Fabrication and properties of Sn(iv) porphyrin-linked porous organic polymer for environmental applications

A robust porous organic polymer cross-linked by Sn(iv) porphyrin (SnPOP) was fabricated by reacting trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(iv) (SnP) with fluorinated polyimide (FPI) via sol-gel formation, followed by supercritical CO2 drying. The structural and porous properties of SnPOP were characterized using FT-IR, UV-vis, and fluorescence spectroscopies, along with field-emission scanning electron microscopy and gas sorption experiments. The reaction between the SnP's oxophilic Sn(iv) center and FPI's carboxylic acid moiety resulted in a controllable cross-linked porous texture. This material features the desirable physical properties of porphyrin and exhibits mesoporous structures with a relatively high surface area. SnPOP is thermally stable at temperatures up to 600 °C and highly resistant to boiling water, strong acids, and bases, owing to its assembly via formation of covalent bonds instead of typically weaker hydrogen bonds. The modified chemical and morphological structures of SnPOP showed an impressive CO2 uptake capacity of 58.48 mg g-1 at 273 K, with a preference for CO2 over N2. SnPOP showed significant efficiency in removing pollutant dyes, such as methylene blue and methyl orange, from dye-contaminated water. Additionally, SnPOP was a photocatalyst for fabricating silver nanoparticles of regular shape and size. All these properties make SnPOP a potential candidate for environmental applications like pollutant removal, gas storage, and separation.

Hybrid Composite of Sn(IV)-Porphyrin and Mesoporous Structure for Enhanced Visible Light Photocatalytic Degradation of Organic Dyes

Two hybrid composites (SnP@MCM-41 and SnP@SiO₂) were fabricated by chemical adsorption of (trans-dihydroxo)(5,10,15,20-tetraphenylporphyrinato)tin(IV) (SnP) on mesoporous structured Mobil Composition of Matter No. 41 (MCM-41) and SiO₂ nanoparticles. These materials were characterized by Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy, and field-emission scanning electron microscopy techniques. The incorporation of SnP into MCM-41 and SiO₂ supports efficient photocatalytic degradation of the anionic erioglaucine, cationic rhodamine B, and neutral m-cresol purple dyes under visible light irradiation in an aqueous solution. The performances of degradation of these dyes by these photocatalysts under visible light irradiation varied from 87 to 95%. The pseudo-first-order degradation rate constant of organic dyes for SnP@MCM-41 was higher than those of SnP@SiO₂ and SnP. These visible light photocatalysts showed remarkable stability and reliable reusability.

Sn(IV)-Porphyrin-Based Nanostructures Featuring Pd(II)-Mediated Supramolecular Arrays and Their Photocatalytic Degradation of Acid Orange 7 Dye

Two robust Sn(IV)-porphyrin-based supramolecular arrays (1 and 2) were synthesized via the reaction of trans-Pd(PhCN)2Cl2 with two precursor building blocks (SnP1 and SnP2). The structural patterns in these architectures vary from 2D to 3D depending on the axial ligation of Sn(IV)-porphyrin units. A discrete 2D tetrameric supramolecule (1) was constructed by coordination of {(trans-dihydroxo)[5,10-bis(4-pyridyl)-15,20-bis(phenyl) porphyrinato]}tin(IV) (SnP1) with trans-PdCl2 units. In contrast, the coordination between the {(trans-diisonicotinato)[5,10-bis(4-pyridyl)-15,20-bis(phenyl)porphyrinato]}tin(IV) (SnP2) and trans-PdCl2 units formed a divergent 3D array (2). Axial ligation of the Sn(IV)-porphyrin building blocks not only alters the supramolecular arrays but also significantly modifies the nanostructures, including porosity, surface area, stability, and morphology. These structural changes consequently affected the photocatalytic degradation efficiency under visible-light irradiation towards acid orange 7 (AO) dye in an aqueous solution. The degradation efficiency of the AO dye in the aqueous solution was observed to be between 86% to 91% within 90 min by these photocatalysts.

