Where would you expect to find the 1H1H NMR signal of (CH3)2Mg(CH3)2Mg relative to the TMS signal

Chemistry

1 answer:

n200080 [17]3 years ago

8 0

Answer:

In diethyl ether, (CH₃)₂Mg(CH₃)₂Mg, show peaks at -1.46 and -1.74 ppm, at -100 °C
In tetrahydrofuran (THF), monomer (CH₃)₂Mg show peaks at -1.76 and -1.81 ppm, at -60 °C

Explanation:

The 1H NMR signal of (CH₃)₂Mg can be obtained in diethyl ether and tetrahydrofuran. (CH₃)₂Mg tends to polymerize in diethyl ether but mostly remain monomer in tetrahydrofuran. The negative value of chemical shifts shows that the protons of (CH₃)₂Mg are more shielded than the protons of TMS.

In diethyl ether, the structure of (CH₃)₂Mg is predicted in Figure A (attached). The A group in the structure represents the solvent. The chemical shift at -1.46 ppm is associated with protons of the bridging methyl groups while the signal at -1.74 ppm is for the proton of the terminal methyl group.

In THF, the two possible structures of (CH₃)₂Mg are predicted in Figure B (attached). Chemical shift at -1.76 ppm is associated with unsolvated monomer of (CH₃)₂Mg while the shift at -1.81 refers to the protons of methyl group bonded to the solvated (CH₃)₂Mg. The solvent is represented as Y in the Figure B.

This study is reported by J. Heard in "NMR of organomagnessium compounds".

You might be interested in

What is the best way to determine if an aqueous solution of sodium nitrate is unsaturated

Marina86 [1]

Solution is said to be saturated, if it contains maximum amount of solute that it can hold. On other hand, if solution contains less amount of solute as compared to its maximum capacity, it is referred as unsaturated solution.

It may be noted that, solubility of system is depends on temperature.

Now, if solution is unsaturated then it will dissolve more solute, when added in it. Thus, <span>sodium nitrate when added to solution get dissolves, it suggest that solution is unsaturated. </span>

6 0

2 years ago

scientist have found many marine fossils on the mountain far from any ocean or sea what is the best explanation for these fossil

DaniilM [7]

The best explanation, though it's controversial, is that a great flood had once covered the earth for a brief period of time.

8 0

3 years ago

Identify the dominant intermolecular attraction in bh3.

k0ka [10]

The molecule BH3 is trigonal planar, with B in the center and H in the three vertices. Ther are no free electrons. All the valence electrons are paired in and forming bonds.

There are four kind of intermolecular attractions: ionic, hydrogen bonds, polar and dispersion forces.

B and H have very similar electronegativities, Boron's electronegativity is 2.0 and Hydrogen's electronegativity is 2.0.

The basis of ionic compounds are ions and the basis of polar compounds are dipoles.

The very similar electronegativities means that B and H will not form either ions or dipoles. So, that discards the possibility of finding ionic or polar interactions.

Regarding, hydrogen bonds, that only happens when hydrogen bonds to O, N or F atoms. This is not the case, so you are sure that there are not hydrogen bonds.

When this is the case, the only intermolecular force is dispersion interaction, which present in all molecules.

Then, the answer is dispersion interaction.

6 0

2 years ago

Many homes that are not

andrew11 [14]

Answer:

pump that is the answer hope its right

6 0

2 years ago

4 outer planets in order

Gwar [14]

Jupiter, Saturn, Uranus, Neptune, Jovian... is your answer.

8 0

2 years ago

Read 2 more answers