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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 INTERPRETATIONOF 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 • Many different factors to take into account simultaneously • Correlation tables and charts take expert’s time and efforts • Structurally aware software required!
ACD/Labs is a structurally aware software Chemical databases Phys-chem property prediction Spectra Drawn Structure Chromatograms NMR spectral prediction Systematic naming
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
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
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
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
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
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
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
“Atom” descriptors: * A [C,H] AnyC SatC Aryl Hal [N,O,S] Bond descriptors: Ar D Rn Ch ACD/Labs Fragment Object
Example set: 15 chloroanhydrides + 19 aldehydes = 34 compounds * 825 wavelengths PCA for Fragment Formulation
PCA for Fragment Formulation: Scores Plot – Structure Classes
PCA for Fragment Formulation: Scores Plot – Structure Classes
PCA for Fragment Formulation: Scores Plot – Structure Classes
1802 cm-1 1742 cm-1 1718 cm-1 PCA for Fragment Formulation:Bi-Plot Reveals Spectral Features
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
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
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
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
Acknowledgements • Yury Zhukov • Alexey Pastutsan Thank you!!!