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1.
The hydrolysis of trimethyltin(IV) has been studied by potentiometry (H+ -glass electrode) and calorimetry in various salt media (NaNO3, NaCl, KCl, Na2SO4, and NaNO3—NaCl mixtures). The effect of ionic strength on the hydrolysis constants is accounted for by a simple Debye–Hückel type equation and by Pitzer equations. The results allow us to obtain H for hydrolysis and the temperature dependence of the Pitzer parameters. The resulting coefficients can be used to examine the speciation of (CH3)3Sn+ in multicomponent electrolyte solutions, such as natural waters, over a wide range of temperature and ionic strength.  相似文献   

2.
We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa‐bridging elements. Their preparation was achieved by salt‐elimination reactions of the dilithiated precursor [Mn(η5‐C5H4Li)(η6‐C6H5Li)]?pmdta (pmdta=N,N,N′,N′,N′′‐pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single‐atom‐bridged derivatives, [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] and [Mn(η5‐C5H4)(η6‐C6H5)SiPh2], could also be determined by X‐ray structural analysis. We investigated for the first time the reactivity of these ansa‐cyclopentadienyl–benzene manganese compounds. The reaction of the distannyl‐bridged complex [Mn(η5‐C5H4)(η6‐C6H5)Sn2tBu4] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn?Sn bond to give a triatomic ansa‐bridge. The investigation of the ring‐opening polymerization (ROP) capability of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] with [Pt(PEt3)3] showed that an unexpected, unselective insertion into the Cipso?Sn bonds of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] had occurred.  相似文献   

3.
A series of arylantimony ferrocenecarboxylates with the formula (C5H5FeC5H4CO2)nSbAr(5?n) (n = 1, 2; Ar = C6H5, 4‐CH3C6H4, 3‐CH3C6H4, 2‐CH3C6H4, 4‐ClC6H4, 4‐FC6H4) were synthesized and characterized by elemental analysis, IR, 1H NMR and mass spectra. The crystal structures of (C5H5FeC5H4CO2)2Sb(4‐CH3C6H4)3 and C5H5FeC5H4CO2SbPh4 were determined by X‐ray diffraction. Four human neoplastic cell lines (HL‐60, Bel‐7402, KB and Hela) were used to screen these compounds. The results indicate that these compounds at 10 µM show certain in vitro antitumor activities. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

4.
The o‐substituted hybrid phenylphosphines, PPh2(o‐C6H4NH2) and PPh2(o‐C6H4OH), could be deprotonated with LDA or n‐BuLi to yield PPh2(o‐C6H4NHLi) and PPh2(o‐C6H4OLi), respectively. When added to a solution of (η5‐C5H5)Fe(CO)2I at room temperature, these two lithiated reagents produce a chelated neutral complex 1 (η5‐C5H5)Fe(CO)[C(O)NH(o‐C6H4)PPh2C,P‐η2] for the former and mainly a zwitterionic complex 2 , (η5‐C5H5)Fe+(CO)2[PPh2(o‐C6H4O?)] for the latter. Complex 1 could easily be protonated and then decarbonylated to give 4 [(η5‐C5H5)Fe(CO){NH2(o‐C6H4)PPh2N,P‐η2}+]. Complexes 1 and 4‐I have been crystallographically characterized with X‐ray diffraction.  相似文献   

