4. I Lab Services 

4.1 Objectives 

In this chapter you will find a list of services available through I Lab with the corresponding 

description and statistical information. 

4.2 HNMR Predictor 

ACD/HNMR Predictor uses parameters gleaned from its internal database with over 1,384,000 

experimental chemical shifts and 449,000 experimental coupling constants for 165,000 

structures.  To quantitate intramolecular interactions in new organic structures and to predict their 

chemical shifts, HNMR Predictor module uses a unique algorithm based on intramolecular 

interaction parameters for over 3,000 structural fragments, which have been carefully derived 

from experimental data using ACD/Labs  specially developed HNMR data processing 

approaches. 

ACD/HNMR: 

Calculates accurate HNMR spectra under any basic frequency.  The most accurate 

spectra are obtained for neat liquid samples or solutes in non polar non aromatic solvents.  

Calculated chemical shifts and coupling constants are provided with 95% confidence 

intervals so that you know the reliability of the calculated values. 

Takes into account second order interactions (strong coupling effects) and long range 

coupling constants. 

Simulates double resonance and plots integral curves. 

Allows you to calculate exact spectra for any strongly coupled system with up to 8 

magnetically non equivalent nuclei (spin 1/2) or more if some nuclei are magnetically 

equivalent. 

You can specify the frequency for the spectrum to be calculated. 

If you are using I Lab via ChemSketch, the results of HNMR spectrum prediction can be viewed 

from a special dialog box that appears automatically as soon as the results are received from the 

server (if the corresponding check box is selected in the ACD/I Lab Options dialog box) or that 

can be opened from the Task Manager by clicking Result.  The results are represented in the 

form of a spectrum that can be viewed with the external viewer (HNMR Viewer) that is included 

into the ChemSketch installation package by default. 

ACD/I Lab via ChemSketch 

User s Guide 

28