| 1. |
- Li, Chengjie, et al.
(författare)
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Expanded N-Confused Phlorin : A Platform for a Multiply Fused Polycyclic Ring System via Oxidation within the Macrocycle
- 2020
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:40, s. 17195-17205
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Tidskriftsartikel (refereegranskat)abstract
- Novel interrupted pi-conjugated macrocycles derived from expanded porphyrinoids were synthesized, and their unique reactivity was investigated in this work. The specific porphyrin analogs, so-called phlorins and isoporphyrins, possess a meso-sp(3) methylene moiety, showing inner 3NH and 1NH pyrrolic cores, respectively, and extended near-infrared (NIR) absorption. Expanded N-confused pentapyrrolic phlorin analog 1 bears an interrupted cyclic pi-conjugated system that is featured by a distinct higher HOMO and a lower LUMO. Oxidation of 1 allowed structural transformations through the expanded isoporphyrin-like species 2. One of the representative products is a spiro-carbon-bridged multiply N-fused product 3 comprising a fused [5.6.5.7.6.5]-hexacyclic ring obtained by oxidation with 2,3-dichloro-5,6-dicyano-p-benzoquinone. When magic blue was used as the oxidant, an aromatic N-confused pentaphyrin 4 was obtained via migration of one of the meso-phenyl groups to the beta-position of the neighboring pyrrolic ring. By employing the flexible cavity of 1 for metal coordination, Pd(II) complexation occurred with a specific meso oxygenation to give a bimetallic complex 5. In contrast to the rich oxidation reactions, reduction of 1 with NaBH4 resulted in the regioselective nucleophilic hydrogen substitution reaction at the para position of one of the meso-C6F5 groups. These results provide a practical approach for synthesizing novel interrupted or aromatic pi-conjugated frameworks showing NIR absorptions.
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| 2. |
- Li, Chengjie, et al.
(författare)
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Tripyrrin-armed isosmaragdyrins : synthesis, heterodinuclear coordination, and protonation-triggered helical inversion
- 2020
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Ingår i: Chemical Science. - : ROYAL SOC CHEMISTRY. - 2041-6520 .- 2041-6539. ; 11:10, s. 2790-2795
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative ring closure of linear oligopyrroles is one of the synthetic approaches to novel porphyrinoids with dinuclear coordination sites and helical chirality. The spatial arrangement of the pyrrolic groups of octapyrrole (P8) affected the position of the intramolecular oxidative coupling of the pyrrolic units; tripyrrin-armed isosmaragdyrin analogue (1) containing a beta,beta-linked bipyrrole moiety was synthesized regioselectively in a high yield by using FeCl3. Ni-II-coordination at the armed tripyrrin site of 1 allowed the formation of diastereomeric helical twisted complexes (2A and 2B) and succeeding Cu-II-coordination at the macrocyclic core afforded heterodinuclear Ni-II/Cu-II-complexes (3A and 3B). Each of them comprised a pair of separable enantiomers, exhibiting P- and M-helices, respectively. Notably, diastereomeric interconversion from 2A to 2B was quantitatively achieved as a consequence of helical transformation under acidic conditions.
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| 3. |
- Li, Qizhao, et al.
(författare)
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Antiaromatic Sapphyrin Isomer : Transformation into Contracted Porphyrinoids with Variable Aromaticity
- 2023
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 62:1
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Tidskriftsartikel (refereegranskat)abstract
- Sapphyrin is a pentapyrrolic expanded porphyrin with a 22π aromatic character. Herein, we report the synthesis of a 20π antiaromatic sapphyrin isomer 1 by oxidative cyclization of a pentapyrrane precursor P5 with a terminal β-linked pyrrole. The resulting isomer 1, containing a mis-linked bipyrrole unit in the skeleton, exhibits a reactivity for further oxidation due to the distinct antiaromatic electronic structure, affording a fused macrocycle 2, possessing a spiro-carbon-containing [5.6.5.6]-tetracyclic structure. Subsequent treatment with an acid afforded a weakly aromatic pyrrolone-appended N-confused corrole 3, and thermal fusion gave a [5.6.5.7]-tetracyclic-ring-embedded 14π aromatic triphyrin(2.1.1) analog 4. The cyclization at the mis-linked pyrrole moiety of P5 played a crucial role in synthesizing the antiaromatic porphyrinoid susceptible to facile transformation to novel porphyrinoids with variable aromaticity.
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| 4. |
- Li, Qizhao, et al.