5.
Boiling temperature measurements have been made at ambient pressure for saturated ternary solutions of NaCl + KNO3 + H2O, NaNO3 + KNO3 + H2O, and NaCl + Ca(NO3)2 + H2O over the full composition range, along with those of the single salt systems. Boiling temperatures were also measured for the four component NaCl + NaNO3 + KNO3 + H2O and five component NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O mixtures, where the solute mole fraction of Ca(NO3)2, x{Ca(NO3)2}, was varied between 0 and 0.25. The maximum boiling temperature found for the NaCl + KNO3 + H2O system is ≈134.9 C; for the NaNO3 + KNO3 + H2O system is ≈165.1 C at x(NaNO3) ≈ 0.46 and x(KNO3) ≈ 0.54; and for the NaCl + Ca(NO3)2 + H2O system is 164.7 ± 0.6 C at x{NaCl} ≈ 0.25 and x{Ca(NO3)2} ≈ 0.75. The NaCl + NaNO3 + KNO3 + Ca(NO3)2 + H2O system forms molten salts below their maximum boiling temperatures and the temperatures corresponding to the cessation of boiling (dry-out temperatures) of these liquid mixtures were determined. These dry-out temperatures range from ≈300 C when x{Ca(NO3)2} = 0 to ≥ 400 C when x{Ca(NO3)2} = 0.20 and 0.25. Mutual deliquescence/efflorescence relative humidity (MDRH/MERH) measurements were also made for the NaNO3 + KNO3 and NaCl + NaNO3 + KNO3 salt mixture from 120 to 180 C at ambient pressure. The NaNO3 + KNO3 salt mixture has a MDRH of 26.4% at 120 C and 20.0% at 150 C. This salt mixture also absorbs water at 180 C, which is higher than expected from the boiling temperature experiments. The NaCl + NaNO3 + KNO3 salt mixture was found to have a MDRH of 25.9% at 120 C and 10.5% at 180 C. The investigated mixture compositions correspond to some of the major mineral assemblages that are predicted to control brine composition due to the deliquescence of salts formed in dust deposited on waste canisters in the proposed nuclear repository at Yucca Mountain, Nevada.  相似文献   

6.
Synthesis, Structure, and Properties of Some Selenidostannates. II. [(C2H5)3NH]2Sn3Se7 · 0,25 H2O and [(C3H7)2NH2]4Sn4Se10 · 4 H2O The new selenidostannate hydrates [(C2H5)3NH]2Sn3Se7 · 0.25 H2O ( I ) and [(C3H7)2NH2]4Sn4Se10 · 4 H2O ( II ) were synthesized from an aqueous suspension of triethylammonium (tripropylammonium), tin, selenium I and in addition sulfur II at 130 °C. I crystallizes at ambient temperature in the monoclinic space group P21/n (a = 2069,3(4) pm, b = 1396,6(3) pm, c = 2342,8(5) pm, β = 114,68(3)°, Z = 8) and is characterized by two different anions, chains from edge‐sharing [Se3Se7]2– units and nets from trigonal SnSe5 bipyramids. II crystallizes at ambient temperature in the tetragonal space group I41/amd (a = 2150,0(3) pm, c = 1174,4(2) pm, Z = 4) and contains adamantane like [Sn4Se10]4–‐cages. The UV‐VIS spectra of the selenidostannates demonstrate that the absorption edges red shift as the dimensionality of the compounds is increased.  相似文献   

7.
The hydrolysis of methyltin(IV) trichloride (CH3SnCl3) has been studied in aqueous NaCl and NaNO3 solutions (0 < I/mol dm−3 ≤ 1), at different temperatures (15 ≤ T/°C ≤ 45) by­potentiometric measurements (H+‐glass electrode). By considering the generic hydrolytic <?tw=97.2%>reaction pCH3Sn3+ + qH2O = (CH3Sn)p(OH)q3pq<?tw>­+ qH+ (logβpq), we have the formation of five species and logβ12 = −3.36, logβ13 = −8.99, logβ14 = −20.27 and logβ25 = −7.61. The first hydrolysis step is measurable only at very low pH values and was not determined: a rough estimate of the hydrolysis constant is logβ11 = −1.5 (± 0.5). The dependence on ionic strength of logβpq is quite different in NaNO3 and NaCl solutions, and the formation at low pH values of the species CH3Sn(OH)Cl+ has been found with logβ = −1.40. Hydrolysis constants strongly depend on temperature and from the relationships logβpq = f(T), ΔH ° values have been calculated. Speciation problems of CH3Sn3+ in aqueous solution are discussed. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

8.
A tetranuclear copper‐calcium complex of pyridinioacetate (C5H5N+CH2CO2), namely [Cu2Ca2(C5H5NCH2CO2)(H2O)3](ClO4)8·H2O was synthesized and characterized by X‐ray crystallography. The complex crystallizes in triclinic, P1¯ (No. 2), a = 15.658(2), b = 18.260(2), c = 18.456(2)Å, α = 91.552(2), β = 94.004(3), γ = 104.928(2)°, V = 5081(1)Å3, Z = 2. In the crystal structure, a square‐planar [Cu(C5H5NCH2CO2)4]2+ entity uses three of its four carboxylate groups to chelate to a calcium atom forming a [CuCa(C5H5NCH2CO2)4]4+ dinuclear subunit, and a pair of such dinuclear subunits are linked by the two remaining pyridinioacetate ligands through the calcium atoms to furnish a tetranuclear [Cu2Ca2 (C5H5NCH2CO2)10(H2O)3]8+ cation.  相似文献   

