Zum Mechanismus Massenspektrometrischer Fragmentierungsreaktionen. XVI—hydrid-Wanderungen bei der Fragmentierung von αω-Dimethoxyalkyl-Ionen

The isomerization and fragmentation of α,ω-dimethoxyalkyl ions a (CH₃OCH₂(CH₂)_n- CH⁺OCH₃, n = 1-6) has been investigated by deuterium labelling. It is shown that a isomerizes to ion a' by hydride transfer from the ω-CH₂ group to the positive charge at the α-C-atom before elimination of methanol. Both methoxy groups are lost as methanol. The amount of isomerization can be deduced from alkene elimination from [a ? CH₃OH]+ ions in deuterated derivatives of a. On average at 70 eV three rearrangement steps involving hydride transfer are observed.     

Heteronuclear Alkoxide Compounds Containing Copper and Alkaline Earth Metals

The tetrameric Cu(β-diketonate) alkoxide complex [Cu(thd)(OCH₂CH₂OCH₃)]₄ (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; 1a ) reacts with the alkaline earth metal alkoxides [M(OCH₂CH₂OCH₃)₂] (M = Ca, 2a ; M = Sr, 2b ; M = Ba, 2c ) to yield the heteronuclear compounds [Cu₂M(thd)₃(OCH₂CH₂OCH₃)₃] (M = Ca, 6a ; M = Sr, 6b ). These heterometallic complexes were also obtained in the reaction of 1a and the mixed Ca and Sr complexes of β-diketonate-alkoxide [M_x(thd)_y(OCH₂CH₂OCH₃)_2x?y] (M = Ca, x = 7, y = 6, 3 ; M = Sr, x = 5, y = 3, 4 ), respectively. In comparison, 1a reacts with the analogous [Ba(thd)(OCH₂CH₂OCH₃)] ( 5a ) to yield a[Ba₂Cu₂(thd)₄(OCH₃)₄(HOCH₂CH₂OCH₃)₂] species ( 8a .) The in situ prepared mixed-ligand Ba Compounds [Ba(thd)OR)] (R = CH₂CH₂OCH₂CH₂OCH₃, ( 5b ); R = CH₂CH₂CH₂OCH₃ ( 5c ) react with the corresponding Cu complexes [Cu(thd)(OR)]_n (R = CH₂CH₂OCH₂CH₂OCH₃), n = 4 ( 1b ); R = CH₂CH₂OCH₂CH₂OCH₃ ( 8b ); R = CH₂CH₂CH₂OCH₃ ( 8c ). However, [Cu(hfd)(OCH₂CH₂OCH₃)]₄ (hfd = 1,1,1,5,5,5,-hexafluoroacetylacetonate; 1e ) is converted in the presence of 2a–c to the simple metathesis products [M(hfd)₂] (M = Ca, Sr, Ba) and [Cu(OCH₂CH₂OCH₃)₂]. Crystalline [Ba₂Cu₂(hfd)₂(thd)₂(OCH₂CH₂CH₂OCH₃)₄(HOCH₂CH₂CH₂OCH₃)₂] ( 9 ) was isolated from the reaction of 1a with in situ prepared [Ba((hfd)OCH₂CH₂CH₂OCH₃)] ( 5d ) in 2-, methoxyethanol. X-Ray crystallographic structure determinations are reported for 6a , 6b , 8b , and 8c .     

A comparison of local structures in crystalline P(EO)3LiCF3SO3 and glyme-LiCF3SO3 systems

The newly discovered crystal structures of CH₃(OCH₂CH₂)OCH₃(LiCF₃SO₃)₂, monoglyme:(LiTf)₂, and CH₃(OCH₂CH₂)₃OCH₃(LiCF₃SO₃)₂, triglyme:(LiTf)₂, are briefly described. The coordination of lithium cations and the CF₃SO₃⁻ anions in these structures is compared with the cation and anion coordination in the crystalline phase of high molecular weight P(EO)₃LiCF₃SO₃. Comparison is also made with the previously reported crystalline phase of CH₃(OCH₂CH₂)₂OCH₃LiCF₃SO₃, diglyme:LiTf. A tendency to form trans-gauche-trans conformations for the bond order -O-C-C-O- is noted in adjacent ethylene oxide sequences interacting with a five-coordinate lithium ion.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP (CH3)3–OP(OCH3)3 und SP(CH3)3–SP(OCH3)3

Vibrational Spectra and Force Constants of the Series OP(CH₃)₃? OP(OCH₃)₃ and SP(CH₃)₃? SP(OCH₃)₃ The vibrational spectra of OP(CH₃)₂(OCH₃), OP(CH₃)(OCH₃)₂, SP(CH₃)₂(OCH₃), and SP(CH₃)(OCH₃)₂, are recorded and assigned to the normal vibration. The valence force constants are calculated by a simplified force field. The results are disscussed for both series and compared with former results.     

