| 1. |
- Du, Yu, et al.
(author)
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N-Confused Hexapyrrolic Phlorinoid with NIR Absorption : Synthesis, Fusion, Oxidation, and Copper(II) Coordination
- 2020
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In: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 22:24, s. 9648-9652
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Journal article (peer-reviewed)abstract
- An N-confused hexapyrrolic phlorinoid 1 and its isomer N-fused hexapyrrolic phlorinoid 2 were synthesized through [4 + 2] condensation. Both 1 and 2 can be readily transformed into N-confused hexapyrrolic phlorinone 3 under aerobic conditions. Coordination of 1 with Cu(acac)(2) afforded two different mono-Cu(II) complexes 4 and 5 with CNNN and ONNN coordination environments, respectively. The NIR absorption bands can be effectively modulated up to 1265 nm through the oxidation, fusion, and metalation reactions.
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| 2. |
- He, Yixing, et al.
(author)
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Chain Length Modulated Dimerization and Cyclization of Terminal Thienyl-Blocked Oligopyrranes
- 2022
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In: Organic Letters. - : AMER CHEMICAL SOC. - 1523-7060 .- 1523-7052. ; 24:29, s. 5428-5432
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Journal article (peer-reviewed)abstract
- Oxidation of thienyl-blocked bilane and pentapyrrane afforded chain length dependent products of the symmetric dimer D1 and the thienyloligopyrrin-appended pentaphyrin analogue P2, respectively, with the latter formed by simultaneous dimerization and cyclization. Coordination of D1 and P2 with Cu(II) afforded di-and monometallic complexes D1-Cu2 and P2 -Cu, respectively. These compounds exhibit distinct NIR absorption, with the absorption tail of D1-Cu2 extended to ca. 1900 nm despite its smaller conjugation framework than that of P2 -Cu.
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| 3. |
- Huang, Yanping, et al.
(author)
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Syntheses and characterization of dithienyl-blocked hexapyrrin and its mononuclear complexes
- 2023
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In: Journal of Porphyrins and Phthalocyanines. - : World Scientific. - 1088-4246 .- 1099-1409. ; 27:07N10, s. 1089-1096
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Journal article (peer-reviewed)abstract
- With the purpose to develop long chain-conjugated oligopyrrin-like compounds and their metal complexes, and thus achieve tunable near-infrared absorption, a dithienyl-blocked hexapyrrane S-2-P-6 was synthesized by acid-catalyzed [2+4+2] condensation, followed by oxidation with DDQ to afford dithiaoctapyrrin 1, and its mononuclear metal complexes 1-Cu and 1-Zn were synthesized by treating 1 with Cu(II) and Zn(II) acetates. All the compounds were systematically characterized by NMR/EPR, and HRMS. The crystal structures revealed that 1 adopts a double hook-like conformation. Whereas, both complexes 1-Cu and 1-Zn adopt spiral-hook hybrid conformations, showing smaller interplanar angles between the rings within the spiral part, compared with those in the hook-like counterpart of molecule 1, which is favorable for red-shifting the absorption. As expected, the absorption band edges for complexes 1-Cu and 1-Zn are red-shifted to ca. 1560 nm, compared with that of 1260 nm observed for 1.
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| 4. |
- Huang, Yanping, et al.
(author)
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Syntheses and coordination of linear and macrocyclic pentapyrroles possessing a fused moiety : Confusion modulated structural diversity
- 2024
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In: Dyes and pigments. - : Elsevier. - 0143-7208 .- 1873-3743. ; 223
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Journal article (peer-reviewed)abstract
- Porphyrinoids have attracted wide interest because of their vital roles in biological processes and fascinating structural and functional characters. In this work, a doubly N-confused pentapyrrane precursor N2C–P5 has been synthesized with terminal pyrrole ring A and middle pyrrole C incorporated in the N-confused mode. On this basis, pentapyrrin 1 and sapphyrin 2 have been synthesized by oxidizing N2C–P5 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Both 1 and 2 possess a [5.5.5]-tricyclic fused ring involving pyrrole B and the neighboring confused pyrrole C. Meanwhile, the formation of 2 involves ring closure between the terminal rings A and E. Notably, 2 exists as a diradical showing a half-field signal in the electron paramagnetic resonance (EPR) spectrum and a singlet ground state with a negative singlet-triplet energy gap of −0.50 kcal/mol. Excellent thermal stability has been observed for 2, which may be related to its large π-conjugated framework involving the fused structure. On this basis, 1 and 2 were treated with Cu(acac)2 to afford Cu(II) complexes 3 and 4, respectively. As a result, an acetylacetonyl moiety is attached at the terminal pyrrole ring E to afford an NNNO coordination environment for complex 3, and the sapphyrin macrocycle of 2 has been cleaved between rings A and B to afford a fused pentapyrrin ligand, furnishing an NNNN coordination environment for complex 4, in which a pentafluorophenyl-ketal group generated during the ring cleavage reaction is attached to ring A, and it can be hydrolyzed to the corresponding pentafluorobenzoyl substituent to afford complex 5. Compared with free bases 1 and 2, complexes 3−5 show more intense low-energy near-infrared (NIR) absorption bands at ca. 791, 926 and 907 nm, respectively. This work provides an effective approach for the syntheses of linear and macrocyclic oligopyrroles with intriguing structures and properties by oxidizing oligopyrranes with precisely designed numbers and positions of N-confused pyrroles.
