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RGroup Files


R Group Files is a selection under the main window File menu, with two sub-menu options: Load R Group, and Save R Group.  R groups are substructures of almost any level of complexity that can be added to a parent molecule  in a single step.  Use Load R Group to change to a new R-group structure in memory.  Use Save R Group to save the current structure on screen for future use as an R group.


Load R Group

When you select this option a standard File Open dialog will appear.  Select the file you want to use and it will become the current active R group structure.  You can check on the identity of the current R group at any time by placing the cursor on the R-group Speedbutton.  The currently active R-group will be displayed as part of the popup hint.  Several default R Groups are included with MSC Pro including methyl, acetyl, benzoyl, TMS, etc.  


Save R Group

To create a new R Group for future use, first draw a structure in the usual way.  Important:  the first atom added to this structure while drawing it will be defined as the attachment site for the new R group, so be careful to plan ahead.  If you are not sure which atom is first, click on Number Atoms under Edit to check.   Also note that aromatic rings and Nitro groups are not permitted in R groups.  However, you can add a cyclohexane ring, and then add three double bonds to it to create an aromatic structure, or use Valence to modify a N atom and add two oxygen atoms to it.   Those structures then can be used as part of an R Group.   After drawing the structure, click on R Group Files and then Save R Group....  Enter a name for the new R group and press Save.  The R Group will be saved with the default .RGF extension, and the screen will be cleared.


Updated information:

1. The restriction on using either aromatic rings or nitro groups in an R- group structure can be easily circumvented by using “Clean” before saving the structure as an R- group file. That will automatically convert the default resonance hybrid representation of benzene to the Kekulé form, and the NO2 group to an O=N=O structure.

2. In some cases, the default location displayed for saving an R-group file may be incorrect due to a bug in the program, causing the file to be saved within Program Files (x86) where it will not be found by MSC when you try to load it.

When you select “Save R Group …” the selected folder should be listed as “RGRP Files”. If it is not, then you will need to first navigate to the correct location before saving the file. The correct location for R Group files is:

C:\users\[username]\AppData\Roaming\QuadtechAssociates\MSCPro\RGRP Files.