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*   Search Constraints
You can restrict all search types, except the name search, by a set of constraints. The dialog boxes for each of these searches contain an option for activating constraints and a button for editing search constraints. When you click Edit, the Search Constraints dialog box opens for setting specific criteria to search selected libraries for matches. See Search Constraints dialog box with default settings.
Four constraint types are available: Molecular Mass range, Number of Atoms range, Allowed Elements, and Good-Bad List. Searches conducted with activated constraints can be time consuming because each library entry is examined to find those that match the criteria you have set. The search constraints are especially useful when you have large libraries and want to retrieve search results that are of interest for your specific problem.
Use the Good List (required substructures) when you want to focus your search results on the particular compound classes you are most interested in. The Bad List (forbidden substructures) eliminates from a result list all structures containing unwanted functional groups. For example, you can use the Good-Bad List in a search of acids with a specific molecular formula, or you can search for spectra similar to an unknown, with the requirement that ketones may not appear in the result list.
The following example shows a Search Constraints dialog box with C, N, and O as allowed elements. The Good-Bad list is set for esters as a required (good) functional group and for naphthalene as a forbidden (bad) functional group.
Search Constraints example
Search Constraints dialog box with default settings
Specifies the required (good) and forbidden (bad) substructures to used to refine your search. Each check box can be in one of three states: Required, Ignored, or Forbidden.
Displays the check box symbols used to indicate Required, Ignored, or Forbidden substructures in the Good-Bad list.

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Related Topics:
  Spectral Tree Search
  Spectrum Search
  (Sub)Structure Search
  Name Search
  Formula Search
  Molecular Mass Search
  ID Number Search
  CAS Number Search
  Fragmentation Data Search
  Retention Time Search
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