Vibrational Spectra of Methyl Ether. I. Assignment of the Spectra

Kanazawa, Yôko; Nukada, Kenkichi

doi:10.1246/bcsj.35.612

Cited by 50 publications

(9 citation statements)

References 9 publications

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“…The MM4 energy for this barrier is 2.68 kcal/mol (Δ E ) and seems better than the MM3 value, which appears to have been a bit low (2.45). The MM4 fit to the vibrational data16–18 is somewhat improved over that of MM3 (Table 3). The rms errors in the frequency calculations were 38 cm −1 and 24 cm −1 with MM3 and MM4, respectively.…”

Section: Results and Discussion4bmentioning

confidence: 97%

Alcohols, ethers, carbohydrates, and related compounds. I. The MM4 force field for simple compounds

et al. 2003

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Simple alcohols and ethers have been studied with the MM4 force field. The structures of 13 molecules have been well fit using the MM4 force field. Moments of inertia have been fit with rms percentage errors as indicated: 18 moments for ethers, 0.28%; 21 moments for alcohols, 0.22%. Rotational barriers and conformational equilibria have also been examined, and the experimental and ab initio results are reproduced substantially better with MM4 than they were with MM3. Much of the improvement comes from the use of additional interaction terms in the force constant matrix, of which the torsion-bend and torsion-torsion are particularly important. Induced dipoles are included in the calculation, and dipole moments are reasonably well fit. It has been possible for the first time to fit conformational energetic data for both open chain and cyclic alcohols (e.g., propanol and cyclohexanol) with the same parameter set. For vibrational spectra, over a total of 82 frequencies, the rms error is 27 cm(-1), as opposed to 38 cm(-1) with MM3. Both the alpha and beta bond shortening resulting from the presence of the electronegative oxygen atom in the molecule are well reproduced. The electronegativity of the oxygen is sufficient that one must also include not only the alpha and beta electronegativity effects on bond lengths, but also on angle distortions, if structures are to be well reproduced. The heats of formation of 32 alcohols and ethers were fit overall to within experimental error (weighted standard deviation error 0.26 kcal/mol).

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Section: Results and Discussion4bmentioning

confidence: 97%

Alcohols, ethers, carbohydrates, and related compounds. I. The MM4 force field for simple compounds

et al. 2003

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“…Dimethyl ether-18O was prepared by a procedure described by Blukis, Kasai, and Myers. 63 By mass spectroscopy the 18 O content was determined to be 86%. Dimethyl ether-d 6 was prepared by a procedure described by Kanazawa and Nukada, 64 and the deuterium content was determined to be 99%.…”

Section: Methodsmentioning

confidence: 99%

“…Dimethyl ether 1 was obtained from Aldrich Company (99% purity) and used without further purification. Dimethyl ether-18O was prepared by a procedure described by Blukis, Kasai, and Myers . By mass spectroscopy the 18 O content was determined to be 86%.…”

Section: Methodsmentioning

confidence: 99%

Reactions of Dimethyl Ether with Atomic Oxygen: A Matrix Isolation and a Quantum Chemical Study

et al. 1999

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The reaction of dimethyl ether (1) with atomic oxygen generated by photolysis of ozone or N 2 O was examined in low-temperature matrices. The major reaction products are two conformers of methoxymethanol (5). IR absorptions of the products were assigned by isotopic labeling ( 18 O and D) and DFT calculations at the B3LYP/ 6-311++G(d,p) level of theory. The mechanism of the formation of 5, in particular H abstraction from 1 by atomic oxygen (O 3 P and O 1 D), was investigated using UMP, UCCSD(T), and UDFT. In both the H abstraction and the O( 1 D) insertion reaction, the out-of-plane C-H bonds of 1 are preferentially attacked since the inplane C-H bonds are about 10 kcal/mol stronger. In the case of a reaction with O( 3 P), an Arrhenius activation energy of 3.5 kcal/mol is calculated at 298 K, which compares well with an experimental value of 2.85 kcal/mol. In the exit channel of the reaction, a radical-radical complex between CH 3 CH 2 • and •OH (-2.7 kcal/mol relative to separated products) is found. The latter is the starting point for the formation of 5 and helps to rationalize the stereoselectivity of the reaction leading to particular conformations of 5.

