Jianji Wang, K. Zhuo, Qiufen Zhang, Zhenning Yan, Han-qing Wang
Thermodynamic parameters of the interaction of HCl with D-galactose in water have been determined from electromotive force measurements at 10 K intervals from 278.15 to 318.15 K. Standard Gibbs energies of transfer of HCl from water to aqueous solutions of 5, 10, 15 wt.% D-galactose were evaluated. Comparison of pair interaction parameters of HCl–D-galactose was made with those of HCl–D-glucose and HCl–D-arabinose. The difference between these parameters was interpreted in terms of the stereochemistry of these monosaccharides. An enthalpy–entropy compensation has been observed with the pair interaction parameters for the HCl–sugar–water systems at each given temperature studied. The salting constants, kS, of D-galactose, D-glucose, D-fructose, D-arabinose, and sucrose by HCl in water were calculated from (a) the Debye–MacAulay theory (DMT); (b) Conway–Desnoyers–Smith theory (CDST); (c) the internal pressure theory developed by McDevit–Long (IPT); (d) the scaled particle theory (SPT). The results show that the calculated values of kS are reasonably in agreement with the experimental ones.
{"title":"Thermodynamics of the interaction of HCl with D-galactose in water at 278.15–318.15 K","authors":"Jianji Wang, K. Zhuo, Qiufen Zhang, Zhenning Yan, Han-qing Wang","doi":"10.1039/A806514D","DOIUrl":"https://doi.org/10.1039/A806514D","url":null,"abstract":"Thermodynamic parameters of the interaction of HCl with D-galactose in water have been determined from electromotive force measurements at 10 K intervals from 278.15 to 318.15 K. Standard Gibbs energies of transfer of HCl from water to aqueous solutions of 5, 10, 15 wt.% D-galactose were evaluated. Comparison of pair interaction parameters of HCl–D-galactose was made with those of HCl–D-glucose and HCl–D-arabinose. The difference between these parameters was interpreted in terms of the stereochemistry of these monosaccharides. An enthalpy–entropy compensation has been observed with the pair interaction parameters for the HCl–sugar–water systems at each given temperature studied. The salting constants, kS, of D-galactose, D-glucose, D-fructose, D-arabinose, and sucrose by HCl in water were calculated from (a) the Debye–MacAulay theory (DMT); (b) Conway–Desnoyers–Smith theory (CDST); (c) the internal pressure theory developed by McDevit–Long (IPT); (d) the scaled particle theory (SPT). The results show that the calculated values of kS are reasonably in agreement with the experimental ones.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"94 1","pages":"3359-3363"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85537749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vanadium was introduced into zeolites in different amounts (0.36–3.3 wt.%) and chemical states and was investigated by XPS, UV–VIS and EPR spectroscopies. The vanadium zeolites studied were vanadium silicalites, vanadyl ion (VO2+)-exchanged ZSM-5, MOR, Y, X and vanadium oxide aggregates deposited in/on ZSM-5 via chemical vapour deposition of VOCl3 with subsequent hydrolysis and calcination. By careful treatment of the X-ray satellite subtraction, reliable XPS analyses were obtained for all samples. Four types of vanadium species (intra-framework V, VO2+ ions, intra-zeolite VV oxide clusters and extra-zeolite V2O5 aggregates) could be discerned by their differing V 2p binding energies. The assignment of their signals was supported by UV–VIS and EPR spectroscopical evidence. It was thus shown that combination of XPS with UV–VIS and EPR provides a useful method for the analysis of vanadium-containing zeolites.
