DEPT method

Dodecamethylcyclohexasilane (1) was chosen as a representative member of this important class of compounds upon which to test INEPT and DEPT methods. The decoupled 29Si NMR of 1 consists of a single resonance... 

A very useful pulse sequence in spectroscopy is employed in the experiment called Distortionless Enhancement by Polarization Transfer, better known as DEPT. The DEPT method has become one of the most important techniques available to the NMR spectroscopist for determining the number of hydrogens attached to a given carbon atom. The pulse sequence involves a complex program of pulses and delay times in both the and ehannels. The result of this pulse sequenee is that carbon atoms with one, two, and three attached hydrogens exhibit different phases as they are recorded. The phases of these hydrogens will also depend on the duration of the delays that are programmed into the pulse sequence. In one experiment, called a DEPT-45, only carbon atoms that... 

DEPT) method was used to discriminate methylene resonances from methyl and methine resonances. 

Despite its utility, off-resonance decoupling is now considered an old-fashioned technique. It has been replaced by more modern methods, the most important of which is Distortionless Enhancement by Polarization Transfer, better known as DEPT. The DEPT technique requires an FT-pulsed spectrometer. It is more complicated than off-resonance decoupling, and it requires a computer, but it gives the same information more reliably and more clearly. Chapter 9 will discuss the DEPT method in detail only a brief introduction to the method and the results it provides will be provided here. 

CUSS the DEPT method in detail only a brief introduction to the method and the results it provides will be provided here. 

The same general methodology ean also be applied to edit (for example) a deeoupled NMR speetnim into four subspeetra, for the CH, CH2, CH and C moieties separately. A eonnnon variant method ealled DEPT... 

Methods Exam. Waters Assoc. Math 1988, United Kingdom Dept, of the Environment Chem. Abstr. 108, 197583v (1988). 

Generally, the most powerful method for stmctural elucidation of steroids is nuclear magnetic resonance (nmr) spectroscopy. There are several classical reviews on the one-dimensional (1-D) proton H-nmr spectroscopy of steroids (267). C-nmr, a technique used to observe individual carbons, is used for stmcture elucidation of steroids. In addition, C-nmr is used for biosynthesis experiments with C-enriched precursors (268). The availability of higher magnetic field instmments coupled with the arrival of 1-D and two-dimensional (2-D) techniques such as DEPT, COSY, NOESY, 2-D J-resolved, HOHAHA, etc, have provided powerful new tools for the stmctural elucidation of complex natural products including steroids (269). 

NIOSH Manual of Analytical Methods, Method No. 54, Vol. 2, U.S. Dept, of Health and Human Services, Washington, D.C., 1977. 

S. V. EUnson and K. L. Petrov, Zirconium, Chemical and Physical Methods of Analysis, Main Administration on the Use of Atomic Energy at the Council of Ministers, Moscow, 1960 English translation. Office of Technical Services, Dept, of Commerce, Washington, D.C., 1962. 

Solderability. Method 2003.5, MiUtary Standard—883C, Test Methods and Procedures for Microelectronics, Dept, of Defense, Washington, D.C., 1987. 

Dr. Woods R. and Kodatsky, W. K., Dept, of Chemical Engineering, McMaster University, Hamilton, Ontario, Discovering Short Cut Methods of Equipment Sizing and Selection, presented at 1985 Annual Conference (Computer Aided Engineering) of American Society For Engineering Education, Atlanta, Georgia, June 16-20, 1985, V ol. 1. 

Nielsen, P. V. The box method—A practical procedure for introduction of an air terminal device in CFD calculation. Report R9744, Dept, of Building Technology and Structural Engineering, Aalborg University, Aalborg, 1997. 

DEPT-NMR (Section 13.6) An NMR method for distinguishing among signals due to CH3, CH2, CH, and quaternary carbons. That is, the number of hydrogens attached to each carbon can be determined. 

In a 30 minute test the results obtained should not differ by more than 1 minute using different lots of paper. On being exposed to nitric oxide fumes, these papers slowly turn green, followed by a salmon pink coloration Methyl Violet Paper Test (Field Test for Pro pint Powders). This method of testing proplnts using 0.1N methyl violet paper directly in the containers in which the powder is stored, was developed at Picatinny Arsenal in 1928—29 (Refs 1 2), and was adopted by the Ordnance Dept to replace the Observation Test about 1931... 

US Dept of Commerce (1967) 37) R. Abbott, N. Gelber N. Liszt, Particle Size Analysis of Ammonium Perchlorate by the MSA Sedimentation Method", PATM 1778 (1967) 38) C.E. 

The most widely used method for determining multiplicities of carbon atoms is DEPT (Distortionless Enhancement by Polarization Transfer). This has generally replaced the classical method of recording off-resonance C spectra with reduced CH couplings from which the multiplicity could be read directly. 

King, P. V., and A. H. Lasseigne, "Hazard Classification of Explosives for Transportation Evaluation Test Methods, Hazard Evaluation, Research, and Engineering," Report No. TSA-20-72-5, prepared for U. S. Dept, of Transportation (1972) (available from NTIS, Springfield, VA). 

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