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1.
Chrysostomos Wesdemiotis Roseann Csencsits Fred W. McLafferty 《Journal of mass spectrometry : JMS》1985,20(2):98-103
The proposed formation of [CH3C(OH)OCH2]+˙ (b) as the intermediate in the isomerization [CH2?C(OH)OCH3]+˙ (c)?b?[CH3COOCH3]+˙ (c has been confirmed by preparation of b from CH3COOCH2OCH3. For the three isomers a–c the dominant metastable ion (MI) dissociation, CH3O˙ loss, involves identical kinetic energy release values. The kinetic barriers for a?b and b?c must be nearly as high as that for CH3O˙ loss from c, as shown by the insensitivity of the mass spectra from collisionally activated dissociation (CAD) of a–c to ionizing electron energy. The H/D scrambling of metastable [CH2?C(OD)OCH3]+˙ and c–D3 ions confirm this, indicating that the barrier for a?b is slightly below that for b?c. Minor low-energy dissociations include losses of CH4 and CH3OH from a and losses of ˙CHO and CH2O from b. Comparison of MI and CAD spectra of a–c with those from [CH3(OH)CH2O]+˙ (d) and [CH3COCH2OH]+˙ (e) give no evidence for skeletal rearrangement of a–c to d or e. 相似文献
2.
Burinsky and Cooks1 have reported that deprotonated dimethyl adipate eliminates methanol via a gas-phase Dieckmann condensation. This is in contrast to the behaviour of simple methyl ester enolates which lose MeOH by a different mechanism, e.g. MeOCOC?HCH2R → [MeO (OCCHCH2R)] → O?C?CHC?HR + MeOH. Evidence is presented which supports the Dieckmann mechanism for adipates. For example, MeOCOC?(Me)CH2CH2CD(Me)CO2Me should eliminate MeOD in a Dieckmann condensation, but MeOH by the alternative mechanism outlined above. Experimentally, MeOD is lost exclusively. Similarly, MeOCOC?DCH2CH2C(Me)2CO2Me also loses MeOD, consistent with a Dieckmann process. 相似文献
3.
Johan K. Terlouw Wigger Heerma John L. Holmes Peter C. Burgers 《Journal of mass spectrometry : JMS》1980,15(11):582-586
The [C4H6O]+˙ ion of structure [CH2?CHCH?CHOH]+˙ (a) is generated by loss of C4H8 from ionized 6,6-dimethyl-2-cyclohexen-1-ol. The heat of formation ΔHf of [CH2?CHCH?CHOH]+˙ was estimated to be 736 kJ mol?1. The isomeric ion [CH2?C(OH)CH?CH2]+˙ (b) was shown to have ΔHf, ? 761 kJ mol?1, 54 kJ mol?1 less than that of its keto analogue [CH3COCH?CH2]+˙. Ion [CH2?C(OH)CH?CH2]+˙ may be generated by loss of C2H4 from ionized hex-1-en-3-one or by loss of C4H8 from ionized 4,4-dimethyl-2-cyclohexen-1-ol. The [C4H6O]+˙ ion generated by loss of C2H4 from ionized 2-cyclohexen-1-ol was shown to consist of a mixture of the above enol ions by comparing the metastable ion and collisional activation mass spectra of [CH2?CHCH?CHOH]+˙ and [CH2?C(OH)CH?CH2]+˙ ions with that of the above daughter ion. It is further concluded that prior to their major fragmentations by loss of CH3˙ and CO, [CH2?CHCH?CHOH]+˙ and [CH2?C(OH)CH?CH2]+˙ do not rearrange to their keto counterparts. The metastable ion and collisional activation characteristics of the isomeric allenic [C4H6O]+˙ ion [CH2?C?CHCH2OH]+˙ are also reported. 相似文献
4.
