Rotating fragment

Hi, I’m trying to make a porphyrin molecule with fragments that must be rotated 90 degrees. I can’t figure out how to select the fragment and rotate it. I’ve tried selecting it, right click and rotate but it shifts the whole molecule instead. Any tips roasting a fragment without rotating the whole molecule? Thanks!

It would help to know what version you’re using, but I suspect you want to change the bond dihedral.

The easiest way to do this is with the bond-centric manipulate tool:

Click on a bond with the tool, then grab one of the “neighboring” atoms and start to spin.

You can also go through the list of torsions in the Torsion Property window, find the appropriate torsion (the atoms will be selected) and set the dihedral angle to 90.0°