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NMR Spectroscopy

1H Chemical Shift Prediction Substituent Constant Approach for Proton Chemical Shifts.

JMM: 1st Order Multiplet Maker for spin-spin splitting multiplets (or, JMM: alternate version without frames or J estimation)

JD: Spin-Spin Splitting Simulation for up to five spins.

Exchange(Netscape) Exchange Lineshape Simulation for 2 site exchange. Exchange(IE) is also available for Internet Explorer.

Mass Spectrometry

Fragment Finder finds the possible formulas that match a given molar mass. Then the M+1 and M+2 ratios and the exact masses of each of the possible fragments is calculated.
Formula Finder finds the possible formulas that match a given molar mass and several fragments. Then the M+1 and M+2 ratios and the exact masses of each of the possible fragments is calculated.
Molar Mass Finder guesses possible molecular ion masses if your spectrum might not have a molecular ion peak. If you have the tabulated peak list as a text file from an HP ChemStation on a disk, you can download the peak list into the MolarMass applet. Currently, this applet does not work with Netscape on a Windows system. Other combinations are OK.
Isotope Cluster calculates the isotope pattern for a given molecular formula. It includes 3rd and 4th period representative and transition metal elements.
Tripeptide Mass Finder searchs for di- or tripeptide ions that match a given mass.
Peptide Mass Finder calculates the masses of ions for a given peptide sequence. You can also plot the isotope cluster for the ion. This applet allows for stable isotope substitution for an amino acid with variable composition for the normal and substituted form.

Infra-Red Spectroscopy

IR Helper is a step-by-step tutorial on the interpretation of Infra-Red spectra. IR Helper is available in two versions:
IR Helper, Internet Explorer version
IR Helper, Netscape 4.03 version

Units Conversions

Here is an energy conversion application that you will find helpful, especially for converting Hartrees and eV to kJ/mol and Boltzman population ratios.

Distance Geometry

Distance geometry is a useful computational technique for building molecular structures when a few distance constraints are known, for example from NMR nOe measurements. Distance geometry is also a powerful way to convert atom connection tables to 3-dimensional form. Distance Geometry is a Web application that does distance geometry calculations for small molecules. This Web page can also be used to set-up complete input files for MOPAC and Gaussian94/98. You can also use distance geometry to build and molecular mechanics minimize a structure with Distance Geometry and MM2. These Web pages now also support Netscape 4.07 as well as Internet Explorer.

HPLC Simulator

The HPLC Simulator uses a purely equilibrium model for chromatography to simulate the separation of two compounds. Equilibrium Constants and Partition coefficients can be set up for all complexes that form including dimers. The mobile phase can have an additive, M, that might be a cyclodextrin, an ion pairing reagent, etc. Detection can be direct or indirect, using the mobile phase additive. Caution: this JavaScript takes a long time to run. A 100 plate column requires 20 sec. on a very fast PC. This script is new and under development, so expect changes. This script runs using Netscape and Internet Explorer on Macs and PCs. Comments and suggestions will be very helpful (11/26/99).

WWW Links

NMR Specific

Proton NMR Spectral Data Viewer
SDBS Integrated Spectral Data Base System for Organic Compounds
Educational NMR Software List
Sweet J A Mac application to calculate J-coupling constants using the Karplus and Altona Equations. This is a local bin-hexed Mac version, for faster downloading than directly from the Web.

NMR Home Page at the University of Potsdam has on-line applications for NMR Spectral Interpretation and Mass Spec interpretation, including:

NMR Tutorials

Introduction at NIH
NMR Spectroscopy: Principles and Application (Prof. H. S. Rzepa)
Introduction to NMR
Applications of 1H NMR spectroscopy (P. Hallpap, H. Händel)

General Spectroscopy

The National Institutes of Standards and Technology Chemical Web Book includes thermochemical and gas phase IR and mass spectral data.
Introduction to Mass Spectrometry (MS)
IR Wizard Interactive IR Correlation Chart
MS Wizard Interactive MS Fragment Chart

Molecular Mechanics and Graphics

The RasMol Home page is a source for RasMol/RasMac applications and information.

Molecular Structure

The Klotho Biochemical Compounds Declarative Database includes 3D-Chime structures of over 400 biochemical compounds.
The National Institutes of Health Drug Structure Data Bank has 3D-structures for important pharmaceuticals.
The Protein Data Bank at Brookhaven National Labs is a repository of X-ray and NMR 3D-structures of proteins and nucleic acids.

General Reference

ChemInfo at the Univ. of Indiana will help you find and learn how to use chemistry information resources on the Internet and elsewhere.

For more information or corrections contact Tom Shattuck at

Colby Chemistry Home Page

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Last modified: 1/28/2000