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1.
UV photolysis of [CpFeII(CO)3]+ PF66? (I) or [CpFeII6-toluene)]+ PF6?? (II) in CH3CN in the presence of 1 mole of a ligand L gives the new air sensitive, red complexes [CpFeII(NCCH3)2L]+PF6? (III, L = PPh3; IV; L = CO; VIII, L = cyclohexene; IX, L = dimethylthiophene) and the known air stable complex [CpFeII(PMe3)2(NCMe)]+ PF6? (V). The last product is also obtained by photolysis in the presence of 2 or 3 moles of PMe3. In the presence of dppe, the known complex [CpFeII (dppe)(NCCH3)]+ (XI) is obtained. Complex III reacts with CO under mild conditions to give the known complex [CpFe(NCCH3)(PPh3)CO]+ PF6? (X). UV photolysis of I in CH3CN in the presence of 1-phenyl-3,4-dimethylphosphole (P) gives [CpFeIIP3]+ PF6? (XII); UV photolysis of II in CH2Cl2 in the presence of 3 moles of PMe3 or I mole of tripod (CH3C(CH2Ph2)3) provides an easy synthesis of the known complexes [CpFeII(PMe3)3]+ PF6? (VII) or [CpFeIIη3-tripod]+ PF6t- (XIII). Since I and II are easily accessible from ferrocene, these photolytic syntheses provide access to a wide range of piano-stool cyclopentadienyliron(II) cations in a 2-step process from ferrocene.  相似文献   

2.
Upconversion luminescence tuning of β‐NaYF4 nanorods under 980 nm excitation has successfully been achieved by tridoping with Ln3+ ions with different electronic structures. The effects of Ce3+ ions on NaYF4:Yb3+/Ho3+ as well as Gd3+ ions on NaYF4:Yb3+/Tm3+(Er3+) have been studied in detail. By tridoping with Ce3+ ions, not only were unusual 5G55I7 and 5F2/3K85I8 transitions from Ho3+ ions and 5d→4f transitions from Ce3+ ions observed in NaYF4:Yb3+/Ho3+ nanorods, but also an increase in the intensity of 5F55I8 relative to 5S2/5F45I8 with increasing Ce3+ concentration, which can be attributed to efficient energy transfers of 5I6 (Ho)+2F5/2 (Ce)→5I7 (Ho)+2F7/2 (Ce) and 5S2/5F4 (Ho)+2F5/2 (Ce)→5F5 (Ho)+2F7/2 (Ce). Interestingly, with increasing pump power density, the luminescence of NaYF4:Yb3+/Ho3+ nanorods is always dominated by the 5S2/5F45I8 transition, whereas the luminescence of Ce3+‐tridoped NaYF4:Yb3+/Ho3+ nanorods is dominated by the 5S2/5F45I8 and 5G55I7 transitions in turn. These observations are discussed on the basis of a rate equation model. Furthermore, Gd3+‐tridoped NaYF4:Yb3+/Tm3+(Er3+) nanorods can emit multicolor upconversion emissions spanning from the UV to the near‐infrared under 980 nm excitation. 6P5/28S7/2 (≈306 nm) and 6P7/28S7/2 (≈311 nm) transitions from Gd3+ ions were observed. In addition to the aforementioned luminescence properties, these Gd3+‐tridoped nanorods also exhibit paramagnetic behavior at room temperature and superparamagnetic behavior at 2 or 5 K.  相似文献   

3.
Studies of the stoichiometry and kinetics of the reaction between hydroxylamine and iodine, previously studied in media below pH 3, have been extended to pH 5.5. The stoichiometry over the pH range 3.4–5.5 is 2NH2OH + 2I2 = N2O + 4I? + H2O + 4H+. Since the reaction is first-order in [I2] + [I3?], the specific rate law, k0, is k0 = (k1 + k2/[H+]) {[NH3OH+]0/(1 + Kp[H+])} {1/(1 + KI[I?])}, where [NH3OH+]0 is total initial hydroxylamine concentration, and k1, k2, Kp, and KI are (6.5 ± 0.6) × 105 M?1 s?1, (5.0 ± 0.5) s?1, 1 × 106 M?1, and 725 M?1, respectively. A mechanism taking into account unprotonated hydroxylamine (NH2OH) and molecular iodine (I2) as reactive species, with intermediates NH2OI2?, HNO, NH2O, and I2?, is proposed.  相似文献   

