Dear all,
I was working on computationally new drug discovery through QSAR. but after optimizing an antimalarial drug named artemisinin in ORCA, TurboMole, and Gaussian using DFT; B3lyp/def2-TZVP I got the optimized structure which torsion angles differ by 10-20 degree from experimental x-ray crystallographic data. I don't know it is acceptable or not. if not then what should I do? should I try with other functionals or basis set?
martin sir the source of crystal structure is CSD (like; QNGHSU, QNGHSU02, 03, 10, 11, WIMMEK)
Hello,
Sometimes these distortions in the computed torsion angles of the structure in relation to the experimental ones occur due to the wrong choice of the basis set.
The server below could help you to select the most appropriate basis set according to the atoms of your molecules.
https://www.basissetexchange.org/
In the article below published by my group, you can find a satisfactory correlation between the experimental and computational results for torsion angles obtained for flavonoids:
Article Analysis of Conformational, Structural, Magnetic, and Electr...
Thank you Kauê Costa sir for your valuable responses. I will try the method.
But sir in my case there is already reported papers those clams have got best optimised structure by using same basis set and functionals that I am using.
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