far-IR Spectra Research Articles

Rotational and vibrational spectra, conformational stability, potential functions and ab initio calculations of methacryloyl chloride

The microwave spectrum of CH 2C(CH 3)C 35ClO has been recorded from 12.4 to 39.0 GHz. Both a- and b-type transitions were observed and an R-branch assignment has been made for the s-trans conformer. The rotational constants were found to have the following values: A=4785.13±0.06, B=2248.74±0.01, and C=1551.54±0.01 MHz. From a diagnostic least-squares adjustment to fit the three rotational constants, and with reasonable carbon—hydrogen bond distances and angles, the following heavy atom skeletal structural parameters were obtained: r(CCl)=1.792±0.008 Å, r(CO) = 1.191 (fixed), r(CCH 3) = 1.509 (fixed), r(CCClO) = 1.492±0.007 Å, r(CC) = 1.342 (fixed), ∠ CCCl = 116.1±1.1°, ∠ CCCClO = 122.7 (fixed), < CCCH 3 = 123.9 (fixed), and ∠ CCO = 123.9±1.5°. The quadrupole coupling constants for the s-trans conformer have the following values: χ aa = −44.9, χ bb = 20.4, and χ cc = 24.5 MHz. The infrared (IR) (3500-20 cm −1) and Raman spectra (3500-10 cm −1) have been recorded for both the gaseous and solid phases of methacryloyl chloride. Additionally, the Raman spectrum of the liquid has been recorded and qualitative depolarization values have been obtained. These data have been interpreted on the basis of a more stable s-trans and high-energy s-cis conformational equilibrium for the fluid phases. The potential functions governing internal rotation of both the CClO and CH 3 tops have been determined from the far-IR spectrum of the gas. The asymmetric potential function, conformational energy difference, and optimized geometries have also been obtained from ab initio calculations at both the 3–21G* and 6–31G* basis-set levels. A normal-coordinate analysis has also been performed with a force field determined from the 3–21G* basis set. All of these results are compared to corresponding quantities for some similar molecules.

ChemInform Abstract: Spectra and Structure of Organophosphorus Compounds. Part 43. Far‐IR Spectra and ab initio Calculations of Ethylphosphine

ChemInformVolume 21, Issue 7 Organoelement Compounds ChemInform Abstract: Spectra and Structure of Organophosphorus Compounds. Part 43. Far-IR Spectra and ab initio Calculations of Ethylphosphine J. R. DURIG, J. R. DURIG Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorM. S. LEE, M. S. LEE Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorR. J. HARLAN, R. J. HARLAN Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorT. S. LITTLE, T. S. LITTLE Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this author J. R. DURIG, J. R. DURIG Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorM. S. LEE, M. S. LEE Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorR. J. HARLAN, R. J. HARLAN Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this authorT. S. LITTLE, T. S. LITTLE Dep. Chem., Univ. S. C., Columbia, SC 29208, USASearch for more papers by this author First published: February 13, 1990 https://doi.org/10.1002/chin.199007239Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue7February 13, 1990 RelatedInformation

ChemInform Abstract: Far‐IR Spectrum of Methyl Amine: Assignment of the Second Torsional State.

ChemInformVolume 21, Issue 7 Physical Organic Chemistry ChemInform Abstract: Far-IR Spectrum of Methyl Amine: Assignment of the Second Torsional State. M. ODA, M. ODA Dep. Phys., Fac. Sci., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorN. OHASHI, N. OHASHI Dep. Phys., Fac. Sci., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this author M. ODA, M. ODA Dep. Phys., Fac. Sci., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this authorN. OHASHI, N. OHASHI Dep. Phys., Fac. Sci., Kanazawa Univ., Kanazawa 920, Jap.Search for more papers by this author First published: February 13, 1990 https://doi.org/10.1002/chin.199007051AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue7February 13, 1990 RelatedInformation

Bis(substituted benzoato) complexes of bis(η-cyclopentadienyl)titanium(IV). Synthesis and mass-, 1H-, 13C-NMR and IR-spectra

The syntheses of 32 complexes of the type (η-C 5H 5) 2Ti(OOCC 6H 4X) 2 are reported together with their mass, 1H NMR, 13C NMR, mid- and far-IR spectra. The data are consistent with a model in which the TiOOC bond strength (weaker than that of TiCp and TiHal) is stabilized by electron-withdrawing substituents X on the phenyl rings. The electronic influence of X also extends into the cyclopentadienyl rings.