《Journal of Coordination Chemistry》2012,65(2):283-291
Abstract Three dimolybdenum alkyne complexes containing functionally substituted ligands [Mo2(μ-CHCH)(CO)4(η5?C5H4C(O)R)2] [R ? OEt, (1a); R ? Me, (1b); R ? Ph, (1c)] were synthesized by reactions of acetylene with in situ generated metal-metal triply bonded complexes [Mo(CO)2(η5?C5H4C(O)R)]2 (R ? OEt, Me, Ph). Further reaction of (1a), (1b) or (1c) with Co2(CO)8 in refluxing toluene gave another three new butterfly compounds [Co2Mo2-(μ4-CHCH)(μ-CO)4(CO)4(η5-C5H4C(O)R)2] [R ? OEt, (2a); R ? Me, (2b); R ? Ph, (2c)]. The resulting compounds were characterized by elemental analyses, IR, 1H NMR and MS. The crystal structure of (2b) was determined by single-crystal X-ray analysis. The results indicate that the existence of functional groups on the cyclopentadienyl ring has an influence on the reactivity of this type of complex. 相似文献
5.
Mass spectra from collisionally activated dissociation (CAD) of [C2H3O]+ ions, including isotopically labeled analogs, provide further information on the isomers [CH3C?O+] (a), [CH2?C?O+H] (b), [+CH2CH?O] (c) and (d). Our data generally support the recent conclusions from theory by Radom and coworkers and from experiment by Terlouw, Holmes and coworkers. Most acetyl-containing molecular ions form a ions in high purity only at low energies, consistent with isomerization of higher energy molecular ions to form the more stable enol which dissociates to b. Isomer d, prepared from (CICH2)2CHOH, undergoes facile hydrogen scrambling, presumably through a degenerate 1,2-hydrogen shift. Theory suggests that c undergoes spontaneous isomerization to a and d; although [C2H3O]+ ions from BrCH2CHO appear to consist of a and ~15% d, the latter are formed without substantial hydrogen scrambling. 相似文献
6.
Véronique Plantevin 《Journal of organometallic chemistry》2004,689(11):2013-2024
Further investigations into the chemistry of the rhenacyclobutadiene complexes (CO)4Re(η2-C(R)C(CO2Me)C(X)) (1: R=Me, X=OEt (1a), O(CH2)3CCH (1b), NEt2 (1c); R=CHEt2, X=OEt (1d); R=Ph, X=OEt (1e)) are reported. Reactions of 1 with alkynes at reflux temperature of toluene and at ambient temperature either under photochemical conditions or in the presence of PdO yield ring-substituted η5-cyclopentadienylrhenium tricarbonyl complexes, 2. The symmetrical alkynes R′CCR′ (R′=Ph, Me, CO2Me) afford the pentasubstituted complexes (η5-C5(Me)(CO2Me)(OEt)(Ph)(Ph))Re(CO)3 (2d), (η5-C5(Me)(CO2Me)(OEt)(Me)(Me))Re(CO)3 (2e), (η5-C5(Me)(CO2Me)(OEt)(CO2Me)(CO2Me))Re(CO)3 (2f), and (η5-C5(Me)(CO2Me)(NEt2)(CO2Me)(CO2Me))Re(CO)3 (2i) on reaction with the appropriate 1, whereas the unsymmetrical alkynes R′CCR″ (R′=Ph; R″=H, Me) give either only one, (η5-C5(Me)(CO2Me)(OEt)(Ph)H)Re(CO)3 (2a)), or both, (η5-C5(Me)(CO2Me) (OEt)(Ph)(Me))Re(CO)3 (2b) and (η5-C5(Me)(CO2Me)(OEt)(Me)(Ph))Re(CO)3 (2c), (η5-C5(Ph)(CO2Me)(OEt)(Ph)H)Re(CO)3 (2g) and (η5-C5(Ph)(CO2Me)(OEt)(H)(Ph))Re(CO)3 (2h), of the possible products of [3 + 2] cycloaddition of alkyne to η2-C(R)C(CO2Me)C(X). Thermolysis of (CO)4Re(η2-C(Me)C(CO2Me)C(O(CH2)3CCH)) (1b) containing a pendant alkynyl group proceeds to (η5-C5(Me)(CO2Me)(O(CH2)3)H)Re(CO)3 (2j), a η5-cyclopentadienyl-dihydropyran fused-ring product. Competition experiments showed that each of PhCCH and MeO2CCCCO2Me reacts faster than PhCCPh with 1a. The results with unsymmetrical