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1.
IR spectra of 3 normal solutions of 14 different salts [chlorides of Al+++, Be++, Mg++, Ca++, Sr++, Ba++, Zn++, Cd++, Li+, Na+, K+, Rb+, Cs+, N(CH3) 4 + ] in both, 96% H2O+4% D2O and 100% H2O, were measured in the frequency range =2 800–2 100 cm–1. From up to 18 single measurements for each solution the frequencies and halfwidths of the O-D stretching bands of isotopically dilute HDO were determined with high accuracy. Frequencies in the range =2 510–2 529 cm–1 and halfwidths in the range =155–205 cm–1 resulted atT=30°C with standard deviations typical less than ±1 cm–1 and ±4 cm–1, respectively. An almost perfect correlation between the O-D stretching band parameters and the polarizing power of the cations was obtained.Herrn Prof. Dr.A. Neckel, Wien, zum 60. Geburtstag gewidmet.  相似文献   

2.
Previously developed additivity schemes for nonelectrolytes have been used to estimate and for tetraalkyl and tetraphenyl methanes in methanol and water. Corrections have been applied to the thermodynamic values of these model compounds to account for a variation in size of the central atom, and these were used to ascertain the effect of charge on and of alkyl and phenyl quaternary ions having N, P and B as central atoms. Investigations of R4NBr, (R=methyl to heptyl) salts show that the charge effect on and of R4N+ ions is large and relatively independent of ion size suggesting that the solvent molecules penetrate the ions. The ability to estimate and of the quaternary ions in the bromide salt solutions has made it possible to make ionic assignments with some confidence; (Br) has been evaluated as 19.7±2 and 30.2±7 cm3-mol–1 and (Br) as –83±7 and –68±30 J-K–1-mol–1 in methanol and water, respectively. The use of organic ions for making ionic assignments of and is critically examined and comparisons with other assignments are made. The scaled particle theory is employed to divide the heat capacities of electrolytes into cavity and interaction contributions.  相似文献   

3.
Summary X-ray structural data are reported for 2-hydroxy-benzhydrazide(monoclinic; P21/n-C 2h 5 ;a=10.569(2) Å,b=11.264(2) Å,c=6.074(1) Å, =98.80(1)°;Z=4;R=0.054) and 2-hydroxy-thiobenzhydrazide (monoclinic; P21/n-C 2h 5 ;a=14.598(6) Å,b=5.975(2) Å,c=9.286(4) Å, =107.80(3)°;Z=4;R=0.044). In both compounds the phenolic OH groups are intramolecularly hydrogen bonded to the (thio)carbonyl oxygens and sulfurs, respectively; the basic intermolecular association patterns consist of closed six-membered hydrogen bonded dimers which are connected via N-H ... NH2 hydrogen bonds. The spectral characteristics of the intramolecular O-H...O/S hydrogen bonds (solid state (OH)=2800/2700 cm–1, CCl4 solution (OH)=3035/3100 cm–1, CDCl3 solution (OH)=11.62/10.56 ppm) are similar to those of corresponding primary and secondary amides. The solid state IR spectra are consistent with hydrogen bonded NH groups and free NH2 groups, the solution IR spectra indicate free NH2 as well as free NH groups.
Wasserstoffbrückenbindung in 2-Hydroxy-benzhydrazid und 2-Hydroxy-thiobenzhydrazid. Strukturelle und spektroskopische Untersuchungen
Zusammenfassung Es werden Röntgenstrukturdaten für 2-Hydroxy-benzhydrazid (monoklin; P21/n- C 2h 5 ;a=10.569(2) Å,b=11.264(2)Å,c=6.074(1)Å, =98.80(1)°;Z=4;R=0.054) und 2-Hydroxy-thiobenzhydrazid (monoklin; P21/n - C 2h 5 ;a=14.598(6)Å,b=5.975(2)Å,c=9.286(4)Å, =107.80(3)°;Z=4;R=0.044) berichtet. In beiden Verbindungen bilden die phenolischen OH-Gruppen intramolekulare Wasserstoffbrücken mit den Carbonyl-Sauerstoff-, bzw. den Thiocarbonyl-Schwefel-Atomen. Das intermolekulare Assoziationsmuster wird durch N-H...NH2 Wasserstoffbrücken bestimmt, die jeweils zwei Moleküle über sechszählige Ringe zu Dimeren verbinden. Die IR- und NMR-spektroskopischen Charakteristika der intramolekularen O-H...O/S Wasserstoffbrücken (kristallin: (OH)=2800/2700 cm–1, CCl4-Lösungen: (OH)=3035/3100 cm–1, CDCl3-Lösungen: (OH)=11.62/10.56 ppm) sind sehr ähnlich zu denen entsprechender primärer und sekundärer Amide. Die Festkörper-IR-Spektren stehen in Einklang mit assoziierten NH- und freien NH2-Gruppen, während die Lösungs-IR-Spektren auch auf das Vorliegen freier NH-Gruppen schließen lassen.
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4.
The ion exchange processes of (OAc) and (OAc) proceeding in shell-core inorganic ion exchanger Ti (HPO4)2·1/2H2O has been studied and the diffusion equation whose boundary conditions are satisfied by a shell-core model was solved. Based on the equation solved and experimental data, the diffusion coefficients corresponding to the exchange process (OAc) and Li+–H+ (OAc) at 17°C are found to be 7.7×10–9 and 6.2×10–8 cm2 s–1 and the activation energies 3.4×104 and 5.0×103 J mol–1, respectively. Compared to the gel type of styrene-divinylbenzene strong acid exchanger with 20% cross linking, it can be concluded that the rate of or exchange is 3.5 times faster than that in the organic exchanger.TIP was obtained from the Salt Lake Institute of the Academy of Science of China.  相似文献   

