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1.
Richard D. Bowen Alex. W. Colburn Peter J. Derrick 《Journal of mass spectrometry : JMS》1990,25(10):509-516
The reactions of ten metastable immonium ions of general structure R1R2C?NH+C4H9 (R1 = H, R2 = CH3, C2H5; R1 = R2 = CH3) are reported and discussed. Elimination of C4H8 is usually the dominant fragmentation pathway. This process gives rise to a Gaussian metastable peak; it is interpreted in terms of a mechanism involving ion-neutral complexes containing incipient butyl) cations. Metastable immonium ions ontaining an isobutyl group are unique in undergoing a minor amount of imine (R1R2C?NH) loss. This decomposition route, which also produces a Gaussian metastable peak, decreases in importance as the basicity of the imine increases. The correlation between imine loss and the presence of an isobutyl group is rationalized by the rearrangement of the appropriate ion-neutral complexes in which there are isobutyl cations to the isomeric complexes containing the thermodynamically more stable tert-butyl cations. A sizeable amount of a third reaction, expulsion of C3H6, is observed for metastable n-C4H9 +NH?CR1R2 ions; in contrast to C4H8 and R1R2C?NH loss, C3H6 elimination occurs with a large kinetic energy release (40–48 kJ mol?1) and is evidenced by a dish-topped metastable peak. This process is explained using a two-step mechanism involving a 1,5-hydride shift, followed by cleavage of the resultant secondary open-chain cations, CH3CH+ CH2CH2NHCHR1R2. 相似文献
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Davies CJ Fawcett J Shutt R Solan GA 《Dalton transactions (Cambridge, England : 2003)》2005,(15):2630-2640
Alkylation of (ArNHCH2CH2){(2-C5H4N)CH2}NH with RX [RX = MeI, 4-CH2=CH(C6H4)CH2Cl) and (2-C5H5N)CH2Cl] in the presence of base has allowed access to the sterically demanding multidentate nitrogen donor ligands, {(2,4,6-Me3C6H2)NHCH2CH2}{(2-C5H4N)CH2}NMe (L1), {(2,6-Me3C6H3)NHCH2CH2}{(2-C5H4N)CH2}NCH2(C6H4)-4-CH=CH2 (L2) and (ArNHCH2CH2){(2-C5H4N)CH2}2N (Ar = 2,4-Me2C6H3 L3a, 2,6-Me2C6H3 L3b) in moderate yield. L3 can also be prepared in higher yield by the reaction of (NH2CH2CH2){(2-C5H4N)CH2}2N with the corresponding aryl bromide in the presence of base and a palladium(0) catalyst. Treatment of L1 or L2 with MCl2 [MCl2 = CoCl2.6H2O or FeCl2(THF)1.5] in THF affords the high spin complexes [(L1)MCl2](M = Co 1a, Fe 1b) and [(L2)MCl2](M = Co 2a, Fe 2b) in good yield, respectively; the molecular structure of reveals a five-coordinate metal centre with bound in a facial fashion. The six-coordinate complexes, [(L3a)MCl2](M = Co 3a, Fe 3b, Mn 3c) are accessible on treatment of tripodal L3a with MCl2. In contrast, the reaction with the more sterically encumbered leads to the pseudo-five-coordinate species [(L3b)MCl2](M = Co 4a, Fe 4b) and, in the case of manganese, dimeric [(L3b)MnCl(mu-Cl)]2 (4c); in 4a and 4b the aryl-substituted amine arm forms a partial interaction with the metal centre while in 4c the arm is pendant. The single crystal X-ray structures of , 1a, 3b.MeCN, 3c.MeCN, 4b.MeCN and 4c are described as are the solution state properties of 3b and 4b. 相似文献
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Microcanonical variational transition-state theory was used to determine the entropies of activation for hydrogen-bond cleavage reactions leading to CH(3)CN + ROH(2)(+) in a series of acetonitrile-alcohol proton-bound pairs (CH(3)CN)(ROH)H(+) (where R = CH(3), CH(3)CH(2), CH(3)CH(2)CH(2), and (CH(3))(2)CH). In each case, the dissociation potential surface was modelled at the MP2/6-31 + G(d) level of theory. The dissociating configurations having the minimum sums-of-states were identified in each case and the resulting entropies of activation were calculated. Combined with previous work on the competing reaction leading to CH(3)CNH(+) + ROH, the results permitted the determination of the Delta(DeltaS) in each proton-bound pair. For the (CH(3)CN)(CH(3)OH)H(+) and (CH(3)CN)(CH(3)CH(2)OH)H(+) proton-bound pairs, the entropies of activation for the two dissociating channels are essentially the same [i.e., Delta(DeltaS) = 0], while Delta(DeltaS) for the propanol-containing pairs ranged between 40 and 45 J K(-1) mol(-1). The latter non-zero values are due to a combination of the location of the dividing surface in each dissociation and the rapidity with the frequencies of the vanishing vibrational modes go to zero as they are converted to product translations and rotations during the dissociation. 相似文献
6.
