Infrared spectra of cyclic ethers and their derivatives

The IR spectra of six monosubstituted and of four 2,6-disubstituted 1,4-dioxanes have been studied in the 650–1800cm^–1 region. The assignment of the bands due to the vibrations of the 1,4-dioxane ring and to the deformation vibrations of the methylene groups of the ring is given. The appearance of a whole series of new absorption bands on passing from unsubstituted 1,4-dioxane to its derivatives is explained by the change in the symmetry of the molecule and the removal of the prohibition from the vibrations previously inactive in the IR spectra connected with this reduction in symmetry. It is proposed to use, in order to confirm the presence of a 1,4-dioxane ring in a molecule from the results of IR spectroscopy, not only the 1126-cm^–1 band but the whole group of bands lying in the frequency ranges 800–950, 1000–1150, and 1200–1300 cm^–1.For part I, see [3].     

Differentiation and quality estimation of Cordyceps with infrared spectroscopy

Heretofore, a scientific and systemic method for differentiation and quality estimation of a well-known Chinese traditional medicine, ‘Cordyceps’, has not been established in modern market. In this paper, Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR) are employed to propose a method for analysis of Cordyceps. It has presented that IR spectra of real Cordyceps of different origins and counterfeits have their own macroscopic fingerprints, with discriminated shapes, positions and intensities. Their secondary derivative spectra can amplify the differences and confirm the potentially characteristic IR absorption bands 1400–1700 cm⁻¹ to be investigated in 2D-IR. Many characteristic fingerprints are discovered in 2D-IR spectra in the range of 1400–1700 cm⁻¹ and hetero 2D spectra of 670–780 cm⁻¹ × 1400–1700 cm⁻¹. The different fingerprints display different chemical constitutes. Through the three steps, different Cordyceps and their counterfeits can be discriminated effectively and their qualities distinctly display. Successful analysis of eight Cordyceps capsule products has proved the practicability of the method, which can also be applied to the quality estimation of other Chinese traditional medicines.     

Infrarotspektroskopische Untersuchungen an Oximen aromatischer Chinone

Zusammenfassung Es wird der Versuch unternommen, die bei den Oximen aromatischer Chinone im Doppelschwingungsbereich auftretenden Banden zuzuordnen.

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The assignment of the infrared absorption bands in the 1700–1500 cm^–1 region has been tried for a number of oximes of aromatic ketones.

     

Characteristic frequencies in the infrared spectra of pyrazolines

Pyrazolines are characterized by valence vibrations at the following frequencies: C=N (1580–1627 cm^–1), H-C³=N (3040–3063 cm^–1), H-N (3270–3305 cm^–1) and CH₃-N (2780–2805 cm^–1). Lowering of the frequencies of the valence vibrations of C=N in pyrazolines, when compared with the magnitudes characteristic of alkyledene amines and oximes, is regarded as a consequence of coupling with the unshared electron pair of the neighboring nitrogen atom. By means of the IR spectra, it is possible to determine the position of the double bonds in the pyrazoline ring, to distinguish between pyrazolines substituted and nonsubstituted in positions 1 and 3, and to establish the presence of geminate (twin) methyl groups and methyl groups in position 1.     

Polymorphism of phenylpyruvic acid studied by IR, Raman and solid state C NMR spectroscopy

Polymorphs I and II of phenylpyruvic acid are obtained as mixtures of both crystal forms or relatively pure crystals, from different solvents. Polymorph I is more stable than polymorph II at room temperature. Spectral characteristics of these polymorphs are discussed on the basis of IR, Raman and solid state ¹³C NMR spectra. Also, the assignment of the IR features observed in the 1600–1700 cm⁻¹ region is re-investigated by referring to the spectra of heavy-atom substituted derivatives. It is suggested that the C=O stretching band is split by the crystal field for both polymorphs.     

