04-12-2018, 03:22 PM

Hi,

The Question is:

'Calculate the proportions of [Mn(12CO)6] + and [Mn(12CO)5( 13CO)]+ present in a sample of [Mn(CO)6]+ containing naturally abundant carbon. Sketch the appearance of the solution-phase 55Mn NMR spectrum of [Mn(CO)6]+ , taking into account these two calculated proportions. Ensure that in your answer you fully account for the number and relative intensities of the peaks in the spectrum.'

Abundance of 12C = 0.989

Abundance of 13C = 0.011

To calculate the proportion of [Mn(12CO)6]+ :

(0.989)^6 = 0.9358

To calculate the proportion of [Mn(12CO)5(13CO)]+ :

(0.989)5 * (0.011) = 0.01041

If the answers for the proportions are correct, I would get the 55Mn NMR spectrum of [Mn(CO)6]+ to consist of:

A large central singlet with relative intensity of 0.9358. Corresponding to [Mn(12CO)6]+

A doublet of satellite peaks, a peak either side of the central singlet. Each peak would have an intensity of (0.01041/2). Corresponding to [Mn(12CO)5(13CO)]+

Can anyone tell me if my way of calculating the probabilities of this is correct, and if it is, is my description of the manganese NMR spectrum correct ? I'mm pretty confident it's right.

Appreaciate any feedback,

The Question is:

'Calculate the proportions of [Mn(12CO)6] + and [Mn(12CO)5( 13CO)]+ present in a sample of [Mn(CO)6]+ containing naturally abundant carbon. Sketch the appearance of the solution-phase 55Mn NMR spectrum of [Mn(CO)6]+ , taking into account these two calculated proportions. Ensure that in your answer you fully account for the number and relative intensities of the peaks in the spectrum.'

Abundance of 12C = 0.989

Abundance of 13C = 0.011

To calculate the proportion of [Mn(12CO)6]+ :

(0.989)^6 = 0.9358

To calculate the proportion of [Mn(12CO)5(13CO)]+ :

(0.989)5 * (0.011) = 0.01041

If the answers for the proportions are correct, I would get the 55Mn NMR spectrum of [Mn(CO)6]+ to consist of:

A large central singlet with relative intensity of 0.9358. Corresponding to [Mn(12CO)6]+

A doublet of satellite peaks, a peak either side of the central singlet. Each peak would have an intensity of (0.01041/2). Corresponding to [Mn(12CO)5(13CO)]+

Can anyone tell me if my way of calculating the probabilities of this is correct, and if it is, is my description of the manganese NMR spectrum correct ? I'mm pretty confident it's right.

Appreaciate any feedback,