Phthalocyanine Network Research Articles

Metallophthalocyanine-based covalently cross-linked polymers as a recycled visible-light photocatalyst in pollutants removal

In this article, we presented a novel and facile method for obtaining a phthalocyanine network polymer via “Thiol-Ene Click” chemistry. A series of metallophthalocyanine-based covalently cross-linked polymers (MTUPc-CCPs, M = Zn, Cu and Co) containing hydrophilic sulfur-containing flexible chain were synthesized successfully, the MTUPc-CCPs had micropores and mesopores coexistence structure and remarkable efficiency for organic dye pollutants and Cr (VI) removal from wastewater. The photocatalytic efficiency of MTUPc-CCPs was significantly improved compared with the corresponding phthalocyanine monomers. Thereinto, ZnTUPc-CCP had the most excellent photocatalytic performances for Methyl orange (MO), Rhodamine B (RhB) degradation and Cr (VI) reduction (3 h, 95.4%, 93.2% and 100%) under visible-light irradiation. These obtained results can be attributed to the wide spectral response, larger surface area and higher micropore ratio of ZnTUPc-CCP. ZnTUPc-CCP was reused for three consecutive cycles without significant loss of activity or structural changes. Furthermore, active species trapping experiments confirmed the crucial role of O2•−, 1O2 and OH•/e− during photocatalytic degradation/reduction, upon which a possible photocatalytic mechanism was proposed. Above all, ZnTUPc-CCP was a promising potential visible-light photocatalyst on the degradation of complex contaminants.

Defect Engineering in Polymeric Cobalt Phthalocyanine Networks for Enhanced Electrochemical CO2 Reduction

AbstractThe electrochemical reduction of CO2 into fuels and valuable chemicals represents an appealing approach to alleviate energy crisis and global warming. Due to its sluggish reaction kinetics and the lack of suitable electrocatalysts it remains a major challenge. In this work, we report a facile synthetic approach to engineer a polymeric cobalt phthalocyanine network with rich defects for significantly enhanced electrocatalytic activity for CO2 reduction. The successful defect engineering not only promotes the formation of a stronger binding surface towards CO2, but also simultaneously turns the electronic character of the resulting cobalt phthalocyanine framework. As a result, the new defective polymer exhibits highly selective catalysis of aqueous reduction of CO2 into CO with a large faradaic efficiency of ca. 97 %, low applied overpotential of 490 mV (versus a reversible hydrogen electrode) and long‐term stability. We anticipated that this new strategy could inspire the discovery of new organic frameworks for efficient CO2 reduction, such as those (defective MOFs, COFs etc.), evidently advancing the development of catalysts for the CO2 reduction reaction.

Catalytic Oxidation of Thiols within Cavities of Phthalocyanine Network Polymers

Two three-dimensional (3D) network polymers (1 and 2), in which zinc(II) or cobalt(II) phthalocyanines were interconnected with twisted 9,9′-spirobifluorene linkers, were synthesized in order to investigate their performance as heterogeneous catalysts for thiol oxidations. From the spectroscopic analyses of two dimers (3 and 4) as component units of the network polymers, 3 connected with a short linker revealed electronic interaction between the two phthalocyanine units. Micrometer-sized polymer particles were formed due to the condensation of the twisted 9,9′-spirobifluorene linkers in the presence of zinc or cobalt ions. The dispersed solutions of 1 and 2 had sharp Q-bands, indicating the prevention of stacking among phthalocyanine moieties within the polymers. Powdered X-ray diffraction pattern and N2 adsorption–desorption analyses suggested that 1 created small and rigid cavities as compared with 2 through the regular spatially arrangement of the phthalocyanine moieties in the 3D networks. The photoca...

Indium(III) phthalocyanine eka-conjugated polymer as high-performance optical limiter upon nanosecond laser irradiation

A novel chloroindium(III) phthalocyanine network polymer (4) was prepared and characterized by energy dispersive X-ray spectrometry, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA) and absorption and emission spectroscopies. The non-linear optical (NLO) profile of the prepared phthalocyanine (Pc) network polymer, derived from a nanosecond open-aperture Z-scan technique at 532 nm, shows a clear reverse saturable absorption and a high non-linear absorption coefficient ( α2) of 9.7 × 10−7 cm W−1. Optical limiting investigations indicated that the prepared Pc network polymer has a relatively low limiting threshold of 900 mJ cm−2. According to these results, the prepared Pc polymer is a promising material for many NLO applications.