{"title":"Investigation of zeolites by photoelectron and ion scattering spectroscopy Part IV XPS studies of vanadium-modified zeolites","authors":"M. Wark, M. Koch, A. Brückner, W. Grünert","doi":"10.1039/A800522B","DOIUrl":"https://doi.org/10.1039/A800522B","url":null,"abstract":"Vanadium was introduced into zeolites in different amounts (0.36–3.3 wt.%) and chemical states and was investigated by XPS, UV–VIS and EPR spectroscopies. The vanadium zeolites studied were vanadium silicalites, vanadyl ion (VO2+)-exchanged ZSM-5, MOR, Y, X and vanadium oxide aggregates deposited in/on ZSM-5 via chemical vapour deposition of VOCl3 with subsequent hydrolysis and calcination. By careful treatment of the X-ray satellite subtraction, reliable XPS analyses were obtained for all samples. Four types of vanadium species (intra-framework V, VO2+ ions, intra-zeolite VV oxide clusters and extra-zeolite V2O5 aggregates) could be discerned by their differing V 2p binding energies. The assignment of their signals was supported by UV–VIS and EPR spectroscopical evidence. It was thus shown that combination of XPS with UV–VIS and EPR provides a useful method for the analysis of vanadium-containing zeolites.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"7 1","pages":"2033-2041"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85804704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The bimolecular rate constants (k) for the reactions of HPO4− radicals with phenol, fluorobenzene, chlorobenzene, bromobenzene, iodobenzene, benzonitrile, tert-butylbenzene and anisole (k = 5.3 × 108, 7 × 106, 6.9 × 106, 4 × 106, 1.2 × 107, 6.5 × 106, 1.0 × 108 and 4.6 × 107 M−1 s−1, respectively) have been determined by flash-photolysis of P2O84− solutions of pH 7.1 containing variable amounts of the organic substrates. The trend observed for the rate constants with the electron withdrawing ability of the substituents in the aromatic ring is discussed in terms of a Hammett type correlation. Phenoxyl type radical formation was observed in the reactions of HPO4˙− with chlorobenzene and phenol. Based on the experimental results, a possible reaction mechanism is proposed. Additional information on the decay kinetics of hydroxycyclohexadienyl radicals of chlorobenzene in the presence of molecular oxygen is also obtained from independent experiments with hydrogen peroxide solutions containing chlorobenzene under nitrogen, air and oxygen saturation.
{"title":"REACTIONS OF PHOSPHATE RADICALS WITH SUBSTITUTED BENZENES. A STRUCTURE-REACTIVITY CORRELATION STUDY","authors":"Sofía S. Cencione, M. Gonzalez, D. Mártire","doi":"10.1039/A804614J","DOIUrl":"https://doi.org/10.1039/A804614J","url":null,"abstract":"The bimolecular rate constants (k) for the reactions of HPO4− radicals with phenol, fluorobenzene, chlorobenzene, bromobenzene, iodobenzene, benzonitrile, tert-butylbenzene and anisole (k = 5.3 × 108, 7 × 106, 6.9 × 106, 4 × 106, 1.2 × 107, 6.5 × 106, 1.0 × 108 and 4.6 × 107 M−1 s−1, respectively) have been determined by flash-photolysis of P2O84− solutions of pH 7.1 containing variable amounts of the organic substrates. The trend observed for the rate constants with the electron withdrawing ability of the substituents in the aromatic ring is discussed in terms of a Hammett type correlation. Phenoxyl type radical formation was observed in the reactions of HPO4˙− with chlorobenzene and phenol. Based on the experimental results, a possible reaction mechanism is proposed. Additional information on the decay kinetics of hydroxycyclohexadienyl radicals of chlorobenzene in the presence of molecular oxygen is also obtained from independent experiments with hydrogen peroxide solutions containing chlorobenzene under nitrogen, air and oxygen saturation.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"19 1","pages":"2933-2937"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86025208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. McInnes, R. Farley, S. Macgregor, K. J. Taylor, L. Yellowlees, C. Rowlands
The X-band EPR and electron–nuclear double resonance (ENDOR) spectra of the formally , 17-electron radical anions [Pt(bipy)L2]− (bipy = 2,2′-bipyridine; L = Cl−, CN−, 13CN−) are reported. The 195Pt (I = 1/2, 34%) anisotropic hyperfine matrices are analysed in terms of both 5d and 6p contributions to the singly occupied molecular orbitals (SOMOs). For L = Cl− there is 5.0% 5dyz and 7.6% 6pz character, for L = CN−there is <1% 5dyz and 13.1% 6pz. The bulk of the unpaired electron density is delocalised about the bipy π* system and ENDOR spectra reveal the superhyperfine couplings to the 1H, 14N and 13C (L = 13CN−) nuclei. The unpaired electron densities in the 14N 2pz orbitals contributing to the π* systems are calculated to be 12% and 4% for L = Cl− and CN−, respectively. The cyanide π-orbitals make little contribution to the SOMO for [Pt(bipy)(CN)2]−. There is a good agreement with density functional theory (DFT) MO calculations on the radical anions. DFT calculations also show the atomic orbital compositions of the lowest unoccupied (LU) MO of [Pt(bipy)L2] and the SOMO of [Pt(bipy)L2]− to be virtually identical.
