Define the relevant bond lengths of interest (the MoC and CO bonds) and apply some constraints

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Click on the ADD3D button on the top left of the sketcher. A pop-up window will appear. Click on the Mo then the C atom: they will be selected and you will notice the pop-up dialogue updates to reflect what is selected, i.e. you can now click on Define next to Distance. Now that this bond length has been defined it will be monitored during the ConQuest search of the Cambridge Structural Database.

•	Define the CO bond in the same way, i.e. by selecting first the C atom then the O atom then by clicking Define: next to Distance.

•	Once you have defined both bond lengths, you will notice they are both recorded in the top right of the sketcher window.

 

•	Hit the Done button to close the Geometric Parameters window.

•	We now need to restrict the cyclicity of all three atoms to specify that they do not belong to cyclic systems (e.g. cyclic ligands in the case of the CO) or organometallic networks.

•	Go to the top level Atoms menu option and select Cyclicity from the resultant pull-down menu. We require the Mo, C and O atoms to be Acyclic, so select this from the menu. Now click on the Mo, C and O atoms, then hit the Done button to complete the definition.

 

•	We now need to restrict the coordination numbers of the C and O atoms to ensure they are not bonded to any other atoms.

•	Right-click on the C atom and pick Number of Bonded Atoms, then 2 from the resultant pull-down menus. This means that ConQuest will consider CSD entries where only the Mo and O atoms are bonded to the carbon.

•	Now right-click on the O atom, but this time pick 1 from the Number of Bonded Atoms pull-down menu. This means that the O atom will form no bonds other than to the C atom.

•	We also need to specify that the Mo atom is 6-coordinate. This is done in the same way as described above for C and O, i.e. right-click on the Mo atom then pick Number of Bonded Atoms then 6 from the resultant pull-down menus.