Generalities

Unlike signal in 1d where signal can include range and include multiplet overlaping resonances, 2D signals correlate a pair of spins. Chemical shifts are not given, instead the labels of the spins are directly provided. (This is to encode directly the data found in tables in articles).

Using Level=2, ambiguities can be coded using “(a,b)” to express that the labels is either a or b.

The attributes list the caracteristics of signals found in 2D spectra. List of signal attributes (“D spectra)

Note that they should apear in this order!

I= Intensity (float)

E= Volume (crude integrals) (float)

Ja= Active scalar coupling (string)

J1= F1 passive coupling (string)

J2= F2 passive coupling (string)

W1= F1 signal width (float)

W2= F2 signal width (float)

Examples attributes of 2D signal

Examples of a correlation between spins a and b (see below for description of the attributes)…

… Only indicating the presence of the cross peak:

a/b

… Providing the intensity of the signal:

a/b, I=133.6

… Including the extracted coupling constants (from a high-resolution DQF-COSY spectrum):

H4eq/H6eq, Ja=2.2, J1= 3.0(H8ax), 3.2(H5e1), 3.3(H5ax), 12.75(H4ax), J2=4.0 (H8ax), 4.5(H10ax), 12.09(H6ax) [see paper...]

If the signal is not assigned, the chemical shift replaces the labels

1.5402/1.4423 I=133.6

Attributes

Signal intensity

I: This provides the signal intensity

Signal volume

E: This provides the signal volume

Active scalar coupling

Ja: Couplings in Hz with two digits after the period separated by the separator. For a correlation between i & j (F1 first):

i/j, Ja=9.30

means the active coupling (between i & j ) is 9.3 Hz

Passive scalar coupling

J1/J2: For a correlation between i & j :

i/j, J1=9.30
i/j, J1=9.30, 4.80`

means: i, the spin in the F1 dimension, is coupled to one or more spin (not the active coupling j) with J=9.3 and 4.8 Hz

For a correlation between i & j :

i/j, J1=9.30(b)
i/j, J1=9.30(b), 4.80(a)

means:J(i,b)=9.30 Hz J(i,a)=4.80 Hz(in the F1 dimension).

See also, tag where assigned coupling should be compiled.

Signal width

W1/W2: Signal widht in F1/F2 in Hz

W1=6.0
W2=1.2