Molecular spectra of nitroisoxazolinones

A study is made of IR and UV spectra of N-oxides of nitroisoxazolinones, and of derivatives of isoxazolidine and isoxazolizidine. Absorption bands are related to valence vibrations of N-O in the NO₂ group; in conjugated systems (in N-oxides of nitroisoxazolines) _s and _as are equal to 1310 and 1510 cm^–1, in nonconjugated systems (in nitroisoxazolidines) 1360 and 1560 cm^–1, respectively. Frequencies of N-O bond vibrations in N-oxides appear in the region 830–870 cm^–1, of the O-N-O fragment in isoxazolidines and isoxazolizidines in the 1010–1060 cm^–1 region. Measurements are made of total intensities of N-O valence vibrations in the NO₂ group in N-oxides of nitroisoxazolines and nitroisoxazolizidines, as well as of C=N valence vibrations in N-oxides of nitroisoxazolines.     

Integral intensities of the absorption bands of the skeletal vibrations of the heteroaromatic ring in the IR spectra of the furanoquinoline alkaloids

1. The integral intensities of the bands of the skeletal vibrations of the heteroaromatic ring in the 1480–1630-cm⁻¹ region of eight furanoquinoline alkaloids have been measured. 2. A connection has been found between the values of ΣA and the structures of the furanoquinoline alkaloids and their derivatives which enables such a series of heteroaromatic compounds to be identified: It has been shown that the introduction of an -OCH₃ group into the γ position of the pyridine nucleus leads to a marked rise (almost twofold) in the value of ΣA;     

Vibrational spectroscopic study of the antimonate mineral bindheimite Pb2Sb2O6(O,OH)

Raman spectroscopy complimented with infrared spectroscopy has been used to characterise the antimonate mineral bindheimite Pb₂Sb₂O₆(O,OH). The mineral is characterised by an intense Raman band at 656 cm⁻¹ assigned to SbO stretching vibrations. Other lower intensity bands at 664, 749 and 814 cm⁻¹ are also assigned to stretching vibrations. This observation suggests the non-equivalence of SbO units in the structure. Low intensity Raman bands at 293, 312 and 328 cm⁻¹ are assigned to the OSbO bending vibrations. Infrared bands at 979, 1008, 1037 and 1058 cm⁻¹ may be assigned to δOH deformation modes of SbOH units. Infrared bands at 1603 and 1640 cm⁻¹ are assigned to water bending vibrations, suggesting that water is involved in the bindheimite structure. Broad infrared bands centred upon 3250 cm⁻¹ supports this concept. Thus the true formula of bindheimite is questioned and probably should be written as Pb₂Sb₂O₆(O,OH,H₂O).     

The infrared spectra (600-140 cm−1 of the imidazole,pyrazine and pyrimidine adducts of cobalt(II), nickel(II) and zinc(II) acetylacetonates

Summary The complexes M(acac)₂(imidazole)₂ (M = Co or NO and [M(acac)₂B]_n (M = Co, Ni or Zn; B = pyrazine or pyrimidine) have been prepared and their i.r. spectra determined over the 600–140 cm^–1. range. The metal-oxygen and metal-nitrogen stretching frequencies, (M-O) and v(M-N), are assigned on the basis of the band shifts induced by deuteriation of the adducted base and by substitution of the metal ion. Three or fourv(M-O) bands are observed within the 600-200 cm^–1 range. The twov(M-O) bands of higher frequency are considered to the coupled with internal ligand modes. TwovM-N) bands are observed within the 280–170 cm^–1. range. The metal-ligand stretching frequencies are in good agreement with the values previously established for these vibrations in the [M(imidazole)₆]²⁺ and Ni(acac)₂(pyridine)₂ complexes.     

Infrared absorption spectra of some derivatives of 1,2,3,4-tetrahydro-Β-carboline

The IR absorption spectra in 3800-1400 cm^–1 region of 1-propyl-, 1-carboxy-, 1-carboxy-1-methyl-, and 1-benzyl-1-carboxy-6-hydroxy-1,-tetrahydro--carbolines, their O-methyl derivatives, and their hydrochlorides are discussed. An assignment of the bands due to the stretching vibrations of NH, NH ₂ ⁺ , OH, COO^–, and COOH groups is proposed. The hypothesis has been put forward that strong intermolecular and intramolecular hydrogen bonds exist in the substances studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 775–778, June, 1970.     