Inside Cover: Porous Azo‐Bridged Porphyrin–Phthalocyanine Network with High Iodine Capture Capability (Chem. Eur. J. 33/2016)

Inside Cover: Porous Azo‐Bridged Porphyrin–Phthalocyanine Network with High Iodine Capture Capability (Chem. Eur. J. 33/2016)

Porous Azo-Bridged Porphyrin-Phthalocyanine Network with High Iodine Capture Capability.

We report a highly efficient iodine adsorbent achieved by rational design of a porous azo-bridged porphyrin-phthalocyanine network (AzoPPN), which was synthesized by a catalyst-free coupling reaction between free-base 5,10,15,20-tetrakis(4-nitrophenyl)-porphyrin and nickel tetraaminophthlocyanine. AzoPPN has a permanent porous structure and plenty of porphyrin and phthalocyanine units in the skeleton as effective sorption sites. It displays excellent adsorption of iodine vapor up to 290 wt. % and also shows remarkable capability as adsorbent for iodine in solution. This strategy of combining physisorption with chemisorption in one adsorbent will pave the way for the development of new materials for iodine capture.

Magnetic anisotropy of metal functionalized phthalocyanine 2D networks

The magnetic anisotropy of metal including Cr, Mn, Fe, Co, Mo, Tc, Ru, Rh, W, Re, Os, Ir atoms functionalized phthalocyanine networks have been investigated with first-principles calculations. The magnetic moments can be expressed as 8-n μB with n the electronic number of outmost d shell in the transition metals. The huge magnetocrystalline anisotropy energy (MAE) is obtained by torque method. Especially, the MAE of Re functionalized phthalocyanine network is about 20meV with an easy axis perpendicular to the plane of phthalocyanine network. The MAE is further manipulated by applying the external biaxial strain. It is found that the MAE is linear increasing with the external strain in the range of −2% to 2%. Our results indicate an effective approach to modulate the MAE for practical application.

Magnetic moment formation in metal-organic monolayers

We investigate the electronic and magnetic properties of a two-dimensional polymeric manganese phthalocyanine (Mn-Pc) network and its derivative, the metal-ligand network Mn-TCNB formed by the transition-metal atom Mn and the organic ligand TCNB (1,2,4,5-tetracyanobenzene), using first-principles calculations on the basis of density functional theory (DFT) with the Hubbard-like Coulomb term. Our calculations show that Mn-Pc and Mn-TCNB are metallic. It is found that the Mn-Pc network is more stable than the Mn-TCNB one, and both have a total magnetic moment of about $3{\ensuremath{\mu}}_{B}$. In the case of Mn-Pc, also the local Mn moment is close to $3{\ensuremath{\mu}}_{B}$. But in Mn-TCNB, we find a high spin state $S=5/2$ at Mn that is partially screened by unpaired electrons at the ligands. That screening is static in the $\mathrm{DFT}+U$ results, but we argue in favor of a dynamical screening in reality. Using our proper model calculation on the basis of a suitable model Hamiltonian, we explain the ab initio calculations, analyze the partial screening effect that exists in the two-dimensional Mn-TCNB network, and compare both systems.

Graphene-Induced Magnetic Anisotropy of a Two-Dimensional Iron Phthalocyanine Network.

A single layer of flat-lying iron phthalocyanine (FePc) molecules assembled on graphene grown on Ir(111) preserves the magnetic moment, as deduced by X-ray magnetic circular dichroism from the Fe L2,3 edges. Furthermore, the FePc molecules in contact with the graphene buffer layer exhibit an enhancement of the magnetic anisotropy, with emergence of an in-plane easy magnetic axis, reflected by an increased orbital moment of the FePc molecules in contact with the C atoms in the graphene sheet. The origin of the increased magnetic anisotropy is discussed, considering the absence of electronic state hybridization, and the breaking of symmetry upon FePc adsorption on graphene.

Properties of Penta-tert-butylcorannulene Molecules Inserted in Phthalocyanine Networks Studied by Low-Temperature Scanning Tunneling Microscopy

Octachloro zinc phthalocyanine networks on Ag(111) have been used as host structures for the insertion of penta-tert-butylcorannulene (PTBC) molecules. At ambient temperature, the resulting coassemblies generally present lines or chessboard structures, depending on the PTBC coverage. In this paper, it is shown that the annealing of these structures leads to the formation of novel networks in which the interplay of both molecules plays a major role. The presence of PTBC is also found to prevent the phase transition that generally appears in the phthalocyanine host lattices. PTBC molecules show two different positions with respect to the phthalocyanine networks when the observations are conducted at 4.6 K while at liquid nitrogen temperature (77 K), some of them appear with six bump features. Calculations suggest that this originates from the rotation barriers of the PTBC molecules in the host molecular structures. Finally, evaporation of the PTBC on a cooled substrate shows that the PTBC adsorbs on top of the Zn atom of the phthalocyanine and presents a nonuniform contrast due to the peculiar geometry of the PTBC/phthalocyanine structure.

