Define geometric parameters

•	In order to analyse the 3D geometry of our 4-coordinate transition metal complexes we need to define some geometric parameters. The values of defined parameters can then be retrieved for each hit structure and analysed collectively.

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We will start by defining the angle between two unique ML2 planes. Return to the Build Queries pane and click on Edit next to the query you just submitted. This should take you back to the Draw window. Click on the ADD 3D button on the left of the Draw window then select one of the X atoms, then the TR, then the next X atom, and finish by hitting the Define button next to Plane in the Geometric Parameters window.

 

•	Repeat with the remaining two ligand atoms and the transition metal to define the second plane in the same way. PLN1 and PLN2 should now have appeared in the Defined Objects box in the Geometric Parameters window.

•	Click on both PLN1 and PLN2. This should allow you to define the angle between the two planes by clicking on the Define button next to Angle in the Geometric Parameters window.

 

•	We will now define the ML2 angles: four ‘cis’ ones and two ‘trans’ ones. Click on one of the X atoms, then the TR, then the next X atom, similarly to the previous angle between the plane definition, except this time hit the Define button next to Angle.

 

•	Now click the Options... button underneath Angle and specify that the angle must lie between 0 and 150o. This will restrict the ‘cis’ angles to less than 180 degrees, meaning that they must be ‘cis’ angles, not ‘trans’.

 

•	Click OK to close the Limits and Options window.

•	Define the other three ‘cis’ angles in the same way.

•	Finally, define the two ‘trans’ angles with no angle constraints, then click on Done in the Geometric parameters window.