(författare)
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Conformation Governed Reactivity of Fused Thia-Sapphyrin Dimers Bearing Multiply Fused Heteroaromatic Rings
- 2023
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Ingår i: CCS CHEMISTRY. - : Chinese Chemical Society. - 2096-5745. ; 5:6, s. 1332-1342
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Tidskriftsartikel (refereegranskat)abstract
- Suitable conformations and proper alignment of complex natural macrocycles are essential for achieving their unique properties. However, such artificial macrocycle prototypes are still limited due to synthetic difficulties. In this respect, directly linked porphyrin analog dimers display tunable conformations and intriguing properties, and thus, they may be employed as a class of promising platforms. Herein, we report that one-pot oxidative dimerization of thiahydrosapphyrin 1 yields dimers, 2(ant)i and 2(syn), comprising a transoid-oriented plate-like bipyrrolo[1,2-a] indolylidene. The thiophene-containing tetrapyrrole arching subunits in 2 lie at the opposite (anti) and same (syn) sides of the plate, respectively. Meanwhile, multiply fused cisoid-orientated dimer 3 was also obtained; a polycyclic pyrrolo-bridged bipyrroloindole derivative tethered with fully pi-conjugated bridges was formed. Notably, the anti-dimer 2(anti) underwent subsequent oxidative fusion to furnish a further-fused [6.5.5.7.5.5.5.6]-octacyclic compound 4(anti). In contrast, the syn-orientated 2(syn) could not be further fused due to the long distance between the potential reaction sites. This study provides a unique approach to the fused dimeric porphyrin analogs for potential near-infrared optical materials by a simple oxidation reaction. It also reveals the importance of conformation-modulated reactivity for constructing complex porphyrin arrays.
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| 5. |
- Li, Qizhao, et al.
(författare)
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Regioselectively Halogenated Expanded Porphyrinoids as Building Blocks for Constructing Porphyrin-Porphyrinoid Heterodyads with Tunable Energy Transfer
- 2019
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Ingår i: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126. ; 141:13, s. 5294-5302
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Tidskriftsartikel (refereegranskat)abstract
- Expanded porphyrins have been attracting increasing attention owing to their unique optical and electrochemical properties as well as switchable aromaticity. Toward material applications, regioselective functionalization of the expanded porphyrins at their periphery is indeed challenging due to the presence of multiple reactive sites. Herein, a set of regioselective halogenated isomers (L5-Br-A/B/C) of neo-confused isosmaragdyrin (L5) are synthesized by a combination of the halogenation reaction of L5 and sequential macrocycleto-macrocycle transformation reactions of its halogenated isomers. On this basis, the regioselectively functionalized isosmaragdyrins are utilized as building blocks for constructing multichromophoric porphyrinoids, specifically, heterodyads L5-ZnP-A/B/C, in which a common zinc porphyrin is linked at three different pyrrolic positions of isosmaragdyrins, respectively, by Sonogashira coupling reactions. The highly efficient energy cascade from porphyrin to isosmaragdyrin is elucidated using steady-state/time-resolved spectroscopies and theoretical calculations. Notably, the energy transfer processes from the porphyrin to the isosmaragdyrin moieties as well as the excitation energy transfer rates in L5-ZnP-A/B/C are highly dependent on the linking sites by through-bond and Forster-type resonance energy transfer mechanisms. The site-selective functionalization and subsequent construction of a set of heterodyads of the expanded porphyrinoid would provide opportunities for developing new materials for optoelectronic applications.
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| 6. |
- Li, Qizhao, et al.
(författare)
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Skeletal Rearrangement of Twisted Thia-Norhexaphyrin : Multiply Annulated Polypyrrolic Aromatic Macrocycles
- 2019
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Ingår i: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773. ; 58:18, s. 5925-5929
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Tidskriftsartikel (refereegranskat)abstract
- A hybrid thia-norhexaphyrin comprising a directly linked N-confused pyrrole and thiophene unit (1) revealed unique macrocycle transformations to afford multiply inner-annulated aromatic macrocycles. Oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone triggered a cleavage of the C-S bond of the thiophene unit, accompanied with skeletal rearrangement to afford unique pi-conjugated products: a thiopyrrolo-pentaphyrin embedded with a pyrrolo[1,2]isothiazole (2), a sulfur-free pentaphyrin incorporating an indolizine moiety (3), and a thiopyranyltriphyrinoid containing a 2H-thiopyran unit (4). Furthermore, 2 underwent desulfurization reactions to afford a fused pentaphyrin containing a pyrrolizine moiety (5) under mild conditions. Using expanded porphyrin scaffolds, oxidative thiophene cleavage and desulfurization of the hitherto unknown N-confused core-modified macrocycles would be a practical approach for developing unique polypyrrolic aromatic macrocycles.
