the conformations of 1-thiacyclooctan-3-one dynamic nuclear magnetic resonance and force-field calculation
نویسندگان
چکیده
the 1h and natural-abundance 13c-nmr spectra of 1-thiacyclooctan-3-one (1) have been measured from 25 to -100°c. coalescence is observed in the 1h-nmr spectra of (1) at about -80°c, and attributed to ring inversion in a boat-chair conformation, which is the predominant conformation of (1). the free energy of activation (dg¹) for this process is 9.2±0.2 kcal/mol. the 13c-nmr spectra of (1) is temperature independent.
منابع مشابه
The Conformations of 1-Thiacyclooctan-3-One Dynamic Nuclear Magnetic Resonance and Force-Field Calculation
The 1H and natural-abundance 13C-NMR spectra of 1-thiacyclooctan-3-one (1) have been measured from 25 to -100°C. Coalescence is observed in the 1H-NMR spectra of (1) at about -80°C, and attributed to ring inversion in a boat-chair conformation, which is the predominant conformation of (1). The free energy of activation (DG¹</s...
متن کاملForce-detected Nuclear Magnetic Resonance
The drive to improve the sensitivity of nuclear magnetic resonance (NMR) to smaller and smaller sample volumes has led to the development of a variety of techniques distinct from conventional inductive detection. In this chapter, we focus on the technique of force-detected NMR as one of the most successful in yielding sensitivity improvements. We review the rationale for the technique, its basi...
متن کاملDynamic nuclear polarization in a magnetic resonance force microscope experiment.
We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton...
متن کاملNUCLEAR MAGNETIC RESONANCE STUDY OF THE STRUCTURE OF GLYOXALDIHYDRAZONE
Study of the nuclear magnetic resonance spectra of glyoxaldihydrazone in dimethylsulfoxide and deuterochlorofonn leads to the conclusion that this compound exists predominantly in non-chelate structure
متن کاملIterative Force-Field Calculation and Molecular Dynamics of Cyclooctanone
Body's iterative force-field computer program has been used to calculate strain energies in cyclooctanone (I). 348 MHZ 1H NMR spectra of (I) have been investigated over the temperature range of 25° to -160°C. Two conformation processes affect the 1H NMR spectrum of (I). Iterative force-field calculations on the conformations and conformational interconversion paths of ...
متن کاملZero-Field Nuclear Magnetic Resonance
Techniques for studying molecular structure, such as x-ray diffraction and nuclear magnetic resonance (NMR), often require the use of single crystals' or oriented samples. ' NMR, for example, is sensitive to interatomic distances and angles through spectral splittings caused by internucl. ear dipol. e-dipole couplings in high magnetic field. Where only polycrystalline powders or amorphous mater...
متن کاملمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
iranian journal of chemistry and chemical engineering (ijcce)ناشر: iranian institute of research and development in chemical industries (irdci)-acecr
ISSN 1021-9986
دوره 14
شماره 1 1995
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023