{"title":"Mapping the unpaired electron density in [Pt(bipy)L2]− (bipy = 2,2′-bipyridine; L = Cl−, CN−, 13CN−): A combined EPR–ENDOR–theoretical study","authors":"E. McInnes, R. Farley, S. Macgregor, K. J. Taylor, L. Yellowlees, C. Rowlands","doi":"10.1039/A804498H","DOIUrl":"https://doi.org/10.1039/A804498H","url":null,"abstract":"The X-band EPR and electron–nuclear double resonance (ENDOR) spectra of the formally , 17-electron radical anions [Pt(bipy)L2]− (bipy = 2,2′-bipyridine; L = Cl−, CN−, 13CN−) are reported. The 195Pt (I = 1/2, 34%) anisotropic hyperfine matrices are analysed in terms of both 5d and 6p contributions to the singly occupied molecular orbitals (SOMOs). For L = Cl− there is 5.0% 5dyz and 7.6% 6pz character, for L = CN−there is <1% 5dyz and 13.1% 6pz. The bulk of the unpaired electron density is delocalised about the bipy π* system and ENDOR spectra reveal the superhyperfine couplings to the 1H, 14N and 13C (L = 13CN−) nuclei. The unpaired electron densities in the 14N 2pz orbitals contributing to the π* systems are calculated to be 12% and 4% for L = Cl− and CN−, respectively. The cyanide π-orbitals make little contribution to the SOMO for [Pt(bipy)(CN)2]−. There is a good agreement with density functional theory (DFT) MO calculations on the radical anions. DFT calculations also show the atomic orbital compositions of the lowest unoccupied (LU) MO of [Pt(bipy)L2] and the SOMO of [Pt(bipy)L2]− to be virtually identical.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"10 1","pages":"2985-2991"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78510879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A set of quinone derivatives with di†erent donor and acceptor groups is obtained. The Ðrst-order hyperpolarizabilities (b) are determined by using the two-level model at the level of AM1/CI. The transition moment the dipole moment di†erence (*k) (kge), between the ground and excited states and the maximum absorption wavelength are calculated. The inNuence of the (jmax) strength of the donorEacceptor pairs upon these crucial two-level parameters is investigated with respect to the electronic features. The relationship between these parameters and the Ðrst-order hyperpolarizability is discussed. For comparison, the results for pushEpull hexatriene, another p-conjugated system, are also discussed.
{"title":"AM1/CI study of the first-order hyperpolarizability for push–pull quinones and push–pull polyenes A two-level model evaluation","authors":"Y. Sheng, Yuansheng Jiang","doi":"10.1039/a800421h","DOIUrl":"https://doi.org/10.1039/a800421h","url":null,"abstract":"A set of quinone derivatives with di†erent donor and acceptor groups is obtained. The Ðrst-order hyperpolarizabilities (b) are determined by using the two-level model at the level of AM1/CI. The transition moment the dipole moment di†erence (*k) (kge), between the ground and excited states and the maximum absorption wavelength are calculated. The inNuence of the (jmax) strength of the donorEacceptor pairs upon these crucial two-level parameters is investigated with respect to the electronic features. The relationship between these parameters and the Ðrst-order hyperpolarizability is discussed. For comparison, the results for pushEpull hexatriene, another p-conjugated system, are also discussed.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"51 1","pages":"1823-1828"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72874562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Satsuma, T. Enjoji, K. Shimizu, Kazuhiro Sato, H. Yoshida, T. Hattori
The reactivity of surface adsorbed species over Na–H-mordenite has been examined by using dynamic insitu IR spectroscopy and the mechanism of the selective reduction of NO with C3H6 discussed. When Na–H-mordenite was exposed to a flow of NO–C3H6–O2 at 573 K, a strong absorption band assignable to NO3− was observed at 1394 cm−1. The intensity of the band significantly decreased when the flowing gas was switched to C3H6–O2. The rate of decrease in NO3− was ca. 3.0 × 10−8 mol g−1 s−1 which was equivalent to the rate of NO conversion to N2 in the NO–C3H6–O2 flow reaction. Thus, it was indicated that NO3− is a reaction intermediate for the formation of N2 and the surface reaction of NO3− is the rate determining step of the formation of N2 in the selective reduction of NO with C3H6. When the flowing gas was switched to C3H6, the rate of decrease in NO3− species was twice as fast as that in C3H6–O2, i.e., the reactivity of NO3− species strongly depended on the presence of O2. Since NO was also formed simultaneously with N2 in the case of NO2–C3H6 reaction, it was suggested that NO3− species oxidize C3H6 accompanying not only the conversion into N2 but also the dissociative decomposition into NO. Weak bands assignable to adsorbed hydrocarbon, carbonyl, nitrite and isocyanate were also observed. On the basis of the changes in the intensity of these bands, the consecutive reaction of surface organic species with NO3− species over Na–H-mordenite was suggested.
