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1.
In this paper we report a chemical oscillation catalyzed by [Ni(Me2[14]1,3-diene N4)]2+ (Me2[14]l,3-diene N4 denotes 2,3-dimethyl-l,4,8,ll-tetraazacyclotetradeca-1,3-diene) in BrO3--pyruvic acid-H2SO4 system.The domain of the existence of the oscillation was obtained.The effects of initial concentration of the components on the oscillation were studied.The features of the oscillations were described in detail.We also examined the effects of Ag+,Hg2+,CCl4,free radical inhibitors,etc.on the osillations.  相似文献   

2.
Coordination equilibrium constants (K NiS) of some donor solvent molecules to 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecanenickel(II) ([Ni(Me4[12]aneN4)]2+) were determined in nitrobenzene (a noncoordinating bulk solvent). The first (K NiS1) and second stepwise coordination equilibrium constants (K NiS2) for 1,4,7,10-tetraazacyclododecanenickel(II) ([Ni([12]aneN4)]2+), 1,4,8,11-tetraazac yclotetradecane- nickel(II) ([Ni([14] aneN4)]2+), 1,4,8,11-tetrathiacyclotetra-decanenickel(II) ([Ni([14]aneS4)]2+) were also reinvestigated. The K NiS values for [Ni(Me4[12]aneN4)]2+ were compared to those of [Ni([12]aneN4)]2+, (1R,4S, 8R,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecanenickel(II) (R,S,R,S-[Ni(Me4[14]aneN4)]2+), R,R,S,S-[Ni(Me4[14]aneN4)]2+, [Ni([14]aneN4)]2+, and [Ni([14]aneS4)]2+. Coordination of pyridine (Py), N,N,N′,N′-tetramethylurea (TMU), and N,N-dimethylacetamide (DMA) to [Ni(Me4[12]aneN4)]2+ was observed, although these donor solvent molecules did not coordinate to R,S,R,S-[Ni(Me4[14]aneN4)]2+. The K NiS values for Py, TMU, and DMA are 7.9, 2.8, and 9.0 dm3⋅mol−1, respectively. Some hydrogen-bonding waters were coordinated to R,S,R,S-[Ni(Me4[14]aneN4)]2+, but such waters did not coordinate to [Ni(Me4[12] aneN4)]2+. Also, the K NiS2 values were larger than the corresponding K NiS1 values for [Ni([14]aneS4)]2+. Furthermore, the K NiS1 values for [Ni([12]aneN4)]2+ were the largest among these nickel(II) complex cations. The K NiS, K NiS1, and K NiS2 values are discussed in terms of properties of the donor solvents and steric strains of these nickel(II) complex cations.  相似文献   

3.
The Fe+-mediated [4+2] cycloaddition of dienes with alkynes has been examined by four-sector ion-beam and ion cyclotron resonance mass spectrometry. Prospects and limitations of this reaction were evaluated by investigating several Me-substituted ligands. Me Substitution at C(2) and C(3) of the diene, i.e., 2-methylbuta-1,3-diene, 2,3-dimethylbuta-1,3-diene, hardly disturbs the cycloaddition. Similarly, variation of the alkyne by use of propyne and but-2-yne does not affect the [4+2] cycloaddition step, but allows for H/D exchange processes prior to cyclization. In contrast, Me substituents in the terminal positions of the diene moiety (e.g., penta-1,3-diene, liexa-2,4-diene) induce side reactions, namely double-bond migration followed by [3+2] and [5+2] cycloadditions, up to almost complete suppression of the [4+2] cycloaddition for 2,4-dimethylhexa-2,4-diene. Similarly, alkynes with larger alkyl substituents (pent-1-yne, 3,3-dimethylbut-1-yne) suppress the [4 + 2] cycloaddition route. Stereochemical effects have been observed for the (E)- and (Z)-penta-1,3-diene ligands as well as for (E,E)- and (E,Z)-hexa-2,4-diene. A mechanistic explanation for the different behavior of the stereoisomers in the cyclization reaction is developed. Further, the regiochemical aspects operative in the systems ethoxyacetylene/pentadiene/Fe+ and ethoxyacetylcne/isoprene/Fe+ indicate that substituents avoid proximity.  相似文献   

