Macs in Chemistry

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A Review of MNova NMR (MestReNova 10.0.1 for Mac, 2015)

MNova NMR is Mestrelab Research’s NMR analysis program that can be used to quickly view, process and analyse both 1D and 2D spectra, as well as to easily produce publication quality assignments and images. The software can be downloaded from Mestrelab’s website (45-day free trial licences are available).

The default view resembles Powerpoint, making it very easy to start using. Each spectrum has its own page (similar to a Powerpoint slide), with the currently selected data set filling the majority of the window. The pages list can be used to browse different spectra within one document and 1D and 2D spectra can be included in the same document.

The main bar above the display contains the tools for processing and analysing spectrum, as well as tools for drawing structures onto the spectra. Hovering over each button shows its function, and each button has shortcuts associated with them (e.g. increasing and decreasing intensity is also completed by mouse wheel). Pressing some shortcut keys multiple times cycles through the possible functions (pressing Z multiple times changes between horizontal, vertical and box zoom). The left-hand bar contains the tools for 2D and stacked spectra. The pages list and toolbars can be changed to floating menus if you would prefer to have more space in the window for the selected data set.

Picture1

Getting started is very simple. Raw data files can be added via File > Open, or by simply dragging and dropping the .fid or .ser file of the raw data into the MNova window. Muliple data files can be added at once and each will be a separate page within the document. MNova will automatically process and Fourier transform the data according to the default processing parameters (these can be changed via Processing > Processing parameters). The top bar contains buttons for automatic phase correction and baseline correction. These can be set to be performed automatically via Edit > Preferences > NMR. The automatic phase correction isn’t perfect and can be corrected using the manual correction button (or shift P). Clicking the Reference button (or pressing L) allows referencing of the spectrum using the solvent peak. Getting from the raw data FID to a readable spectrum takes only a few seconds.

Manual integration and pick picking can be quickly completed by clicking the relevant button or pressing the correct hotkey, followed by clicking and dragging over the correct area in the main viewer. Elements of the spectra, such as peak shifts and integration values, can be moved around by simply clicking on them and dragging them to the desired position. Right clicking on an element allows editing, such as changing the integral value or the peak type (e.g. compound, impurity or solvent – distinguished by the colour of the label). Right clicking on the spectrum background and selecting Properties opens up a menu to change the appearance of the spectrum for everything from the size of the text to the thickness of lines. Properties can be set as default or saved, so all future spectra opened will have the same format. The whole process of manual analysis is intuitive and almost everything is customisable. Making spectra takes no time at all.

The automatic analysis and assignment function is very good for small molecules. The above screenshot of MNova took only a few minutes to make. Drawing the structure was the most time-consuming part of the analysis. The drawing tool is quite clunky, so it may be easier to just paste structures from Chemdraw. Automatic multiplet analysis followed by automatic peak assignment took only a minute or two. It’s worth checking through the automatic assignments manually, I’ve noticed it finding 13C peaks in the background noise fairly regularly. There are plenty of tools in MNova that can be used to manually edit the automatic assignments for complex or overlapping peaks. MNova can report the multiplet analysis in journal or patent format for you to copy into your experimental. MNova struggles with automatic assignment in larger molecules, where a fair amount of manual correction will be required.

Processing 2D spectra in MNova is also very intuitive. To add a 1D spectrum to the axis of a 2D, you just drag and drop one from the pages list in the document to the desired axis. Any assignments made on the in 1D spectrum appear in the 2D to help with assignment on the other axis. To stack or overlay spectra, just select the spectra in the pages list, and click the relevant button. Use the right clicking followed by Properties allows full customisation of the overlaid or stacked spectra.

Picture2

Making publication quality images is very easy in MNova. Everything is customisable to fit the desired format. Annotations, structures, lines and arrows can be added, as well as tables for acquisition parameters, peaks, integrals etc. When you’ve got a lot of spectra that need to be processed in the same way it’s possible to create a template of the design and open all your spectra using it. Spectra can be exported as a variety of file types with control over the resolution and vector graphics. It’s possible to copy spectra directly from the pages list and paste into other documents as a pdf.

A mentioned before there are a few problems with MNova. Drawing structures is quick a slow process when compared to chemical drawing applications such as Chemdraw. Whilst changing between different spectra within one document is very quick, switching between different documents is not as simple as it could be. I’ve not been able to find a method to colour certain parts of the spectrum to highlight peaks and ended up having to export the spectrum as an image and later processing using a separate graphics processing application.

MNova’s main rival is Bruker’s TopSpin. MNova is considerably easier to start using, it’s interface is much more intuitive for the average chemist than TopSpin’s command line interface. MNova looks much nicer than TopSpin and I’ve found it much easier to produce nice looking spectra. For more advanced NMR experiments TopSpin may be a more powerful application, but for general organic synthesis MNova is a much better option.

Last Updated 6 June 2014