Synthesis and X-ray crystal structure of a mercury(II)-telluroamine complex. Monodentate behaviour by a potentially bidentate hybrid telluride ligand, 1-(NMe 2)-2-(TeC 6H 4-4-OEt)-4-MeC 6H 3

The telluroamines 1-(NMe 2)-2-(TeAr)-4-MeC 6H 3 ( 1) (Ar = 4-MeOC 6H 4 or 4-EtOC 6H 4) react with mercury(II) halides forming adducts of composition HgX 2 · 1 (X = Cl or Br). The IR, far-IR (up to 50 cm −1), 1H and 13C NMR spectra of the mercury(II) complexes indicate that the ligands ( 1) behave as monodentate donors, coordinating through tellurium only. The complexes seem to be dimers of the composition [ 1 · XHg(μ-X) 2HgX · 1]. The crystal structure of the adduct obtained from mercury(II) bromide has been determined. It reveals that the NMe 2 group does not coordinate with mercury(II) and the complex is a dimer in which two somewhat asymmetrical bromine bridges are present between the mercury atoms. The coordination environment of each mercury is almost tetrahedral [91.25(3)–118.40(4)°]. The HgBr bridging bond lengths are 2.755(1) and 2.710(1) Å.

Study of bulk and surface phonons and plasmons in GaAs/AlAs superlattices by Far-IR and Raman spectroscopy

Measurements by Raman spectroscopy, oblique incidence far-IR power reflection spectroscopy and attenuated total reflection spectroscopy have been used to study bulk and surface phonons and plasmons in semiconductor superlattices and multiple quantum wells. Raman spectroscopy has been used to investigate the properties of confined optical phonons, and far-IR measurements have been used to investigate the dielectric response parallel and perpendicular to the layers. Measurements are presented on 2 + 2, 4 + 4 and 6 + 6 GaAs/AlAs superlattice specimens and on a GaAs/ Al 0.35Ga 0.65 As multiple quantum well. The far-IR spectra of all samples are in good agreement with spectra calculated from superlattice dielectric functions which take account of the optical response of the confined transverse and longitudinal optical modes, using phonon frequencies taken from the Raman spectra.

The Infrared and1H-NMR Spectra of 8-Hydroxyquinoline Adducts of 8-Hydroxyquinoline Complexes of Dioxouranium(VI), Thorium(IV) and Scandium(III)

Abstract The 1H-nmr and infrared spectra of the complexes [M(ox)n(Hox)] where M = UO2 (n = 2), Th (n = 4) or Sc (n = 3) and Hox = 8-hydroxyquinoline are discussed. The nmr spectra of the adducts are uninformative with respect to the bonding and structure of these molecules since they dissociate in solution. The solid state ir spectra show that the adducted molecule of 8-hydroxyquinoline is bound to the metal through the phenolic oxygen, the proton forming an intramolecular hydrogen bond between the nitrogen atom of the adducted molecule and the oxygen atom of a neighbouring chelate ring. The mid-and far-ir spectra are reported for the first time and assignments for the δN-H, νM-O and νM-N modes have been made.

Spectra and structure of organophosphorus compounds: Part XLIII. Far-infrared spectra and ab initio calculations of ethylphosphine

The far-IR spectra (350 to 30 cm −1) of gaseous ethylphosphine and the P- d 2 derivative have been recorded at 0.1 cm −1) resolution. These data have been utilized to reinterpret and verify assignments to the methyl torsional fundamentals. The fundamental vibrational frequencies for both the more stable trans (methyl group oriented trans to the lone pair on the phosphorus atom) and high energy gauche rotamers are calculated by ab initio Hartree-Fock gradient calculations employing the 3–21G ∗ basis set and these frequencies are compared to those obtained experimentally. Potential surfaces for both the methyl and asymmetric torsional modes have been calculated utilizing both the 3–21G ∗ and 6–31G ∗ basis sets. The theoretically determined barriers for both torsional modes are compared to those determined from analysis of the torsional bands observed in the far-IR spectra. The optimized geometries for both conformations are compared to the structures obtained from microwave spectroscopy. It is concluded that at these levels of calculation the structure, potential surface and vibrational frequencies for ethylphosphine are well determined.

