Molecular recognition and self-assembly special feature: Supramolecular polymer formed by reversible self-assembly of tetrakisporphyrin.
S-shaped tetrakisporphyrin 2 forms supramolecular polymeric assemblies via a complementary affinity of its bisporphyrin units in solution. The self-association constant determined by applying the isodesmic model is >10(6) L mol(-1), which suggests that a sizable polymer forms at millimolar concentrations at room temperature. The electron deficient aromatic guest (TNF) binds within the molecular clefts provided by the bisporphyrin units via a charge-transfer interaction. This guest complexation completely disrupts supramolecular polymeric assembly. The long, fibrous fragments of the polymeric assemblies were characterized by atomic-force microscopy imaging of a film cast on a mica surface. The polymeric assemblies have lengths of >1mum and show a coiled structure with a higher level of organization. The approach discussed in this report concerning the quick preparation of supramolecular polymeric assemblies driven by noncovalent forces sets the stage for the preparation of a previously undescribed class of macromolecular porphyrin architectures.
Haino
Takeharu
T
Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan. haino@sci.hiroshima-u.ac.jp
Fujii
Takashi
T
Watanabe
Akihide
A
Takayanagi
Urara
U
D019281:Dimerization; D005449:Fluorenes / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*
C522539:5,10,15,20-tetrakis(3,5-dihydroxyphenyl)porphyrin; D005449:Fluorenes; D011108:Polymers; D011166:Porphyrins; C005644:2,4,7-trinitrofluorenone