4.
Abstract

Binuclear oxygenated cobalt complexes with 5,7,12,14-tetramethy I-1,4,8,II-tetraazacyclotetradeca-4,II -diene (Me4[14]dieneN4) and 5,7,7,12,14,14-hexamethyl-1,4,8,11 -tetraazacyclotetradeca-4,11 -diene (Me6[14]dieneN4) with axial ligands (NCO?, NCS?, NCSe?, N? 3, OH?, NO? 2, ON-C(CN)2 ?, Im) have been isolated and characterised by physical and chemical methods, including derivatography, electronic, IR and X-ray photoelectron spectroscopy, magnetic measurements and EPR. The electronic structure of the cobalt ion-dioxygen fragment conforms to the scheme Co(III)-O2-Co(III). The coordinated dioxygen species is activated owing to the transfer of an appreciable electron density to it. Irreversible oxidation in aqueous solution is illustrated by [μO2{Co(Me4[14]dieneN4)(H2O)}2](CIO4)4. Activation parameters for this process are E* = 54 ± 4 kJ mol?1 and ΔS* = -140 ± 16 J mol K?1. A possible mechanism is proposed.  相似文献   

5.
The cationic dibenzocyclamnickel(II) complex, [Ni(Me4Bzo2[14]aneN4)]2+, was obtained in good yield by Fe/HCl reduction of the corresponding tetraazaannulene complex [Ni(Me4taa)], (1) {Me4Bzo2[14]aneN4 = 5,7,12,14-tetramethyldibenzo[b,i]-1,4,8,11-tetraazacyclotetradecane; Me4taa = 5,7,12,14-tetramethyldibenzo[b,i]-1,4,8,11-tetraazaannulene(2-)}. The orange–red product was isolated as the chloride (2) and perchlorate (3) salts. Analogous reduction with Zn/HCl yielded a diprotonated silky-white product [Ni(Me4Bzo2[14]aneN4-H2)][ZnCl4]2, (4). In the dry state, complex (4) is stable only under an HCl atmosphere and readily dissociates to give a solution of (2) when dissolved in polar solvents. Complexes (2) and (3), upon treatment with an excess of aqueous NaCN, undergo facile demetallation yielding the metal free macrocycle Me4Bzo2[14]aneN4, (5). These compounds were characterized using a combination of i.r., u.v.–vis., 1H-n.m.r., mass spectroscopy and voltammetry techniques. Unlike the parent tetraazaannulene complex (1), the reduced macrocycle complex, [Ni(Me4Bzo2[14]aneN4)]2+ exhibits mild catalytic activity towards electro-reduction of CO2 in MeCN solution.  相似文献   

6.
The transition-metal-carbonyl-induced cyclodimerization of 5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene is strongly affected by substitution at C(1) While 5,6-dimethylidene-7-oxabicyclo[2.2.1]hept–2-ene-l-methanol ( 7 ) refused to undergo [4 + 2]-cyclodimerization in the presence of [Fe2(CO)9] in MeOH, 1-(dimethoxymethyl)-5,6-di-methylidene-7-oxabicyclo[2.2.1]hept-2-ene ( 8 ) led to the formation of a 1.7:1 mixture of ‘trans’ ( 19, 21, 22 ) vs. ‘cis’ ( 20, 23, 24 ) products of cyclodimerization together with tricarbonyl[C, 5,6, C-η-(l-(dimethoxymethyl)-5,6-di-methylidenecyclohexa-1,3-diene)]iron ( 25 ) and tricarbonyl[C,3,4, C-η-(methyl 5-(dimethoxymethyl)-3,4-di-methylidenecyclohexa-1,5-diene-l-carboxylate)]iron ( 26 ). The structures of products 19 and of its exo ( 21 ) and endo ( 22 ) [Fe(CO)3(1,3-diene)]complexes) and 20 (and of its exo ( 23 ) and endo (24) (Fe(CO)3(1,3-diene)complexes) were confirmed by X-ray diffraction studies of crystalline (1RS, 2SR, 3RS, 4RS, 4aRS, 9aSR)-tricarbonyl[C, 2,3, C-η-(1,4-epoxy-1,5-bis(dimethoxymethyl])-2,3-dimethylidene-1,2,3,4,4a,9,9a,10-octahydroanthracene)iron ( 21 ). In the latter, the Fe(CO)3(1,3-diene) moiety deviates significantly from the usual local Cs symmetry. Complex 21 corresponds to a ‘frozen equilibrium’ of rotamers with η-alkyl, η3-allyl bonding mode due to the acetal unit at the bridgehead centre C(1).  相似文献   