Structural, vibrational and solid-state NMR studies of the halogenocuprate(I) complexes [(PPh3)2CuI2]- and [(PPh3)CuI3Cu(PPh3)

Single-crystal X-ray diffraction, vibrational spectroscopy, and solid state NMR spectroscopy have been used to characterize two new types of ionic copper(1) complexes. The anion in [PPh3Me]+[(PPh3)2Cu12]c-o ntains two PPh, ligands coordinated to the copper atom of a Cu12 unit in a pseudotetrahedral arrangement, with Cu-P = 2.292 (2), 2.288 (2) A, Cu-I = 2.692 (I), 2.702 ( I ) A, P-Cu-P = 121.24 (9), and I-Cu-I = 108.62 (4)' (monoclinic, P21/c, a = 12.138 (5) A, b = 14.776 (6) A, c = 28.197 (14) A, 0 = 103.76 (4)O, Z = 4, R = 0.040 for 4490 'observed (I > 3 4 ) ) reflections). The far-IR spectrum shows a strong band at 118 cm-l that is assigned to the antisymmetric Cu-I stretching mode of the CUI, unit. The CPMAS ,*P NMR spectrum shows a strong singlet at 18.1 ppm (relative to 85% H3Po4) due to the cation and a weaker quartet centered at -16.7 ppm due to the coordinated PPh, in the anion, with line spacings due to Cu-P coupling of 1.08, 1.20, and 1.23 kHz. The anion in [PPh,Me]+[ (PPh,)CuI,Cu(PPh,)]- consists of an approximately D,h Cu213 unit with three iodine atoms bridging the two copper atoms and with one PPh, molecule completing a pseudotetrahedral arrangement around each copper atom. The crystallographically imposed symmetry of the ion is C,,, with the 3-fold axis passing through the P-Cu bonds. The core structural parameters are (5)O, and Cu-I-Cu = 54.88 (4)' (cubic, P2,3, a = 17.744 (IO) A, Z = 4, R = 0.036 for 1390 observed reflections). This is the first reported example of a binuclear copper(1) complex with three bridging ligands and is an example of an unusual bonding situation in which two coordination tetrahedra are linked by sharing a common face. This has the effect of producing an unusually short Cu-- -Cu separation of 2.50 A. The far-IR spectrum shows a band at 127 cm-' that is assigned to the doubly degenerate perpendicular Cu-I stretching mode of the CutIl unit. The CPMAS NMR spectrum shows a strong singlet at 20.1 ppm due to the cation and a broad quartet centered at -15.8 ppm due to the coordinated PPh, in the anion. The splitting pattern for this quartet does not conform to expectations for an AX spin system involving coupling between I = I / , and I = ,/, nuclei. The assignments of the ~(CU-I)I R bands in both complexes are supported by approximate normal-wordinate analyses, and the resulting Cu-I force constants are compared with the values obtained in similar analyses of related iodocopper(1) complexes.

Far-Ir Study of Tin Tetrahalide Diphosphine Adducts

Abstract Thirteen tin tetrahalide diphoshine adducts of the general formula cis-SnX4. (L-L), X = Cl, Br, I; L-L = DPPE (Ph2 P CH2 CH2 PPh2), DMPE (Me2 P CH2 CH2 P Me2), DMPP (Me2 P CH2 CH2 CH2 P Me2), DEPE (Et2 P CH2 CH2 P Et2), DEPP (Et2 P CH2 CH2 CH2 PEt2), twelve of which are reported for the first time in this work, have been synthesized and their far-ir spectra in the 400–40 cm−1 region have been investigated. The vibrations in the 295–310 cm−1, 208–210 cm−1 and 156–185 cm−1 regions were attributed to Sn - X strectching vibrations of chloro, bromo and iodo adducts, respectively, and the vibrations in the 100–116 cm−1 region were attributed to the Sn - P stretching vibrations for the twelve adducts investigated. The weak vibrations in the lower frequency region were evaluated as skeletal bending vibrations.