Ivanov A. V. Bredyuk O. A. Antzutkin O. N. Forsling W. 《Russian Journal of Coordination Chemistry》2004,30(7):480-485
Alkylxanthate complexes of the general formula [M{S(S)COR}2] (M = Ni, 63Cu, and 65Cu; R = C2H5, i-C3H7, i-C4H9, s-C4H9, and C5H11) were synthesized and studied by EPR and high-resolution solid-state 13C CP/MAS NMR. In the copper(II) complexes stabilized in the matrix of nickel(II) compounds, square planar chromophores [CuS4] are characterized by rhombic distortion (EPR data). Experimental EPR spectra were simulated at the second order of perturbation theory. Nickel(II) complexes were characterized by 13C NMR spectra. In all cases, the –OC(S)S– groups were found to exhibit intramolecular structural equivalence. 相似文献
7.
Dialkylindium Acetates R2InOOCCH3 (R = CH3, C2H5). Preparation, Properties, and Structure. Dimethyl- and diethylindium acetate were prepared and the vibrational spectra (IR and RAMAN ) discussed. The X-ray structure determination shows that diethylindium acetate belongs to the orthorhombic space group Pnma. The unit cell with lattice constants a = 8.40, b = 7.41, c = 15.13 Å contains four molecules. Each indium atom forms with an acetate group a planar four-membered ring. The indium-oxygen distance within such a ring is only a little shorter than the distance of this oxygen to the indium of the next neighboured ring. Indium has therefore the coordination number six. 相似文献
8.
采用1HNMR谱研究了通式为〔M3ⅢO(OOCR)6L3〕+(M=Cr,Fe,Mn;R=CH3,C2H5,CH2NH2;L=C5H5N,H2O)的一系列氧心三核过渡金属配合物,主要考察其1H化学位移随金属、配体、温度、溶剂等因素变化而变化的规律。结果表明,骨架金属对化学位移的影响最大,M3O中的3个金属离子间存在反铁磁交换相互作用。对Mn配合物中顺磁中心对化学位移和线宽的影响机制的研究表明,其1H各向同性位移主要由接触作用贡献 相似文献
9.
Fortman GC Kégl T Li QS Zhang X Schaefer HF Xie Y King RB Telser J Hoff CD 《Journal of the American Chemical Society》2007,129(46):14388-14400
Conversion of N=N=CHSiMe3 to O=C=CHSiMe3 by the radical complexes .Cr(CO)3C5R5 (R = H, CH3) derived from dissociation of [Cr(CO)3(C5R5)]2 have been investigated under CO, Ar, and N2 atmospheres. Under an Ar or N2 atmosphere the reaction is stoichiometric and produces the Cr[triple bond]Cr triply bonded complex [Cr(CO)2(C5R5)]2. Under a CO atmosphere regeneration of [Cr(CO)3(C5R5)]2 (R = H, CH3) occurs competitively and conversion of diazo to ketene occurs catalytically as well as stoichiometrically. Two key intermediates in the reaction, .Cr(CO)2(ketene)(C5R5) and Cr2(CO)5(C5R5)2 have been detected spectroscopically. The complex .Cr(13CO)2(O=13C=CHSiMe3)(C5Me5) has been studied by electron spin resonance spectroscopy in toluene solution: g(iso) = 2.007; A(53Cr) = 125 MHz; A(13CO) = 22.5 MHz; A(O=13C=CHSiMe3) = 12.0 MHz. The complex Cr2(CO)5(C5H5)2, generated in situ, does not show a signal in its 1H NMR and reacts relatively slowly with CO. It is proposed to be a ground-state triplet in keeping with predictions based on high level density functional theory (DFT) studies. Computed vibrational frequencies are also in good agreement with experimental data. The rates of CO loss from 3Cr2(CO)5(C5H5)2 producing 1[Cr(CO)2(C5H5)]2 and CO addition to 3Cr2(CO)5(C5H5)2 producing 1[Cr(CO)3(C5H5)]2 have been measured by kinetics and show DeltaH approximately equal 23 kcal mol(-1) for both processes. Enthalpies of reduction by Na/Hg under CO atmosphere of [Cr(CO)n(C5H5)]2 (n = 2,3) have been measured by solution calorimetry and provide data for estimation of the Cr[triple bond]Cr bond strength in [Cr(CO)2(C5H5)]2 as 72 kcal mol(-1). The complex [Cr(CO)2(C5H5)]2 does not readily undergo 13CO exchange at room temperature or 50 degrees C implying that 3Cr2(CO)5(C5H5)2 is not readily accessed from the thermodynamically stable complex [Cr(CO)2(C5H5)]2. A detailed mechanism for metalloradical based conversion of diazo and CO to ketene and N2 is proposed on the basis of a combination of experimental and theoretical data. 相似文献
10.
