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sp3 count [message #1369]

Tue, 10 August 2021 00:22

mvamos
Messages: 24
Registered: January 2015
Location: US

Junior Member

I'm curious about the sp3-Atoms count from the Calculate Properties->Atom Counts section. Generally for fraction sp3 calculations, it's # of sp3 carbon atoms divided by total carbon atoms. The sp3-Atoms count from DW seems to over-count, just not sure what else it's including.

In the attached photo, for the compound I count 3 sp3 carbon atoms, but DW returns 5.

Feature request: it might be more useful for users if it calculated the fraction of sp3 carbons instead of just # of sp3 atoms, as it's common to report the fraction for druglike compounds.
https://pubs.acs.org/doi/10.1021/jm901241e

Thanks and keep up the good work!

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Re: sp3 count [message #1370 is a reply to message #1369]

Tue, 10 August 2021 22:24

nbehrnd
Messages: 233
Registered: June 2019

Senior Member

Dear mvamos,

based on the SMILES string generated by DW for this very structure, yet submitted to RDKit (2020.09.4) suggests different programs assign sp3-hybridization differently. In the case of RDKit, including fluorine [sic!], a total of 6.

Norwid

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Re: sp3 count [message #1380 is a reply to message #1370]

Thu, 19 August 2021 21:23

thomas
Messages: 730
Registered: June 2014

Senior Member

Dear Mvamos,

DataWarrior considers C,N,O,P,S as potential sp3 atoms. In your case the 2 oxygen atoms are considered to be sp3 in addition to the 3 obvious carbon atoms. I agree that an ether-oxygen doesn't contribute much to the 3D-shape of a molecule, but the same is true for an (sp3) methyl group. It is a formal number. sp3 fraction in carbon atoms is simple and I will add it...

Thomas

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Re: sp3 count [message #1381 is a reply to message #1369]

Fri, 20 August 2021 12:05

thomas
Messages: 730
Registered: June 2014

Senior Member

I just deployed an update with 'sp3-Carbon Fraction', which is the count of sp3 carbons devided by all carbons as proposed in the 'Escape from flatland' paper.

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