9.
The scandium(III) cations in the structures of pentaaqua(biuret‐κ2O,O′)scandium(III) trichloride monohydrate, [Sc(C2H5N3O2)(H2O)5]Cl3·H2O, (I), and tetrakis(biuret‐κ2O,O′)scandium(III) trinitrate, [Sc(C2H5N3O2)4](NO3)3, (II), are found to adopt very different coordinations with the same biuret ligand. The roles of hydrogen bonding and the counter‐ion in the establishment of the structures are described. In (I), the Sc3+ cation adopts a fairly regular pentagonal bipyramidal coordination geometry arising from one O,O′‐bidentate biuret molecule and five water molecules. A dense network of N—H...Cl, O—H...O and O—H...Cl hydrogen bonds help to establish the packing, resulting in dimeric associations of two cations and two water molecules. In (II), the Sc3+ cation (site symmetry 2) adopts a slightly squashed square‐antiprismatic geometry arising from four O,O′‐bidentate biuret molecules. A network of N—H...O hydrogen bonds help to establish the packing, which features [010] chains of cations. One of the nitrate ions is disordered about an inversion centre. Both structures form three‐dimensional hydrogen‐bond networks.  相似文献   

10.
About Selenidostannates. I Synthesis, Structure, and Properties of [Sn2Se6]4–, [Sn4Se10]4–, and [Sn3Se7]2– The selenidostannates [(C4H9)2NH2]4Sn2Se6 · H2O ( I ), [(C4H9)2NH2]4Sn4Se10 · 2 H2O ( II ) und [(C3H7)3NH]2Sn3Se7 ( III ) were prepared by hydrothermal syntheses from the elements and the amines. I crystallizes in the monoclinic spacegroup P21/n (a = 1262.9(3) pm, b = 1851.3(4) pm, c = 2305.2(4) pm, β = 104.13(3)° and Z = 4). The [Sn2Se6]4– anion consists of two edge‐sharing tetrahedra. II crystallizes in the orthorhombic spacegroup Pna21 (a = 2080.3(4) pm, b = 1308.2(3) pm, c = 2263.5(5) pm and Z = 4). The anion is formed from four SnSe4 tetrahedra which are joined by common corners to the adamantane cage [Sn4Se10]4–. III crystallizes in the orthorhombic spacegroup Pbcn (a = 1371.1(3) pm, b = 2285.4(5) pm, c = 2194.7(4) pm and Z = 8). The anion is a chain, built from edge‐sharing [Sn3Se5Se4/2]2– units, in which two corner sharing tetrahedra are connected to a trigonal bipyramid by an edge of one and a corner of the other tetrahedron. The results of the TG/DSC measurements and of temperature dependent X‐ray diffractograms reveal that I and II decompose at first by release of minor quantities of triethylammonium to compounds with layer structure and larger cell dimensions. At still higher temperature the rest of triethylammonium and H2Se is evolved, leaving SnSe2 and Se in the bulk. The former decomposes partially at the highest temperature to SnSe. In the measurements of III the complex intermediate compound was not observed. III decomposes directly to SnSe2.  相似文献   