5.
When making use of some single comparator or absolute standardization methods in reactor neutron and in epicadmium neutron activation analysis, the knowledge of the effective resonance energy ( ) is essential to correct for the effect of the nonideal epithermal flux distribution on the analysis result. can be calculated from neutron resonance data, but when these are incomplete, not accurate or even not known at all, experimental determination should be considered. Such a method, providing both and the resonance integral to 2200 ms–1 cross-section ratio (QO), is described in this paper. Results are given for 11 isotopes.  相似文献   

6.
Summary Phenylacetylene reacts stoichiometrically or in excess with the Ru—H bond of RuH(CO)(PPh3)2(L) (LH = 2-hydroxypyridine, 2-hydroxy-6-methylpyridine, acetylacetone, benzoylacetone, 2-hydroxyacetophenone, 2-hydroxypropiophenone, 2-hydroxybenzophenone and 4-methoxy-2-hydroxybenzophenone) in boiling benzene to give -vinylic or -vinylalkynyl complexes of the type Ru(CO)-(PPh3)2(L)(CH CHPh) and Ru(CO)(PPh3)2(L){C-(C CPh) CHPh} in good yield. The vinylic complex can also be obtained by reacting the sodio derivative of the chelating ligand with the 16e unsaturated complex, [Ru(CO)Cl(CH CHPh)(PPh3)2], in CH2Cl2/MeOH mixture at ambient temperature. These complexes have been characterized by elemental analyses, and i.r., 1H, 13C and 31P n.m.r. spectroscopy.N.C.L Communication No. 5404.  相似文献   

7.
Group contributions to in seven solvents and to in three solvents have been tabulated. The variation of group parameters is discussed in terms of the solvent compressibility coefficient, T. The scaled particle theory (SPT) is used to calculate cavity contributions to and C p2 o . Interaction contributions are obtained from the cavity terms and and values estimated through the additivity schemes. values are more sensitive to solute-solvent interactions than in water and less sensitive in methanol. The SPT results for heat capacities support the concept of structural promotion by hydrophobic solutes in water.  相似文献   

8.
Zusammenfassung Bei niedrigen Umsätzen und einer Polymerisationstemperatur von 50°C erhaltene Polyvinylacetate sind unverzweigt; das gleiche gilt für Polyvinylchoracetate. Bei diesen wurde die bei höheren Umsätzen auftretende Verzweigung durch Verseifung und Acetylierung der Polymeren sowie durch Messung von []-, und Werten an den Polymeren bestimmt. Eine Selbstverzweigung der wachsenden Kette konnte nicht gefunden werden. *** DIRECT SUPPORT *** A3615144 00012
Chain branching in vinyl chloroacetate and vinyl acetate polymerization
Polymerization of vinyl acetate and vinyl chloroacetate to low conversions at 50°C gave unbranced polymers. The branching of polyvinyl chloroacetates at higher conversions was determined by hydrolysis and acetylation of the polymers and by measuring [], and . No self-branching of the growing chains could be found.
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9.
The reactivity of preheated and -irradiated TiO2 was observed in KI solution by studying the kinetics of liberation of I2. The rate of the reaction was found to be low. species proposed on the surface of oxide probably dissociate into . surface sites which oxidize I ions to produce free I2. During irradiation and are produced which are reducing in nature and therefore very low yields of I2 are observed for low -doses. In further irradiation the reformation of –O–O–, peroxy linkages is proposed hence the observed higher yields. All the processes ultimately lead to an oscillatory variation in yields of I2 with -doses.  相似文献   