Catalytic oxidation of sulphide ions using a novel microporous cobalt phthalocyanine network polymer in aqueous solution

Abstract A novel microporous cobalt phthalocyanine network polymer (CoPc-PIM1), prepared by the Pc-forming reaction from a rigid and nonplanar bisphthalonitrile, exhibits high surface area (650 m 2 /g) with high concentration of subnanometer pores (0.6–0.7 nm). High resolution transmission electron microscopic image shows microporous structure with nanoscale voids. This material shows pronounced efficiency for desulphurisation of salt water by catalyzing the oxidation of sulphide ions with aerobic oxygen. The reaction product includes mainly elemental sulphur which poisons the catalyst. The catalyst efficiency was easily regenerated, and found to be equivalent to the fresh catalyst for several cycles.

Influence of stress on hydrogen-bond formation in a halogenated phthalocyanine network

Influence of stress on hydrogen-bond formation in a halogenated phthalocyanine network

Adsorption Studies of a Microporous Phthalocyanine Network Polymer

The adsorption/desorption of N2 at 77 K and the adsorption from aqueous solution at 298 K of four organic probe molecules of different sizes (phenol, 4-nitrophenol, orange II, naphthol green B) were studied for a phthalocyanine network polymer of intrinsic microporosity (PIM) and for an activated carbon (Darco 20-40 mesh). N2 sorption analysis gave similar surface areas for the PIM and the carbon (610 and 545 m2 g(-1), respectively) but showed differences in pore size distribution, the PIM being essentially microporous (pore size < 2 nm), with a high proportion of ultramicropores (<0.7 nm), while the carbon had a broader pore size distribution, extending into the mesopore region. The carbon acted as an adsorbent for all the organic probe molecules studied, while the PIM was more selective, adsorbing the smaller molecules but rejecting the large dye naphthol green B. The PIM offers selectivity combined with a well-defined chemical structure incorporating catalytic sites.

ChemInform Abstract: Towards Phthalocyanine Network Polymers for Heterogeneous Catalysis

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Dioxa-dithia Macrocycle-bridged Dimeric with Hexakis(alkylthio) Substituents and Network Polymer Phthalocyanines

1,7-dithia (12-crown-4)-bridged phthalocyanine network polymers were prepared from tetracyanodibenzo-[1,7-dithia(12-crown-4)]. In addition, the synthesis of two 1,7-dithia (12-crown-4) linked peripherally octa-substituted dimeric phthalocyanines, which contain a combination of hexakis(alkylthia) side chains, is described. These extremely soluble compounds were prepared by the condensation of an iminoisoindoline derivative and a subphthalocyanine. The novel compounds are characterized by elemental analyses, UV/vis, IR, mass,1H NMR and13C NMR spectroscopy. The electrical conductivity measurements of three of the four network polymers were unsuccessful; however chemical doping with NOBF4could be increased to a measurable value. The electrical conductivity of the dimeric phthalocyanines are in the semiconductor range.

Crown‐ether‐substituted phthalocyanines. Control of supramolecular organization by monovalent and divalent metal salts

AbstractAggregation of crown‐ether‐substituted phthalocyanines with monovalent metal ions (K+, Rb+, and Cs+) results in cofacially ordered phthalocyanine stacks. Aggregation with Ba2+ leads to the formation of phthalocyanine networks.

Synthesis and characterisation of conductive metal-free phthalocyanine copolyoxyethylene polymeric networks

A novel route for the thermal conversion of phthalonitrile derivatives into metal-free phthalocyanine electroactive entities has been investigated. Three new phthalonitrile end-capped polyoxyethylene oligomers were synthesized. These oligomers were thermally polymerized with 3,4-dicyanbenzhydrol. The reaction occurred by an oxidoreduction process involving the transformation of the benzhydrol alcohol functional group into a ketonic function. The characterization of the yielded metal-free phthalocyanine networks showed that their thermal stability and their mechanical properties are closely dependent on the molecular mass of the aliphatic polyether linkages. The polymeric networks exhibited an elastomeric behavior with glass transition temperatures at 182°C, 131°C and −2°C and softening temperatures at 308°C, 195°C and 162°C respectively for the networks carrying polyoxyethylene sequences M = 88, M = 200 and M = 400. X-ray diffraction analysis revealed a very restricted structural order resulting from the coplanar association of phthalocyanine rings. The study of the electrical dc conductive properties showed that the initial superficial resistivity could be increased by five orders of magnitude to reach 3.5 × 10 6 Ω/ square after doping with iodine vapor.