4.
Structures and enthalpies of formation have been calculated, in the MNDO approximation using UHF wave-functions for open shell species, for tetramethyldiphosphine, Me4P2, and the major ions in its mass spectrum: Me4P2+, Me3P2H+, Me3P2+, Me2P2H2+ (3 forms), Me2P2H+ (3 forms), Me2P2+ (3 forms), MePPCH2+ (3 forms), MeP2+ and MePCH2+, together with all the corresponding neutral fragments. Appearance potentials are calculated for all the ions, and possible fragmentation pathways deduced.  相似文献   

5.
The assembly of [Cd(L1)] {[L1]3— = N[CH2CH2N=C(CH3)COO]3} into the tetranuclear cluster {[Cd(L1)]Na(H2O)2}2 in the presence of Na+ is mediated by Na+‐carboxylate interactions; in contrast In3+ and Fe3+ induce the partial hydrolysis of [L1]3— to afford the complexes [In(L2)Cl] and {[Fe(L2)]2O} {[L2]2— = N[CH2CH2NH2][CH2CH2N=C(CH3)COO]2} which aggregate via intermolecular H‐bonding.  相似文献   

6.
Novel catalytically active monooxomolybdenum(IV) species containing four thiolate ligands obtainable in solution by NaBH4 reduction of [MovO(SC6H5)4], [MovO(Z-cys-Val-OMe)4], (Z=benzyloxycarbonyl), or [MovO(S2C6H4)2] perform the pyridine-N-oxide oxidation of benzoin in N,N-dimethylformamide at 30 °C. The order of catalytic activity is [MovO(Z-cys-Val-OMe)4] > [MovO(S2C6H4)2] > [MovO(SC6H5)4] ([benzoin]/[oxidant]/[catalyst]= 20/20/1), while the oxidation by air under the same catalytic conditions gives a different order, [MovO(Z-cys-Val-OMe)4]> [MovO(SC6H5)4] >[MovO(S2C6H4)2]. During the catalytic cycle in the amine-N-oxide oxidation, two intermediate species, [MoIVOL4]2− and [MoVIO2L4]2−, were detected by 1H NMR, while in the air oxidation an unidentified Mo(VT) species is involved.  相似文献   

7.
The effect of the acidity of the medium on the hydroxylation and nitration of alkanes (RH) in 90–98% H2SO4 at 25°C is described quantitatively by a model taking account of the thermodynamic activity of the RH, H2O, and HSO4- particles. It was concluded that in the transition states the reagents H3O2+HSO4- and NO2+ HSO4- are present as HO+ and NO2+ ions without the bases H–O and HSO4-, the alkanes are present without hydrophobic shells, and the initial reaction products are ROH2+ and RNO2H+.  相似文献   

8.
In this study, we investigated the effects of four inorganic anions (Cl, SO42−, H2PO4/HPO42−, and HCO3/CO32−) on titanium dioxide (TiO2)-based photocatalytic oxidation of aqueous ammonia (NH4+/NH3) at pH  9 and ∼10 and nitrite (NO2) over the pH range of 4–11. The initial rates of NH4+/NH3 and NO2 photocatalytic oxidation are dependent on both the pH and the anion species. Our results indicate that, except for CO32−, which decreased the homogeneous oxidation rate of NH4+/NH3 by UV-illuminated hydrogen peroxide, OH scavenging by anions and/or direct oxidation of NH4+/NH3 and NO2 by anion radicals did not affect rates of TiO2 photocatalytic oxidation. While HPO42− enhanced NH4+/NH3 photocatalytic oxidation at pH  9 and ∼10, H2PO4/HPO42− inhibited NO2 oxidation at low to neutral pH values. The presence of Cl, SO42−, and HCO3 had no effect on NH4+/NH3 and NO2 photocatalytic oxidation at pH  9 and ∼10, whereas CO32− slowed NH4+/NH3 but not NO2 photocatalytic oxidation at pH  11. Photocatalytic oxidation of NH4+/NH3 to NO2 is the rate-limiting step in the complete oxidation of NH4+/NH3 to NO3 in the presence of common wastewater anions. Therefore, in photocatalytic oxidation treatment, we should choose conditions such as alkaline pH that will maximize the NH4+/NH3 oxidation rate.  相似文献   