Far-infrared spectra and conformational stability of the epihalohydrins

The far-IR spectra of gaseous (360-50 cm −1) and solid (500-50 cm −1) epifluorohydrin, epichlorohydrin, and epibromohydrin, OCH 2CH(CH 2X), have been recorded and the asymmetric torsional modes of two conformations of the epichlorohydrin and epibromohydrin molecules have been observed and assigned. The asymmetric torsional modes for all three conformers of epifluorohydrin have been observed and assigned, and an asymmetric potential function governing internal rotation is calculated. The potential constants obtained are V 1=590±167, V 2=−245±203, V 3=1175±98, V 6=−60±40 cm −1 which are coefficients for the cosine terms, and V′ 1=775± 80, V′ 2=−365±216, V′ 3=−135±33 cm −1 which are terms associated with the sine portion of the function. The calculated enthalpy difference between the most stable gauche I and next more stable conformation, the cis form, is 269 cm −1 (769 cal mol −1) with the enthalpy difference between the gauche I and gauche II conformers calculated to be 1007 cm −1 (2.88 kcal mol −1). The results of a Raman temperature study of epifluorohydrin in the gaseous phase are also included. Some reassignments of the low frequency bending vibrations are suggested for the epihalohydrins as well. The results are compared to the corresponding quantities for the similar halomethylcyclopropane molecules.

Infrared spectroscopy characterization of thin films used in solid state micro-batteries

In the perspective to use thin solid films of both Li borate glasses and layered insertion compounds in Li microbatteries, we have investigated their structural characterization as function of the growth conditions by IR spectroscopy. Taking into consideration the ratio of absorption peaks in the mid-IR spectrum of the binary glass system, the composition of the film is determined with good accuracy, and measurements on films doped with different Li salts are comparable to those obtained for bulk material. The far-IR reflectivity spectra of the semiconductors of the In-Se family are found to be those of InSe and In 2Se 3 for given ratio of fluxes during the film preparation by the MBD technique.

Inversion and torsional motions of methylhydrazine studied by microwave and far-infrared spectroscopy and ab initio calculation

The microwave spectra of the inner and outer conformers of methylhydrazine have been measured. The rotational constants and the 14N nuclear quadrupole coupling constants (in MHz) for the outer conformer are determined as: A 0=38091.6(3), B 0=9591.93(6), C 0=8494.42(6), χ aa1 =3.7(3), χ bb1 =0.7(4), χ aa2 =3.2(3), and χ bb2 =−2.5(3). The values in parentheses represent estimated limits of error, and suffixes 1 and 2 represent the N nuclei with and without the methyl group, respectively. The inversion motion at the N 1 nuclei is found to split the rotational levels; the barrier heights of the inversion for the inner and outer conformers are estimated to be 1960 and 2480 cm −1, respectively. Far-IR spectra have been measured for the normal and CH 3NDND 2 species with a resolution of 0.1 cm −1. The observed absorption peaks are assigned to transitions related to the NN and NC torsional modes. The potential function for the NN torsion is determined by joint use of the far-IR data and the results of an SCF 4-31G(N*) calculation. The equilibrium dihedral angles for the NN torsion are estimated to be 93° and 268° for the inner and outer conformers, respectively.

The Phase Transition ofm-Nitrophenol

Abstract The monocrystals of two polymorphic phases of m-nitrophenol were studied by the DSC method, and near IR (NIR) and far IR (FIR) spectroscopy. We found the phase transition of the first order 14 degrees below the melting point. The temperatures, enthalpies and entropies of the phase transition and the melting are presented. The polarized NIR spectra in the region of the overtones of the OH…O stretching vibrations for the two phases are presented. The polarized FIR spectra of the two phases in the room and liquid nitrogen temperature from 0 to 200 cm−1 are presented.

Vibrational and x-ray photoelectron spectroscopy for tetrachlorotetrakis(trimethylphosphine)molybdenumtungsten

Far-ir and Raman vibrational spectra and x-ray photoelectron spectra (XPS) have been obtained on the heteronuclear complex MoWCl{sub 4}(PMe{sub 3}){sub 4}. A band at 326 cm{sup {minus}1} in the far-ir spectrum and at 322 cm{sup {minus}1} in the Raman spectrum has been attributed to the Mo-W stretching mode. The force constant for the heteronuclear M-M stretching mode is significantly larger compared to those of its homonuclear analogues. The XPS results for the heteronuclear complex indicate a partial shift in electron density from tungsten to molybdenum. 4 tabs., 1 fig., 15 refs.