Substitution reactions of IF5

Using silyl protected organic hydroxo compounds substitution of fluorine in IF₅ is successful.Reacting IF₅ with Si(OCH₃)₄ in CH₃CN or SO₂ using different molar ratios it was shown that in the series IF_5?n(OCH₃)_n only the first member IF₄(OCH₃) (n=1) is stable enough to be isolated. The product in solution with n=2 bismutates to products with n=1 and n=3 if isolated as solids. The last one decomposes to the new oxo compound IF₂O(OCH₃) under elimination of CH₃OCH₃. With n=4,5 only redox reaction products could be isolated.IF₂O(OCH₃) can also be obtained by treating IF₄(OCH₃) with (CH₃)₆Si₂O. Similarly reaction of IF₅ with the disiloxane represents a new method to win IOF₃. Excess of the oxygen transfer reagent leads to formation of IO₂F and I₂O₅. An other oxo compound, IO(CH₃COO)₃, can be prepared by disolving IF₅, IOF₃ or IO₂F in acetic acid anhydride.Reactions of IF₅ with trimethylsilyl protected fluorinated benzoic acids R_fCOOSi(CH₃)₃ (R_f = C₆F₅, 4HC₆F₄) appeared to be independent of the educts molar ratios because the only products are IF(R_fCOO)₄.In order to stabilize iodine (V) derivates with bifunctional chelating oxo ligands we applicated bis(trimethylsilyl) pinacolate, and in smooth reactions we yielded IF₃[OC(CH₃)₂C(CH₃)₂O] and IF[OC(CH₃)₂  C(CH₃)₂O]₂, in which iodine is part of five membered heterocyclic rings. The ¹⁹F-nmr-spectra are consistent with the diolate occupying the axiale and equatorial positions.An extension of the silyl method is the new synthesis of C₆F₅IF₄ which could be obtained in the smooth reaction of IF₅ with stochiometric amounts of Si(C₆F₅)₄.     

Mass spectra of monohapto-cyclopentadienyl derivatives of group IVB elements

Dissociative ionisation of organometallic cyclopentadiene derivatives containing one, two or three M(CH₃)₃ groups (M  Si, Ge, Sn) has been studied.Among the monometallated compounds, C₅H₅Si(CH₃)₂Cl, C₅H₅Si(CH₃)₂OCH₃ and (C₅H₅)₄Sb have also been investigated. To verify fragmentation patterns, the spectra of deuterated compounds such as C₅D₅Si(CH₃)₃, C₅D₅Sn(CH₃)₃, C₅D₄Si₂(CH₃)₆ and C₅D₃Si₃)₉ have been measured. Dissociative ionisation of h¹-cyclopentadienyl derivatives has been shown to differ essentially from that of h⁵-compounds.     

Präparative und spektroskopische Untersuchungen an einigen substituierten Trisilanen

Zusammenfassung Für Si₃Cl₈ (I) wird eine verbesserte Darstellungsmethode angegeben, Si₃(OCH₃)₈ (II) wird erstmals dargestellt. Die Schwingungsspektren von I, II und Si₃(C₆H₅)₈ werden aufgenommen und unter Berücksichtigung von Kopplungseffekten zugeordnet; insbesondere wird die Lage der beiden SiSi₂-Valenzschwingungen diskutiert.

---

Preparative and spectroscopic investigations of some substituted trisilanes

An improved preparation for Si₃Cl₈ and the preparation and properties of the new trisilane Si₃(OCH₃)₈ are described. The vibrational spectra of these compounds and of Si₃(C₆H₅)₈ are reported and assigned, considering vibrational coupling. The position of the two SiSi₂ stretching vibrations is discussed in detail.

