Re: [OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-08-01 Thread David van der Spoel
On 2021-07-27 12:33, David van der Spoel wrote: On 2021-07-27 10:39, Noel O'Boyle wrote: OBBond.IsAromatic(). See the docs. Thanks for the suggestion. That works fine for aromatic rings, but not for COO- or NO2 groups. Is there another flag to test, I cannot find anything in the

Re: [OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-07-27 Thread David van der Spoel
On 2021-07-27 10:39, Noel O'Boyle wrote: OBBond.IsAromatic(). See the docs. Thanks for the suggestion. That works fine for aromatic rings, but not for COO- or NO2 groups. Is there another flag to test, I cannot find anything in the documentation. An OBbond.IsResonant() would be great... I

Re: [OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-07-27 Thread Noel O'Boyle
OBBond.IsAromatic(). See the docs. I would not use Smarts patterns to type atoms or bonds, but rather do it in code. The former is just too error prone, slow and less readable. On Tue, 27 Jul 2021, 07:18 David van der Spoel, wrote: > On 2021-07-27 07:51, Noel O'Boyle wrote: > > Is there a

Re: [OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-07-27 Thread David van der Spoel
On 2021-07-27 07:51, Noel O'Boyle wrote: Is there a particular problem you are trying to solve where underlying kekule representation is causing a problem? Yes, I am extracting bond orders from OB and they go into my force field code. Different bond orders means different bond properties

Re: [OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-07-26 Thread David Koes
In my opinion, if the only fractional value will be 1.5 then non-integer bond orders aren't worth the pain of breaking compatibility since this state can be (and is, for rings) represented by setting the aromatic property of the bond. Perhaps we should provide additional, more nuanced

[OpenBabel-Devel] Non-integer bond orders for resonant groups

2021-07-26 Thread David van der Spoel
Hi, maybe this has been discussed earlier, but I would like to hear your opinion on implementing non-integer bond orders. For e.g. benzene the average CC bond order would be 1.5, and likewise for COO- groups or NOO groups. Quantum-chemically such resonant groups turn out to be symmetrical and