values as follows: ∠HCTi = 91.5, r(H?Ti) = 2.150, r(CTi) = 1.811; ∠HCZr = 92.9, r(H?Zr) = 2.299, r(CZr) = 1.955; ∠HCHf = 95.6, r(H?Hf) = 2.352, r(CHf) = 1.967. As far as the MH2 symmetric and asymmetric stretching and CH2 wagging frequencies are concerned, the IEF-PCM calculated values are in better agreement with the experimental argon matrix ones than those calculated based on a gas phase model. 相似文献
14.
Xiaojun Tan Weihua Wang Qiufen Wang Fei Liu 《Journal of organometallic chemistry》2008,693(3):475-482
The geometries and isomerization of the imine germylenoid HNGeNaF as well as its insertion reactions with R-H (R = F, OH, NH2, CH3) have been systematically investigated at the B3LYP/6-311+G∗ level of theory. The potential barriers of the four insertion reactions are 117.2, 172.6, 219.7, and 322.3 kJ/mol, respectively. Here, all the mechanisms of the four reactions are identical to each other, i.e., an intermediate has been formed first during the insertion reaction. Then, the intermediate could dissociate into the substituted germylene (HNGeHR) and NaF with a barrier corresponding to their respective dissociation energies. Correspondingly, the reaction energies for the four reactions are 185.0, 208.1, 224.4, and 266.9 kJ/mol, respectively, which are linearly correlated with the calculated barrier heights. Compared with the insertion reaction of HNGe: and R-H, the introduction of NaF makes the insertion reaction occur easily though it is more difficult to proceed than that of insertion reaction between H2GeNaF and R-H. Furthermore, the effects of halogen (F, Cl, Br) substitution and inorganic salts employed on the reaction activity have also been discussed. As a result, the relative reactivity among the four insertion reactions should be as follows: H-F > H-OH > H-NH2 > H-CH3. 相似文献
15.
N. Khelidj X. Colin L. Audouin C. Monchy-Leroy 《Polymer Degradation and Stability》2006,91(7):1598-1605
This paper deals with the kinetic modelling of unstabilised polyethylene thermal oxidation, particular attention being paid to the domain of low temperatures, typically below 80 °C. Experimental data show that the temperature dependence of the induction time ti and the steady state rate of oxygen absorption rS display a discontinuity at 80 °C. A model based on the hypothesis that this discontinuity concerns only the PO2 bimolecular combination processes and is essentially explained by the competition between terminating and non-terminating PO2 + PO2 reactions, was proposed. With pertinent values of the Arrhenius parameters of the elementary reactions under consideration, the model fits well the experimental data (in the 40-200 °C temperature range) and is consistent with previously analysed results of radiochemical ageing. According to this model, 35-40% of the bimolecular PO2 combinations would not be terminating at 45 °C and this proportion would increase with the temperature. Concerning terminations, the relative fraction of coupling processes, leading to peroxide bridges, would decrease relatively to the disproportionation processes when the temperature increases. 相似文献
16.
Yi-Qiang Tang 《Journal of organometallic chemistry》2011,696(23):3741-3744
A new type of well-defined N-heterocyclic carbene (NHC)-palladium chloride-imidazole complexes derived from IPrHCl or IMesHCl, PdCl2 and 1-methylimidazole exhibits high catalytic activity in the room-temperature Suzuki-Miyaura coupling reactions of aryl or heteroaryl chlorides. Moreover, the large-scale (20.0 mmol) couplings in the presence of 0.01 mol% catalyst loading can also give the corresponding coupling products in high yields. 相似文献
17.
Reacting [PtCl(PTA)3]Cl(PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane) with KSeCN in aqueous or MeOH medium results in the abstraction of the PTA ligands to yield SePTA. The reaction also proceeds quantitatively by direct reaction of PTA and KSeCN in water or methanol. The methylated PTA ligand, [PTA-Me]I (1-methyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3.1.13,7]decane iodide), reacts accordingly with KSeCN, albeit significantly slower. The crystal structure of SePTA, 1, and [SePTA-Me]I · CH3OH, 2, revealed PSe bond distances of 2.0991(19) and 2.100(2) Å, respectively. The first order phosphorous selenium coupling constants, 1JP-Se (D2O), of 722 and 788 Hz for SePTA and [SePTA-Me]I, respectively, indicates the latter is significantly less electron rich. 相似文献
18.
