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Dimeric Self‐Assembly of Pyridyl Guanidinium Carboxylates in Polar Solvents
Author(s) -
Irfan Ashiq Muhammad,
Tesfatsion Biniam F.,
Gaggini Francesca,
Dixon Sally,
Kilburn Jeremy D.
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001861
Subject(s) - carboxylate , chemistry , aqueous solution , salt (chemistry) , solubility , isothermal titration calorimetry , guanidinium chloride , substrate (aquarium) , crystallography , medicinal chemistry , polymer chemistry , organic chemistry , enzyme , oceanography , geology
A series of pyridyl guanidinium–carboxylates has been prepared and the dimeric self‐assembly of these studied in H 2 O/DMSO mixtures, principally using dilution isothermal calorimetry. Compounds 5 and 6 , incorporating an aromatic ring in the “tethering” region between the guanidinium and carboxylate groups, demonstrate the strongest dimerisation in neat DMSO. X‐ray crystal structures of 5 and 6 reveal two different dimerisation architectures in the solid‐state, but both involve carboxylate–guanidinium salt bridges as anticipated, and π–π interactions. Compounds 10 – 16 incorporating peptidic fragments between the guanidinium and carboxylate groups, showed reduced dimerisation strength with increased amino acid content, but also sustained dimerisation under increasingly aqueous conditions, up to 50 % H 2 O/DMSO in the case of 14 and 15 . The extent of our study in H 2 O/DMSO mixtures was determined by substrate solubility of 10 – 16 , and not the limit of self‐assembly.