7.
The reactions of silver(I) with isocyclam, scorpiand,trans-Me2[14]anN4, cis-Me6[14]anN4,(N-Me)Me2py[14]anN4 and py[12]anN4 were investigated.The stability constant of the Ag(I) complex with py[12]anN4 was determined. The aqueous solutions of the silver(II) complexes with the 14-membered ligands were obtained, and characterized by means of UV-VIS and CVA measurements. The Ag2+ ion does not form a five-coordinate complex with scorpiand. The formal potentials of the Ag(II)/Ag(I) system in the presence of scorpiand, trans-Me2[14]anN4, cis-Me6[14]anN4 and(N-Me)Me2py[14]anN4 were determined. The mechanism is also proposedfor the electroreduction of the silver(II) complexes with these compounds on a platinum electrode in aqueous solution.  相似文献   

8.
Among seventeen different Lewis acids, TiCl4 was found to be the best catalyst for the [4 + 2] cycloaddition of cyclopentadiene to N,N′-fumaroylbis[(2R)-bornane-10,2-sultam] ((?)- 1 ). Independently of the TiCl4 molar concentration, almost constant and complete (98–89% d.e.) diastereofacial π-selection was achieved in the Diels-Alder addition of (?)- 1 to cyclopentadiene, cyclohexadiene, isoprene, and 2,3-dimethylbuta-1,3-diene.  相似文献   

9.
Solvolysis of [RhMe(CF3SO3)2(Me3[9]aneN3)] ( 1 ) (Me3[9]aneN3 = 1, 4, 7‐trimethyl‐1, 4, 7‐triazacyclononane) in CH3CN, DMSO or pyrazole (L) leads to substitution of both trifluoromethylsulfonate ligands and formation of the cationic complexes [RhMeL2(Me3[9]aneN3)](CF3SO3)2 3—5 . In contrast, treatment of [RuCl3(Me3[9]aneN3)] ( 2 ) with Ag(CF3SO3) in a 1:3 ratio for 2h in CH3CN leads to formation of the tetranuclear complex [{RuCl3(Me3[9]aneN3)}2Ag2(CF3SO3)(CH3CN)](CF3SO3) · CH3CN ( 6 ) with a novel [(RuCl3)2Ag2] core. More forcing conditions enable the substitution of respectively one or two chloride ligands by CH3CN (reflux 18h) or DMF (85°C, 1h) to afford [RuCl2(CH3CN)(Me3[9]aneN3)](CF3SO3) ( 7 ) and [RuCl(DMF)2(Me3[9]aneN3)](CF3SO3)2 ( 8 ). The heteroleptic sandwich complex [Ru([9]aneS3)(Me3[9]aneN3)](CF3SO3)2 ( 9 ) can be prepared by reduction of 2 with Zn powder in acetone in the presence of 3 equiv. of Ag(CF3SO3), followed by addition of [9]aneS3 (1, 4, 7‐trithiacyclononane). The redox potential E°(Ru3+/Ru2+) of +1.87 V vs NHE for 9 is only —0.12 V lower than that of the homoleptic complex [Ru([9]aneS3)2]2+. Crystal structures are reported for 3 — 9 .  相似文献   