11.
Ab initio molecular orbital theory using basis sets up to 6-311G* *, with electron correlation incorporated via configuration interaction calculations with single and double substitutions, has been used to study the structures and energies of the C3H2 monocation and dication. In agreement with recent experimental observations, we find evidence for stable cyclic and linear isomers of [C3H2]+ ˙. The cyclic structure (, a) represents the global minimum on the [C3H2]+ ˙ potential energy surface. The linear isomer (, b) lies somewhat higher in energy, 53 kJ mol?1 above a. The calculated heat of formation for [HCCCH]+ ˙ (1369 kJ mol?1) is in good agreement with a recent experimental value (1377 kJ mol?1). For the [C3H2]2+ dication, the lowest energy isomer corresponds to the linear [HCCCH]2+ singlet (h). Other singlet and triplet isomers are found not to be competitive in energy. The [HCCCH]2+ dication (h) is calculated to be thermodynamically stable with respect to deprotonation and with respect to C? C cleavage into CCH+ + CH+. The predicted stability is consistent with the frequent observation of [C3H2]2+ in mass spectrometric experiments. Comparison of our calculated ionization energies for the process [C3H2]+ ˙ → [C3H2]2+ with the Qmin values derived from charge-stripping experiments suggests that the ionization is accompanied by a significant change in structure.  相似文献   

12.
The reaction of stoichiometric MeLi with the 1:1 mixture of (?5‐C5H5)Fe(CO)2I/P(OR)3 (R = Me, Et, and Ph) at ?78°C changes the bonding mode between metal and ring from (?5‐C5H5) to (?4exo‐MeC5H5) and the oxidation state of metal from Fe(II) to Fe(O), the novel complexes (?4exo‐MeC5H5)Fe(CO)2P(C)R)3 being obtained in 45‐57% yields. The reaction of trace MeLi with the 1:1 mixture of (?5‐C5H5)Fe(CO)2I/P(OMe)3 at ?78°C results in 70% yield of the phosphonate complex (?5‐C5H5)Fe(CO)2P(O)(OMe)2 which is an Arbuzov‐like dealkylation product from the cationic intermediate [(?5‐C5H5)Fe(CO)2P(OMe)3+] and the iodide. The amines could assist the Arbuzov‐like dealkylation of [(?5‐C5H5)Fe(CO)2P(OMe)3+] [PF6?] where iron‐carbamoyl intermediates are likely involved in the case of primary amines.  相似文献   

13.
1,2-Diphenyl-1,2-dimethyldisilanylene-bridged bis-cyclopentadienyl complex[η~5,η~5-C_5H_4PhMeSiSiMePh-C_5H_4]Fe_2(CO)_2(μ-CO)_2(1)was synthesized by a modified procedure,from which the trans-isomer 1b that was pre-viously difficult to obtain has been isolated for the first time.More interestingly,two new regio-isomers[η~5,η~5C_5H_4SiMe(SiMePh_2)C_5H_4]Fe_2(CO)_2(μ-CO)_2(2)and [η~5,η~5-C_5H_4Me_2SiSiPh_2C_5H_4]Fe_2(CO)_2(μ-CO)_2(3)were occa-sionally obtained during above process,the novel structures of which opened up new options for further study ofthis type of Si—Si bond-containing transition metal complexes.The molecular structure of 2 has been determinedby the X-ray diffraction method.  相似文献   

14.
This study focuses on a series of cationic complexes of iridium that contain aminopyridinate (Ap) ligands bound to an (η5‐C5Me5)IrIII fragment. The new complexes have the chemical composition [Ir(Ap)(η5‐C5Me5)]+, exist in the form of two isomers ( 1+ and 2+ ) and were isolated as salts of the BArF? anion (BArF=B[3,5‐(CF3)2C6H3]4). Four Ap ligands that differ in the nature of their bulky aryl substituents at the amido nitrogen atom and pyridinic ring were employed. In the presence of H2, the electrophilicity of the IrIII centre of these complexes allows for a reversible prototropic rearrangement that changes the nature and coordination mode of the aminopyridinate ligand between the well‐known κ2‐N,N′‐bidentate binding in 1+ and the unprecedented κ‐N3‐pseudo‐allyl‐coordination mode in isomers 2+ through activation of a benzylic C?H bond and formal proton transfer to the amido nitrogen atom. Experimental and computational studies evidence that the overall rearrangement, which entails reversible formation and cleavage of H?H, C?H and N?H bonds, is catalysed by dihydrogen under homogeneous conditions.  相似文献   