Assembly of Sn(IV)-Porphyrin Cation Exhibiting Supramolecular Interactions of Anion···Anion and Anion···π Systems

Trans-diaqua[meso-tetrakis(4-pyridyl)porphyrinato]Sn(IV) dinitrate complexes were assembled in a two-dimensional manner via hydrogen bonding between aqua ligands and pyridyl substituents. Interestingly, this supramolecular assembly was accompanied by unconventional noncovalent interactions, such as anion···anion and anion···π interactions, which were confirmed by X-ray crystallographic analysis. Two nitrate anions close to 2.070 Å were constrained in a confined space surrounded by four hydrogen-bonded Sn(IV)-porphyrin cations. The nitrate anion was also 3.433 Å away from the adjacent pyrrole ring, and the dihedral angle between the two mean planes was estimated to be 7.39°. The preference of the anion···π interaction was related to the electron-deficient π-system owing to the high-valent Sn(IV) center and cationic nature of the porphyrin complex. These two unconventional noncovalent interactions played an important role in the formation of a one-dimensional array with pairs of Sn(IV)-porphyrin cation and nitrate anion.

Sn(IV) Porphyrin-Based Ionic Self-Assembled Nanostructures and Their Application in Visible Light Photo-Degradation of Malachite Green

A series of porphyrin-based ionic complexes were prepared through the reaction of two porphyrin precursors, 5,10,15,20-tetrakis(4-(2-pyridyl)phenyl)porphyrin H2TPhPyP (1) and trans-dihydroxo [5,10,15,20-tetrakis(4-(2-pyridyl)phenyl)porphyrinato]tin(IV) Sn(OH)2TPhPyP (2), with various acids (HCl, HNO3, CF3COOH, H2SO4, H2CO3, and H3PO4). The complexes were characterized via elemental analysis, 1H nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV)-visible spectroscopy, fluorescence spectroscopy, and field-emission scanning electron microscopy (FE-SEM). Each compound exhibited different results for UV-visible, fluorescence, FT-IR, and FE-SEM studies depending on the counter anions. The complexes possessed different self-assembled nanostructures based on electronic interactions between the cations of compounds 1 and 2 with different counter anions. These aggregated species are stabilized by electrostatic forces and the π-π stacking interactions between the two porphyrin rings, in which the counter anions play an important bridging role. The counter anions also play an important role in controlling the morphology and photocatalytic properties of the as-developed materials. The complexes were then used for the photocatalytic degradation of the malachite green (MG) dye in aqueous media under visible light irradiation for up to 70 min. A morphology-dependent photocatalytic degradation of the MG dye was observed for all the ionic complexes, with efficiencies ranging from 50% to 95%.

Three Isomeric Zn(II)-Sn(IV)-Zn(II) Porphyrin-Triad-Based Supramolecular Nanoarchitectures for the Morphology-Dependent Photocatalytic Degradation of Methyl Orange

Three isomeric Zn(II)-Sn(IV)-Zn(II) porphyrin-based triads (T2, T3, and T4) were synthesized by the reaction of common Zn(II) porphyrins (ZnL) with different Sn(IV) porphyrins (SnP n ). The Sn(IV) porphyrin precursors differ with respect to the position of the pyridyl-N atoms. All compounds were characterized by 1H NMR, UV-vis, fluorescence spectroscopy, electrospray ionization-mass spectrometry, and field-emission scanning electron microscopy measurements. In these structures, the intramolecular cooperative metal-ligand coordination of the 3-pyridyl nitrogen in SnP 3 with axial ZnL and the π-π interactions between the adjacent porphyrin triad are the determining factors affecting the nanostructures of T3. Owing to the geometrical constraints of the SnP 2 center, this type of interaction is not possible for T2. Therefore, only the π-π interactions affect the self-assembly process. In the case of SnP 4 , intermolecular coordinative interactions and then π-π interactions are responsible for the nanostructure of T4. The morphology-dependent photocatalytic degradation of methyl orange (MO) dye in aqueous solution under visible light irradiation was observed for these photocatalysts, and the degradation ratio of MO varied from 76 to 94% within 100 min. Nanorod-shaped T3 exhibited higher performance compared to nanosphere T2 and nanoflake T4.