alkynes are rationalized by steric properties of substituents at the CC and ReC bonds and by a preference of ReC(Me) over ReC(OEt) to undergo alkyne insertion. A mechanism is proposed that involves substitution of a trans CO by alkyne in 1, insertion of alkyne into ReC bond to give a rhenabenzene intermediate, and collapse of the latter to 2. Complexes 1a and 1d undergo rearrangement in MeCN at reflux temperature to give rhenafuran-like products, (CO)4Re(κ2-OC(OMe)C(CHCR2)C(OEt)) (R=H (3a) or Et (3b)). The reaction of 1d also proceeds in EtCN, PhCN, and t-BuCN at comparable temperature, but is slower (especially in t-BuCN) than in MeCN. In pyridine at reflux temperature, 1a undergoes a similar rearrangement, with CO substitution, to give (CO)3(py)Re(κ2-OC(OMe)C(CHCEt2)C(OEt)) (4). A mechanism is proposed for these reactions. The sulfonium ylides Me2SCHC(O)Ph and Me2SC(CN)2 (Me2SCRR′) react with 1a in acetonitrile at reflux temperature by nucleophilic addition of the ylide to the ReC(Me) carbon, loss of Me2S, and rearrangement to a rhenafuran-type structure to yield (CO)4Re(κ2-OC(OMe)C(C(Me)CRR′)C(OEt)) (R=H, R′=C(O)Ph (5a); R=R′CN (5b)). All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy. 相似文献
7.
The rhenacyclobutadienes (CO)4Re(η2- C(R)C(CO2Me)C(OR′)) (2) undergo a number of reactions that mirror those of Fischer alkoxycarbene complexes. Thus, (CO)4Re(η2-C(Me)C(CO2Me)C(OEt)) (2a) can be deprotonated by LDA, Na[OBu-t], or Na[CH(CO2Me)2] to give the ylide-like conjugate base [(CO)4Re(η2-C(CH2)C(CO2Me)C(OEt)]− (3), which was isolated as PPN(3). Li(3) undergoes deuteriation with DCl/D2O and alkylation with Et3OPF6 at ReCCH2, with the latter reaction affording (CO)4Re(η2-C(CH2Et)C(CO2Me)C(OEt)) (4). Repetition of the sequence deprotonation-ethylation on 4 generates (CO)4Re(η2-C(CHEt2)C(CO2Me)C(OEt)) (5). The nature of the alkoxy substituent in 2 can be varied by use of the rhenacyclobutenones Na[(CO)4Re(η2-C(R)C(CO2Me)C(O))] (Na(1)) in conjunction with AcCl and R′OH to produce a series of new complexes (R=Ph, R′=Et (2b); R=Me, R′=CH2CHCH2 (2c), (CH2)3CCH (2d), Me (2e)). Aminolysis of 2a with the primary and secondary amines PhNH2, HO(CH2)2NH, p-TolNH2, and Et2NH yields the aminorhenacyclobutadiene complexes (CO)4Re(η2-C(Me)C(CO2Me)C(NHR′ or NR′2)) (R2′=Et2 (6a); R′=Ph (6b), (CH2)2OH (6c), p-Tol (6d)). These complexes display lesser carbene-like character than their alkoxy counterparts 2, as evidenced by 1H and 13C NMR spectroscopic properties and lack of reactivity toward LDA by 6a. Reactions of each 2a and 6a with PPhMe2 at low temperature afford (CO)4Re(η2-C(Me)(PPhMe2)C(CO2Me)C(OEt)) (7) and (CO)3(PPhMe2)Re(η2-C(Me)C(CO2Me)C(NEt2)) (9), respectively, further in agreement with the more carbenoid nature of 2a than 6a. 7 undergoes conversion to (CO)3(PPhMe2)Re(η2-C(Me)C(CO2Me)C(OEt)) (8) upon heating. 2a reacts with each of (NH4)2[Ce(NO3)6], DMSO, EtNO2/Et3N, and Me3NO under various conditions to afford one or both of the oxygen atom insertion products into the ReC bonds, (CO)4Re(κ2-OC(Me)C(CO2Me)C(OEt)) (10) and (CO)4Re(κ2-C(Me)C(CO2Me)C(OEt)O) (11). In contrast, no reaction occurred between 2a and S8 on heating. However, 6a was converted to the NH insertion product (CO)4Re(κ2-NHC(Me)C(CO2Me)C(NEt2)) (12) by the action of H2NNH2 · H2O at 0 °C. All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy. 相似文献
8.