Synthesis and absorption spectra of 3,5-diaryl-1,2,4-triazoles

1,2,4-Triazoles with symmetrical tolyl substituents were obtained from the corresponding 1,3,4-oxadiazoles by reaction with formamide and subsequent hydrolysis of the resulting formyl derivatives; 1,2,4-triazoles with unsymmetrical substituents were obtained from iminoesters and hydrazides of acids. A set of bands of the triazole ring at 1470–1480, 1390, 1270–1290, 1140–1150, and 725–750 cm^–1 and of NH vibrations at 2400–3200, 1580–1620, and 830–900 cm^–1 are characteristic for the IR spectra of these triazoles. The UV spectra of the triazoles are characterized by phenyl ring absorption at about 200 nm and a band of electron transitions between the phenyl and triazole rings at 230–290 nm.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1682–1685, December, 1977.     

IR spectroscopic study of thioacrolein and its photoisomerization to methylthioketene

The molecules of thioacrolein (1) and metylthioketene (3), which are labile under normal conditions, have been studied by the matrix Fourier transform infrared spectroscopy method. Compound1 was obtained by vacuum pyrolysis (1120 K, 10^–4 Torr) of diallyl sulfide. The analysis of its IR spectrum shows that1 exists as a mixture ofs-trans ands-cis conformers. UV irradiation ( > 248 nm) of matrix isolated1 results in a 1,3 hydrogen shift and the formation of3, which is characterized by a strong band of antisymmetric stretching vibrations of the thioketene fragmentvC=C=S at 1777.2 cm^–1. The experimental IR bands of molecules1 and3 were assigned to fundamental modes. The relatively low frequencies of the stretching vibrations of the double bonds (vC=C at 1598.0 cm^–1 andvC=S at 1071.8 cm^–1) and the heightened frequency of the C-C single bond stretching (vC-C 1173.7 cm^–1) in the spectrum of1 indicate appreciable delocalization of the electron density in the conjugated -orbital system.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 464–470, March, 1995.     

Use of Raman spectroscopy for the establishment of the structure of pyrimidine derivatives

Intense bands of stretching vibrations are characteristic for the ER spectra of compounds of the pyrimidine series, whereas strong polarized bands of the radially symmetrical vibrations of the pyrimidine skeleton are characteristic for the Raman spectra. The band of the radially symmetrical vibration at 1000 cm^–1 is not observed in the Raman spectra of pyrimidines having a substituent in the 5 position.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1399–1401, October, 1975.     

Synthesis and characterization of novel α- or β-tetra[6,7-dihexyloxy-3-(4-oxyphenyl)coumarin]-substituted metal-free and metallo phthalocyanines

The synthesis of novel phthalonitriles substituted at 3- or 4-position with 6,7-dihexyloxy-3-(4-oxyphenyl)coumarin were performed. The metal-free and metallo phthalocyanines (MPcs) (M = Zn, Co, Cu) were prepared by cyclotetramerization of 6,7-dihexyloxy-3-[p-(2′,3′-dicyanophenoxy)phenyl]coumarin or 6,7-dihexyloxy-3-[p-(3′,4′-dicyanophenoxy)phenyl]coumarin. The newly prepared compounds, phthalonitriles and Pcs, have been characterized by elemental analysis, ¹H NMR, ¹³C NMR, MALDI-TOF, IR, UV–Vis and fluorescence spectral data. The electronic spectra exhibit bands of coumarin identity along with characteristic Q and B bands of the Pc core. The IR-spectra of all Pcs showed three characteristic intense bands at 1709–1700 cm⁻¹ for lactone carbonyl, two bands at 1489–1604 cm⁻¹ for conjugated olefinic system.     

Integral intensities of the absorption bands of the skeletal vibrations of the heteroaromatic ring in the IR spectra of the furanoquinoline alkaloids

Summary 1. The integral intensities of the bands of the skeletal vibrations of the heteroaromatic ring in the 1480–1630-cm^–1 region of eight furanoquinoline alkaloids have been measured.2. A connection has been found between the values of A and the structures of the furanoquinoline alkaloids and their derivatives which enables such a series of heteroaromatic compounds to be identified: It has been shown that the introduction of an -OCH₃ group into the position of the pyridine nucleus leads to a marked rise (almost twofold) in the value of A;In derivatives of dictamnine (VII-XII), the value of A depends on the position of the methoxy group and on the nature of the substituent in position 7 of the benzene ring;With an increase in the delocalization of the unshared pair of electrons of the oxygen atom of the furan ring, the value of A of the series of alkaloids investigated (VI-XIV) decreases; andCompounds (V-XIV) have the very high values of A of 5.0–7.0 practical units and they exceed the value of the intensities of the carbonyl bandsv(C=0).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 223–227, March–April, 1976.     

