ABSTRACT
Verloop parameters are indices calculated with the Sterimol Software which express dimensional characteristics for one substituent. The calculus is made using the Corey-Pauling-Koltun atomic models. Sterimol parameters were developed in the 1970s, by Arie Verloop and his coworkers as a result to the lack of steric describing parameters. Verloop preferred to create two different parameters which are describing different dimensional properties of the studied substituent: the width and the length. The Sterimol parameters are expressed as length units so it easy to perceive the influence of a steric effect. The calculus of these parameters is made using software: STERIMOL QCMP93 program, and it is based on physical classic parameters like van der Waals radii, bond lengths, bond angles (between atoms in the substituent) and hypothetically most likely conformations of the substituent. Sterimol parameters, in contrast, are not based on a mechanistically discrete reaction.
