I was recently denied a scientific position based on the fact that I did not have expertise in solid state NMR. I have expertise in liquid NMR but my concern is that what is the difference in both techniques apart from sample's physical state.
I would like to know specifically the practical perspective of the Solid State NMR.
It's not surprising that the position was looking for someone with solid-state NMR experience since it is significantly different from standard solution-state NMR techniques. Someone even with many years of solution state nmr experience can't usually do solid-state without assistance. I will list some of differences below:
1. Probes: Solid-state NMR uses different probes, capable of handling higher powers and not all labs have the facilities. Hence labs that do have the capacity are usually focused on solid-state NMR work for the most part.
2. Sample prep: Solid state NMR is done using 'rotors' of various outer diameters (1 mm - 7 mm usually), usually made of zirconia. The solid samples are packed inside these rotors. It is a bit more involved and time-consuming than solution-state sample prep.
3. Experiments: The NMR-relevant parameters of a solid sample are significantly different from that of a liquid sample. Things are usually a lot simpler in the liquid state since parameters such as chemical shift anisotropy (CSA) and dipolar coupling are averaged out due to random motion. CSA and dipolar coupling dominate in solid-state, so we have to use completely different experiments, which are generally a lot more complex than solution state stuff, and require a bit more theoretical knowledge on the user's part. The relaxation behavior is also different in the solid state. Things get even more complicated when dealing with quadrupoles, and certain groups specialize in that area. Hence solid-state NMR is a field in itself, separate from solution-state NMR, and is generally considered more difficult. Which is why it is not as routine as solution state nmr.
4. Major advantage: Provides more information on the spatial orientation of the molecules since the information is not lost to random motion.
Disadvantage: Signals are generally much broader than solution-state nmr.
This is only scratching the surface.
Another important point is that someone with no solid-state NMR experience can easily destroy the probe if not supervised, since the experimental set-up involves a lot of playing around with power levels of the pulses. Missetting these can fry the probe. This is not something most solution state NMR users have to deal with usually.
Bottomline: Solid-state NMR is a lot more involved and less trivial than most standard solution state techniques.
Dear Yasir, the response you have received from Dr Majumdar and others are to the point but by necessity brief. If you seriously wish to learn more about the theory and practice of solid state I suggest you should purchase some of the more recent introductory textbooks on the field. May I suggest "Solid-State NMR: Basic Principles and Practice" Hardcover – 10 Jun 2012
by David C Apperley (Author), Robin K Harris (Author), Paul Hodgkinson (Author).
Somewhat expensive but authorative - paperback copies are available from for example Amazon,uk and other book stores on the internet.
It pays to spend time on assimilating new NMR techniques!
Best regards
Sture F.
One can use ss-NMR for probing the surface acidity/ basicity. check out the review for further reading. Chem. Rev. 2017, 117, 12475-12531 , DOI: 10.1021/acs.chemrev.7b00289
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