     

Synthesis of polyphosphazenes bearing alkoxyethoxy and trifluoroethoxy groups

The synthesis of various phosphoranimines including (CH₃OCH₂CH₂O) (CF₃CH₂O)₂P?N? Si(CH₃)₃, (CH₃OCH₂CH₂OCH₂CH₂O) (CF₃CH₂O)₂P?N? Si (CH₃)₃, (CH₃OCH₂CH₂O)₂(CF₃CH₂O) P?N? Si(CH₃)₃, and (CH₃OCH₂CH₂OCH₂CH₂O)(CF₃CH₂O) P?N? Si(CH₃)₃ via the Staudinger reaction of (CH₃)₃SiN₃ with the suitably substituted phosphite is reported. These monomers were polymerized using tetra-n-butylammonium fluoride and N-methylimidazole in various solvents at several temperatures. In situ ³¹P-NMR kinetic studies and M_n versus time studies were also performed for the monomers to understand the propagation mechanism. © 1994 John Wiley & Sons, Inc.     

Reaktionen von Alkoholen und Mercaptanen mit Tetraphosphatrichalkogenadiiodiden

Reactions of Alcohols and Mercaptans with Tetraphosphorus Trichalcogenide Diiodides α-P₄E₃(I)R and α-P₄E₃R₂ (R = -OCH₃, -OC₂H₅, -OCH(CH₃)₂, -OC(CH₃)₃ and -OC₆H₅) have been detected in the reaction solutions of α-P₄E₃I₂ (E = S, Se) with alcohols in the presence of triethylamine, or with trimethyltin alkoxides in CS₂. β-P₄S₃I₂ reacted with methanol at 243 K in CS₂ to yield β-P₄S₃(I)OCH₃, β-P₄S₃(OCH₃)_exo(OCH₃)_endo, and β-P₄S₃[(OCH₃)_exo]₂. The thiolates α-P₄Se₃R₂′ (R′ = -SC₂H₅, -n-SC₅H₁₁, -n-SC₇H₁₅, -SC(CH₃)₃ and -SC₆H₅) were found in reaction solutions of α-P₄Se₃I₂ with thiols HR′. The ³¹P NMR data of these compounds are given.     

Synthesis,spectroscopic and X‐ray single‐crystal structure study of bis(2‐methoxy‐ethanolato)‐bis(8‐quinolinato)titanium(IV)

Reaction of Ti(OCH₂CH₂OR)₄ (R?CH₃ and C₂H₅) with 8‐hydroxyquinoline in benzene at room temperature resulted in the formation of Ti(C₉H₆NO)₂(OCH₂CH₂OR)₂, characterized by IR, ¹H‐NMR, UV and mass spectroscopies. The molecular structure of Ti(C₉H₆NO)₂(OCH₂CH₂OCH₃)₂ has been determined by single‐crystal X‐ray structure analysis. The geometry at titanium is a distorted octahedron, with the nitrogen atoms of quinolinate occupying the trans position with respect to oxygens of the 2‐methoxyethoxy groups. The prepared quinolinate derivatives of titanium alkoxides are very stable towards hydrolysis and harsh conditions are required for hydrolytic cleavage. Copyright © 2005 John Wiley & Sons, Ltd.     

Structure and Magnetic Characteristics of New Binuclear Complexes Based on Bisbenzoylhydrazones of 2,6-Diformyl-4-R-phenols and Copper(II) Nitrate

A series of binuclear Cu(II) complexes with bisbenzoylhydrazones of 2,6-diformyl-4-R-phenols (R = OCH₃, CH₃, CH₂Ph, Cl, Br, CO₂CH₃) with H₂LCu₂(NO₃)₂(OCH₃) composition, where H₂L^–are monodeprotonated bishydrazones, was synthesized. The structure of the obtained complexes was established using IR spectro-scopy and conductometric and magnetochemical data. The title complexes were shown to exhibit exchange interaction of the antiferromagnetic type. Results of quantum-chemical calculations of structures modeling the state of a ligand in the complex were used to discuss the effect of substituent R nature on magnetic exchange in the complexes.     

