Controlling the Photophysics of Aromatic Guests Using a Cyclic Porphyrin Dimer: Synthesis, Structure, and Encapsulation‐Mediated “ON‐OFF” Switch

Mondal, Pritam; Banerjee, Sayantani; Rath, Sankar Prasad

doi:10.1002/ejic.201900639

Cited by 10 publications

(5 citation statements)

References 116 publications

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“…Indeed, many ligands and molecules show a preference for binding inside the cavity of porphyrin cages. [56][57][58][59] The H2O proton signals appear as singlets because of the quick dynamic behavior on Investigated gold(I) complexes are displayed in Figure 5. The calculated Au + -CNHC distances of ~2.05-2.06 Å are in agreement with distances measured in X-ray crystal structures of linear bis(NHC) gold(I) complexes.…”

Section: Resultsmentioning

confidence: 99%

“…Integration values are above 2H (∼2.5–3H) and suggest that probably two H 2 O molecules are axially coordinated to zinc(II) porphyrins (one H 2 O per zinc(II) ion) and directed inside the cavity. Indeed, many ligands and molecules show a preference for binding inside the cavity of porphyrin cages. − The H 2 O proton signals appear as singlets because of the quick dynamic behavior on the 1 H NMR timescale. Both signals of free H 2 O and encapsulated H 2 O are independently observed as sharp signals.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis, Characterization, and Encapsulation Properties of Rigid and Flexible Porphyrin Cages Assembled from N-Heterocyclic Carbene–Metal Bonds

et al. 2021

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Four porphyrins equipped with imidazolium rings on the para positions of their meso aryl groups were prepared and used as tetrakis(N-heterocyclic carbene) (NHC) precursors for the synthesis of porphyrin cages assembled from eight NHC-M bonds (M = Ag + or Au + ). The conformation of the obtained porphyrin cages in solution and their encapsulation properties strongly depend on the structure of the spacer -(CH2)n-(n = 0 or 1) between meso aryl groups and peripheral NHC ligands. In absence of methylene groups (n = 0), porphyrin cages are rather rigid and the short porphyrin-porphyrin distance prevents encapsulation of guest molecules like 1,4diazabicyclo[2.2.2]octane (DABCO). By contrast, the presence of methylene functions (n = 1) between meso aryl groups and peripheral NHCs offers additional flexibility to the system allowing the inner space between the two porphyrins to expand enough to encapsulate guest molecules like water molecules or DABCO. The peripheral NHC-wingtip groups also play a significant role on the encapsulation properties of the porphyrin cages.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis, Characterization, and Encapsulation Properties of Rigid and Flexible Porphyrin Cages Assembled from N-Heterocyclic Carbene–Metal Bonds

et al. 2021

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“…Instead, it is a clear indication of the excimer formation upon exciting the TCDD molecule in the presence of the AgTi surface. The excited state bonding between adjacent units (called an Excimer) is well known for planar conjugated molecules like anthracene as well as the metal-metal excimers in the case of silver clusters [23][24][25][26][27][28][29][30][31]. The adsorbed TCDD on the surface provides a suitable orientation for two adjacent TCDD units to establish electron transfer from a TCDD π-electrons to the excited conjugated π-π* bond in another molecule which leads to the dimer (excimer formation).…”

Section: Photodegradation Experimentsmentioning

confidence: 99%

The Photocatalytic Degradation of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in the Presence of Silver–Titanium Based Catalysts

et al. 2020

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Polychlorinated dibenzo-p-dioxins (PCDD) are persistent toxic compounds that are ubiquitous in the environment. The photodegradation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the presence of silver titanium oxide (AgTi) and silver titanium doped into the Y-zeolite (AgTiY) was tested using high (254 nm) and mid (302 nm) energy UV irradiation sources. AgTi and AgTiY, both showed success in the photodegradation of 2,3,7,8-TCDD dissolved in methanol/tetrahydrofuran solution. Both catalysts were found to effectively decompose TCDD at 302 nm (lower energy) reaching in between 98–99% degradation after five hours, but AgTiY showed better performance than AgTi at 60 min reaching 91% removal. Byproducts of degradation were evaluated using Gas chromatography/mass spectrometry (GC–MS), resulting in 2,3,7-trichlorodibenzo-p-dioxin, a lower chlorinated congener and less toxic, as the main degradation product. Enzyme Linked Immunosorbent Assay (ELISA) was used to evaluate the relative toxicity of the degradation byproducts were a decrease in optical density indicated that some products of degradation could be potentially more toxic than the parent TCDD. On the other hand, a decrease in toxicity was observed for the samples with the highest 2,3,7,8-TCDD degradation, confirming that AgTiY irradiated at 302 nm is an excellent choice for degrading TCDD. This is the first study to report on the efficiency of silver titanium doped zeolites for the removal of toxic organic contaminants such as dioxins and furans from aquatic ecosystems.

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“…One-dimensional (1D) objects have also been controlled in this manner when polymethylene chains in rotaxane axles are considered during shuttle behavior . Aromatic rings of guests being captured within cyclophanes or released are two-dimensional (2D) nano-objects of this kind. ,, Now, we present the first three-dimensional (3D) nano-object in this progression in the form of 1 ’s binding and unbinding since 1 ’s octahedral structure extends to nanometric lengths along all three dimensions. 3D nano-objects being captured, but not released, are known, e.g., C 70 , Mo 6 O 19 2– , and Mo 12 PO 40 3– .…”

Section: Introductionmentioning

confidence: 99%

Taming Tris(bipyridine)ruthenium(II) and Its Reactions in Water by Capture/Release with Shape-Switchable Symmetry-Matched Cyclophanes

et al. 2022

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Electron/proton transfers in water proceeding from ground/excited states are the elementary reactions of chemistry. These reactions of an iconic class of molecules—polypyridineRu(II)—are now controlled by capturing or releasing three of them with hosts that are shape-switchable. Reversible erection or collapse of the host walls allows such switchability. Some reaction rates are suppressed by factors of up to 120 by inclusive binding of the metal complexes. This puts nanometric coordination chemistry in a box that can be open or shut as necessary. Such second-sphere complexation can allow considerable control to be exerted on photocatalysis, electrocatalysis, and luminescent sensing involving polypyridineRu(II) compounds. The capturing states of hosts are symmetry-matched to guests for selective binding and display submicromolar affinities. A perching complex, which is an intermediate state between capturing and releasing states, is also demonstrated.

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Controlling the Photophysics of Aromatic Guests Using a Cyclic Porphyrin Dimer: Synthesis, Structure, and Encapsulation‐Mediated “ON‐OFF” Switch

Cited by 10 publications

References 116 publications

Synthesis, Characterization, and Encapsulation Properties of Rigid and Flexible Porphyrin Cages Assembled from N-Heterocyclic Carbene–Metal Bonds

Synthesis, Characterization, and Encapsulation Properties of Rigid and Flexible Porphyrin Cages Assembled from N-Heterocyclic Carbene–Metal Bonds

The Photocatalytic Degradation of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in the Presence of Silver–Titanium Based Catalysts

Taming Tris(bipyridine)ruthenium(II) and Its Reactions in Water by Capture/Release with Shape-Switchable Symmetry-Matched Cyclophanes

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