Multi-centre and molecular weight

I might do this wrong. But I can not get the correct Mr when adding a position variable bond or multi-centre.


The simple bromobenzene in the picture get one hydrogen extra. It looks as Marwin still count the hydrogen at the substitution position of the phenyl ring.


Or do I not understand how to use the program?





LarsT

I would suggest to use multicentre for coordinative bonds (like ferrocene), or for Markush structure, because it currently does not modify the number of hydrogens. I understand, that bromobensene is just for illustration here, as the all positions mean the same molecule.





We need o consider this issue and will get back to you soon.

Thank you for reporting this problem. We discussed the situation. The number of hydrogens on a certain atom cannot be determined correctly, because the ligand is connected to only one of the atoms, but its position is uncertain. However, in this special case, the molecular weight and formula could be calculated properly. We will improve those calculations to consider the presence of multicenter covalent bonds.

Used the bromobenzene only to easy the the extra hydrogen in the formula.


You see where this originates from?


Especially when drawing metabolites there is an uncertainty where the substituent is located. Like a hydroxylgroup.


It is is necessary to draw the molecule and get a correct Mr even if we do not know exactly where the substituent is located.


Tried to use the Marcush formula, but that is intended to use in writing patents.





I guess you will need a different defined bond.


The Mr would be correct if it was a coordination type of bond and not as in this case a covalent bond.





LarsT

You will not be able to calculate molweight or formula for most of the Markush structures, because they usually contains variable atom types, R-groups, and so on. A Markush structure usually represents a set of various molecules, so you have no specific molweight.





However, you can enumerate the individual molecules of a Markush structure, or search withing the Markush structure without enumeration.





Have you seen Markush features integrated into Instant JChem?