Abstract
All the catechol moieties of a hexapus triaza[3.3.3]paracyclophane having three catechol moieties and six hydrocarbon chains (1) undergo coordination interactions with the iron(III) ion in a 1:1 molar ratio of 1 to iron(III) above pH 6 in an aqueous medium. Two different iron(III) complexes of 1, A and B in a 1:1 molar ratio, are in the high spin iron(in) state as characterized by electronic, EPR and Mössbauer spectroscopy: A is a hexacoordinated mononuclear complex with half-protonated catecholato groups, subjected to considerable structural distortion; B is a hexa-coordinated mononuclear complex with complete dissociation of all the catechol protons, retaining high structural symmetry. The molecular recognition behaviour of 1 and Fe-complex A toward hydrophobic guest molecules has been investigated in aqueous HEPES and acetate buffers at 30.0 °C and μ 0.10 mol dm-3. The hexapus cyclophane 1 recognizes organic guests through hydrophobic and electrostatic interactions; anionic and non-ionic guests, 7-hydroxy-8-phenylazonaphthalene-1, 3-disulfonate (OG) and 2-hydroxy-1-(2-pyridylazo)naphthalene (PAN), respectively, are incorporated into host 1 with binding constants of the order of 105 dm3 mol-1, while a cationic guest, 2-(p-dimethylaminostyryl)-1-ethylquinolinium (QR), is not included in the host. The guest-binding behaviour of Fe-complex A toward OG and PAN is much enhanced relative to that of 1 as effected by hydrophobic, electrostatic and coordination interactions under conditions identical to those applied to 1; the binding constant for OG is nearly pH-independent in a pH range of 3-8, while that for PAN is pH-dependent because the coordination interaction with the host is subject to change by pH.
| Original language | English |
|---|---|
| Pages (from-to) | 595-604 |
| Number of pages | 10 |
| Journal | Journal of the Chemical Society, Perkin Transactions 2 |
| Issue number | 4 |
| Publication status | Published - Dec 1 1992 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
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Azaparacyclophanes with metal-binding sites. Part 1. Preparation, characterization, and molecular recognition behaviour of hexapus azaparacyclophane and its iron(III) complex. / Hisaeda, Yoshio; Ihara, Takeshi; Ohno, Teruhisa; Murakami, Yukito; Maeda, Yonezo.
In: Journal of the Chemical Society, Perkin Transactions 2, No. 4, 01.12.1992, p. 595-604.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Azaparacyclophanes with metal-binding sites. Part 1. Preparation, characterization, and molecular recognition behaviour of hexapus azaparacyclophane and its iron(III) complex
AU - Hisaeda, Yoshio
AU - Ihara, Takeshi
AU - Ohno, Teruhisa
AU - Murakami, Yukito
AU - Maeda, Yonezo
PY - 1992/12/1
Y1 - 1992/12/1
N2 - All the catechol moieties of a hexapus triaza[3.3.3]paracyclophane having three catechol moieties and six hydrocarbon chains (1) undergo coordination interactions with the iron(III) ion in a 1:1 molar ratio of 1 to iron(III) above pH 6 in an aqueous medium. Two different iron(III) complexes of 1, A and B in a 1:1 molar ratio, are in the high spin iron(in) state as characterized by electronic, EPR and Mössbauer spectroscopy: A is a hexacoordinated mononuclear complex with half-protonated catecholato groups, subjected to considerable structural distortion; B is a hexa-coordinated mononuclear complex with complete dissociation of all the catechol protons, retaining high structural symmetry. The molecular recognition behaviour of 1 and Fe-complex A toward hydrophobic guest molecules has been investigated in aqueous HEPES and acetate buffers at 30.0 °C and μ 0.10 mol dm-3. The hexapus cyclophane 1 recognizes organic guests through hydrophobic and electrostatic interactions; anionic and non-ionic guests, 7-hydroxy-8-phenylazonaphthalene-1, 3-disulfonate (OG) and 2-hydroxy-1-(2-pyridylazo)naphthalene (PAN), respectively, are incorporated into host 1 with binding constants of the order of 105 dm3 mol-1, while a cationic guest, 2-(p-dimethylaminostyryl)-1-ethylquinolinium (QR), is not included in the host. The guest-binding behaviour of Fe-complex A toward OG and PAN is much enhanced relative to that of 1 as effected by hydrophobic, electrostatic and coordination interactions under conditions identical to those applied to 1; the binding constant for OG is nearly pH-independent in a pH range of 3-8, while that for PAN is pH-dependent because the coordination interaction with the host is subject to change by pH.
AB - All the catechol moieties of a hexapus triaza[3.3.3]paracyclophane having three catechol moieties and six hydrocarbon chains (1) undergo coordination interactions with the iron(III) ion in a 1:1 molar ratio of 1 to iron(III) above pH 6 in an aqueous medium. Two different iron(III) complexes of 1, A and B in a 1:1 molar ratio, are in the high spin iron(in) state as characterized by electronic, EPR and Mössbauer spectroscopy: A is a hexacoordinated mononuclear complex with half-protonated catecholato groups, subjected to considerable structural distortion; B is a hexa-coordinated mononuclear complex with complete dissociation of all the catechol protons, retaining high structural symmetry. The molecular recognition behaviour of 1 and Fe-complex A toward hydrophobic guest molecules has been investigated in aqueous HEPES and acetate buffers at 30.0 °C and μ 0.10 mol dm-3. The hexapus cyclophane 1 recognizes organic guests through hydrophobic and electrostatic interactions; anionic and non-ionic guests, 7-hydroxy-8-phenylazonaphthalene-1, 3-disulfonate (OG) and 2-hydroxy-1-(2-pyridylazo)naphthalene (PAN), respectively, are incorporated into host 1 with binding constants of the order of 105 dm3 mol-1, while a cationic guest, 2-(p-dimethylaminostyryl)-1-ethylquinolinium (QR), is not included in the host. The guest-binding behaviour of Fe-complex A toward OG and PAN is much enhanced relative to that of 1 as effected by hydrophobic, electrostatic and coordination interactions under conditions identical to those applied to 1; the binding constant for OG is nearly pH-independent in a pH range of 3-8, while that for PAN is pH-dependent because the coordination interaction with the host is subject to change by pH.
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M3 - Article
AN - SCOPUS:37049082907
SP - 595
EP - 604
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
SN - 1470-1820
IS - 4
ER -