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Dynamic equilibrium of self‐assembled cyclic trimer and tetramer of 1‐methyl‐5‐imidazolylcobalt(III)porphyrin
Author(s) -
Tanaka Akira,
Ryuno Aya,
Okada Saori,
Satake Akiharu,
Kobuke Yoshiaki
Publication year - 2005
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/c64h-mnq6-58ma-ffq2
Subject(s) - tetramer , trimer , chemistry , porphyrin , intermolecular force , crystallography , solvent , computational chemistry , photochemistry , organic chemistry , molecule , dimer , enzyme
Dynamic equilibrium of self‐assembled multi‐porphyrin systems is of interest in obtaining switchable photoresponsive material, but rarely reported. 1‐methyl‐5‐imidazolylcobalt(III)porphyrin ( 1Co ) synthesized here assembled automatically into cyclic trimer and tetramer by intermolecular imidazolyl‐cobalt(III) coordination. The trimer‐tetramer equilibrium was dependent on concentration and solvent, as examined by NMR spectrometry. In CDCl 3 , the tetramer formation was favored at high concentrations, as the ratio of the trimer to the tetramer was 1:2 at 14.8 mM 1Co , and shifted to 1:8 at 74 mM. Further, when the sample was concentrated from a CHCl 3 solution to dryness, the ratio increased to 1:24 on dissolution. In CD 3 OD, on the other hand, only the trimer was observed in the wide concentration range. Accordingly, both the trimeric and the tetrameric structures could be prepared selectively by the choice of concentration and solvent.