9.
The recombination energy of N22+ has been computed using N22+, N22+ and N2 potential curves from the literature. Vibrational overlaps and energies liberated in the various N22+3?g,1g+, 3Πu, 1Πu → N2+(X2+g, A 2+g, A 2Πu, B2u+,C2u+) vibronic transitions have been computed and used as input for determination of the N2+ recombination energy.  相似文献   

10.
The effect of Cl?, Br?, I?, ClO4?, NO3?, HSO4?, HCrO4? and H2PO4? on the of Al in 2 M HCl is studied by the thermometric method. Three sets of experiments are carried out, which allow the variation of the concentration of the various species in a programmed manner. Dissolution promotion is noted in solutions to which HCl, HBr and H2CrO4 are added. The way of action of each of these anions is discussed. Additions of HI, HClO4, H2SO4 and H3PO4, on the other hand, first retard and later enhance the dissolution of Al in 2 M HCl, as their concentration in solution is increased. This is related to anion adsorption, which is counterbalanced by increase in acidity. HNO3 differs from the other tested acids in causing only dissolution retardation. Experiments in which LaCl3 is added to the test solution indicate that the NO3? is adsorbed as such on Al2O3. The ability of the various anions to retard the dissolution of Al in 2 M HCl decreases in the succession: NO3? (strong)>I?>HSO4?>H2PO4?>Br?, ClO4? (weak)  相似文献   

11.
In aqueous H2SO4, Ce(IV) ion oxidizes rapidly Arnold's base((p-Me2NC6H4)2CH2, Ar2CH2) to the protonated species of Michler's hydrol((p-Me2NC6H4)2CHOH, Ar2CHOH) and Michler's hydrol blue((p-Me2NC6H4)2CH+, Ar2CH+). With Ar2CH2 in excess, the rate law of the Ce(IV)-Ar2CH2 reaction in 0.100 M H2SO4 is expressed -d[Ce(IV)]/dt = kapp[Ar2CH2]0[Ce(IV)] with kapp = 199 ± 8M?1s?1 at25°C. When the consumption of Ce(IV) ion is nearly complete, the characteristic blue color of Ar2CH+ ion starts to appear; later it fades relatively slowly. The electron transfer of this reaction takes place on the nitrogen atom rather than on the methylene carbon atom. The dissociation of the binuclear complex [Ce(III)ArCHAr-Ce(III)] is responsible for the appearance of the Ar2CH+ dye whereas the protonation reaction causes the dye to fade. In highly acidic solution, the rate law of the protonation reaction of Michler's hydrol blue is -d[Ar2CH+]/dt = kobs[Ar2CH+] where Kobs = ((ac + 1)[H*] + bc[H+]2)/(a + b[H+]) (in HClO4) and kobs= ((ac + 1 + e[HSO4?])[H+] + bc[H+]2 + d[HSO4?] + q[HSO4?]2/[H+])/(a + b[H+] + f[HSO4?] + g[HSO4?]/[H+]) (in H2SO4), and at 25°C and μ = 0.1 M, a = 0.0870 M s, b = 0.655 s, c = 0.202 M?1s?1, d = 0.110, e = 0.0070 M?1, f = 0.156 s, g = 0.156 s, and q = 0.124. In highly basic solution, the rate law of the hydroxylation reaction of Michler's hydrol blue is -d[Ar2CH+]/dt = kOH[OH?]0[Ar2CH+] with kOH = 174 ± 1 M?1s?1 at 25°C and μ = 0.1 M. The protonation reaction of Michler's hydrol blue takes place predominantly via hydrolysis whereas its hydroxylation occurs predominantly via the path of direct OH attack.  相似文献   

12.
Iron(II), (Fe(H2O)62+, (FeII) participates in many reactions of natural and biological importance. It is critically important to understand the rates and the mechanism of FeII oxidation by dissolved molecular oxygen, O2, under environmental conditions containing bicarbonate (HCO3), which exists up to millimolar concentrations. In the absence and presence of HCO3, the formation of reactive oxygen species (O2, H2O2, and HO⋅) in FeII oxidation by O2 has been suggested. In contrast, our study demonstrates for the first time the rapid generation of carbonate radical anions (CO3) in the oxidation of FeII by O2 in the presence of bicarbonate, HCO3. The rate of the formation of CO3 may be expressed as d[CO3]/dt=[FeII[[O2][HCO3]2. The formation of reactive species was investigated using 1H nuclear magnetic resonance (1H NMR) and gas chromatographic techniques. The study presented herein provides new insights into the reaction mechanism of FeII oxidation by O2 in the presence of bicarbonate and highlights the importance of considering the formation of CO3 in the geochemical cycling of iron and carbon.  相似文献   