10.
The apparent molal volumes (v) and compressibilities (K) of CaSO4 solutions have been determined at 25°C from precise density and sound-speed measurements. The large deviations of the values of v and K from the limiting law and various additivity estimates for the free ions (Ca2+, SO 4 2– ) have been used to estimate the partial molal volume ( ) and compressibility ( ) for the formation of the CaSO 4 0 ion pair. Values of = 25 ± 3 cm3-mole–1 and = (54±21)×10–4 cm3-mole–1-bar–1 were found. Since these values are larger than the value for the formation of MgSO 4 0 , the results indicate that more inner-sphere ion pairs are formed when SO 4 2– complexes with Ca2+ than with Mg2+. Using a simple model for ion-water interactions, the percent of inner-sphere or contact ion pairs in CaSO4 solutions is estimated to be 36 to 37%.  相似文献   

11.
The structures of proanthocyanidins CS-3 and CS-4, isolated from the roots ofClementsia semenovii have been established on the basis of chemical and spectral studies. CS-3 is 7-O-(6-O-galloyl--D-Glcp O--D-Glcp O--D-Glcp O--D-Glcp O--D-Glcp)-(+)-catechin-(4—8)-(–)-epigallocatechin-(4—8)-(+)-catechin-(4—8)-(–)-epigaLLocatechin-(4—8)-(–)-epigallocatechin-(4—8)-(–)-epigallocatechin, and CS-4 is 3-O-galloyl-7-O-[6-O-galloyl--D-Glcp O--D-Glcp O--D-Glcp-(+)-gallocatechin-(4—8)-[(+)-catechin-(4—8)-(3-O-galloyl-(–)-epigallocatechin]2-(4—8)-(–)-epicatechin.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–58, January–February, 1999.  相似文献   

12.
The interaction of the onium salts [Me2 Et=O]BF4 , [Me2 =CH-OEt]BF4 , and [Me3 =O]I with metallic copper in DMSO, DMF, and acetonitrile (AN) has been investigated. It has been shown that the reaction takes place with an intermediate step involving the formation of Cu(I) compounds. The complexes [CuI(AN)4]BF4, [CuII(DMSO)5](BF4)2, [CuII(DMSO)4(AN)2](BF4)2, [CuII(DMSO)2(DMF)(AN)](BF4)2, and [ME3 ]3CuII4 · [Me3 =O]I have been isolated and characterized. It has been established that dipolar onium compounds which simulate the intermediate products of the interaction of the components of donor-acceptor electron-transport systems are responsible for the oxidation of metals in organic complex-forming media.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1325–1330, June, 1991.  相似文献   

13.
By choosing a suitable linear combination of the constants of the motion , it is shown that the calculation of the density matrix(t) can be simplified by subdividing the Hamiltonian into . In particular, this technique can be used to obtain closed form solutions for the eigenfunctions and eigenvalues of spin 1/2ABC andXBCD spin systems, evolving in the presence of Zeeman offsets, scalar coupling and dipolar interactions. In general, the eigenvalues and eigenvalues of are very transparent, while those of require more effort. Nevertheless, simplifications can be made. Firstly, the effective size of the Hamiltonian matrix which needs to be considered, is reduced fromN ×N to at least (N – 2) × (N – 2), while forXBC ... systems it is reduced to (N – 4) × (N – 4). Secondly, the highest rank and highest/lowest order tensor operators available to the spin ensemble are constants of the motion under . Finally, by exploiting the fact that is a good quantum number, it is possible to block-diagonalize the matrix into no more than 3 × 3 matrices.  相似文献   

14.
Summary A general definition of reaction graphs is presented. For a pair of isomeric molecular graphs and , related by a chemical transformation , the reaction graph is determined using a maximal common subgraph defined for vertex mapping . A binary operation defined for graphs constructed over the same vertex set enables us to decompose the reaction graph into the sum of prototype reaction graphs. A decomposition of an overall reaction graph can be advantageously used for the construction of a reaction network. An oriented path in this network beginning at and ending at corresponds to a breakdown of the transformation into a sequence of intermediates.  相似文献   

