Abstract
A series of free-base and zinc porphyrin hexamers, where six porphyrin units are linked to a triphenylene core through amide or ester linkage, was designed and synthesized in an effort to study their spectroscopic and electrochemical properties, and aggregate formation. The distances between triphenylene core and porphyrin moieties are tuned by changing the lengths of spacer alkyl chains. The absorption spectral studies indicates that the porphyrin units in a hexamer behave like monomeric porphyrins, while a strong fluorescence quenching of triphenylene core was observed suggesting the deactivation of the excited state of triphenylene. The redox potentials of porphyrin units in a hexamer were estimated by differential pulse voltammetry (DPV). These values are very similar to those of the corresponding monomer. Consequently, absorption and electrochemical data demonstrate that six porphyrin units of (H 2PAC 5) 6TPh behave like monomers independently in the ground state. The hexamers undergo supramolecular aggregation spontaneously in different fashions based on the solvent systems as well as spacer lengths. Highly ordered and aligned monolayer-based patterns are formed when hexamers are allowed to aggregate from toluene solution onto carbon-coated copper films. In contrast, hexamers undergo aggregation to nanoparticles in toluene/acetonitrile mixed solvent system and the particle sizes increase with increasing the spacer alkyl chain lengths.
| Original language | English |
|---|---|
| Pages (from-to) | 639-651 |
| Number of pages | 13 |
| Journal | Journal of Porphyrins and Phthalocyanines |
| Volume | 15 |
| Issue number | 7-8 |
| DOIs | |
| Publication status | Published - 2011 Jul |
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Keywords
- porphyrin
- supramolecular formation
- triphenylene
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Porphyrin hexamer with a triphenylene core unit. / Sakai, Hayato; Rabbani, Mohammad Gulam; Hasobe, Taku.
In: Journal of Porphyrins and Phthalocyanines, Vol. 15, No. 7-8, 07.2011, p. 639-651.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Porphyrin hexamer with a triphenylene core unit
AU - Sakai, Hayato
AU - Rabbani, Mohammad Gulam
AU - Hasobe, Taku
PY - 2011/7
Y1 - 2011/7
N2 - A series of free-base and zinc porphyrin hexamers, where six porphyrin units are linked to a triphenylene core through amide or ester linkage, was designed and synthesized in an effort to study their spectroscopic and electrochemical properties, and aggregate formation. The distances between triphenylene core and porphyrin moieties are tuned by changing the lengths of spacer alkyl chains. The absorption spectral studies indicates that the porphyrin units in a hexamer behave like monomeric porphyrins, while a strong fluorescence quenching of triphenylene core was observed suggesting the deactivation of the excited state of triphenylene. The redox potentials of porphyrin units in a hexamer were estimated by differential pulse voltammetry (DPV). These values are very similar to those of the corresponding monomer. Consequently, absorption and electrochemical data demonstrate that six porphyrin units of (H 2PAC 5) 6TPh behave like monomers independently in the ground state. The hexamers undergo supramolecular aggregation spontaneously in different fashions based on the solvent systems as well as spacer lengths. Highly ordered and aligned monolayer-based patterns are formed when hexamers are allowed to aggregate from toluene solution onto carbon-coated copper films. In contrast, hexamers undergo aggregation to nanoparticles in toluene/acetonitrile mixed solvent system and the particle sizes increase with increasing the spacer alkyl chain lengths.
AB - A series of free-base and zinc porphyrin hexamers, where six porphyrin units are linked to a triphenylene core through amide or ester linkage, was designed and synthesized in an effort to study their spectroscopic and electrochemical properties, and aggregate formation. The distances between triphenylene core and porphyrin moieties are tuned by changing the lengths of spacer alkyl chains. The absorption spectral studies indicates that the porphyrin units in a hexamer behave like monomeric porphyrins, while a strong fluorescence quenching of triphenylene core was observed suggesting the deactivation of the excited state of triphenylene. The redox potentials of porphyrin units in a hexamer were estimated by differential pulse voltammetry (DPV). These values are very similar to those of the corresponding monomer. Consequently, absorption and electrochemical data demonstrate that six porphyrin units of (H 2PAC 5) 6TPh behave like monomers independently in the ground state. The hexamers undergo supramolecular aggregation spontaneously in different fashions based on the solvent systems as well as spacer lengths. Highly ordered and aligned monolayer-based patterns are formed when hexamers are allowed to aggregate from toluene solution onto carbon-coated copper films. In contrast, hexamers undergo aggregation to nanoparticles in toluene/acetonitrile mixed solvent system and the particle sizes increase with increasing the spacer alkyl chain lengths.
KW - porphyrin
KW - supramolecular formation
KW - triphenylene
UR - http://www.scopus.com/inward/record.url?scp=84860254807&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84860254807&partnerID=8YFLogxK
U2 - 10.1142/S1088424611003574
DO - 10.1142/S1088424611003574
M3 - Article
VL - 15
SP - 639
EP - 651
JO - Journal of Porphyrins and Phthalocyanines
JF - Journal of Porphyrins and Phthalocyanines
SN - 1088-4246
IS - 7-8
ER -