13.
The vibrational spectra of a number of transition-metal complexes containing terminal or bridging nitrido (N3?) and oxo (O2?) ligands are reported. Full assignments of fundamental modes are given for (OsO314N)?, (OsO315N)?, (Os14NX4)?, (Os15NX4)?, (Ru14NX4)?, (Os14NX5)2?, (Os15NX5)2? and (Ru14NX5)2? (X = Cl, Br), and also for the oxo complexes (Mo16OCl4, (Mo18OCl4)?, (Mo16OCl5)2? and (Mo18OCl5)2?. Force constants have been evaluated for the four- and five-coordinate complexes. The significance of the results is discussed in terms of the metalligand bonding involved in these species.  相似文献   

14.
Tandem mass spectrometric studies show that SiH+5 is formed in bimolecular reactions of SiH4 and NH+2, C2H+3, C2H+6 and C3H+8 ions. The dependence of the reaction cross sections on ion energy indicates the formation of SiH+5 from NH+2, C2H+3, and C2H+6 to be exothermic reactions, while formation from C3H+8 is endothermic. Using known thermochemical data, these facts permit the assignment of 150 and 156 kcal/mole to the lower and upper limits of the proton affinity of monosilane.  相似文献   

15.
The reaction of UO2(OAc)2 ⋅ 2H2O with the biologically inspired ligand 2-salicylidene glucosamine (H2 L1 ) results in the formation of the anionic trinuclear uranyl complex [(UO2)3(μ3-O)( L1 )3]2− ( 1 2−), which was isolated in good yield as its Cs-salt, [Cs]2 1 . Recrystallization of [Cs]2 1 in the presence of 18-crown-6 led to formation of a neutral ion pair of type [M(18-crown-6)]2 1 , which was also obtained for the alkali metal ions Rb+ and K+ (M=Cs, Rb, K). The related ligand, 2-(2-hydroxy-1-naphthylidene) glucosamine (H2 L2 ) in a similar procedure with Cs+ gave the corresponding complex [Cs(18-crown-6)]2[(UO2)3(μ3-O)( L2 )3 ([Cs(18-crown-6)]2 2 ). From X-ray investigations, the [(UO2)3O( Ln )3]2− anion (n=1, 2) in each complex is a discrete trinuclear uranyl species that coordinates to the alkali metal ion via three uranyl oxygen atoms. The coordination behavior of H2 L1 and H2 L2 towards UO22+ was investigated by NMR, UV/Vis spectroscopy and mass spectrometry, revealing the in situ formation of the 1 2− and 2 2−dianions in solution.  相似文献   

16.
Deconvolutions of measured absorption line profiles in the 1n0 (n = 0 to 5) and the 320 bands of the Ã2A2X?2B1 electronic transition of ClO2 reveal subnanosecond lifetimes for all rotational levels of the 2A2 state. Observed ratios of radiationless rates from spin-doublet components identify direct spin-orbit coupling of the 2A2 state with 2A1 and/or 2B1 vibronic states as a predominant predissociation mechanism. Variations of rates with ν′1 locate an intersection of a second potential surface with that of the 2A2 state.  相似文献   