Morphology-controlled self-assembled nanostructures of complementary metalloporphyrin triads obtained through tuning their intermolecular coordination and their photocatalytic degradation of Orange II dye

Tuning the intermolecular metal–ligand coordination mode in a series of (Zn–Sn–Zn) porphyrin triads resulted in the formation of specific nanostructured photocatalysts for the visible light photodegradation of Orange II dye.

Coordination framework materials fabricated by the self-assembly of Sn(IV) porphyrins with Ag(I) ions for the photocatalytic degradation of organic dyes in wastewater

Two porphyrin-based coordination frameworks, [Ag2(TPyP)Sn(OH)2](NO3)2●(solv)x (1) and [Ag2(TPyP)Sn(INA)2](OTf)2●(CH3CN)2 (2) (INA = isonicotinato anion, OTf = CF3SO3-), were constructed by the self-assembly of hexacoordinated (meso-tetra-(4-pyridyl)porphyrinato)Sn(IV) building blocks with Ag(I) ions. They...

Spectrophotometric Study of Bridging N-Donor Ligand-Induced Supramolecular Assembly of Conjugated Zn-Trisporphyrin with a Triphenylamine Core

This article studies the supramolecular assembly behavior of a Zn-trisporphyrin conjugate containing a triphenylamine core (1) with bridging N-donor ligands using the UV-vis spectrophotometric titration method at micromolar concentrations. Our results show that pyridine, a non-bridging ligand, formed a 3:1 open complex with 1. The corresponding binding constant was estimated to be (2.7 ± 0.15) × 1014 M-3. In contrast, bridging ligands, 4,4-bipyridine (BIPY) and 1,3-di(4-pyridyl)propane (DPYP), formed stable 3:2 double-decker complexes with 1 in solution, which collapsed to yield a 3:1 open complex when excess BIPY or DPYP was added. The binding constants for forming BIPY and DPYP double-decker complexes were estimated to be (9.26 ± 0.07) × 1027 M-4 and (3.62 ± 0.16) × 1027 M-4, respectively. The UV-vis titration profiles supported the conclusion that the degradation of the 3:2 double-decker 1∙BIPY complex is less favorable compared to that of 1∙DPYP. Consequently, the formation of the 3:1 1∙DPYP open complex proceeded more readily than that of 1∙BIPY.

Self-Assembled Nanomaterials Based on Complementary Sn(IV) and Zn(II)-Porphyrins, and Their Photocatalytic Degradation for Rhodamine B Dye

A series of porphyrin triads (1–6), based on the reaction of trans-dihydroxo-[5,15-bis(3-pyridyl)-10,20-bis(phenyl)porphyrinato]tin(IV) (SnP) with six different phenoxy Zn(II)-porphyrins (ZnLⁿ), was synthesized. The cooperative metal–ligand coordination of 3-pyridyl nitrogens in the SnP with the phenoxy Zn(II)-porphyrins, followed by the self-assembly process, leads to the formation of nanostructures. The red-shifts and remarkable broadening of the absorption bands in the UV–vis spectra for the triads in CHCl₃ indicate that nanoaggregates may be produced in the self-assembly process of these triads. The emission intensities of the triads were also significantly reduced due to the aggregation. Microscopic analyses of the nanostructures of the triads reveal differences due to the different substituents on the axial Zn(II)-porphyrin moieties. All these nanomaterials exhibited efficient photocatalytic performances in the degradation of rhodamine B (RhB) dye under visible light irradiation, and the degradation efficiencies of RhB in aqueous solution were observed to be 72~95% within 4 h. In addition, the efficiency of the catalyst was not impaired, showing excellent recyclability even after being applied for the degradation of RhB in up to five cycles.