P. Reich 《无机化学与普通化学杂志》1979,450(1):131-138
Infrared and Raman Spectroscopic Investigations on the Organosubstituted Silicon Hydrides (XCH2)(CH3)2SiH (X = Cl, Br, J), X(YO)2SiH (X = CH2, C2H5/Y = CH3, C2H5 … tert.-C4H9), (C6H5)2SiH2 and C6H5SiH3 Typical band splittings, specially for the SiH stretching vibration, are shown in the infrared and Raman spectra of the silicon hydrides (XCH2)(CH3)2SiH (X = Cl, Br, J), and X(YO)2SiH (X = CH3, C2H5/Y = CH3, C2H5 … tert.-C4H9). The cause of this behavior is in all probability the existence of rotational isomers. Raman polarization measurements at organosubstituted silicon di- and trihydrides demonstrate the accidental degeneracy of the SiH valence vibrations. 相似文献
11.
Formation and Properties of Li2P7R (R = Si(CH3)3, CH3, C(CH3)3) The reaction of P7(Sime3)3 with Li3P7 in the molar ratio of 2:1 yields LiP7(Sime3)2, and in the molar ratio of 1:2 Li2P7Sime3 is formed. Li2P7me and Li2P7Cme3 (me = CH3) are obtained by reaction of white phosphorus with Lime, or LiCme3, respectively [2]. The compounds Li2P7R (R = Sime3, Cme3, me) show typical valence tautomerism, as established by 31P-n.m.r. spectroscopy at various temperatures. Also LiP(Sime3)2 transforms P7(Sime3)3 to yield Li2P7Sime3 but in this reaction considerable cleavage of P? P bonds occurs, too. 相似文献
12.
Some new N‐4‐Fluorobenzoyl phosphoric triamides with formula 4‐F‐C6H4C(O)N(H)P(O)X2, X = NH‐C(CH3)3 ( 1 ), NH‐CH2‐CH=CH2 ( 2 ), NH‐CH2C6H5 ( 3 ), N(CH3)(C6H5) ( 4 ), NH‐CH(CH3)(C6H5) ( 5 ) were synthesized and characterized by 1H, 13C, 31P NMR, IR and Mass spectroscopy and elemental analysis. The structures of compounds 1 , 3 and 4 were investigated by X‐ray crystallography. The P=O and C=O bonds in these compounds are anti. Compounds 1 and 3 form one dimensional polymeric chain produced by intra‐ and intermolecular ‐P=O···H‐N‐ hydrogen bonds. Compound 4 forms only a centrosymmetric dimer in the crystalline lattice via two equal ‐P=O···H‐N‐ hydrogen bonds. 1H and 13C NMR spectra show two series of signals for the two amine groups in compound 1 . This is also observed for the two α‐methylbenzylamine groups in 5 due to the presence of chiral carbon atom in molecule. 13C NMR spectrum of compound 4 shows that 2J(P,Caliphatic) coupling constant for CH2 group is greater than for CH3 in agreement with our previous study. Mass spectra of compounds 1 ‐ 3 (containing 4‐F‐C6H4C(O)N(H)P(O) moiety) indicate the fragments of amidophosphoric acid and 4‐F‐C6H4CN+ that formed in a pseudo McLafferty rearrangement pathway. Also, the fragments of aliphatic amines have high intensity in mass spectra. 相似文献
13.