10.
[Me4N]10[Fe4(OH)4(PW10O37)2] · 15H2O was synthesized by the reaction of FeCl3 ·6H2O, with △-Na8HPW9O34 and Me4NBr. Crystal data: M = 6225.75, space group P21/c with the monoclinic parameters: a = 1.3228(5), b = 3.5634(3), c = 1.5226(2) nm, β = 94.20(2)°, V = 7.1576nm3, 7 = 2,DC = 2.888 g/cm3, Mo Kαradiation (λ = 0.071069 nm), μ= 168.534 cm-1, F(000)=5576, final R = 0.0428 and Rw = 0.1204 for 7086 observed reflections with I > 2σ( I) . The structure of the title compound is the first structurally characterized heteropolymetalate with hydroxo-bridging metal aggregation Fe4OH4 encapsulated in the dimer of Keggin polyoxoanion.  相似文献   

11.
TAS+[P4N4F8NMe2]? ( 2 ) was prepared from TAS+[P4N4F9]? ( 1 ) via F/NMe2 exchange using Me3SiNMe2. The salt was characterised by nmr‐spectroscopy and by X‐ray crystallography. The bonding situation in the anion is briefly discussed. The structural properties of the anion are compared with those of the starting material.  相似文献   

12.
N, N-Dimethylformamide dimethyl acetal transforms an allylic OH group, which is part of a tetracyclic hydrocarbon in a unique elimination reaction into a [5.5.5.5]fenestradiene ( 2b → 4 ). In topologically selective reactions of this diene 4 with [Fe2(CO)9,], the [Fe(CO)42-diene)] and the [Fe(CO)3(η4-diene)] complexes 8 and 9 , respectively, are formed by complexation on one side of the diene moiety, whereas complexation on the other side leads to a [Fe(CO)2(Cp)] complex 10 .  相似文献   

13.
The transparent dark orange compounds Cs2[Pd(N3)4] and Rb2[Pd(N3)42/3H2O are synthesized by reaction of the respective binary alkali metal azides with K2PdCl4 in aqueous solutions. According to single‐crystal X‐ray diffraction investigations, the novel ternary azidopalladates(II) crystallize in the monoclinic space group P21/c (no. 14) with a = 705.7(2) pm, b = 717.3(2) pm, c = 1125.2(5) pm, β = 104.58(2)°, mP30 for Cs2[Pd(N3)4] and a = 1041.4(1) pm, b = 1292.9(2) pm, c = 1198.7(1) pm, β = 91.93(1)°, mP102 for Rb2[Pd(N3)42/3H2O, respectively. Predominant structural features of both compounds are discrete [PdII(N3)4]2– anions with palladium in a planar coordination by nitrogen, but differing in point group symmetries., The vibrational spectra of the compounds are analyzed based on the idealized point group C4h of the spectroscopically relevant unit, [Pd(N3)4]2– taking into account the site symmetry splitting due to the symmetry reduction in the solid phase.  相似文献   

14.
The N2 negative ion chemical ionization (NICI) mass spectra of aniline, aminonaphthalenes, aminobiphenyls and aminoanthracenes show an unexpected addition appearing at [M + 11]. This addition is also observed in the N2 positive chemical ionization (PCI) mass spectra. An ion at [M – 15]? is found in the NICI spectra of aminoaromatics such as aniline, 1- and 2-aminonaphthalene and 1- and 2-aminoanthracene. Ion formation was studied using labeled reagents, variation of ion source pressure and temperature and examination of ion chromatograms. These experiments indicate that the [M + 11], [M – 15] and [M + 11] ions result from the ionization of analytes altered by surface-assisted reactions. Experiments with 15N2, [15N] aniline, [2,3,4,5,6-2H5] aniline and [13C6] aniline show that the [M + 11] ion corresponds to [M + N – 3H]. The added nitrogen originates from the N2 buffer gas and the addition occurs with loss of one ring and two amino group hydrogens. Fragmentation patterns in the N2 PCI mass spectrum of aniline suggest that the neutral product of the surface-assisted reaction is 1,4-dicyanobuta-1,3-diene. Experiments with diamino-substituted aromatics show analogous reactions resulting in the formation of [M – 4H] ions for aromatics with ortho-amino groups. Experiments with methylsubstituted aminoaromatics indicate that unsubstituted sites ortho to the amino group facilitate nitrogen addition, and that methyl groups provide additional sites for nitrogen addition.  相似文献   