Guy Bouchoux Yannik Hoppilliard Jean-Pierre Flament 《Journal of mass spectrometry : JMS》1985,20(9):560-564
The relative energies of 11 [C3H3O]+ ions are calculated by different molecular orbital methods (MINDO/3, MNDO, ab initio with 3-21G and 4-31G* basis set and configuration interaction). The four most stable structures are: a ([CH2?CH? CO]+), b c ([CH?C? CHOH]+) and d ([CH2?C?COH]+); their relative energies at the CI/4-31G*//3-21G level are 0, 117, 171 and 218 kJ mol?1, respectively. The isomerizations c→[CH?CH? CHO]+→[CH2?C? CHO]+→ a and dissociations into [C2H3]++CO and [HCO]++C2H2 are explored. The calculated potential energy profile reveals that the energy-determining step is the 1,3-H migration c→[CH?CH? CHO]+. This explains the value of unity of the branching ratio and the spread of kinetic energy released for the two dissociation channels. 相似文献
9.
Yichao Lin Wugai An Xingxing Ge Mingzhu Liu Yue Wang 《Journal of Coordination Chemistry》2019,72(5-7):987-1001
Seven diorganotin complexes with the Schiff bases derived from salicylaldehyde and l-tyrosine, R2Sn[2-O-5-XC6H3CH?=?NCH(CH2C6 H4OH-4)COO] (X?=?H (1), Br (2); R?=?Me (a), Et (b), Bu (c), Cy (cyclohexyl) (d)), were synthesized and characterized by elemental analysis, IR, 1H and 13C NMR spectra, and the single-crystal X-ray diffraction. In methanol, the racemization of chiral center of l-tyrosinate fragment occurred and the racemic products were obtained. X-ray analyses of 1c, 1d, and 2a–2c showed that the tin atoms of the complexes exhibit distorted trigonal-bipyramidal geometries. In 1c, 1d, and 2c, the intermolecular O–H???O hydrogen bonds connected the molecules into 1-D supramolecular chain or a R22(20) macrocyclic dimer, and 2a and 2b formed the 2-D supramolecular network by the intermolecular Sn???O and O–H???O interactions. Bioassay results indicated that 1a, 1c, and 1d had moderate antibacterial activity against Escherichia coli and 1c, 1d, and 2c belonged to the efficient cytostatic agents against two human tumor cell lines (A549 and HeLa) and the activity tends to follow the order Cy > Bu?>?Et?>?Me for the R group attached to tin. 相似文献
10.
The polymeric precursor [RuCl2(CO)2]n reacts with the ligands, P∩P (a, b) and P∩O (c, d), in 1:1 M ratio to generate six-coordinate complexes [RuCl2(CO)2(?2-P∩P)] (1a, 1b) and [RuCl2(CO)2(?2-P∩O)] (1c, 1d), where P∩P: Ph2P(CH2)nPPh2, n = 2(a), 3(b); P∩O: Ph2P(CH2)nP(O)Ph2, n = 2(c), 3(d). The complexes are characterized by elemental analyses, mass spectrometry, thermal studies, IR, and NMR spectroscopy. 1a–1d are active in catalyzed transfer hydrogenation of acetophenone and its derivatives to corresponding alcohols with turnover frequency (TOF) of 75–290 h?1. The complexes exhibit higher yield of hydrogenation products than catalyzed by RuCl3 itself. Among 1a–1d, the Ru(II) complexes of bidentate phosphine (1a, 1b) show higher efficiency than their monoxide analogs (1c, 1d). However, the recycling experiments with the catalysts for hydrogenation of 4-nitroacetophenone exhibit a different trend in which the catalytic activities of 1a, 1b, and 1d decrease considerably, while 1c shows similar activity during the second run. 相似文献
11.
