how to draw Pi-Allyl with the right molecular weight ?

Hello all,

I'am interested in drawing Fe-Pi-allyl with a dative bond between Fe and the allyl group. However, when I draw it with the aromatic bonds, the corresponding molecular weight is not correct (M=95.9 g/mol instead of M=96.9 g/mol). It seems that the proton connected to the center carbon is missing.

How can I draw it properly with the right weight ?

Regards

Vincent

Hi Vincent !

To draw the structure you should do as follows :

1. Add a multi-center group to the allyl molecule with selecting it and Structure > Add > Multicenter.

2. To add  dashed bonds between the atoms,  use "Aromatic Bonds".

3. Add the Fe atom a with dative bond to the center C with using "Hashed bond".

4. To add the H properly, attach the H to the center C. 

With that you should get the correct molecular weight.

Daniel

The key issue here: drawing the H explicitly.

Please try with the following MRV file: (you can copy it to the Edit>Source directly than choose: File>"Import As")

 

<?xml version="1.0"?>
<cml version="ChemAxon file format v5.10.0, generated by v5.10.0">
<MDocument>
  <MChemicalStruct>
    <molecule molID="m1">
      <atomArray atomID="a1 a2 a3 a4 a5 a6 a7" elementType="C C C X H X Fe" sgroupRef="sg2 sg2 sg2 0 sg2 0 0" x2="-6.324999809265137 -4.991320687437101 -3.6576415656090653 -4.991320687437101 -3.6576415656090653 -4.6579009069800925 -5.170000076293945" y2="3.4100000858306885 2.6400000858306885 3.4100000858306885 3.153333419164022 1.8700000858306884 2.832500085830689 0.7149999737739563"/>
      <bondArray>
        <bond atomRefs2="a1 a2" order="A"/>
        <bond atomRefs2="a2 a3" order="A"/>
        <bond atomRefs2="a2 a5" order="1"/>
        <bond atomRefs2="a4 a7" convention="cxn:coord"/>
      </bondArray>
      <molecule id="sg1" role="MulticenterSgroup" molID="m2" atomRefs="a1 a2 a3" center="a4"/>
      <molecule id="sg2" role="MulticenterSgroup" molID="m3" atomRefs="a1 a2 a3 a5" center="a6"/>
    </molecule>
  </MChemicalStruct>
</MDocument>
</cml>

Hello,

Both solutions are not correct : when an elemental analysis is made on the corresponding structure, the formula is not correct. It should be C3H5Fe instead of C3H4Fe. The added Hydrogen is not considered.

Do you have any idea how to solve this problem ?

Thanks a lot,

Vincent

Sorry, the corresponding picture is the one below.

Best regards,

Vincent

Hi Vincent !

The problem that you mentioned was a bug before, but has been fixed for Marvin 5.10.0. So if you use that  version,

you will get the correct result. Download that from

http://www.chemaxon.com/download/marvin/for-end-users/

Also note that you have to connect the Fe atom to the coordinative multi-center, not to the central C.

If you do that, the asterisk from the Elemental Analysis window will disappear.

 

Daniel

 

Hello Daniel,

thank you for your quick answer.
Regards,

Vincent