15.
The reaction of CuBr2 with 1,10‐phen‐H2O (1,10‐phen = 1,10‐phenanthroline) gave two compounds: CuBr2(C12H8N2) and Cu3Br3(C12H8N2)2. Their structures have been characterized by single‐crystal X‐ray diffraction analysis, elemental analyses, thermogravimetric analyses (TGA) and measurement of variable temperature magnetic susceptibility. Crystal data for CuBr2(C12‐H8N2): monoclinic, space group P21/n, a = 0.9977(3) nm, b = 0.65138(14) nm, c = 1.8207(4) nm, β = 91.624(18)°, V = 1.1828(5) nm3, Z = 2. Crystal data for Cu3Br3(C12H8N2)2: monoclinic, space group C2/c, a = 1.00167(11) nm, b = 1.4523(4) nm, c = 1.6295(3) nm, β = 94.386(14)°, V = 2.3635(8) nm3, Z = 3.  相似文献   

16.
Two uranyl sulfate hydrates, (H3O)2[(UO2)2(SO4)3(H2O)] · 7H2O (NDUS) and (H3O)2[(UO2)2(SO4)3(H2O)] · 4H2O (NDUS1), and one uranyl selenate‐selenite [C5H6N][(UO2)(SeO4)(HSeO3)] (NDUSe), were obtained and their crystal structures solved. NDUS and NDUSe result from reactions in highly acidic media in the presence of L ‐cystine at 373 K. NDUS crystallized in a closed vial at 278 K after 5 days and NDUSe in an open beaker at 278 K after 2 weeks. NDUS1 was synthesized from aqueous solution at room temperature over the course of a month. NDUS, NDUS1, and NDUSe crystallize in the monoclinic space group P21/n, a = 15.0249(4) Å,b = 9.9320(2) Å, c = 15.6518(4) Å, β = 112.778(1)°, V = 2153.52(9) Å3,Z = 4, the tetragonal space group P43212, a = 10.6111(2) Å,c = 31.644(1) Å, V = 3563.0(2) Å3, Z = 8, and in the monoclinic space group P21/n, a = 8.993(3) Å, b = 13.399(5) Å, c = 10.640(4) Å,β = 108.230(4)°, V = 1217.7(8) Å3, Z = 4, respectively.The structural units of NDUS and NDUS1 are two‐dimensional uranyl sulfate sheets with a U/S ratio of 2/3. The structural unit of NDUSe is a two‐dimensional uranyl selenate‐selenite sheets with a U/Se ratio of 1/2. In‐situ reaction of the L ‐cystine ligands gives two distinct products for the different acids used here. Where sulfuric acid is used, only H3O+ cations are located in the interlayer space, where they balance the charge of the sheets, whereas where selenic acid is used, interlayer C5H6N+ cations result from the cyclization of the carboxyl groups of L ‐cystine, balancing the charge of the sheets.  相似文献   

17.
The potential energy surfaces of both neutral and dianionic SnC2P2R2 (R=H, tBu) ring systems have been explored at the B3PW91/LANL2DZ (Sn) and 6‐311+G* (other atoms) level. In the neutral isomers the global minimum is a nido structure in which a 1,2‐diphosphocyclobutadiene ring (1,2‐DPCB) is capped by the Sn. Interestingly, the structure established by X‐ray diffraction analysis, for R=tBu, is a 1,3‐DPCB ring capped by Sn and it is 2.4 kcal mol?1 higher in energy than the 1,2‐DPCB ring isomer. This is possibly related to the kinetic stability of the 1,3‐DPCB ring, which might originate from the synthetic precursor ZrCp2tBu2C2P2. In the case of the dianionic isomers we observe only a 6π‐electron aromatic structure as the global minimum, similarly to the cases of our previously reported results with other types of heterodiphospholes. 1 , 4 , 19 The existence of large numbers of cluster‐type isomers in neutral and 6π‐planar structures in the dianions SnC2P2R22? (R=H, tBu) is due to 3D aromaticity in neutral clusters and to 2D π aromaticity of the dianionic rings. Relative energies of positional isomers mainly depend on: 1) the valency and coordination number of the Sn centre, 2) individual bond strengths, and 3) the steric effect of tBu groups. A comparison of neutral stannadiphospholes with other structurally related C5H5+ analogues indicates that Sn might be a better isolobal analogue to P+ than to BH or CH+. The variation in global minima in these C5H5+ analogues is due to characteristic features such as 1) the different valencies of C, B, P and Sn, 2) the electron deficiency of B, 3) weaker pπ–pπ bonding by P and Sn atoms, and 4) the tendency of electropositive elements to donate electrons to nido clusters. Unlike the C5H5+ systems, all C5H5? analogues have 6π‐planar aromatic structures as global minima. The differences in the relative ordering of the positional isomers and ligating properties are significant and depend on 1) the nature of the π orbitals involved, and 2) effective overlap of orbitals.  相似文献   

