Finding Physical Properties and Spectral Diagrams for a Known Chemistry Substance: Quick Tips for Chemistry 130

Library Guide: http://libguides.stanford.edu/chem130

Grace Baysinger [email protected] Swain Chemistry and Chemical Engineering Librarian What is a CAS Registry Number? ◦ It is a unique numeric identifier that has no chemical significance.

◦ Designates only one substance. A different CAS RN is assigned for charged, isotopically labeled, or stereoisomers of a substance.

◦ A CAS Registry Number can contain up to 10 digits, divided by hyphens into three parts. Example: 58- 08-2 is the CAS RN for caffeine.

◦ About 12,000 new substances are added to the CAS Registry each day. For more information, see: http://www.cas.org/expertise/cascontent/registry/regsys.html#q2

Using CAS Registry Numbers in Database Searches  CAS RNs are a quick way to search for a specific chemical substance in different chemistry databases.

 CAS RNs may not be present for all substances in a resource or may have the wrong CAS RN listed for a substance.

 If CAS RN search fails, try searching by chemical name or by molecular formula. ChemIDplus Advanced http://chem.sis.nlm.nih.gov/chemidplus/

Sample Search: Find CAS RN for Cyclohex-4-ene-cis- 1,2-dicarboxylic acid. Enter name without numbers and stereochemistry. ChemIDplus Advanced Results ChemIDplus Advanced Brief Record

Includes a CAS Registry Number Enter CAS RN in SDBS to Find Spectral Data SDBS Summary Search Results

Yes and No are used to indicate what kind of spectral data is present SDBS – IR Spectra for 2305-26-2 Enter CAS RN into POC for Physical Properties Information POC Search Results Using CAS RN Search POC by Molecular Formula

Enter Molecular Formula in Hill System Order: Carbon first, Hydrogen second, and all remaining elements in alphabetical order. Element symbol is case-sensitive. Example: C8H10O4 Same Compound but With No Stereochemistry Found in POC

Note it has a different CAS Registry Number than same substance with stereochemistry POC Full Display for Similar Compound

Click on Benzene icon to view structure

Appearance - abbreviated keywords. Use Help and then choose Abbreviations to translate terms. POC > Help > Abbreviations POC – Some Compounds Have Spectral Data CAS RN Search in DOC

Search for physical properties in DOC if your compound is not in POC DOC Summary Search Results DOC Full Display Format DOC Full Display Format Continued

References typically include synthesis, crystallography, and spectroscopy citations. Use Citation Linker form on Ejournals page to locate full-text (see next slide) http://ejournals.stanford.edu eJournals Results – Possible Matches

Click on S icon for title that matches best eJournals – Full-Text is Available Use SciFinder to Find Spectra

Must create personal account and then login before searching SciFinder SciFinder Results - Substance Search

Click on CAS Registry Number to view Substance Details SciFinder – Substance Details

Synonyms shown to left of structure. Summary info by role the substance has in articles/patents is displayed next. SciFinder Results – Predicted Properties SciFinder Results – Predicted Spectra

Predictions are based on ACD Labs software SciFinder – Predicted C13 NMR Spectra SciFinder – Experimental Properties SciFinder – IR Spectra (Based on Experimental Data) SciFinder – More Experimental Data SciFinder – Looking for Preparation Papers for a Chemical Substances

After doing substance search, click on Get References and then on Preparation. Synthesis papers may have a physical description for a substance if you haven’t found one using POC or DOC. SciFinder – Preparation Papers – Tip: Sort by Most cited SciFinder – Citation, Abstract, and Link to Full-text Article Find it @ Stanford – Full-Text Link Full-Text of Article is Available and it was written in German

Even if you don’t know German, based on article layout you may be able to locate physical description and then translate those few words using the Beilstein Dictionary. Reaxys – Choose Substances and Properties tab Reaxys – Generate Structure from Name (or CAS RN) Reaxys – Choose Structure Reaxys – Summary of Results – View Properties of Interest Reaxys – Melting Point Data with Link to Literature Reference Reaxys – Spectral Data > NMR

Chemical shifts but not spectra are available for some references. Must go to full-text article to view data. Need More Help?

 Please contact Grace Baysinger ([email protected]), Dave Keller ([email protected]) or a TA if you need more assistance.

 Happy searching!