Query: total number of hydrogens

A silly question, target is "C", query is "[#6H1]", jchem considers this a match (version 5.1.4). If "H1" means the carbon has total number of 1 hydrogen, why this is a match? Thanks.

This depends on the input format of the query, because different formats have different semantics for the H property. See:





http://www.chemaxon.com/jchem/doc/user/query_appendix.html


(Especially section "H query property".)





An alternative solution for the problem could be a search option. Dou you think that would be easier to handle / interpret?





(At least the default behaviour could be consistent.)








Best regards,





Szabolcs

Thanks, I was actually using MRV as the query format, not smarts, so that explains the behavior.





However, in document http://www.chemaxon.com/jchem/doc/user/query_features.html,


The note that links to "H-query" was placed with "h<n>" not "H<n>". You need to update the document to put the "*" at the end of the "H<n>" line in the list before Table 4.





That leads to the next question about "h<n>". I am using MRV/MOL format for the query "[#6;h0]". If I say "h0" (means no implicit hydrogen), it matches target "C". I am confused because I thought "[#6;h4]" should have the match instead, does not "C" implies 4 implicit H?

I am also confused by "D". For target "C=C", I thought the carbon has only 1 explicit connection, however the query with "D1" does not match, but "D3" matches.

Well spotted the footnote! We will fix that.





Regarding the behaviour of h and D properties: I agree, it should work as you described, and it does for me on these example interfaces:





http://www.chemaxon.com/jchem/examples/sss/index.jsp





http://www.chemaxon.com/jchem/examples/db_search/index.jsp





(In the latter, C and C=C are the last records of table editexample.)











The behaviour at your environment looks as if you had an "Add explicit Hydrogen" standardization on the table.

Thanks! Yes, I added explicit hydrogen to the target in a step and did not realize that cause the problem.