18.
A number of alkyltin(IV) paratoluenesulfonates, RnSn(OSO2C6H4CH3‐4)4?n (n = 2, 3; R = C2H5, n‐C3H7, n‐C4H9), have been prepared and IR spectra and solution NMR (1H, 13C, 119Sn) are reported for these compounds, including (n‐C4H9)2Sn(OSO2X)2 (X = CH3 and CF3), the NMR spectra of which have not been reported previously. From the chemical shift δ(119Sn) and the coupling constants 1J(13C, 119Sn) and 2J(1H, 119Sn), the coordination of the tin atom and the geometry of its coordination sphere in solutions of these compounds is suggested. IR spectra of the compounds are very similar to that observed for the paratoluenesulfonate anion in its sodium salt. The studies indicate that diorganotin(IV) paratoluenesulfonates, and the previously reported compounds (n‐C4H9)2Sn(OSO2X)2 (X = CH3 and CF3), contain bridging SO3X groups that yield polymeric structures with hexacoordination around tin and contain non‐linear C? Sn? C bonds. In triorganotin(IV) sulfonates, pentacoordination for tin with a planar SnC3 skeleton and bidentate bridging paratoluenesulfonate anionic groups are suggested by IR and NMR spectral studies. The X‐ray structure shows [(n‐C4H9)2Sn(OSO2C6H4CH3‐4)2·2H2O] to be monomeric containing six‐coordinate tin and crystallizes from methanol–chloroform in monoclinic space group C2/c. The Sn? O (paratoluenesulfonate) bond distance (2.26(2) Å) is indicative of a relatively high degree of ionic character in the metal–anion bonds. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

19.
The electron impact induced mass spectra of [CF3SMn(CO)4]2, [CF3SeMn(CO)4]2, [CF3SFe(CO)3]2, [CF3SeFe(CO)3]2, CF3SeFe(CO)2C5H5 and CF3SCr(NO)2C5H5 are reported. These compounds exhibit weak molecular ion peaks and undergo preferential loss of CO or NO groups. The CO or NO free fragments suffer typical loss of ECF2(E = S, Se) with the simultaneous shift of F from carbon to metal. The ions [FFeC5H5]+ and [FCrC5H5]+ in the spectra of the cyclopentadienyl compounds prefer expulsion of π-cyclopentadienyls. The pyrolysis effects on the spectra of the compounds have been studied. An increase in temperature eases the expulsion of ECF2 groups from all the compounds and favors the formation of [Fe(C5H5)2]+ and [Cr(C5H5)2]+ in the cyclopentadienyl compounds.  相似文献   

20.
Specific ion/molecule reactions are demonstrated that distinguish the structures of the following isomeric organosilylenium ions: Si(CH3) 3 + and SiH(CH3)(C2H5)+; Si(CH3)2(C2H5)+ and SiH(C2H5) 2 + ; and Si(CH3)2(i?C3H7)+, Si(CH3)2(n?C3H7)+, Si(CH3)(C2H5) 2 + , and Si(CH3)3(π?C2H4)+. Both methanol and isotopically labeled ethene yield structure-specific reactions with these ions. Methanol reacts with alkylsilylenium ions by competitive elimination of a corresponding alkane or dehydrogenation and yields a methoxysilylenium ion. Isotopically labeled ethene reacts specifically with alkylsilylenium ions containing a two-carbon or larger alkyl substituent by displacement of the corresponding olefin and yields an ethylsilylenium ion. Methanol reactions were found to be efficient for all systems, whereas isotopically labeled ethene reaction efficiencies were quite variable, with dialkylsilylenium ions reacting rapidly and trialkylsilylenium ions reacting much more slowly. Mechanisms for these reactions and differences in the kinetics are discussed.  相似文献   

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