Synthesis and IR spectra of some derivatives of phenanthridine and 4,9-diazapyrene

A number of acylamino- and diacylaminobiphenyls and the corresponding derivatives of phenanthridine and 4, 9-diazapyrene, including the previously unknown 2,2-dipropionamidobiphenyl, 5, 10-diethyl-4, 9-diazapyrene, 2, 4-dibenzamidobiphenyl, and 3-benzamido-6-phenylphenanthridine, have been synthesized. The IR spectra of all the compounds have been studied and a group of bands characteristic for the phenanthridine ring in the 1570–1620 cm^–1 region and a group of five bands characteristic for the 4, 9-diazapyrene ring in the 1330–1640 cm^–1 region have been identified. The nature of the IR spectra of phenanthridine derivatives containing unsubstituted amide groups has also been established.     

IR-spektroskopische Untersuchungen über Wasserstoffbrücken in N-Methylacetamid

Zusammenfassung Es wurden IR-spektroskopische Untersuchungen an N-Methylacetamid in CC14-Lösungen durchgeführt. Der durch Wasserstoffbrücken assoziierte Molekülanteil konnte in einem Konzentrationsbereich von 0.01–0.3 Mol/1 durch Messungen der integralen Absorption quantitativ bestimmt werden. Eine Auflösung und Zuordnung der Banden im C=O-Streck-schwingungsbereich (1683–1650 cm^-1) war möglich. Eine Korrelation mit den Ergebnissen im NH-Bereich weist auf 1:1 H-Brückenkomplexe hin. Die beobachtete Wellenzahlverschiebung der NH-Assoziatbande (3390–3310 cm^–1) wird ausschließlich auf den insgesamt erreichten Assoziationsgrad zurückgeführt, in Übereinstimmung mitFlory-Schulz. Der Temperatureinfluß auf die Assoziatbildung wird diskutiert.

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Summary The infrared spectra of N-Methylacetamide in CCl₄ solution have been studied. A quantitative determination of the species associated by hydrogen bonding has been carried out by measuring the absorbance in the NH stretching region. Separation and assignment of bands in the carbonyl stretching region (1683–1650 cm 1) could be accomplished. A correlation of the formation of 1:1 complexes of hydrogen bonds. The frequency of the absorption maximum of the bonded NH band (3390–3310 cm^–1) with increasing concentration and this shift is exclusively attributable to the degree of association. The effect of temperature on the hydrogen bonded species has been examined.

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Mit 10 Abbildungen und 2 Tabellen     

Synthesis of some new analogs of kinetin

The IR spectra of compounds I–IV have the bands of an amide C=O group at 1697, 1691, 1696, and 1695 cm^–1, respectively. In the reduced products (V and VI), the bands of a C=O group are absent, as was to be expected.     

IR spectroscopic study of adsorption of ammmonia on Brønsted acid centers of a fluorinated surface of silica

The adsorption of aqueous ammonia solution vapor on a fluorinated surface of aerosil was studied by IR spectroscopy. The adsorption of NH₃ is accompanied by the appearance of absorption bands at 740, 1450, and 3330 cm^–1 in the IR spectra. The surface compounds were identified from the results of a study on the thermal degradation of adsorbed complexes and an analysis of literature data. The IR absorption bands at 1450 and 3330 cm^–1 correspond to deformational and stretching vibrations of the N-H bonds of the ammonium cation, The 740 cm^–1 band was assigned to the vibrations of the Si-F bonds in the complex anion, containing a fragment of SiO₂ surface, a fluorine atom, a hydroxyl group and a molecule of water. In this surface-coordinated compound, the silicon atom has a coordination number of six.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 6, pp. 747–751, November–December, 1986.