Quantification of Solid Structure Similarity Thomas Gelbrich University

Quantification of Solid Structure Similarity Thomas Gelbrich University of Southampton

A B C D E Compound Polymorphic forms i ii Crystal Structure 3 D 2 D Construct 1 D 0 D

“Family” ? • Formation of crystals Robust building blocks • Crystal engineering • Prediction • …

A B Construct

A B Method Construct

A ? Construct B

Construct, Cluster and Shell

Construct, Cluster and Shell

Construct, Cluster and Shell of a molecule in a crystal structure One molecule + nearest neighbours Representative cluster of a supramolecular construct All independent molecules + their nearest neighbours: 1. Representative 2. Similar constructs have similar clusters 3. Component of a shell

Construct, Cluster and Shell Similar constructs >> Similar clusters >> Shells will contain certain similar components 1. Generate all shells 2. Identify similar components in shells 3. These are the representative clusters of a common construct

Corresponding Points

Corresponding Points

Corresponding Points

Corresponding Points A B C 1 C 2 O 5 S 1 N 2 C 11 C 23 O 3 S 1 N 1 CPS 1. 2. 3. 4. 5. Pairs of points which would conceivably adopt similar relative positions in different instances of a supramolecular construct.

Example 1

Example 1 (i) (ii) II Hecht et al. , Z. Anorg. Allg. Chem. , 624 (1998), 315.

Example 1 – CP CP

Example 1 – Parameters

Example 1 – Shell (i) (ii)

Example 1 (i) (ii)

A CIF, CP General information Corresponding vectors Degree of similarity Construct B

Families of N Structures

Families of N Structures N (N-1) / 2 individual tests N T 4 6 20 50 200 190 1225 19900 N Structures Construct Construct

Example 2

Five structures based on C 1 stacks

X~I X~CF 3 CH 3~CF 3 Br~Br(ii) Br~Br (i) I~Br CF 3~Cl Br~Br (iii) I~Cl I~Br (ii) I~I (iii) CN~Br (i) CN~CN 3 D (X = CF 3, I, Br, Cl, F, H) C 2 C 3 2 D C 1 1 D I-Dimer 0 D

Example 3 – Alkali and ammonium H-tartrates Chiral / racemic pairs : hydrogen tartrates racemic chiral

Example 3 – 144 structures of H-tartrates racemic / chiral: K+, Rb+, Cs+, NH 4+, Tl+, mixed crystals H 2 O QAPTEG ZELRUD LIGXEE BYPTAR 10 H 2 O ½ [ ] H 2 O ENHTAR HIDGOQ NETXAL

Example 3 – Chains

Example 3 – Chains A 55 Structures B 34 Structures

Example 4 – Small degree of packing similarity

Example 4 – Small degree of packing similarity

Examples Racemic / chiral alkali and ammonium H-tartrates Gelbrich et al. , Z. Anorg. Allg. Chem. , 630 (2004), 1451. Ag. I/ Fe. II coordination polymers Krautscheid et al. , Z. Anorg. Allg. Chem. , 630 (2004), 1427. Polymorphism in TNT Vrcelj et al. , Cryst Growth Des. , 3 (2003), 1027.

Conclusion ü Polymorphs ü Multi-component structures ü Coordination polymers ü Small degree of packing similarity ü Large families (N > 100)

What next? q Reverse search (find matching structures to a known construct ) q GUI / Output. . . q Database of supramolecular constructs