Zusammen

In this eighth installment of a sixty-four part series on free chemistry databases and services, we take a look at nmrdb.org from the creators of mylims.org.

The nmrdb.org service consists of four basic services in the area of proton NMR spectroscopy:

• NMR Resurrector Given a set of peaks, reported as in standard journal format, reconstruct the spectrum.
• NMR Assigner Semi-automatic peak assignment and reporting.
• NMR Predictor Draw a structure then view its predicted spectrum.
• NMR Search Search for specific resonances.

The service is very easy to navigate and supplies default structures and spectra so that you can quickly see what there is to offer. For example, this set of peaks taken directly from a paper's supplementary material:

7.31 (d, J = 8.8 Hz, 2 H), 7.26 (dd, J1 = 7.8 Hz, J2 = 1.8 Hz, 1 H), 7.11 (ddd, J1 = 8.8 Hz, J2 = 7.2 Hz, J3 = 1.6 Hz, 1 H), 6.91-6.87 (m, 2 H), 6.73-6.63 (m, 2 H), 4.31 (d, J = 3.3 Hz, 2 H), 4.17 (br s, 1 H), 3.81 (s, 3 H), 1.41 (s, 9 H);

yielded the spectrum below nearly instantaneously:

I had difficulties getting NMR Assigner to work properly. Using the sample data provided on the page, various attempts to create a peak list in "ACS format" resulted in blank text, only partial recognition of the spectrum (Safari 3/Mac), or apparently no response at all (Firefox Ubuntu).

I had a bit more luck with NMR Predictor. Using the structure of N-[(4-Methoxyphenyl)methyl]-2-(1,1-dimethylethyl)aniline (exported as a molfile with ChemWriter), I was able to obtain a spectrum that looked reasonable enough, but which on closer comparison to the published spectral data showed significant differences. Others have noted differences between expected spectra and measured spectra when using nmrdb.org.

Unfortunately, at the time of this writing the NMR Search feature was not working, instead downloading incompletely when selected.

nmrdb.org is a remarkable service that has a lot of potential. While it might not be ready to handle certain tasks reliably, there's enough there have a look around.

Kudos

• Easy to navigate.
• Convenient combination of chemical structures and spectra in a single tool.
• Many options for export in a variety of raster image formats.
• Good use of default data makes for quick evaluation of various services.

Ideas for Improvement

• Export spectra as JCAMP-DX from applet.
• Load molfiles or spectra from URLs would prevent needless disk saves.
• Eliminate frames for upload user interface elements.