采用动态原位红外光谱研究了na - h -丝光沸石表面吸附物质的反应性，并探讨了C3H6选择性还原NO的机理。当na - h -丝光沸石在573 K下暴露于NO-C3H6-O2流中时，在1394 cm−1处观察到NO3−的强吸收带。当流动气体切换为C3H6-O2时，条带强度显著降低。NO3−的减少速率约为3.0 × 10−8 mol g−1 s−1，相当于NO - c3h6 - o2流动反应中NO转化为N2的速率。说明NO3−是生成N2的反应中间体，NO3−的表面反应是C3H6选择性还原NO过程中N2生成速率的决定步骤。当流动气体切换为C3H6时，NO3−种类的减少速度是C3H6 - O2时的两倍，即NO3−种类的反应性强烈依赖于O2的存在。在NO2-C3H6反应中，NO也与N2同时生成，说明NO3−物质对C3H6的氧化不仅伴随着转化成N2，而且伴随着解离分解成NO。吸附的烃类、羰基、亚硝酸盐和异氰酸酯也有弱带。根据这些谱带强度的变化，提出了表面有机物质与NO3−物质在na - h -丝光沸石上的连续反应。
{"title":"Reactivity of surface nitrate species in the selective reduction of NO with propene over Na–H-mordenite as investigated by dynamic FTIR spectroscopy","authors":"A. Satsuma, T. Enjoji, K. Shimizu, Kazuhiro Sato, H. Yoshida, T. Hattori","doi":"10.1039/A705292H","DOIUrl":"https://doi.org/10.1039/A705292H","url":null,"abstract":"The reactivity of surface adsorbed species over Na–H-mordenite has been examined by using dynamic insitu IR spectroscopy and the mechanism of the selective reduction of NO with C3H6 discussed. When Na–H-mordenite was exposed to a flow of NO–C3H6–O2 at 573 K, a strong absorption band assignable to NO3− was observed at 1394 cm−1. The intensity of the band significantly decreased when the flowing gas was switched to C3H6–O2. The rate of decrease in NO3− was ca. 3.0 × 10−8 mol g−1 s−1 which was equivalent to the rate of NO conversion to N2 in the NO–C3H6–O2 flow reaction. Thus, it was indicated that NO3− is a reaction intermediate for the formation of N2 and the surface reaction of NO3− is the rate determining step of the formation of N2 in the selective reduction of NO with C3H6. When the flowing gas was switched to C3H6, the rate of decrease in NO3− species was twice as fast as that in C3H6–O2, i.e., the reactivity of NO3− species strongly depended on the presence of O2. Since NO was also formed simultaneously with N2 in the case of NO2–C3H6 reaction, it was suggested that NO3− species oxidize C3H6 accompanying not only the conversion into N2 but also the dissociative decomposition into NO. Weak bands assignable to adsorbed hydrocarbon, carbonyl, nitrite and isocyanate were also observed. On the basis of the changes in the intensity of these bands, the consecutive reaction of surface organic species with NO3− species over Na–H-mordenite was suggested.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"28 1","pages":"301-307"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81462644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solutions of alkali metals in liquid ammonia show a metal–non-metal (MNM) transition at about 4 mol% metal (MPM). In this paper, we present the results of electron paramagnetic resonance (EPR) studies of sodium–ammonia solutions at 200 MHz as a function of temperature and metal concentration. It has been suggested that the transverse spin relaxation rate consists of two contributions: a hyperfine interaction with 14N nuclei, which is dominant at lower metal concentrations, and a spin–orbit interaction, dominant at higher metal concentrations. The cross-over occurs around 1.5 MPM, a little below the bulk MNM transition point of 4 MPM. From the integrated intensity data of EPR we have examined the spin-pairing equilibrium of excess electrons in the solutions.