Ab initio calculations with full electron correlation by the perturbation method to second order and hybrid density functional theory calculations by the B3LYP method utilizing the 6-31G(d), 6-311+G(d, p), and 6-311+G(2d, 2p) basis sets have been carried out for the XNCO and XOCN (X = H, F, Cl, Br) molecules. From these calculations, force constants, vibrational frequencies, infrared intensities, Raman activities, depolarization ratios, and structural parameters have been determined and compared to the experimental quantities when available. By combining previously reported rotational constants for HNCO, ClNCO and BrNCO with the ab initio MP2/6-311+G(d, p) predicted structural values, adjusted r0 parameters have been obtained. The r0 values for BrNCO are: r(BrN) = 1.857(5); r(NC) = 1.228(5); r(CO) = 1.161(5) Å; BrNC = 117.5(5) and NCO = 172.3(5)°. For ClNCO the determined r0 parameters are in excellent agreement with the previously determine rs values, whereas those for HNCO the HNC angle is larger with a value of 126.3(5)° compared to the previous reported value of 123.9(17)°. However, considering the relatively large uncertainty in the value given initially the two results are in near agreement. Structural parameters are also estimated for FNCO and XOCN (X = H, F, Cl, Br). The centrifugal distortion constants have been calculated and are compared to the experimentally (XNCO: X = H, Cl, Br) determined values. Predicted values for the barriers of linearity are given for both the XNCO (X = H, F, Cl, Br) molecules and the results were compared to the corresponding isothiocyanate molecules. The predicted frequencies for the fundamentals of the XNCO molecules compare favorably to the experimental values but some of the predicted intensities differ significantly from those in the observed spectra. The two OCN bends for HOCN have been assigned and the frequencies for the two corresponding fundamentals of DOCN are predicted. 相似文献
19.
Alexander Yu. Makarov Ruediger Mews Andrey V. Zibarev 《Journal of fluorine chemistry》2006,127(3):437-442
Mismatched molecular 1:1 complexes of C10F8 with catenated chalcogen-nitrogen compounds C6H5-X-NSN-SiMe3 (X = S, Se) were prepared and characterized by X-ray crystallography. The complexes provide examples of structurally non-rigid polyheteroatom molecules involved in non-covalent arene-polyfluoroarene π-stacking interactions. In going from homocrystals to the co-crystals, the molecular Z, E configuration of the catenated compounds changes from noticeably non-planar to perfectly planar, i.e. C10F8 acts as “molecular iron”. On the other hand, C10H8 does not produce complexes with C6F5-X-NSN-SiMe3 (X = S, Se). 相似文献
20.
Evaluation of chemiluminescence reagents for selective detection of reactive oxygen species 总被引:2,自引:0,他引:2
Shinya Yamaguchi Kaname Ohyama Maiko Kohno Akira Takadate Naotaka Kuroda 《Analytica chimica acta》2010,665(1):74-27
In order to evaluate the chemiluminescence (CL) reagents for selective detection of reactive oxygen species (ROS), we comprehensively measured the CL responses of 20 CL reagents (three luminol derivatives, two imidazopyrazinone derivatives, eight lophine derivatives, six acridinium ester derivatives and lucigenin) against six types of ROS (superoxide anion: O2−, hydroxyl radical: OH, hydrogen peroxide: H2O2, hypochlorite anion: ClO−, singlet oxygen: 1O2, and nitric oxide: NO). As a result of the screening, it was found that nine CL reagents selectively detected O2− while one CL reagent selectively detected OH. However, no CL reagent had selectivity on the detection of H2O2, ClO−, 1O2 and NO. Our screening results could help to select the most suitable CL reagent for selective determination of different ROS.As an application study, 4-methoxyphenyl-10-methylacridinium-9-carboxylate (MMAC), one of the acridinium ester derivatives, showed high selectivity on the detection of O2−, and thus was applied to the assay of superoxide dismutase (SOD) activity. The dynamic range and detection limit of the developed CL assay were 0.1-10 and 0.06 U mL−1, respectively. Significant correlation (r = 0.997) was observed between the results by the CL assay using MMAC and the spectrophotometric assay using 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt. 相似文献