Gas-phase ion–molecule reactions in dilute mixtures of dimethyl ether in krypton. Bimolecular and clustering reactions

The results of high-pressure variable-temperature and variable ionizing electron energy studies of gas-phase ion-molecule reactions of dimethyl ether in krypton are presented. Near the ionization threshold a series of peaks corresponding to (CH₃OCH₃)_nH⁺ (n = 1-4) clusters are observed. At higher ionizing electron energies, two new series of peaks appear, corresponding to [CH₃OCH₂]⁺(CH₃OCH₃)_n and [(CH₃)₃O]⁺ (CH₃OCH₃)_n clusters. The onium ion, [(CH₃)₃O]⁺, has been previously reported at elevated temperatures under methane chemical ionization conditions. It was suggested that the onium ion is formed by reaction of (CH₃)₂OH⁺ with CH₃OCH₃ with subsequent elimination of methanel, i.e. by fragmentation of an adduct ion. The present results strongly suggest that, under our conditions, [CH₃OCH₂]⁺ rather than thermal (CH₃)₃OH⁺, is the precursor to [(CH₃)₃O]⁺.     

羧酸铜催化反应的研究——Ⅰ.羧酸铜催化醛肟转变为睛

本文报道了在多种羧酸铜催化下,醛肟在含有氰基的溶剂中(如CH_3CN、CH_3OCH_2CH_2CN等),均可脱水转变成相应的腈。反应条件温和,产率较高。具有不同空间和电性效应取代基的羧酸铜对反应的产率影响不大。实验中还发现溶剂乙腈参与了上述反应。     

Dissoziative ionisierung von 2-trimethylsilyl-1-phenoxyethan. Nachweis des nicht-klassischen ethylen-trimethylsilanium-ions in der gasphase

The mass spectrometric investigation of specifically deuterium and ¹³C labelled 2-trimethylsilyl-l-phenoxyethanes proves that the dissociative ionization of β-silyl-substituted ethane derivatives (loss of PhO^?; p-CH₃C₆H₄O^?; and C₄H^?₉ from PhOCH₂CH₂SiMe₃, p-MeC₆H₄OCH₂CH₂SiMe₃ and CH₃CH₂CH(CH₃)CH₂-CH₂SiMe₃, respectively) yields the non-classical bridge ethylene trimethylsilanium ion and not the open-chain isomer. Other stable C₅H₁₃Si^+? ions, characterised by collisional activation mass spectrometry, are the dimethyl n-propyl silicenium ion and the l-trimethylsilyl ethyl cation, both generated from the molecular ions of CH₃CH₂CH₂Si(Cl)Me₂ and CH₃CH(Cl)SiMe₃ via unimolecular loss of Cl^?.     

Über die Reaktion des käfigartigen Kieselsäurederivats [(CH3)2HSi]8Si8O20 mit ungesättigten organischen Verbindungen

Reaction of the Cage-like Silicic Acid Derivative [(CH₃)₂HSi]₈Si₈O₂₀ with Unsaturated Organic Compounds By ²⁹Si, ¹H, and ¹³C NMR investigations were shown that the eight HSi?groups of the double four-ring silicic acid derivative [(CH₃)₂HSi]₈Si₈O₂₀ react with the following unsaturated compounds: vinylcyclohexene, allyl glycidyl ether, methyl methacrylate, octadecene-1, and styrene. The resulting oily products are soluble in organic solvents. The compounds were characterized by the chemical shifts of the ²⁹Si, ¹H, and ¹³C NMR signals. Their formulae are [C₆H₉(CH₂)₂Si(CH₃)₂]₈Si₈O₂₀, [CH₃OOCCH(CH₃)CH₂Si(CH₃)₂]₈Si₈O₂₀, [CH₃(CH₂)₁₇Si(CH₃)₂]₈Si₈O₂₀ and [C₆H₅(CH₂)₂Si(CH₃)₂]₈Si₈O₂₀, and [C₆H₅CH(CH₃)Si(CH₃)₂]₈ Si₈O₂₀, respectively. Mainly the addition reactions do not follow the Markovnikov rule.     

