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STRUCTURALLY AWARE APPROACH TO THE INTERPRETATION OF VIBRATIONAL SPECTRA

STRUCTURALLY AWARE APPROACH TO THE INTERPRETATION OF VIBRATIONAL SPECTRA. Eugene Karpushkin , Yury Zhukov, Andrey Bogomolov. www.acdlabs.com. What makes “manual” IR interpretation challenging?. IR spectral signals are “volatile” due to overlap and influence of chemical environment.

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STRUCTURALLY AWARE APPROACH TO THE INTERPRETATION OF VIBRATIONAL SPECTRA

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  1. STRUCTURALLY AWARE APPROACH TO THE INTERPRETATIONOF VIBRATIONAL SPECTRA Eugene Karpushkin, Yury Zhukov, Andrey Bogomolov www.acdlabs.com

  2. What makes “manual” IR interpretation challenging? • IR spectral signals are “volatile” due to overlap and influence of chemical environment • Many different factors to take into account simultaneously • Correlation tables and charts take expert’s time and efforts • Structurally aware software required!

  3. ACD/Labs is a structurally aware software Chemical databases Phys-chem property prediction Spectra Drawn Structure Chromatograms NMR spectral prediction Systematic naming

  4. What does structural awareness mean? • Easy drawing of chemical structures • 2D-cleaning/3D-optimization • Attaching molecule to a spectrum • Fragment structure analysis • Peak-to-fragment assignment • Structure/substructure DB search • Reporting with structures

  5. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Spectrum Interpretation Chart Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  6. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Searching Database: Example 1 Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  7. Raw Spectrum Peak Table Hit List Possible Fragments Candidate fragments: CH3 – 9 hits; NO2 – 7 hits; aromatics - 4 hits Confirmed Structure Hypothetic Structures Report Searching Database: Example 2 Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  8. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Peak Analysis Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  9. Knowledge Base: classes • alkanes, alkenes, alkynes, allenes, alicyclic compounds • alcohols, ethers, aldehydes, ketones, non-carbon acids, peroxy compounds, halogen compounds • carboxylic acids, halogenides, anhydrides, carbonates, carboxylates, esters • aromatic compounds, heterocycles • amides, amines, imides, imines, nitrocompounds, other N compounds • B, P, S, Se, Si compounds • inorganic ions

  10. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Knowledge Base Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  11. “Atom” descriptors: * A [C,H] AnyC SatC Aryl Hal [N,O,S] Bond descriptors: Ar D Rn Ch ACD/Labs Fragment Object

  12. Powerful means selective

  13. Example set: 15 chloroanhydrides + 19 aldehydes = 34 compounds * 825 wavelengths PCA for Fragment Formulation

  14. PCA for Fragment Formulation:Captured Variance

  15. PCA for Fragment Formulation: Scores Plot – Structure Classes

  16. PCA for Fragment Formulation: Scores Plot – Structure Classes

  17. PCA for Fragment Formulation: Scores Plot – Structure Classes

  18. 1802 cm-1 1742 cm-1 1718 cm-1 PCA for Fragment Formulation:Bi-Plot Reveals Spectral Features

  19. PCA for Fragment Formulation

  20. Knowledge Base is Interactive

  21. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Structure Verification Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  22. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Successful Verification is… Failed One Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  23. Raw Spectrum Peak Table Hit List Possible Fragments Confirmed Structure Hypothetic Structures Report Assignment and Reporting Peak Analysis Knowledge Base DB Search Find Repeating Construct Compare Verify Assign More Data

  24. Conclusions 1. Full qualitative analysis spectral interpretation tools in the same product interface 2. Authentic Fragment Object provides almost unlimited flexibility in specifying group environment 3. Advanced tool for fragmental analysis of molecules 4. Knowledge Base with about 2400 highly selective fragments 5. Facilitated IR spectral interpretation and automated structure verification

  25. Acknowledgements • Yury Zhukov • Alexey Pastutsan Thank you!!!

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