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Thermodynamic Stability of Hydrogen‐Bonded Nanostructures: A Calorimetric Study
Author(s) -
ten Cate Mattijs G. J.,
Huskens Jurriaan,
CregoCalama Mercedes,
Reinhoudt David N.
Publication year - 2004
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.200400085
Subject(s) - calorimetry , hydrogen bond , solvent , rosette (schizont appearance) , crystallography , chemistry , stoichiometry , polar , methanol , polarity (international relations) , materials science , molecule , organic chemistry , thermodynamics , physics , astronomy , biology , immunology , biochemistry , cell
The self‐assembly of hydrogen‐bonded aggregates (rosettes) in solvent mixtures of different polarity has been studied by calorimetry. The C 50 parameter, the concentration when 50 % of the components are incorporated in the assembly, is used to compare assemblies with different stoichiometry. C 50 for the single rosette 1 3 ⋅(BuCYA) 3 ( 1 = N , N ‐di(4‐ tert ‐butylphenyl)melamine; BuCYA= n ‐butylcyanuric acid) in 1,2‐dichloroethane is 25 μ M , whereas for double rosettes 2 a 3 ⋅(BuCYA) 6 and 2 b 3 ⋅(BuCYA) ( 2 =calix[4]arene–dimelamine) it is 0.7 and 7.1 μ M , respectively. Δ G °, Δ H °, and T Δ S ° values indicate that the thermodynamics of double rosettes reflect the independent assembly of two individual single rosette structures or two rosettes reinforced by additional stabilizing interactions. In more polar solvents the stability of double rosettes decreases. From the correlation of Δ G ° with solvent polarity it is predicted that it should be possible to assemble double rosettes in methanol or water. The assembly of 2 b 3 ⋅(BuCYA) 6 in 100 % MeOH was proven by 1 H NMR and CD spectroscopy.