Supramolecular Porphyrin Nanostructures Based on Coordination-Driven Self-Assembly and Their Visible Light Catalytic Degradation of Methylene Blue Dye

A series of porphyrin triads (1–4), in which each triad is composed of a Sn(IV) porphyrin and two free-base (or Zn(II)) porphyrins, was synthesized and their self-assembled nanostructures were studied. Depending on the substituent on porphyrin moieties, each triad was self-assembled into a different nanostructure. In particular, the cooperative coordination of 3-pyridyl groups in the Sn(IV) porphyrin with the axial Zn(II) porphyrins in triad 4 leads to forming uniform nanofibers with an average width of 10–22 nm. Other triads without the coordinating interaction between the central Sn(IV) porphyrin and the axial porphyrins formed irregularly shaped aggregates in contrast. The morphologies of nanofiber changed drastically upon the addition of pyrrolidine, in which pyrrolidine molecules break down the self-assembly process by coordinating with the axial Zn(II) porphyrins. All porphyrin aggregates exhibited efficient photocatalytic performances on the degradation of methylene blue dye under visible light irradiation. The degradation efficiencies after 2 h were observed to be between 70% and 95% for the aggregates derived from the four triads.

Crystal structure of bis(benzoato-κO)[5,15-diphenyl-10,20-bis(pyridin-4-yl)porphyrinato-κ4 N,N′,N′′,N′′′]tin(IV)

In the crystal structure of the title compound, [Sn(C42H26N6)(C7H5O2)2], the SnIV ion is located on a crystallographic inversion centre and is octahedrally coordinated with an N4O2 set. Four N atoms of the porphyrin ring form the equatorial plane while the axial positions are occupied by two O atoms from benzoate anions. The molecular packing of the title complex involves non-classical hydrogen bonds of the types C—H...O and C—H...N, leading to a three-dimensional network structure.

Anionic Water Cluster Polymers [(H₂O)18(OH)₂]n2n- Is Stabilized by Bis(2,2'-bipyridine) Cupric Chloride [Cu(bipy)₂Cl]. Molecules 2018;23:molecules23010195. [PMID: 29351191 PMCID: PMC6017829 DOI: 10.3390/molecules23010195]

Anionic water clusters have long been studied to infer properties of the bulk hydrated electron. In particular, the question of whether the excess electron is on the surface of the cluster or in the interior of the clusters has been the subject of much speculation. The successes of solid-state physics are built on exploiting the regularity of atomic arrangements in crystal. Describing the crystalline order of solids is relatively straightforward. Here we report the crystal structure of an anionic water cluster polymer [(H₂O)₁₈(OH)₂]_n^2n- moiety that is stabilized by bis(2,2'-bipyridine) cupric chloride [Cu(bipy)₂Cl]^- host.

A Water Cluster Conduit in Crystal

The crystal structure of compound (1), [CuCl(phen)(H₂NCH₂COO)]∙4H₂O, reveals an unusual hydrogen-bond water cluster aggregate T6(2)6(2). Four water molecules in (1) form an isolated water cluster, [(H₂O)₁₄]_n, resembling a “phenanthro-[1,2]phenanthrene polymer structure shape” along the ac plane. The two face-face parallel [(H₂O)₁₄]_n planes are bridged by Cl atoms in [CuCl(phen) (H₂NCH₂COO)] with a strong O-H∙∙∙Cl hydrogen bond to form a water cluster conduit.

Aggregation-controlled excimer emission in an axial anthracene–Sn(iv)porphyrin–anthracene triad in the solid and solution phases

An anthracene–porphyrin donor–acceptor triad has been synthesized and its photophysical properties along with excimer behavior are investigated.