《Journal of Coordination Chemistry》2012,65(4):233-246
Abstract Cobalt(III) complexes of the type [Co(en)2(chel)]X.nH2O where en = ethylenediamine, chel = phthalato = C6H4CO2)2? 2, maleato = (O2CCH = CHCO2)2?, succinato = (O2CCH2CH2CO2)2?, homophthalato = (O2CC6H4(CH2)CO2)2?, citraconato = (O2CC(CH3) = CHCO2)2?, itaconato = (CH2 = C(CO2)CH2CO2)2?, X = NO? 3, Br?, (O2CC6H4CO2H)?, (O2CHC = CHCO2H)?, (O2C(CH2)2CO2H)?, (O2CC6H4(CH2)CO2H)?, (O2CHC = C(CH2)-CO2H)?, and (O2C-CH2?C(= CH2)-CO2H)?, [Co(en)2(malonato)]X.2H2O (where malonato = (O2CCH2CO2)2?, X = Cl?, Br?, and NO? 3) and [Co(en)2CO3]Cl.2H2O have been investigated for their bacterial activity against Escherichia coli B growing on EMB agar and in minimal glucose media both in lag and log phases. Among the most active are where chel = phthalato and homophthalato. The effects are distinct from those known for compounds of Pt, e.g., cis?[Pt(NH3)2Cl2] and rhodium, e.g., trans?[Rh(C5H5N)4,Cl2].6H2O. Antagonisms are reported. 相似文献
12.
The collisional activation mass spectra prove that non-decomposing ionized methyl acetate [CH3COOCH3]+? and its enolic isomer [CH2?C(OH)OCH3]+? exist as stable species in potential wells. It is shown, however, that prior to CH3O? loss the decomposing [CH2?C(OH)OCH3]+? ion isomerizes via a rate determining symmetry forbidden [1.3] hydrogen rearrangement to ionized methyl acetate. The alternative mode of two consecutive formally symmetry allowed [1.2] hydrogen migrations can be certainly excluded for this isomerization. The activation energy of such hydrogen rearrangements is of the order of 41–83 kcal · mol?1 depending on the electronic nature of the cations (“open” or “closed” shell systems). 相似文献
13.
Synthesis and Characterization of a Gold Vinylidene Complex Lacking π‐Conjugated Heteroatoms
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Robert J. Harris Prof. Ross A. Widenhoefer 《Angewandte Chemie (International ed. in English)》2015,54(23):6867-6869
Hydride abstraction from the gold (disilyl)ethylacetylide complex [( P )Au{η1‐C?CSi(Me)2CH2CH2SiMe2H}] ( P =P(tBu)2o‐biphenyl) with triphenylcarbenium tetrakis(pentafluorophenyl)borate at ?20 °C formed the cationic gold (β,β‐disilyl)vinylidene complex [( P )Au?C?CSi(Me)2CH2CH2Si (Me)2]+B(C6F5)4? with ≥90 % selectivity. 29Si NMR analysis of this complex pointed to delocalization of positive charge onto both the β‐silyl groups and the ( P )Au fragment. The C1 and C2 carbon atoms of the vinylidene complex underwent facile interconversion (ΔG≠=9.7 kcal mol?1), presumably via the gold π‐disilacyclohexyne intermediate [( P )Au{η2‐C?CSi(Me)2CH2CH2Si (Me)2}]+B(C6F5)4?. 相似文献
14.