{"title":"LOW-FIELD EPR STUDY OF THE METAL-NON-METAL TRANSITION IN SODIUM-AMMONIA SOLUTIONS","authors":"O. Terakado, T. Kamiyama, Y. Nakamura","doi":"10.1039/A708597D","DOIUrl":"https://doi.org/10.1039/A708597D","url":null,"abstract":"Solutions of alkali metals in liquid ammonia show a metal–non-metal (MNM) transition at about 4 mol% metal (MPM). In this paper, we present the results of electron paramagnetic resonance (EPR) studies of sodium–ammonia solutions at 200 MHz as a function of temperature and metal concentration. It has been suggested that the transverse spin relaxation rate consists of two contributions: a hyperfine interaction with 14N nuclei, which is dominant at lower metal concentrations, and a spin–orbit interaction, dominant at higher metal concentrations. The cross-over occurs around 1.5 MPM, a little below the bulk MNM transition point of 4 MPM. From the integrated intensity data of EPR we have examined the spin-pairing equilibrium of excess electrons in the solutions.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"41 1","pages":"867-869"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76204574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Krause, L. Dunsch, G. Seifert, P. Fowler, A. Gromov, W. Krätschmer, R. Gutiérez, D. Porezag, T. Frauenheim
Raman and IR spectra of C60, C60O, C120O and C120O2, measured at room temperature, are discussed using geometric structures, normal modes, Raman and IR intensities from density functional-based tight-binding (DF-TB) calculations. An assignment of the most important vibrational modes is given. In the studied compounds the splitting of the C60 modes is explained by the removal of degeneracy and the vibrational coupling between the C60 cages. Strong IR absorptions of both dimeric oxides between 950 and 1150 cm-1 are assigned to the furan-like structures connecting the buckyballs. The inter-ball Raman lines below 200 cm-1 are shown to be dependent on the bonding strength between the cages. Both the bridge-based IR absorptions and the inter-ball Raman modes are suitable for the identification of the nature and number of bridging structures in oligomeric fullerene oxides.
{"title":"Vibrational signatures of fullerene oxides","authors":"M. Krause, L. Dunsch, G. Seifert, P. Fowler, A. Gromov, W. Krätschmer, R. Gutiérez, D. Porezag, T. Frauenheim","doi":"10.1039/A802560F","DOIUrl":"https://doi.org/10.1039/A802560F","url":null,"abstract":"Raman and IR spectra of C60, C60O, C120O and C120O2, measured at room temperature, are discussed using geometric structures, normal modes, Raman and IR intensities from density functional-based tight-binding (DF-TB) calculations. An assignment of the most important vibrational modes is given. In the studied compounds the splitting of the C60 modes is explained by the removal of degeneracy and the vibrational coupling between the C60 cages. Strong IR absorptions of both dimeric oxides between 950 and 1150 cm-1 are assigned to the furan-like structures connecting the buckyballs. The inter-ball Raman lines below 200 cm-1 are shown to be dependent on the bonding strength between the cages. Both the bridge-based IR absorptions and the inter-ball Raman modes are suitable for the identification of the nature and number of bridging structures in oligomeric fullerene oxides.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"16 1","pages":"2287-2294"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87824380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ground-state rotational spectra of the three isotopomers C5H514N···H35Cl, C5H514N···H37Cl and C5H514N···D35Cl of a complex formed by pyridine with hydrogen chloride have been observed by using a fast-mixing nozzle in combination with a pulsed-nozzle, FT microwave spectrometer. Rotational constants A0, B0, C0, centrifugal distortion constants, ΔJ, ΔJK, δJ, δK and nuclear quadrupole coupling constants χaa(A) and χbb(A) − χcc(A) (where A = 14N or Cl) were determined in each case. A detailed interpretation of the spectroscopic constants led to the conclusion that the observed complex has a planar, C2v geometry, with the HCl subunit forming a hydrogen bond to N and lying along the C2 axis of pyridine. The nitrogen to chlorine distance was determined to be 2.999(2) A. The magnitudes of the nuclear quadrupole coupling constants χaa(A) and the intermolecular stretching force constants kσ in comparison with those expected in the hydrogen-bond C5H5N···HCl and ion-pair C5H5NH+···Cl− limits show that the extent of proton transfer from HCl to pyridine is small.