Interfacial self-assembly driven formation of hierarchically structured nanocrystals with photocatalytic activity

We report the synthesis of hierarchical structured nanocrystals through an interfacial self-assembly driven microemulsion (μ-emulsion) process. An optically active macrocyclic building block Sn (IV) meso-tetraphenylporphine dichloride (tin porphyrin) is used to initiate noncovalent self-assembly confined within μ-emulsion droplets. In-situ studies of dynamic light scattering, UV-vis spectroscopy, and electron microscopy, as well as optical imaging of reaction processes suggest an evaporation-induced nucleation and growth self-assembly mechanism. The resulted nanocrystals exhibit uniform shapes and sizes from ten to a hundred nanometers. Because of the spatial ordering of tin porphyrin, the hierarchical nanocrystals exhibit collective optical properties resulting from the coupling of molecular tin porphyrin and photocatalytic activities in the reduction of platinum nanoparticles and networks and in photodegradation of methyl orange (MO) pollutants.

1D water chain stabilized by meso-expanded calix[4]pyrrole

A new core expanded calix[4]pyrrole is reported, in which the opposite bridging sp³-carbons are replaced by ethylene moieties.

Bis-(methane-sulfonato-κO)(5,10,15,20-tetra-phenyl-porphyrinato-κ(4)N,N',N'',N''')tin(IV) chloro-form tris-olvate

In the crystal structure of the title compound, [Sn(C₄₄H₂₈N₄)(CH₃O₃S)₂]·3CHCl₃, the Sn^IV ion is located on an inversion center and is octa­hedrally coordinated. The porphyrin N atoms occupy the equatorial positions while the axial positions are occupied by the O atoms of the methane­sulfonate anions. The phenyl rings make dihedral angles of 77.02 (13) and 87.89 (14)° with the porphyrin ring. Of the three solvent chloro­form mol­ecules, one is disordered over a twofold rotation axis. In the crystal a three-dimensional assembly is accomplished via C—H⋯O hydrogen bonds between the H atoms of the phenyl groups in the porphyrin ring and the O atoms of the methane­sulfonate ligands.

Sn(IV) porphyrin based axial-bonding type porphyrin triads containing heteroporphyrins as axial ligands

The thiaporphyrin building blocks with N(3)S and N(2)S(2) cores containing one hydroxyphenyl functional group at the meso position were synthesized by adopting the unsymmetrical thiophene diol method. These monohydroxy thiaporphyrins were used to construct the first examples of axial bonding type Sn(IV) porphyrin triads in which Sn(IV) porphyrin acts as basal unit and the two thiaporphyrin units as axial ligands by treating with SnTTP(OH)(2) in benzene at refluxing temperature. The axial bonding type triads were confirmed by mass, 1D and 2D NMR studies. The absorption and electrochemical studies support weak ground state interaction among the porphyrin subunits within the porphyrin triads. The fluorescence studies indicate there is a possibility of energy transfer at the singlet state from basal Sn(IV) porphyrin unit to axial thiaporphyrin units.

Conformations and Electronic Structures of Axially Coordinated Fullerene−Porphyrin−Fullerene Triad (C60CHCOO)2−Sn(IV) Porphyrin

The conformational (cis and trans) stability and electronic structures of (C(60)CHCOO)(2)-Sn(IV) porphyrin, recently synthesized as a novel fullerene-porphyrin-fullerene triad linked by metal axial coordination, have been studied by ab initio calculations. The cis conformer was found to be slightly more stable than the trans by 1.38 kcal/mol in the neutral compound. Upon the addition of an electron to the triad, the relative stability of the cis conformer was found to be higher (3.29 kcal/mol) than that in the neutral one. From the investigation of frontier molecular orbitals, for the cis conformer, it was found that the electrons are localized in HOMO of the porphyrin, while the electrons are localized in LUMO of the syn-fullerene. For the trans conformer, it was found that the electrons are localized in HOMO of the porphyrin, while the electrons are localized in LUMO of one of the two fullerene moieties, and the electrons are localized in LUMO2 of the other fullerene moiety, but the LUMO and LUMO2 have the same orbital energy. Thus, the PET may take place unidirectionally in the cis conformer from the porphyrin to the syn-fullerene, while it is bidirectional from the porphyrin to both of the fullerene moieties.