Synthesis of new titanatranes containing organic substituents in the atrane fragment

Titanatrane CpTi(OCH(CH₃)CH₂)₃N (3) was prepared by the reaction of CpTiCl₃ with N(CH₂CH(CH₃)OH)₃ in the presence of triethylamine. The reaction of CpTi(OMe)₃ (8) with N(CH₂CH₂OH)₂(CH₂CHPhOH), erythro-N(CH₂CH₂OH)₂(CHPhCHPhOH), and N(CH₂CH₂OH)₂(CH₂CPh₂OH) gave cyclopentadienyltitanatranes 12–14. Compound 8 reacts with threo-N(CH₂CH₂OH)₂(CHPhCHPhOH) to give a mixture of threo-CpTi(OCH₂CH₂)₂(OCHPhCHPh)N and threo-MeOTi(OCH₂CH₂)₂(OCHPhCHPh)N. Slow hydrolysis of the latter product gave threo-[Ti₃O(OMe){(OCH₂CH₂)₂₋ (OCHPhCHPh)N} ₃]₂, which was studied by X-ray diffraction analysis. The crystal structures of 3 and 12 were also determined by X-ray diffraction analysis. The titanium coordination polyhedron in these complexes is a distorted trigonal bipyramid in which the equatorial positions are occupied by three oxygen atoms and the axial positions contain the N atom and the Cp group. The titanium—nitrogen distances (2.313(2), 2.291(2) Å in two independent molecules of 3 and 2.271(2) Å in compound 12) confirm the presence of Ti←N transannular interaction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2736–2744, December, 2005.     

An ab initio study of the electronic and steric structure of Cl<Subscript>2</Subscript>ZX molecules (Z = P and As)

The electronic and steric structure of the Cl₂ZX molecules [Z = P and As, X = C₂H₅, N(CH₃)₂, and OCH₃] was examined by RHF/6-31G(d) and MP2/6-31G(d) calculations. The data on the electron distribution at the Cl atoms are compared with the published ³⁵Cl NQR data. The main reason for a decrease in the NQR frequency of the molecules with X = N(CH₃)₂ and OCH₃ as compared to the ethyl-substituted compounds is an increase in the population of the 3p components of their p _z(p _σ) orbitals. With X = N(CH₃)₂, electron distribution at two Cl atoms differs significantly.     

Novel Copolymers of Styrene and Alkoxy Ring‐Substituted 2‐Cyano‐N,N‐Dimethyl‐3‐Phenyl‐2‐Propenamides

Electrophilic trisubstituted ethylene monomers, alkoxy ring‐substituted 2‐cyano‐N,N‐dimethyl‐3‐phenyl‐2‐propenamides, RC₆H₄CH?C(CN)CON(CH₃)₂ (where R is 2‐OCH₃, 3‐OCH₃, 4‐OCH₃, 2‐OCH₂CH₃, 3‐OCH₂CH₃, 4‐OCH₂CH₂CH₃, 4‐OCH₂CH₂CH₂CH₃), were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and N,N‐dimethyl cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ACBN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 300–450°C range.     

Liquid Densities and Excess Molar Volumes for Binary Systems (Ionic Liquids + Methanol or Water) at 298.15, 303.15 and 313.15 K,and at Atmospheric Pressure

Binary excess molar volumes, V _m ^E, have been evaluated from density measurements, using a vibrating tube densimeter over the entire composition range for binary liquid mixtures of ionic liquids 1-ethyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-butyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [BMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-methyl-3-octyl-imidazolium diethyleneglycol monomethylethersulphate [MOIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+methanol and [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+water at 298.15, 303.15 and 313.15 K. The V _m ^E values were found to be negative for all systems studied. The V _m ^E results are explained in terms of intermolecular interactions and packing effects. The experimental data were fitted by the Redlich-Kister polynomial.     

Lyotropic liquid crystalline phase behavior of a polymeric amphiphile polymerized via their hydrophilic ends

The reaction of the nonionic low molecular mass surfactant 3, 6, 9, 12, 15, 18, 21, 24-octaoxaoctatriacontane-1-ol (CH₃(CH₂)₁₃(OCH₂CH₂)₈OH, C₁₄E₈) with acryloyl chloride yielded the monomeric amphiphile II (CH₃(CH₂)₁₃(OCH₂CH₂)₈O₂C-(CH:CH₂) with the polymerizable group located at the hydrophilic end of the molecule. Using radical polymerization, the polymeric surfactant III is obtained. These three surfactant water systems exhibit lyotropic liquid crystalline phases. The binary phase diagrams are compared with each other. In changing from the monomer-water to the polymer-water system a stabilization of the lyotropic mesophases is observed with amphiphiles which are connected via their hydrophilic ends; it is known for the surfactants to be connected via their hydrophobic ends. The appearance of the inverse mesophases, as expected from the molecular geometry of the polymer, is not observed.