I am having some unusual 13C spectra for some compounds containing fused aromatic rings (all of them have about 22 carbons and one iodine). Some of them contain 2 to 3 methoxy substituents in one of the aromatic rings. Proton spectra looks normal and 13C spectra looks normal except for the methoxy carbon. It is split by about 1 Hz that disappears when the acquisition time is shorter or changed to a lower field strength.
I also have some spiro compounds where about 4 carbons (probably the ones in the 6-membered spiro ring containing alpha, gamma-unsaturated ketone) come like a hump next to really sharp signals for the same compound.
I am wondering if this is just a relaxation issue. Has anyone has seen like this or is it a machine problem.
-Gopal
Dr. Gopal Subramaniam (718-997-4123)
Department of Chemistry & Biochemistry
Queens College - CUNY
Flushing, NY 11367
Received on Wed Dec 11 2013 - 08:56:26 MST