1H-, 13C-, and 17O-NMR spectra for the 2-substituted enaminones MeC(O)C(Me)?CHNH(t-Bu) ( 1 ), EtC(O)C(Me)?CHNH(t-Bu) ( 2 ), PhC(O)C(Me)?CHNH(t-Bu) ( 3 ), and MeC(O)C(Me)?CHNH(t-Bu) ( 4 ) are reported. These data show that 3 exists mainly in the (E)-form, 4 in (Z)-form, and 1 and 2 as mixtures of both forms. Polar solvents favour the (E)-form. The (Z)- and (E)-forms exist in the 1,2-syn,3,N-anti and 1,2-anti,1,N-anti conformations A and B , respectively. The structures of the (E)- and (Z)-form are confirmed by X-ray crystal-structure determinations of 3 and 4. The shielding of the carbonyl O-atom in the 17O-NMR spectrum by intramolecular H-bonding (ΔλHB) ranging from ?28 to ?41 ppm, depends on the substituents at C(l) and C(2). Crystals of 3 at 90 K are monoclinic. with a = 9.618(2) Å, b = 15.792(3) Å, c = 16.705(3) Å, and β = 94.44(3)°, and the space group is P21/c with Z = 8 (refinement to R = 0.0701 on 3387 independent reflections). Crystals of 4 at 101 K are monoclinic, with a = 16.625(8) Å, b = 8.637(6) Å, c = 11.024(7) Å, and β = 101.60(5)°, and the space group is Cc with Z = 4 (refinement to R = 0.0595 on 2106 independent reflections). 相似文献
15.
《Journal of Coordination Chemistry》2012,65(16):1777-1788
Chlorodiorganotin(IV)pyrazolinates of the type R2SnCl(C15H12N2O?·?X) [where C15H12N2O?·?X?=?3(2′-Hydroxyphenyl)-5(4-X-phenyl)pyrazoline {where X?=?H (a); CH3 (b); OCH3 (c); Cl (d) and R?=?Me, Pr n and Ph}] have been synthesized by reaction of R2SnCl2 with the sodium salt of pyrazolines in 1?:?1 molar ratio, in anhydrous benzene. These newly synthesized derivatives have been characterized by elemental analysis (C, H, N, Cl and Sn), molecular weight measurement and spectral studies [IR and multinuclear NMR (1H, 13C and 119Sn)]. The bidentate behavior of the ligands was confirmed by IR, 1H and 13C NMR spectral data. Trigonal bipyramidal structure around tin(IV) for R2SnCl(C15H12N2O?·?X) is suggested. The free pyrazoline and some chlorodiorganotin(IV) pyrazolinates have been screened for their antibacterial and antifungal activities. Some chlorodiorganotin(IV) pyrazolinates exhibit higher antibacterial and antifungal effect than free pyrazoline and some antibiotics. 相似文献
16.
D. V. Airapetyan T. P. Murasheva S. Yu. Bylikin A. A. Korlyukov A. G. Shipov S. V. Gruener E. P. Kramarova Vad. V. Negrebetskii S. A. Pogozhikh G. Ya. Zueva M. Yu. Antipin Yu. I. Baukov 《Russian Chemical Bulletin》2012,61(3):642-651
The reactions of GeCl4, GeBr4, and MeGeCl3 with O-trimethylsilyl derivatives of N,N-disubstituted amides of 2-hydroxycarboxylic acids afforded pentacoordinate and hexacoordinate neutral (O,O)-mono- and (O,O)-bischelates. The reactions of glycolic acid derivatives with GeX4 produced bischelates X2Ge[OCH2C(O)NR2R3]2 7a,c,d (X = Cl, R2 = R3 = Me (a), (CH2)5 (c), (CH2CH2)2O (d)) and 8a (X = Br). By contrast, the reactions of lactic and mandelic acid derivatives with GeCl4 and MeGeCl3 gave monochelates Cl3Ge[OCH(R1)C(O)NR2R3] (S)-9a–c (R1 = Me) and Cl2MeGe[OCH(R1)C(O)NR2R3] 10a (R1 = H), (S)-11a,b (R1 = Me), and (S)-12a (R1 = Ph) (R2R3 = (CH2)4 (b)), respectively. According to the X-ray diffraction data, the Ge atom in bischelates 7c,d and 8a has a coordination number 6, and its coordination polyhedron can be described as a slightly distorted octahedron. In monochelates (S)-9a-c, 10a, (S)-11a,b, and (S)-12a, the Ge atom has a coordination number 5, and its coordination polyhedron can be described as a trigonal bipyramid with two halogen atoms or one halogen atom and one ethereal oxygen atom in equatorial positions and the halogen atom and the amide oxygen atom in the axial positions. The bonds in the axial positions are somewhat longer than the corresponding bonds in tetracoordinate Ge compounds. 相似文献
17.