15.
In this article the kinetics of the interaction between the teteraaza Schiff bases as donor with organotin(IV)chlorides as acceptor was studied in acetonitrile. Teteraaza Schiff bases are (Me4‐Bzo2[14]tetraeneN4) (tmtaa), (Me4‐4‐CH3Bzo2[14]tetraeneN4) (Metmtaa), (Me4‐4‐ClBzo2[14]tetraeneN4) (Cltmtaa), i.e., [(Me4‐Bzo2[14]tetraeneN4)] means that (5,7,12,14‐tetramethyldibenzo[b,i][1,4,8,11] tetraazacyclotetradecine) (tmtaa) and organotin(IV)chlorides are methyltin(IV) trichloride, phenyltin(IV)trichloride, dimethyltin (IV)dichloride, diphenyltin(IV) dichloride, and dibutyltin(IV)dichloride. The kinetic parameters and the second‐order k2 rate constants show the donor properties of tetraaza Schiff bases as Me4‐4‐CH3Bzo2[14]tetraeneN4 > Me4‐Bzo2[14]tetraeneN4 > Me4‐4‐ClBzo2[14]tetraeneN4 and also the acceptor properties of organotin(IV)chlorides as PhSnCl3 > MeSnCl3 > Ph2SnCl2 > Me2SnCl2 > Bu2SnCl2. An excellent linearity of kobs vs. the molar concentration of the acceptor, the high span of k2 values, the large negative values of ΔS, and the low ΔH values suggest an associative (A) mechanism for the acceptor–donor interaction. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 247–254, 2011  相似文献   

16.
Single crystals of three new strontium nitridogermanates(IV) were grown in sealed niobium ampules from sodium flux. Dark red Sr4[GeN4] crystallizes in space group P21/c with a = 9.7923(2) Å, b = 6.3990(1) Å, c = 11.6924(3) Å and β = 115.966(1)°. Black Sr8Ge2[GeN4] contains Ge4– anions coexisting with [GeIVN4]8– tetrahedra and adopts space group Cc with a = 10.1117(4) Å, b = 17.1073(7) Å, c = 10.0473(4) Å and β = 115.966(1)°. Black Sr17Ge6N14 features the same anions alongside trigonal planar [GeIVN3]5– units. It crystallizes in P1 with a = 7.5392(1) Å, b = 9.7502(2) Å, c = 11.6761(2) Å, α = 103.308(1)°, β = 94.651(1)° and γ = 110.248(1)°.  相似文献   

17.
Summary A series of complexes of formula {Ni(Me6[14]aneN4)X2| (Me6[14]aneN4) = C-meso-5,5,7,12,12,14-hexamethyl-1,4,-8,11-tetraazacyclotetradecane and X = N3 (1), NCO (2), NCS (3), AcO (4) or I (5) has been synthesized. The crystal structure of (5) has been determined by X-ray diffraction methods. The nickel atom is surrounded by a square-planar array of nitrogen atoms, giving a low-spin complex. The macrocyclic ligand shows the most stable conformation, the six-membered rings exhibiting the chair form while the gauche conformation is adopted by the five-membered rings. Spectroscopic and magnetic data for (1)–(4) are consistent with octahedral coordination around the nickel atom, which is achieved by four N atoms of the macrocyclic ligand in a single plane and by two azido-N (1), cyanato-N (2), thiocyanato-N (3) and carboxylato-O (4) groups occupying the axial positions. An electrochemical study of the oxidation of (1)–(5) has been carried out in nonaqueous solvents and the prospects of synthesis of the corresponding nickel(III) species are discussed in the light of the electrochemical data.  相似文献   