15.
Zusammenfassung Die Verbindung GeY · 2 H2O wird nach einem Verfahren dargestellt, das die Verwendung von flüchtigem GeCl4 vermeidet und direkt von Germaniumsäure-Lösungen ausgeht. Der Komplex, der analysenrein anfällt, wird thermogravimetrisch untersucht. In Wasser gelöst, erweist er sich als einbasige Säure, H[Ge(OH)Y]. Die Dissoziationskonstante der komplexen Säure wird potentiometrisch bestimmt:K c =3,99 · 10–3 (pK c =2,40). Die Stabilitätskonstanten der komplexen Säure sowie des komplexen Anions werden ermittelt: =6,27 · 104 (log =4,80); =3,34 · 104 (log =4,52) (25°C; Ionenstärke 0,1m).
The complex compound GeY · 2 H2O is prepared directly from germanic acid solutions, avoiding volatile GeCl4. It has been submitted to thermogravimetric analysis. Dissolved in water, it proves to be a monobasic acid, H[Ge(OH)Y]. The dissoziation constant of the complex acid is determined potentiometrically:K c =3,99 · 10–3 (pK c =2,40). The stability constants of the complex acid as well as of the complex anion are evaluated: =6,27 · 104 (log =4,80); =3,34 · 104 (log =4,52), at 25°C; ionic strength 0,1m.


Mit 4 Abbildungen

Herrn Prof. Dr.J. W. Breitenbach zum 60. Geburtstag gewidmet.  相似文献   

16.
Excess partial molar volumes of 2-butanone V m E (B) and thermal expansivities p were measured in the water-rich region of aqueous 2-butanone. The composition derivatives of both quantities showed anomalies at about X B =0.033 (x B is the mole fraction of B). showed a step anomaly, while exhibited a peak anomaly. The compositions at which these anomalies occurred match those of the step anomalies observed earlier in and in aqueous 2-butanone. These results are discussed in comparison with those obtained previously for aqueous 2-butoxyethanol.Presented at the Symposium, 76th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65th birthday.  相似文献   

17.
Vibrational spectroscopy and x-ray structure analysis have been used to investigate three new types of sulfonium nitroimides: N-nitrosulfylimides, N-nitrosulfoximides, and N,N-dinitrosulfodiimides. Structural parameters have been determined for the molecules , , and .Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2489–2496, November, 1991.  相似文献   

18.
The apparent molal volumes of dilute (0.002 to 1.0m) aqueous HCl and NaOH solutions have been determined at 0, 25, and 50°C and NaCl solutions at 50°C. The partial molal volumes ( ) of HCl, NaOH, and NaCl solutions have been determined from these apparent molal volumes and other reliable data from the literature. The partial-molal-volume changes ( ) for the ionization of water, H2OH++OH, have been determined from 0 to 50°C and 0 to 1m ionic strength from the partial molal volumes of HCl, NaOH, NaCl, and H2O. The partial molal compressibilities ( for HCl, NaOH, NaCl, and H2O have been estimated from data in the literature and used to determine the partial molal compressibility changes ( ) for the ionization of water from 0 to 50°C and 0 to 1m ionic strength. The effect of pressure on the ionization constant of water has been estimated from partial-molal-volume and compressibility changes using the relation from 0 to 50°C and 0 to 2000 bars. The results agree very well with the directly measured values.Contribution Number 1548 from the University of Miami.  相似文献   

19.
A flow heat capcity calorimeter and a flow vibrating tube densimeter have been used to measure the apparent molal heat capacities and volumes of benzene and 25 polar compounds in methanol at 25°C. These quantities have been extrapolated to infinite dilution to obtain the standard partial molal heat capacities and volumes. The and data have been used in conjunction with an additivity scheme previously determined for alkanes. Group contributions were evaluatd for –OH, –NH2, –COOH, –C6H5, C=O, –COO–, –CONH–, –O–, –S–, and –S2–. The concentration dependences of cp and v of nonelectrolytes in methanol are qualitatively similar but much smaller than in water.  相似文献   

20.
Zusammenfassung Das Konzept basiert darauf, die Wellenfunktionen zur Berechnung von Übergangselementen und Erwartungswerten (ohne So) nicht der Energievariation zu entnehmen, sondern aus bestimmten Ungleichungen für die gesuchten Größen, die auch als Variationscrechnungen brauchbar sind, da die aus der Energievariation erhaltenen Näherungslösungen in der Regel in den Raumbereichen die wirklichen Wellenfunktionen am besten approximieren, die für bestimmte Erwartungswerte und Übergangselemente weniger von Bedeutung sind.Es werden weitere Abschätzungen für angegeben.
A new concept in quantum chemical analytical methodology
The concept is based on the derivation of the wave functions for calculating transition elements and expectancy values (without So) from specific inequalities for the variables sought instead of from the energy variation. The inequalities can also be used as a calculus of variations, as the approximate solutions obtained from the energy variation are generally the best approximations in the spatial regions to the actual wave functions, which are of less significance for specific expectancy values and transition elements.Further estimates of are given.


Herrn Prof. Dr.H. Nowotny gewidmet  相似文献   

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