things clocked during workshop

Question 1

AX
explain signal

Answer 1

a is coupled 1 thing

so u get one split

so u get a doublet

Question 2

AX2
explain signal

Answer 2

a is coupled to 2 things

so u split twice

but theyre the same
so they have the same cc which means they will overlap and give a high intensity where they do so.

triplet

Question 3

AMX

explain signal

Answer 3

A is coupled to 2 diff things

2 splits
diff things so diff cc so they dont overlap

doublet of doublets

Question 4

AMX2

explain signal

Answer 4

A is coupled to 3 diff things
one is the same,, 2 are the same

3 things but 2 diff coupling constants

3 splits
1/3 splits will overlap

doublet of triplets

Question 5

same cc

Answer 5

they overlap and itensify the signal

Question 6

different cc

Answer 6

they dont overlap and are separate

Question 7

how to find the chemical shift

Answer 7

the middle of the peaks

use ppm

Question 8

how to find the cc in hz

Answer 8

multipy the ppm difference by the strength of the nmr magnet

ppm x mhz will give the units in hz

Question 9

if the signals arent symmetric what do we not find

Answer 9

we dont find the cc between them bc theyre not coupled together,, theyre 2 different signals

Question 10

see the signal then what

Answer 10

draw the splitting tree
then figure out what split system it is by looking what things overlap etccc

Question 11

room temp : averaged peaks,, due to what

Answer 11

ring flips: axial and equitoril swap

bond rotations

Question 12

cold temp : more peaks

Answer 12

no morw averaging, ring flips and bond rotations slow down

Question 13

finding coupling constants between multiplet peaks

Answer 13

• draw tree diagram briefly
• follow the tree diagram peaks and look at the corresponding actul multiplet peaks to find J vlues.
• look at the first split and follow it down both sides,, following the peaks that correspond to eachother and find the J value that way.

from the first split for J1
from the 2nd splits for J2 and for the last splits for J3 etc!!1

Question 14

cyclohexane and finding whether we’re looking at a multiplet for a H that is axial or equitorial

Answer 14

1H : axial oor equiitorial.

multiplet has 15Hz J, 14.5 Hz J and a 4Hz, J.

u have 2 big J’s (2J and axial axial)
1 small J (axial equitorial)

Question 15

big j values are due to

Answer 15

close proximity: bonds between the 2 things

being both axial // being 180 to eachother.