The energy dependence of the fragmentation of a selection of ester enolate ions has been studied by variable, low-energy collision-induced dissociation experiments in the quadrupole collision cell of a hybrid BEQQ mass spectrometer. The dominant fragmentation reactions observed are where ΔH1 ? ΔH2=PA([RCCO]?) ? PA([?O]?) (PA=proton affinity). The anion of lowest proton affinity is formed preferentially at low internal energies with the yield of the anion of higher proton affinity increasing with increasing internal energy. The [CH3OCOCOCH2]? anion derived from methyl pyruvate forms [CH3OCO]? by reaction (2); this anion readily fragments to [CH3G]?+ CO consistent with a structure represented by a dipole-stabilized cluster of [CH3O]? and CO. Comparison of the 8-keV with the 50-eV collision-induced dissociation mass spectra indicated that the average internal energy of the fragmenting ions is considerably lower in the high-energy collisional experiments than it is in the low-energy collisional experiments. 相似文献
18.
Petr Štěpni?ka Martin Zábranský Ivana Císa?ová 《Journal of organometallic chemistry》2008,693(10):1779-1786
Ferrocene-based β-aminoalcohols FcCH2NHCR2CH2OH (R = H, 1a; R = Me, 1b) and (S)-FcCH2NHCH(CHMe2)CH2OH (1c; Fc = ferrocenyl) react with 2,4,6-trinitrophenol (Hpic) under proton transfer to afford the corresponding ammonium picrates 2a-c. In the crystal, these picrates associate predominantly via N-H?O and O-H?O bifurcated hydrogen bonds between the NH2+ and OH groups in the aminoalcohol chain as the donors and the phenoxide and NO2 oxygen atoms of the picrate anion as the acceptors. Compounds 2a and 2b form closed dimeric assemblies [1nH]2[pic]2 (n = a, b) around the crystallographic inversion centres. By contrast, their chiral analogue 2c gives rise to monomeric units [1cH][pic] (albeit through similar interactions), that further aggregate into infinite linear chains via N-H?O hydrogen bonds. The formed assemblies are interconnected by the soft C-H?O hydrogen bonds and via π?π stacking interactions of the picrate ions. 相似文献
19.
20.
《Journal of Coordination Chemistry》2012,65(23):2541-2547
In the presence of ethylenediamine template agents, a metal(II) phosphonate, [NH3CH2CH2NH3][Fe2(O3PCH(OH)CO2)2(H2O)2]?·?2H2O (1) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction as well as infrared spectroscopy, elemental analysis and thermogravimetric analysis. The compound crystallines in the monoclinic space group P21/n: Crystal data for 1: a?=?8.4523(8)?Å, b?=?9.8196(9)?Å, c?=?10.9217(10)?Å, β?=?105.9500(10)°, V?=?871.58(14)?Å, Z?=?2, D c?=?2.103?g?cm?3, R 1?=?0.0290, wR 2?=?0.0811. The Fe (II) cation is octahedrally coordinated by six oxygen atoms from the three ligands and one coordinated water molecule to form a 2D layered structure with a one-dimensional channel system in the a-axis direction. 相似文献