17.
Upon collisional activation, gaseous metal adducts of lithium, sodium and potassium oxalate salts undergo an expulsion of CO2, followed by an ejection of CO to generate a product ion that retains all three metals atoms of the precursor. Spectra recorded even at very low collision energies (2 eV) showed peaks for a 44‐Da neutral fragment loss. Density functional theory calculations predicted that the ejection of CO2 requires less energy than an expulsion of a Na+ and that the [Na3CO2]+ product ion formed in this way bears a planar geometry. Furthermore, spectra of [Na3C2O4]+ and [39K3C2O4]+ recorded at higher collision energies showed additional peaks at m/z 90 and m/z 122 for the radical cations [Na2CO2]+? and [K2CO2]+?, respectively, which represented a loss of an M? from the precursor ions. Moreover, [Na3CO2]+, [39K3CO2]+ and [Li3CO2]+ ions also undergo a CO loss to form [M3O]+. Furthermore, product‐ion spectra for [Na3C2O4]+ and [39K3C2O4]+ recorded at low collision energies showed an unexpected peak at m/z 63 for [Na2OH]+ and m/z 95 for [39K2OH]+, respectively. An additional peak observed at m/z 65 for [Na218OH] + in the spectrum recorded for [Na3C2O4]+, after the addition of some H218O to the collision gas, confirmed that the [Na2OH] + ion is formed by an ion–molecule reaction with residual water in the collision cell. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

18.
The kinetics of the base catalysed racemization of [Co(EN3A)H2O]
  • 1 Abbreviations: EN3A3?=(?OOCCH2)2N(CH2)2NHCH2COO?; ME3A3?=(?OOCCH2)2N(CH2)2 N(CH3)CH2COO?; EDDA2?=?OOCCH2NH(CH2)2NHCH2COO?; EDTA4?=(?OOCCH2)2N(CH2)2N(CH2COO?)2;TNTA4?=(?OOCCH2)2N(CH2)3N(CH3COO?)2; HETA3?=(?OOCCH2)2N(CH2)2N(CH2COO?)CH2CH2OH; en=H2N(CH2)2NH2; Meen=H2N(CH2)2NHCH3; sar?=?OOCCH2NHCH3.
  • were studied polarimetrically in aqueous buffer solution. The reaction rate is first order in OH? and in complex, in weakly acidic medium. Activation parameters are ΔH≠=22 kcal · mol?1, ΔS≠=26 cal · K?1. The results are discussed in terms of an SN1CB mechanism involving exchange of the ligand water molecule. The N-methylated analogue [Co(ME3A)H2O] does not racemize in the pH-range investigated. Loss of optical activity occurs at a rate which is about 1,000 times slower than the racemization of [Co(EN3A)H2O](60°) and coincides with the decomposition of the complex.  相似文献   

    19.
    Abstract

    This study focusses on the preparation of ifosfamide (1; R1=CH2CH2Cl, R2=NHCH2CH2Cl) and cyclophosphamide (2 R1=H, R2=N(CH2CH2Cl)2), standard drugs in tumor therapy, in order to avoid the alkylating educts like 2-chloroethylamine by introducing chlorine in the final reaction step. The reaction of the trimethylsilyl compounds (3; R1=CH2CH2Cl, R2=NHCH2CH20SiMe3) and (4; R1=H, R2=N(CH2CH20SiMe3)2), respectively, with 2-chloro- 1,3,5-trimethyl-1,3,5-triaza-σ3λ3-2-phosphoM-4,6-dione, followed by chlorination of the resulting product with sulphuryl chloride, furnished the cytotoxic drugs (1) and (2) [l].  相似文献   

    20.
    The mass spectra of 30 sulfinamide derivatives (RSONHR', R' alkyl or p-XC6H4) are reported. Most of the spectra had peaks attributable to thermal decomposition products. For some compounds these were identified by pyrolysis under similar conditions to be: RSO2NHR', RSO2SR, RSSR and NH2R' (in all kinds of sulfinyl amides); RSNHR' (in the case of arylsulfinyl arylamides); RSO2C6H4NH2, RSOC6H4NH2 and RSC6H4NH2 (in the case of arylsulfinyl arylamides of the type of X = H) The mass spectra of the three thermally stable compounds showed that there are several kinds of common fragment ions. The mass spectra of the thermally labile compounds had two groups of ions; (i) characteristic fragment ions of the intact molecules and (ii) the molecular ions of the thermal decomposition products. It was concluded that the sulfinamides give the following ions after electron impact: [M]+, [M ? R]+, [M ? R + H]+, [M ? SO]+, [RS]+, [NHR']+, [NHR' + H]+, [RSO]+, [RSO + H]+, [R]+, [R + H]+, [R']+ and [M ? OH]+, and that the thermal decomposition products give the following ions: [RSO2SR]+, [RSSR]+, [M ? O]+, [M + O]+ and [RSOC6H4NH2]+.  相似文献   

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