Robert A. Grigsby Kurt J. Irgolic Furn F. Knapp 《Journal of organometallic chemistry》1983,253(1):31-37
Methyl telluraalkanoates, CnH2n+1Te(CH2)mCOOR (n, m: 4, 7; 6, 4; 6, 7; 6, 9; 7, 4; 8, 7; 11, 2; 11, 5; 18, 11) were synthesized in yields ranging from 33 to 82 percent based on the quantities of the methyl ω-bromoalkanoates substrates. Disodium ditelluride was obtained from tellurium and sodium in ethylenediamine and was treated with alkyl bromides to give dialkyl ditellurides. The crude ditellurides were reduced with NaBH4 to the alkane tellurolates which were coupled with methyl ω-bromoalkanoates to give the methyl telluraalkanoates. Ethyl 4-tellurapentadecanoate was prepared similarly from ethyl 3-bromopropanoate. The telluraalkanoates were characterized by elemental analyses, mass spectrometry, NMR spectrometry, and UV and IR spectrophotometry. Telluraalkanoates radiolabeled with 123mTe or other radioisotopes have been reported elsewhere to be preferentially taken up by the heart and promise to be useful as myocardial imaging agents. 相似文献
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1 INTRODUCTION The chemistry of organotin(IV) complexes was extensively studied due to their biological activity and coordination chemistry[1~7]. More recently, phar- maceutical properties of alkyltin(IV) complexes with dithiocarbamate ligands have bee… 相似文献
15.
Ivan Bernal George M. Reisner Henri Brunner Georg Riepl 《Journal of organometallic chemistry》1985,284(1):115-128
The crystal structures and absolute configurations of (η5-C5H5)-CoI(NC4H3-C(R)=N(S)-CH(CH3)(C6H5)) (R = H, compound I; R = CH3, compound II) have been determined by single crystal X-ray diffraction. Crystals of compound I are orthorhombic, with a 11.084(6), b 12.107(6) and c 13.121(7) Å, space group P212121 and d (calcd, Z = 4) 1.69 g cm?3 The structure was solved by the Patterson technique and refined with use of full matrix least-squares methods to R(F) = 0.031 and Rw(F) = 0.028. Compound II is nearly isomorphous and isostructural; a 11.246(6), b 11.923(6) and c 13.370(7) Å, d(calc., Z = 4) 1.71 g cm?3 and was refined to the final agreement factors of R(F) = 0.044 and Rw(F) = 0.035. The Co atom has a distorted tetrahedral coordination, with Co-I 2.595(2) for I and 2.607(2) Å for II; Co-(η5-C5H5 ring centroid) 1.681(4) and 1.703(5) Å; Co-N(pyrrole) 1.905(9) and 1.885(9) Å; Co-N(imine) 1.971(8) and 2.003(9) Å, all the parameters being well within values found in the literature. The configuration around the chiral carbon of the phenylethylamine is S for both compounds, whereas the configuration around the metal is R in I and S in II. The different metal configurations in I and II have their origin in the two different substituents (R = H, CH3) at the imine carbon atoms of the chelate ring, which induce completely different conformations of the (S)-CH(CH3)(C6H5) moiety in the two complexes. For both compounds the thermodynamically less stable isomer is enriched upon crystallization. Also, for compound I the solution and solid state conformations are almost opposite to each other, the conformation in the solid reflecting intramolecular interactions (phenyl/C5H5 attraction). 相似文献
16.