18.
The reactions of [Ru(N2)(PR3)(‘N2Me2S2’)] [‘N2Me2S2’=1,2‐ethanediamine‐N,N′‐dimethyl‐N,N′‐bis(2‐benzenethiolate)(2?)] [ 1 a (R=iPr), 1 b (R=Cy)] and [μ‐N2{Ru(N2)(PiPr3)(‘N2Me2S2’)}2] ( 1 c ) with H2, NaBH4, and NBu4BH4, intended to reduce the N2 ligands, led to substitution of N2 and formation of the new complexes [Ru(H2)(PR3)(‘N2Me2S2’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH3)(PR3)(‘N2Me2S2’)] [ 3 a (R=iPr), 3 b (R=Cy)], and [Ru(H)(PR3)(‘N2Me2S2’)]? [ 4 a (R=iPr), 4 b (R=Cy)]. The BH3 and hydride complexes 3 a , 3 b , 4 a , and 4 b were obtained subsequently by rational synthesis from 1 a or 1 b and BH3?THF or LiBEt3H. The primary step in all reactions probably is the dissociation of N2 from the N2 complexes to give coordinatively unsaturated [Ru(PR3)(‘N2Me2S2’)] fragments that add H2, BH4?, BH3, or H?. All complexes were completely characterized by elemental analysis and common spectroscopic methods. The molecular structures of [Ru(H2)(PR3)(‘N2Me2S2’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH3)(PiPr3)(‘N2Me2S2’)] ( 3 a ), [Li(THF)2][Ru(H)(PiPr3)(‘N2Me2S2’)] ([Li(THF)2]‐ 4 a ), and NBu4[Ru(H)(PCy3)(‘N2Me2S2’)] (NBu4‐ 4 b ) were determined by X‐ray crystal structure analysis. Measurements of the NMR relaxation time T1 corroborated the η2 bonding mode of the H2 ligands in 2 a (T1=35 ms) and 2 b (T1=21 ms). The H,D coupling constants of the analogous HD complexes HD‐ 2 a (1J(H,D)=26.0 Hz) and HD‐ 2 b (1J(H,D)=25.9 Hz) enabled calculation of the H? D distances, which agreed with the values found by X‐ray crystal structure analysis ( 2 a : 92 pm (X‐ray) versus 98 pm (calculated), 2 b : 99 versus 98 pm). The BH3 entities in 3 a and 3 b bind to one thiolate donor of the [Ru(PR3)(‘N2Me2S2’)] fragment and through a B‐H‐Ru bond to the Ru center. The hydride complex anions 4 a and 4 b are extremely Brønsted basic and are instantanously protonated to give the η2‐H2 complexes 2 a and 2 b .  相似文献   

19.
The resol polycondensation ofC-phenylcalix[4]resorcinarene with formaldehyde affords a corss-linked polymer possessing ion-exchange ability. The ion-exchange capacity of the polymer with respect to NH4 +, Me4N+, Et4N+, Bu4N+, and K+ cations was determined. The equilibrium in the systemsC-phenylcalix[4]resorcinarene-based polymer—binary or ternary aqueous solutions of electrolytes was studied by potentiometric titration and quantumchemical MNDO/PM3 calculation Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1475–1477, August, 2000.  相似文献   

20.
Solvothermal reactions of the calix[4]arene tetraacetic acid (H4CTA) with zinc nitrate in the presence of α,ω‐diaminoalkanes afford two‐dimensional metallopolycapsular networks of the formula {[Me2NH2]2[G@(Zn2(CTA)2)] ? (DMF)2 ? (H2O)4}n (G=+NH3–(CH2)n–NH3+, n=2, 3, 4; DMF=N,N‐dimethylformamide). These metallopolycapsular networks are built up of metallocapsules that consist of two CTA and two ZnII ions. Short alkanediyldiammonium (+NH3–(CH2)n–NH3+, n=2, 3, 4) guest ions are accommodated in each capsule of the metallopolycapsular network through a variety of supramolecular interactions. The thermal behaviours and the solid‐state photoluminescent properties of these complexes were also investigated.  相似文献   

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