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“…The IR and Raman spectra of DME and DME-d 6 have already been reported, − and ab initio molecular orbital calculations of vibrational frequencies have been performed on DME by McKean et al As for DME on metal surfaces, Sexton and Hughes performed temperature-programmed desorption (TPD) and spectroscopic studies on the adsorbate on Cu(100), indicating the existence of two phases , i.e., a weakly bound monolayer phase with a desorption temperature (T d ) of 150 K and a multiplayer or condensed phase with T d = 100 K. The high-resolution electron energy loss spectroscopy (HREELS) has been applied to DME on Al(111) and on Rh(111); , the results proved the existence of molecularly adsorbed DME on the surfaces at 90−100 K and the desorprtion of the adsorbate without any sign of decomposition at elevated temperatures (100−200 K). The IR spectra of DME adsorbed on metal surfaces have not been reported yet.…”

Section: Introductionmentioning

confidence: 99%

Infrared Reflection Absorption Spectroscopic and DFT Calculation Studies on the Adsorption Structures of Dimethyl Ether on Ag(110), Cu(110), and Their Atomic Oxygen-Reconstructed Surfaces

et al. 2001

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Infrared spectra were measured at 80 K for dimethyl ether (CH3OCH3, DME) and dimethyl ether-d6 (CD3OCD3, DME-d6) with increasing amounts of exposures to metal substrates, Ag(110), Cu(110), and their atomic oxygen-reconstructed surfaces, p(2 × 1)O−Ag(110) and p(2 × 1)O−Cu(110). At relatively lower surface coverages, the IR spectra of DME on Ag(110) and Cu(110) in the 1500−800 cm-1 region give rise to IR bands mainly ascribable to A1 species, including symmetric COC stretching (νs(COC)) bands at 903 cm-1 on Ag(110) and 895 cm-1 on Cu(110), while at nearly saturation coverages, the adsorbate gives IR bands ascribable to B1 and/or B2 species in addition to the A1 bands with the νs(COC) band discretely sifted to 915 cm-1 on Ag(110) and to 901 cm-1 on Cu(110). Similar distinct spectral changes were observed also for DME and DME-d6 on the reconstructed surfaces. The stepwise spectral changes were interpreted in terms of a conversion from a state of DME with the C 2 axis almost perpendicular to the surfaces to a state with the C 2 axis tilted away from the perpendicular orientation. Fermi resonance effects cause stepwise but complicated spectral changes in the CH3 stretching vibration region of DME during the conversion. The changes strongly depend on the kind of the substrates, in contrast to the spectral changes in the 1500−800 cm-1 region, suggesting that the analyses of Fermi resonances can delineate subtle differences in the DME/substrate interaction modes among the substrates. Density functional theory (DFT) molecular orbital calculations were carried out on the cluster models of DME/Cu(110), where the oxygen atom of DME is coordinated to two copper atoms in the surface of metal clusters consisting of 12 copper atoms in the first layer and six copper atoms in the second layer. The results of calculations reproduce the observed frequencies appreciably well, substantiating the coordination interaction model.

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Vibrational Spectra of Methyl Ether. I. Assignment of the Spectra

Cited by 50 publications

References 9 publications

Alcohols, ethers, carbohydrates, and related compounds. I. The MM4 force field for simple compounds

Alcohols, ethers, carbohydrates, and related compounds. I. The MM4 force field for simple compounds

Reactions of Dimethyl Ether with Atomic Oxygen: A Matrix Isolation and a Quantum Chemical Study

Infrared Reflection Absorption Spectroscopic and DFT Calculation Studies on the Adsorption Structures of Dimethyl Ether on Ag(110), Cu(110), and Their Atomic Oxygen-Reconstructed Surfaces

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