Differences

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--- structurelevels [2012/10/15 12:50] – sanmark
+++ structurelevels [2012/11/07 12:38] – rkiss
@@ Line 17: / Line 17: @@
 //Compounds// can have more symmetries than //structures//. In //compounds// neither the number of hydrogens nor the position of some hydrogens are fixed. A //compound// can represent all realistic tautomeric and protonation states (//structures//). Therefore those asymmetry centers that are present only in one potential //structure// (tautomer and protonation state) are not treated as stereogenic at the //compound level//. Similarly, some cis-trans bonds found a //structure// might be missing from the corresponding //compound//.
+{{ :speclevel2.png |}}
+====Relations====
+The three structure levels have the following relations: //compounds// can have (can be represented by) multiple //structures//, and //structures// with well-defined, known configurations can have multiple //conformers//. Inversely, //conformers// have exactly one //structure//, and //structures// have exactly one //compound//.
+===Relation to products===
+//Product// is a special entry type that can appear on the mcule.com’s interface. It is connected to the chemical structures stored in the mcule database. Suppliers’ //products// are real, physical substances. Since these products can contain molecules in different tautomer and protonation states, their structural content can be best described at the //compound level//. The chemical content of products might be undetermined and in exceptional cases it can be changed, for example when supplier notices that the molecular structure was misdrawn or incorrectly determined previously.
+In the mcule system only //products// with determined structures are registered. In the rare event of //product// structure correction, the corrected new structure is registered and will be associated with the //product//. Their structures are represented by //compounds// in the database: products with structures drawn in a different tautomeric form or protonation state are treated structurally equivalent.
+===Comparison to user structures/conformers===
+During the registration user structures/conformers (link) are kept intact. Structural equivalence is not detected, all entries are registered with an unique identifier in the user database. The only restriction is that user structures should have 2D coordinates whereas conformers should have 3D coordinates.
+During calculations they are treated similar to //structures// and //conformers// of the mcule database. User structures are considered as being in that specific tautomer and protomer form represented in the 2D structure.