Polymères Thermostables: Thermoplastiques Et Thermodurcissables, Nouvelles Tendances

AbstractThis paper deals with the recent developments and the trends in the field of the heat resistant linear and thermosetting polymers.Two driving forces can explain the recent important efforts of research and development. The first target is the improvement of the processability for these materials and the second one is the strong demand for heat resistant macromolecules with specific properties such as low thermal expansion coefficient, low loss factor, low permittivity, improved toughness…Three types of material will be discussed in this paper: the linear polymers, the thermosetting resins and the semi‐interpenetrated networks (semi IPN's).The heat resistant linear polymers are generally amorphous, their high viscosities above the glass transition (Tg) limits the processability and the rather low Tg does not allow the high temperature application. In order to solve these problems, three main approaches have been studied. First the crystalline polyimides were prepared by introducing ether ketone sequences in the main chain so the high temperature properties are governed by the crystalline transitions. The second approach is the development of amorphous fully cyclized polymers exhibiting high Tg. These polymers were obtained with bulky or fluorinated group in the backbone. Finally a new concept is now developed, it is based on an intramolecular thermal rearrangement occuring in a flexible main chain and leading to a rigid one.Concerning the heat resistant thermosetting resins, the following problems have to be solved: the low solubility of this type of telechelic oligomers, their high melting point and, as a consequence, the very narrow processability window and the brittle character of the final network. For these purposes, the bis‐maleimide were crosslinked with allylic resins, a new soluble precyclized nadimide resin was developed and a new concept of redox reaction for the formation of phthalocyanine network was discovered.Very promising seems the semi IPN's networks in the field of the heat resistant polymers. Starting from the same diamine for the preparation of linear and thermosetting resins (bis‐maleimides and end‐capped acetylenic resins) allows a good miscibility of the mixture of linear and thermoset before curing.After crosslinking a phase segregation occurs. Good mechanical properties are observed above the Tg of the linear polyimide. The thermal stability of the semi‐IPN is strongly dependent on the nature of the thermosetting resins, so the semi‐IPN's with acetylenic are more thermostable than the semi IPN's with bis‐maleimide.

Synthesis and properties of (18‐crown‐6)‐bridged phthalocyanine network polymers

Abstract(18‐Crown‐6)‐bridged phthalocyanine network polymers 4–8 as well as a low‐molecular‐weight model compounds with only one phthalocyanine unit (3a, b) were prepared from tetracyanodibenzo‐18‐crown‐6 (2a). The cyano end groups were partially converted into imido groups during the cyclotetramerization reaction, as detected from the IR spectra. In order to obtain structurally uniform compounds with the same end groups, the C  N groups were hydrolyzed into imido groups with conc. sulfuric acid. The metal‐free phthalocyanine polymer 4a was obtained by the reaction of 2a either with hydroquinone or PbO in ethylene glycol. The chlorides of Cu(II), Ni(II), and Co(II) were empolyed in order to synthesize the corresponding metal‐phthalocyanine polymer, and Fe(CO)5 was used for the preparation of the Fe‐analog 7a. For the preparation of the Co‐containing polymer 8a ammonium molybdate has to be added as catalyst. The selectivity of 7a for Rb+ was found to be highest in the heterogeneous phase extraction experiments. Polymers 4–8 are also capable of binding silver from aqueous and methanolic solutions.

Synthesis of polyphthalocyanines by an oxidoreduction reaction initiated by the benzhydrol functional group. I. Model study

AbstractA novel route for the thermal conversion of bis(phthalonitrile)monomers into metal‐free phthalocyanine network polymers was investigated on the basis of a model study on the tetramerization reaction of 4‐benzoylphthalonitrile and benzhydrol derivatives into metal‐free phthalocyanine compounds. This procedure of conversion of phthalonitrile derivatives involved an oxidoreduction reaction initiated by the alcohol functional group of benzhydrol coreactant. The influence of molar ratio of phthalonitrile and benzhydrol functional groups, chemical environment of the benzhydrol reducing group has been studied by microcalorimetry and electronic spectroscopy. It was observed that the theoretical 4 : 1 phthalonitrile: benzhydrol molar ratio is respected and the reductive capacity of the benzhydrol group is increased by the electron withdrawing effect of its substituants.