Hello, I am the first time confronted with a 13C-NMR, in which a coupling between the 13C and 31-P cores takes place.
I am very unsure about the signal assignment in the molecule present in the appendix. I have assigned the signals so that the coupling becomes smaller at a greater distance from the 31P core.

My "Assignment":

13C NMR (101 MHz, CDCl3): δ (ppm) = 232.64 (d, J = 25.2 Hz, C (14.15)), 138.32 (d, J = 40.3 Hz, C (8)), 133.07 (i.e. , J = 9.9Hz, C (9.13)), 129.59 (C (10.12)), 128.23 (d, J = 8.9Hz, 3.4)), 87.57 (C (2.5)), 80.98 (C (1)), -3.10 (C (6.7)).

However, I 'm very unsure about the assignment of the 13C signals of the cyclopentadienyl ring.
I would like to understand the correct assignment correctly.

I am very grateful for any help

best regards

Sonja

In my experience with linear phosphonates (no metal ion was present), the three-bond coupling constants are often larger than the two-bond coupling constants.  I don't know enough about phosphines or the cyclopentadienyl system to have any expectation one way or another.

Edited October 23, 20178 yr by BabcockHall