cis decaline shows one proton where as trans decaline shows two -explain
2007-01-23 03:54:30 · 5 answers · asked by k_m_shri 1 in Science & Mathematics ➔ Chemistry
I think you need to build yourself a model of the molecule to discover the answer. The answer lies in the symmetry in the cis isomer, and the asymmetry in the trans isomer.
In the trans isomer the two protons will be decoupled and they will split each other into a doublet.
2007-01-23 04:12:15 · answer #1 · answered by Dr Dave P 7 · 2⤊ 0⤋
Well it certainly doesn't show only one proton.
In either case, there is 3 different protons in decalin. But in the trans isomer, there is 4 different protons.
It's difficult to discuss isomerism without drawings, so I will refer to a site, where you clearly can see why I say that in the cis compound, the two H-atoms at the two joining centres are identical, but in the trans they are actually different.
The cis is on the left!
http://upload.wikimedia.org/wikipedia/commons/c/cf/Cis-trans_isomerism_of_decahydronaphthalene.png
2007-01-23 12:14:10 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Shielding of the proton in cis
2007-01-23 12:12:23 · answer #3 · answered by ag_iitkgp 7 · 0⤊ 1⤋
Nuclear magnetic resonance (NMR) is a physical phenomenon based upon the magnetic properties of an atom's nucleus. All nuclei that contain odd numbers of nucleons and some that contain even numbers of nucleons have an intrinsic magnetic moment. The most commonly used nuclei are hydrogen-1 and carbon-13, although certain isotopes of many other elements nuclei can also be observed. NMR studies a magnetic nucleus, like that of a hydrogen atom (protium being the most receptive isotope at natural abundance) by aligning it with a very powerful external magnetic field and perturbing this alignment using an electromagnetic field. The response to the field by perturbing is what is exploited in nuclear magnetic resonance spectroscopy and magnetic resonance imaging.
NMR spectroscopy is one of the principal techniques used to obtain physical, chemical, electronic and structural information about a molecule. It is a powerful technique that can provide detailed information on the three-dimensional structure of biological molecules in solution. Also, nuclear magnetic resonance is one of the techniques that has been used to build elementary quantum computers.
For details go to:
http://en.wikipedia.org/wiki/Nuclear_Magnetic_Resonance
Decahydronaphthalene (also known as decalin, or as bicyclo[4.4.0]decane), a bicyclic organic compound, is an industrial solvent. A colorless liquid with an aromatic odor, it is used as a solvent for many resins. It is the saturated analog of naphthalene and can be prepared from it by hydrogenation in a fused state in the presence of a catalyst. Decahydronaphthalene easily forms explosive organic peroxides upon storage in the presence of air.
It occurs in cis and trans forms. The trans form is energetically more stable because of less steric interactions.
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2007-01-23 12:08:59 · answer #4 · answered by Yo tu amigo 2 · 0⤊ 2⤋
draw it out with all the hydrogens. if the hydrogens have the same environment they are equivalent and show 1 signal. if they aren't they show different signals.
2007-01-23 12:11:39 · answer #5 · answered by shiara_blade 6 · 0⤊ 0⤋