Three novel metal-organic complexes with formulas [Ni(C9N2O2H7)2(CH3OH)2](1),[Zn(C9N2O2H7)2(H2O)2](2) and [Cd(C9N2O2H7)2(CH3OH)2](3) were synthesized by the reactions of Ni,Zn and Cd salts with ethyl 2-benzimidazolylacetate under hydrothermal conditions or layering technique,and characterized by single-crystal X-ray diffraction analysis,IR spec-troscopy,solid-state luminescent properties and thermogravimetric(TG) analysis.The crystal data for these three complexes are as follows:for 1,monoclinic,space group P21/c,a = 9.384(3),b = 9.634(3),c = 11.292(3) ,β = 95.787(5)°,V = 1015.7(5) 3,Z = 2,F(000) = 492,Dc = 1.547 Kg/m3,μ = 1.002 mm-1,the final R = 0.0451 and wR = 0.0900 for 1833 observed reflections with Ⅰ 2σ(Ⅰ);for 2,orthorhombic,space group Pbca,a = 10.031(4),b = 10.379(4),c = 17.525(7),V = 1824.6(12) 3,Z = 4,F(000) = 928,Dc = 1.645 Kg/m3,μ = 1.392 mm-1,the final R = 0.0452 and wR = 0.0996 for 1661 observed reflections with Ⅰ 2σ(Ⅰ);for 3,monoclinic,space group P21/c,a = 9.9114(13),b =10.4852(15),c = 10.4120(14) ,β = 108.453(5)°,V = 1026.4(2) 3,Z = 2,F(000) = 532,Dc = 1.705 Kg/m3,μ = 1.110 mm-1,the final R = 0.0322 and wR = 0.0805 for 1822 observed reflections with Ⅰ 2σ(Ⅰ).In the three complexes,the ethyl 2-benzimidazolylacetate shows the same chelating mode,and the adjacent units are interlinked into a two-dimensional layer through hydrogen-bonds(O-H···O,N-H···O). 相似文献
17.
A. V. Ivanov O. A. Bredyuk O. N. Antzutkin W. Forsling 《Russian Journal of Coordination Chemistry》2005,31(1):45-50
Crystalline thallium(I) alkylxanthate complexes [Tl{S(S)COR}]n (R = C2H5, i-C3H7, i-C4H9, s-C4H9, and C5H11) and isotope-substituted heteropolynuclear Cu(II)Tl(I) complexes [63(65)CuTl6(S2COR)8] (R= i-C4H9 and C5H11) were obtained and studied by ESR and high-resolution solid-state 13C CP/MAS NMR spectroscopy. According to the 13C NMR data, polynuclear thallium(I) complexes contain structurally equivalent alkylxanthate ligands. The ESR study revealed the Jahn-Teller dynamic effect in Cu(II)Tl(I) complexes; the nuclei of six Tl atoms are involved in the hyperfine interaction.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 48–54.Original Russian Text Copyright © 2005 by Ivanov, Bredyuk, Antzutkin, Forsling. 相似文献
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Samuel A. Sangokoya Gregory H. Robinson 《Journal of inclusion phenomena and macrocyclic chemistry》1988,6(3):263-266
The optically active quaternary ammonium salt (S)-(?)-α-[(C6H5)CH(CH3)N(CH3)3I] reacts with AlR3 to afford optically active organoaluminum based inclusion compounds, liquid clathrates, of the formula (S)-(?)-α-[(C6H5)CH(CH3)N(CH3)3][Al2R6I] (R=CH3, C2H5). Specific rotation ([α] 25 D ) for the Al(CH3)3 compound was determined to be ?13.19° while that for the Al(C2H5)3 analog was determined to be ?14.30°. There are 13.8 toluene molecules per anionic moiety for the trimethylaluminum based liquid clathrate while there are 15.0 toluene molecules per anion for the corresponding triethylaluminum inclusion compound. 相似文献
20.
Contributions to the Chemistry of Phosphorus. 72. About the Alkyl Cyclomonocarba Phosphanes (PR)4CH2, R = CH3, C2H5, t-C4H9 The alkyl-substituted cyclomonocarbaphosphanes (PR)4CH2 (R = CH3 1 , C2H5 2 , t-C4H9 3 ) are obtained in very good yield by the reaction of the corresponding dipotassium alkylphosphides K2(PR)n (n = 2, 3, 4) with methylene chloride. Besides, small amounts of the homocyclic rings characteristic for the given substituent and of the five-membered cyclodicarbaphosphanes (PR)3(CH2)2 with isolated CH2 groups are formed. For the alkylcyclomonocarbaphosphanes 1 and 2 , configuration isomers could be identified for the first time. The “all-trans” forms are always predominant; the relative amounts of the other isomers decrease strongly with increasing number of cis relationships between the substituents at adjacent phosphorus atoms. The 31P n.m.r. parameters for three of the all together six isomers of 1 distinguishable by n.m.r. spectrometry and for the “all-trans” isomers of 2 and 3 are reported and discussed. A definite separation is possible between substituent and configuration influence on the chemical shifts as well as on the coupling constants. 相似文献