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| 7. |
- Wei, Pingchun, et al.
(författare)
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Neo-Fused Hexaphyrin : A Molecular Puzzle Containing an N-Linked Pentaphyrin
- 2014
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 53:51, s. 14069-14073
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Tidskriftsartikel (refereegranskat)abstract
- The first neo-confused hexaphyrin(1.1.1.1.1.0) was synthesized by oxidative ring closure of a hexapyrrane bearing two terminal "confused" pyrroles. The new compound displays a folded conformation with a short interpyrrolic C center dot center dot center dot N distance of 3.102 angstrom, and thus it readily underwent ring fusion to afford a neo-fused hexaphyrin with an unprecedented 5,5,5,7-tetracyclic ring structure. Furthermore, coordination of Cu-II triggered a ring opening/contracting reaction to afford a Cu-II complex of an N-linked pentaphyrin derivative. The roles of reactive N-C bonds in the porphyrinoid macrocycles were demonstrated.
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| 8. |
- Xie, Yongshu, et al.
(författare)
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Macrocycle Contraction and Expansion of a Dihydrosapphyrin Isomer
- 2013
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 135:51, s. 19119-19122
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Tidskriftsartikel (refereegranskat)abstract
- Cyclization of a pentapyrrane with two terminal beta-linked pyrroles afforded a dihydrosapphyrin isomer (1) with the pyrroles linked in a unique beta,alpha-alpha,beta mode, which was rather reactive, and thus it readily underwent a ring-contracted rearrangement to a pyrrolyl norrole (2), and succeeding ring expansion to a terpyrrole-containing isosmaragdyrin analogue (4). 1, 2, and 4 contain the internal ring pathways with a minimum of 17, 15, and 16 atoms, respectively. 1, 2, and 4 are almost nonfluorescent, whereas the complex of 2 with Zn2+ shows a distinct NIR emission peak at 741 nm. The unprecedented pyrrole transformation chemistry by confusion approach is illustrated.
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| 9. |
- Yasuda, Kazuki, et al.
(författare)
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Variants in KCNQ1 are associated with susceptibility to type 2 diabetes mellitus
- 2008
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 40:9, s. 1092-1097
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Tidskriftsartikel (refereegranskat)abstract
- We carried out a multistage genome-wide association study of type 2 diabetes mellitus in Japanese individuals, with a total of 1,612 cases and 1,424 controls and 100,000 SNPs. The most significant association was obtained with SNPs in KCNQ1, and dense mapping within the gene revealed that rs2237892 in intron 15 showed the lowest P value (6.7 x 10(-13), odds ratio (OR) = 1.49). The association of KCNQ1 with type 2 diabetes was replicated in populations of Korean, Chinese and European ancestry as well as in two independent Japanese populations, and meta-analysis with a total of 19,930 individuals (9,569 cases and 10,361 controls) yielded a P value of 1.7 x 10(-42) (OR = 1.40; 95% CI = 1.34-1.47) for rs2237892. Among control subjects, the risk allele of this polymorphism was associated with impairment of insulin secretion according to the homeostasis model assessment of beta-cell function or the corrected insulin response. Our data thus implicate KCNQ1 as a diabetes susceptibility gene in groups of different ancestries.
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| 10. |
- Zhang, Kai, et al.
(författare)
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Synthesis of a Neo-Confused Octaphyrin and the Formation of Its Mononuclear Complexes
- 2015
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 17:19, s. 4806-4809
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Tidskriftsartikel (refereegranskat)abstract
- Novel neo-confused octaphyrin(1.1.1.1.1.1.1.0) (1) was synthesized by oxidative ring closure of an octapyrrane bearing two terminal "confused" pyrroles. Crystal structures of its Zn(II) and Cu(II) complexes (2 and 3) show a figure-of-eight conformation with unique mononuclear coordination structures. Photophysical data and theoretical calculations suggest that the neo-confused octaphyrin 1 is a 34 pi electron conjugated species showing nonaromaticity. Coordination of pocopper and zinc ions results in the further narrowing of the HOMO-LUMO gaps.
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