Atom_CIPStereochemistry Property

CDXML Name:AS
CDX Constant Name:kCDXProp_Atom_CIPStereochemistry
CDX Constant Value:0x0437
Data Size:INT8
Property of objects:kCDXObj_Node
First written/read in:ChemDraw 6.0
Required?No

Description:

The node's absolute stereochemistry according to the Cahn-Ingold-Prelog system.

ChemDraw will preserve any value present in a file without confirming its accuracy -- as long as the structure is not edited in ChemDraw. Any change to a structure has the potential of changing its stereochemical descriptors, and so ChemDraw will recalculate the structure's chemistry after any change. As a practical matter, we are very confident about the accuracy of ChemDraw's calculation of stereochemical descriptors, so this behavior should rarely cause problems.

The Cahn-Ingold-Prelog system for describing absolute stereochemistry is defined in the following references:

This is an enumerated property. Acceptible values are shown in the following list:
Value CDXML Name Description
0 U Undetermined
1 N Determined to be symmetric
2 R Asymmetric: (R)
3 S Asymmetric: (S)
4 r Pseudoasymmetric: (r)
5 s Pseudoasymmetric: (s)
6 u Unspecified: The node is not symmetric (might be asymmetric or pseudoasymmetric), but lacks a hash/wedge so absolute configuration cannot be determined

If this property is absent:

The node is treated as having Undetermined stereochemistry.

 


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