electron-flow arrows and multicenter attachment points

Consider this drawing:

<?xml version="1.0"?>

<cml version="ChemAxon file format v5.10.0, generated by v5.11.5">

<MDocument>

  <MChemicalStruct>

    <molecule molID="m1">

      <atomArray atomID="a1 a2 a3 a4 a5 a6 a7" elementType="Pd C C X Cl Cl O" sgroupRef="0 sg1 sg1 0 0 0 0" x2="-3.8499999046325684 -2.117500066757202 -2.117500066757202 -2.117500066757202 -5.301925828668946 -5.301925828668946 0.9625000059604645" y2="0.43312498927116394 1.2512500286102295 -0.28874997138977054 0.4812500286102295 1.8850509133075415 -1.0188009347652136 2.9356253147125244"/>

      <bondArray>

        <bond atomRefs2="a2 a3" order="2"/>

        <bond atomRefs2="a4 a1" convention="cxn:coord"/>

        <bond atomRefs2="a1 a5" order="1"/>

        <bond atomRefs2="a1 a6" order="1"/>

      </bondArray>

      <molecule id="sg1" role="MulticenterSgroup" molID="m2" atomRefs="a2 a3" center="a4"/>

    </molecule>

  </MChemicalStruct>

</MDocument>

</cml>

1. I cannot draw an electron-flow arrow from O to either an O...C incipient bond or directly to a C.


2. I can start an electron-flow arrow at the C=C π bond (although I have to be careful to avoid the fictional atom between the two C atoms), but I cannot get it to point to anything.  I want to be able to point it to a C...Pd incipient bond.  


3. I can start an electron-flow arrow at Pd, but I cannot get it to point to either C or to a C...Pd incipient bond.  


4. I can start an electron-flow arrow at the coordinate bond between C=C and Pd, and I can place the end of that arrow at either Pd or at the multicenter attachment point, but I cannot point the end of that arrow to between Pd and one of the C atoms.  I do not need this behavior if I can get behavior (2) above.  

See picture (made in ChemDraw) for the kinds of pictures I would like to be able to draw in MarvinSketch.

No comments on this feature/bugfix request?

Sorry for the late answer.

We discussed it with the team. And it looks like, we do not allow to draw an electronflow from/to the atom of a multicenter. We plan to fix this in the version 6.1.

Best Regards,

Efi

Great, thanks!

It looks like this bug has been fixed in version 6.1.0 -- thanks! --  but I did not see it in the History of Changes document. You  may want to add it there.

Thank you very much, we will do it!

Hi,

Sorry to bear bad news, but there is still a minor problem with this feature.  When I have a structure (A=B)->M, and I try to draw an electron-flow arrow from the coordinate bond to a B-M bond, the head of the arrow ends up close to atom B (see figure), but it should either be close to the metal atom M, or halfway between B and M.

-- Bob

Here's another problem: When I try to draw an electron-flow arrow from the A=B bond itself (not the multicenter attachment point associated with it) to the B-M bond, as shown in the attached picture, when I release the mouse, the electron-flow arrow is not retained.

Dear Bob,

thank you for reporting this to us. Regarding your latest remark, it is a known bug, which we plan to fix in version 6.3 (next spring).

Best regards,

Dóra