{"title":"Is pyridinium hydrochloride a simple hydrogen-bonded complex C5H5N···HCl or an ion pair C5H5NH+···Cl- in the gas phase? An answer from its rotational spectrum","authors":"S. Cooke, G. Corlett, D. G. Lister, A. Legon","doi":"10.1039/A708458G","DOIUrl":"https://doi.org/10.1039/A708458G","url":null,"abstract":"The ground-state rotational spectra of the three isotopomers C5H514N···H35Cl, C5H514N···H37Cl and C5H514N···D35Cl of a complex formed by pyridine with hydrogen chloride have been observed by using a fast-mixing nozzle in combination with a pulsed-nozzle, FT microwave spectrometer. Rotational constants A0, B0, C0, centrifugal distortion constants, ΔJ, ΔJK, δJ, δK and nuclear quadrupole coupling constants χaa(A) and χbb(A) − χcc(A) (where A = 14N or Cl) were determined in each case. A detailed interpretation of the spectroscopic constants led to the conclusion that the observed complex has a planar, C2v geometry, with the HCl subunit forming a hydrogen bond to N and lying along the C2 axis of pyridine. The nitrogen to chlorine distance was determined to be 2.999(2) A. The magnitudes of the nuclear quadrupole coupling constants χaa(A) and the intermolecular stretching force constants kσ in comparison with those expected in the hydrogen-bond C5H5N···HCl and ion-pair C5H5NH+···Cl− limits show that the extent of proton transfer from HCl to pyridine is small.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"19 1","pages":"837-841"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87553198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interaction of diethanolamine, a model epoxy resin compound, with aluminium surfaces is characterised using static secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS). Diethanolamine does not adsorb on γ-alumina but does adsorb on phosphoric acid anodised aluminium, suggesting that the adsorption site is a Bronsted acid. A static SIMS spectrum is obtained consistent with a protonated species and the XPS N 1s signal shows two states for the adsorbate. Diethanolamine on an ion-bombarded aluminium surface does not show the characteristic SIMS spectrum observed with the anodised substrate. It is postulated that the hydroxy groups of the diethanolamine form a dialkoxide covalently bound to the ion-bombarded aluminium. The corresponding XPS N 1s signal showed a single binding energy in the range of Lewis site interactions on alumina.The interaction of all three functionalities of the diethanolamine with the anodised aluminium surface results in stronger adsorption than for a similar difunctional compound, (methylamino)ethanol, indicating that both hydroxy groups are involved in hydrogen bonding to surface acid sites
{"title":"Interaction of a model epoxy resin compound, diethanolamine, with aluminium surfaces studied by static SIMS and XPS","authors":"S. Affrossman, R. Comrie, S. M. Macdonald","doi":"10.1039/A706261C","DOIUrl":"https://doi.org/10.1039/A706261C","url":null,"abstract":"The interaction of diethanolamine, a model epoxy resin compound, with aluminium surfaces is characterised using static secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS). Diethanolamine does not adsorb on γ-alumina but does adsorb on phosphoric acid anodised aluminium, suggesting that the adsorption site is a Bronsted acid. A static SIMS spectrum is obtained consistent with a protonated species and the XPS N 1s signal shows two states for the adsorbate. Diethanolamine on an ion-bombarded aluminium surface does not show the characteristic SIMS spectrum observed with the anodised substrate. It is postulated that the hydroxy groups of the diethanolamine form a dialkoxide covalently bound to the ion-bombarded aluminium. The corresponding XPS N 1s signal showed a single binding energy in the range of Lewis site interactions on alumina.The interaction of all three functionalities of the diethanolamine with the anodised aluminium surface results in stronger adsorption than for a similar difunctional compound, (methylamino)ethanol, indicating that both hydroxy groups are involved in hydrogen bonding to surface acid sites","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"8 1","pages":"289-294"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87716288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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