Bis(substituted benzoato) complexes of bis(η-cyclopentadienyl)titanium(IV). Synthesis, mass, 1H, 13C NMR and IR spectroscopy

The synthesis of 31 complexes of the type Cp2Ti(OCOPhX)2 (X = substituent, Cp = η-C5H5) is reported together with their mass, 1H NMR, 13C NMR, mid- and far-IR spectra. The data are consistent with a model in which the TiOOC bond strength—weaker than TiCp and TiHal—is stabilized by electron-withdrawing groups, X, on the phenyl ring. The influence of the electronic properties of X also extends into the cyclopentadienyl rings.

Torsional transitions and barriers to internal rotation of the 2-halopropenes

For each of the 2-halopropenes CH 2CXCH 3 (where XF, Cl, Br, and I), the far-IR spectrum from 370 to 80 cm −1 has been recorded at a resolution of 0.10 cm −1 in the gas phase. The gas phase Raman spectra have also been obtained. At least two torsional transitions have been observed for each molecule from which a barrier to internal rotation of the methyl group is calculated. The values of V 3 for the fluoride, chloride, bromide, and iodide are, respectively, 823 cm −1 (2353 cal mol −1), 928 cm −1 (2654 cal mol −1), 928 cm −1 (2654 cal mol −1), and 894 cm −1 (2555 cal mol −1). Rotational structure partially resolved in some far-IR bands is also interpreted. The far-IR spectrum of each solid has been recorded and from the torsional fundamental frequencies a value of the barrier is obtained to compare with the value in the gas phase.

Metalmetal bonds extended over a porphyrin ring. II. Resonance raman and far-infrared spectra of metalloporphyrins containing InM bonds

The low-frequency resonance Raman (RR) and far-IR spectra of (TPP)InM(CO) 3Cp (M = Mo and W) are reported. The ν(InM) vibrations were located at ∼ 160 and 147 cm −1, respectively, for the Mo and W compounds. The RR excitation profiles were used to distinguish ν(InM) from TPP vibrations which dominate the low-frequency spectra and to demonstrate that the split component of the Soret transition near 460 nm contains some σ(InM)σ*(InM) character.

Infrared spectra of hydrogen bonded complexes in solutions of noble gases

The far-IR spectra (250-50 cm −1) of a number of H-complexes of HCl and fluoroalcohols with bases in solutions in liquid Xe and n-pentane ( T, 150–250 K) have been investigated in order to clarify the influence of a solvent (atomic and molecular) on the frequencies and bandwidths of the intermolecular stretching vibration ν σ. In contrast to narrowing (up to 10 times) of the bandwidths of the stretching vibration of the proton donor ν (AH) a similar dependence is not observed for ν σ bandwidths upon changing over from molecular to atomic solvent. The ν σ bandwidths turn out to be small (up to 30 cm −1). The results obtained for the dependence of the ν (AH) and ν σ (AB) bandwidths on the solvent type agree with the model of vibrational relaxation based on a generalized Langevin equation. The parameters of the model are estimated for H-complexes in molecular solvents.

Far infrared and low frequency Raman spectra and conformational stability of gaseous chloromethylcyclopropane and bromomethylcyclopropane

The far-IR (350-50 cm −1) and low frequency Raman spectra (200-70 cm −1) of gaseous chloro- and bromomethylcyclopropane have been recorded. The asymmetric torsion arising from the gauche conformer of the bromide has been observed at 91.8 cm −1 but the corresponding transition for the cis conformer was not observed. However, IR bands for all the skeletal bending modes indicate the presence of a second conformer at ambient temperature. For chloromethylcyclopropane, the asymmetric torsions of both the cis and the gauche conformers have been observed at 99.54 and 96.84 cm −1, respectively, along with two excited state transitions for each conformer. From these data a potential function for the chloromethylcyclopropane molecule has been calculated and the determined potential constants have the following values: V 1=200±65, V 2=−34±16, and V 3=1138±6 cm −1 with the gauche conformer calculated to be more stable by 178±87 cm −1 (510±25 cal mol −1) than the cis conformer. The gauche to cis barrier is 1239 cm −1 (3.54 kcal mol −1) and the gauche to gauche barrier is 1114 cm −1 (3.19 kcal mol −1). A variable temperature Raman study of the gaseous chloride was carried out and the enthalpy difference was found to be Δ H=273±108 cm −1 (782±309 cal mol −1) with the gauche conformer being more stable. The results of this study are compared with previous studies of these and similar molecules.