When does a supramolecular synthon fail? Comparison of bridgehead-functionalized adamantanes: the tri- and tetra- amides and amine hydrochlorides

0506307 - ÚACH 2020 RIV US eng J - Journal Article
Boldog, I. - Reiss, G. - Domasevitch, K.V. - Baše, Tomáš - Bräse, S.
When does a supramolecular synthon fail? Comparison of bridgehead-functionalized adamantanes: the tri- and tetra- amides and amine hydrochlorides.
Crystal Growth & Design. Roč. 19, č. 9 (2019), s. 5218-5227. ISSN 1528-7483. E-ISSN 1528-7505
Institutional support: RVO:61388980
Keywords : adamantane * crystal structure * H-bond, prediction * supramolecular synthon * violation
OECD category: Inorganic and nuclear chemistry
Impact factor: 4.089, year: 2019
Method of publishing: Limited access
https://pubs.acs.org/doi/10.1021/acs.cgd.9b00594

1,3,5-trisubstituted adamantane carboxamide and amine hydrochloride, Ad(CONH2)3 · 2.5H2O and [Ad(NH3)3]Cl3 · H2O (Ad = adamant-n-yl) respectively, crystallized from aqueous solutions, possess crystal structures with predictable H-bonded assembly, consistent with the C3v symmetry of the building blocks. The triamide structure consists of interpenetrated hexagonal networks, sustained by the well-known cyclic H-bonded bis-amide synthon, R22(8), which ensures linear connectivity. The structure of the triamine hydrochloride, assembled through the tetrahedral {RN+H3---(Cl-)3} synthon, features a remarkably symmetric assembly with narrow trigonal pore-channels, hosting water molecules. The structures of the tetrahedral 1,3,5,7-tetrasubstituted Ad(CONH2)4 and [Ad(NH3)4]Cl4, obtained similarly, demonstrate a formal prediction failure of synthon based approach. Instead of the anticipated bis-amide synthon based diamond network (1.485 g cm-3) analogous to the 5-fold interpenetrated paradigmatic structure of Ad(COOH)4, a non-interpenetrated assembly, sustained by a dense network of H-bonds, is realized (1.433 g cm-3). Lessened geometric regularity was also found in the tetrahydrochloride salt assembled via 5-connected nodes, {RN+H3---(Cl-)4}, which involve a bifurcated H-bond. The failures of the supramolecular synthons in these simple cases could be interpreted either in terms of symmetry and/or limitations associated with the ‘synthon-density’. A potential machine learning approach oriented on heuristic retrosupramolecular synthesis relies on such selected high-weight conceptual cases.
Permanent Link: http://hdl.handle.net/11104/0299089


Research data: CCDC, ACS publications