The Axial and Equatorial Hydrogen Bonds in the Tetrahydropyran⋅⋅⋅HF Complex

Revealing the multiple structures of serine

“…It has been proposed (45) that this is a consequence of collisional relaxation at the onset of the supersonic expansion, which causes higher-energy forms to collapse to the preferred lower-energy ones due to collisions with the carrier gas. The extent of conformational relaxation depends on several factors, most significantly barrier heights between conformers (46-48) and the carrier gas (49)(50)(51)(52). Type III conformers are ''missing'' in the supersonic expansion for all ␣-amino acids with nonpolar side chains studied up to now (19-25, 27-30, 34-36).…”

Revealing the multiple structures of serine

“…It has been proposed (45) that this is a consequence of collisional relaxation at the onset of the supersonic expansion, which causes higher-energy forms to collapse to the preferred lower-energy ones due to collisions with the carrier gas. The extent of conformational relaxation depends on several factors, most significantly barrier heights between conformers (46-48) and the carrier gas (49)(50)(51)(52). Type III conformers are ''missing'' in the supersonic expansion for all ␣-amino acids with nonpolar side chains studied up to now (19-25, 27-30, 34-36).…”

Adducts of NH3 with the Conformers of Glycidol: A Rotational Spectroscopy Study

“…For example, in saturated cyclic ethers, such as tetrahydropyran, two different lone pairs (axial and equatorial) are available at the ether oxygen atom to accept a proton. Alonso and collaborators could assign the supersonic-jet Fourier-transform microwave (FTMW) spectra of both axial and equatorial complexes in the case of tetrahydropyran···HCl, [13] tetrahydropyran···HF, [14] and pentamethylene sulfide···HF, [15] thus characterizing relative energies and structural differences. Three conformers have been observed for formamide···water, [4] and six conformers in the molecular recognition study of the self-aggregation of propylene oxide.…”

Pulsed Nozzle Fourier Transform Microwave Spectrometer: Advances and Applications

“……”

Revealing the multiple structures of serine

“…It has been proposed (45) that this is a consequence of collisional relaxation at the onset of the supersonic expansion, which causes higher-energy forms to collapse to the preferred lower-energy ones due to collisions with the carrier gas. The extent of conformational relaxation depends on several factors, most significantly barrier heights between conformers (46-48) and the carrier gas (49)(50)(51)(52). Type III conformers are ''missing'' in the supersonic expansion for all ␣-amino acids with nonpolar side chains studied up to now (19-25, 27-30, 34-36).…”

Adducts of NH3 with the Conformers of Glycidol: A Rotational Spectroscopy Study

“…For example, in saturated cyclic ethers, such as tetrahydropyran, two different lone pairs (axial and equatorial) are available at the ether oxygen atom to accept a proton. Alonso and collaborators could assign the supersonic-jet Fourier-transform microwave (FTMW) spectra of both axial and equatorial complexes in the case of tetrahydropyran···HCl, [13] tetrahydropyran···HF, [14] and pentamethylene sulfide···HF, [15] thus characterizing relative energies and structural differences. Three conformers have been observed for formamide···water, [4] and six conformers in the molecular recognition study of the self-aggregation of propylene oxide.…”

Pulsed Nozzle Fourier Transform Microwave Spectrometer: Advances and Applications

“……”

Revealing the multiple structures of serine

“…It has been proposed (45) that this is a consequence of collisional relaxation at the onset of the supersonic expansion, which causes higher-energy forms to collapse to the preferred lower-energy ones due to collisions with the carrier gas. The extent of conformational relaxation depends on several factors, most significantly barrier heights between conformers (46-48) and the carrier gas (49)(50)(51)(52). Type III conformers are ''missing'' in the supersonic expansion for all ␣-amino acids with nonpolar side chains studied up to now (19-25, 27-30, 34-36).…”

Adducts of NH3 with the Conformers of Glycidol: A Rotational Spectroscopy Study

“…For example, in saturated cyclic ethers, such as tetrahydropyran, two different lone pairs (axial and equatorial) are available at the ether oxygen atom to accept a proton. Alonso and collaborators could assign the supersonic-jet Fourier-transform microwave (FTMW) spectra of both axial and equatorial complexes in the case of tetrahydropyran···HCl, [13] tetrahydropyran···HF, [14] and pentamethylene sulfide···HF, [15] thus characterizing relative energies and structural differences. Three conformers have been observed for formamide···water, [4] and six conformers in the molecular recognition study of the self-aggregation of propylene oxide.…”

Pulsed Nozzle Fourier Transform Microwave Spectrometer: Advances and Applications

“……”