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| 5. |
- Li, Qizhao, et al.
(author)
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Antiaromatic Sapphyrin Isomer : Transformation into Contracted Porphyrinoids with Variable Aromaticity
- 2023
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In: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 62:1
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Journal article (peer-reviewed)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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| 6. |
- Li, Qizhao, et al.
(author)
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Conformation Governed Reactivity of Fused Thia-Sapphyrin Dimers Bearing Multiply Fused Heteroaromatic Rings
- 2023
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In: CCS CHEMISTRY. - : Chinese Chemical Society. - 2096-5745. ; 5:6, s. 1332-1342
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Journal article (peer-reviewed)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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| 7. |
- Li, Qizhao, et al.
(author)
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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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In: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126. ; 141:13, s. 5294-5302
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Journal article (peer-reviewed)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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| 8. |
- Li, Qizhao, et al.
(author)
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Skeletal Rearrangement of Twisted Thia-Norhexaphyrin : Multiply Annulated Polypyrrolic Aromatic Macrocycles
- 2019
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In: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773. ; 58:18, s. 5925-5929
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Journal article (peer-reviewed)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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| 9. |
- Li, Qizhao, et al.
(author)
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Twisted-Planar-Twisted expanded porphyrinoid dimer as a rudimentary reaction-based methanol indicator
- 2020
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In: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
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Journal article (peer-reviewed)abstract
- Directly linked porphyrin dimers have attracted considerable attention because of their intriguing electronic features. Most emphasis has been placed on either dimers with large dihedral angles between the constituent planar monomeric subunits or those with overall planarity, referred to as "Planar-Twisted-Planar" and "Planar-Planar-Planar", respectively. Herein, we report a "Twisted-Planar-Twisted" framework, the hexaphyrin dimer D that exists in a trans configuration. Treatment of D with MeOH affords two isomeric dimers, MD1 and MD2, both of which incorporate a methoxy moiety and exist in cis orientations with respect to the tethering linkage. The methanol-promoted conversion is accompanied by a readily discernible color change from green to brown and is not induced to an appreciable level by other alcohols. Dimer D thus acts as a rudimentary, albeit highly selective, reaction-based methanol indicator. This work provides a promising approach for constructing reaction-based chemosensors using porphyrinoid dimers of nonplanar subunits with biased reactivity. Directly linked porphyrin dimers show intriguing electronic features but emphasis has been placed on planar monomeric units. Here, the authors report a Twisted-Planar-Twisted framework which can undergo a cis-trans transformation accompanied by a colour change in presence of methanol, making this framework applicable as a methanol sensor.
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| 10. |
- Lv, Jiezhao, et al.
(author)
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Numerical Investigation of the Stimulated Growth of Single-Crystal Fibers by Point-Effect-Induced Fluid Dynamics
- 2022
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In: Crystal Growth & Design. - : AMER CHEMICAL SOC. - 1528-7483 .- 1528-7505. ; 22:12, s. 7031-7039
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Journal article (peer-reviewed)abstract
- Using molecular dynamics analysis and a two-component diffusion model that accounts for the time-dependent crystal surface chemical reaction, we show by extensive numerical simulations that the recently observed prismatic facet growth suppression in single-crystal fibers is the combined action of self-shielding by crystal surface selectivity and self-channeling arising from a point effect due to fibers small diameters and large aspect ratios. We further show that the self-channeling leads to a pyramidal-face-aiming solute flow, resulting in accelerated single-crystal fiber growth. This mesoscopic stimulated matter growth acceleration theory can satisfactorily explain all experimental results reported to date. This new crystal fiber growth technology opens a realm of application possibilities for single-crystal fiber architectures in chip-size photonics.
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