Graphene Oxide/Zinc Phthalocyanine Selective Singlet Oxygen Visible-Light Nanosensor for Raman-Inactive Compounds.

A novel phthalocyanine-based hybrid nanofilm is for the first time successfully applied as an oxidative platform for surface enhanced Raman spectroscopy (SERS) sensing to fine-resolve Raman-inactive compounds. The hybrid is formed by self-assembly of zinc(II) 2,3,9,10,16,17,23,24-Octa[(3',5'-dicarboxy)-phenoxy]phthalocyaninate (ZnPc*) with the solid-supported monolayer of graphene oxide (GO) mediated by zinc acetate metal cluster. Atomic force microscopy, UV-vis and fluorescence spectroscopies confirm that this simple coordination motive in combination with molecular structure of ZnPc* prevents contact quenching of the light-excited triplet state through aromatic stacking with GO particles.

Pivotal Role of the Intracellular Microenvironment in the High Photodynamic Activity of Cationic Phthalocyanines.

To investigate the influence of phthalocyanine aggregation on their photodynamic activity, a series of six cationic water-soluble zinc(II) phthalocyanines bearing from four to sixteen 4-((diethylmethylammonium)methyl)phenoxy substituents was synthesized. Depending on their structure, the phthalocyanines have different aggregation behaviors in phosphate buffer solutions ranging from fully assembled to monomeric states. Remarkably, independent of aggregation in buffer, very high photodynamic efficiencies against the tumor cell lines MCF-7 and MDA-MB-231 in the nanomolar range were found for all investigated phthalocyanine, and the IC(light) varied from 27 to 358 nM (3.

An unexpected imidazole-induced porphyrinylphosphonate-based MOF-to-HOF structural transformation leading to the enhancement of proton conductivity.

Post-synthetic modification of proton-conducting metal-organic frameworks (MOFs) by loading small molecules capable of generating protons into pores is an efficient approach for developing a new type of material with improved ionic conductivity. Herein, the synthesis, characterization and proton conductivity of a novel electroneutral MOF based on palladium(II) -tetrakis(4-(phosphonatophenyl))porphyrinate, IPCE-1Pd, are reported. The exposure of the obtained framework to imidazole by the diffusion vapor method has surprisingly led to its complete crystal-to-crystal MOF-to-HOF transformation, resulting in the formation of a novel hydrogen-bonded organic framework (HOF) IPCE-1Pd_Im, which is the first example of such kind of structural change among all known MOFs.

Phosphonate-Substituted Pyrazinoporphyrin - a General Photocatalyst for Efficient Sulfoxidation.

An exceptional efficiency of pyrazine-annelated porphyrin as a general photocatalyst for the oxidation of organic sulfides is demonstrated. It is shown that phosphonate-substituted pyrazinoporphyrin 2H-1 brings together sufficient photostability and high efficiency in the aerobic photooxidation of a series of various sulfides. The influence of the reaction conditions onto the efficiency of homogeneous sulfide photooxidation in the presence of the photosensitizer (PS) was investigated and strong dependence on the solvent system was observed.

Synergism of primary and secondary interactions in a crystalline hydrogen peroxide complex with tin.

Despite the significance of HO-metal adducts in catalysis, materials science and biotechnology, the nature of the interactions between HO and metal cations remains elusive and debatable. This is primarily due to the extremely weak coordinating ability of HO, which poses challenges in characterizing and understanding the specific nature of these interactions. Herein, we present an approach to obtain HO-metal complexes that employs neat HO as both solvent and ligand.

Unexpected Supramolecular-Induced Redox Switching in Sandwich Gd Bisphthalocyaninate.

The redox state of the phthalocyanine in sandwich lanthanide complexes is crucial for their applications. In this work, we demonstrate that the cation-induced supramolecular assembly of crown-substituted phthalocyanine lanthanide complexes Ln[(15C5)Pc] can be used to control the redox state of the ligand simultaneously with the coordination sphere of the central metal. We achieve unprecedented redox switching of phthalocyanine ligands in a double-decker Gd(III) complex, resulting from the intramolecular inclusion of potassium cations between the decks with simultaneous twisting of the ligands (the skew angle between them decreases from 44.

Magnetic Anisotropy of Homo- and Heteronuclear Terbium(III) and Dysprosium(III) Trisphthalocyaninates Derived from Paramagnetic H-NMR Investigation.

H-NMR spectroscopy of lanthanide complexes is a powerful tool for deriving spectral-structural correlations, which provide a clear link between the symmetry of the coordination environment of paramagnetic metal centers and their magnetic properties. In this work, we have first synthesized a series of homo- (M = M* = Dy) and heteronuclear (M ≠ M* = Dy/Y and Dy/Tb) triple-decker complexes , where BuO- and 15C5- are, respectively, butoxy and 15-crown-5 substituents on phthalocyanine (Pc) ligands. We provide an algorithmic approach to assigning the H-NMR spectra of these complexes and extracting the axial component of the magnetic susceptibility tensor, χax.

Phthalocyanine aggregates in the photodynamic therapy: dogmas, controversies, and future prospects.

Photodynamic therapy (PDT), a rapidly developing method for the treatment of cancer and bacterial diseases, is based on the photosensitization of oxygen to generate reactive oxygen species (ROS) that destroy specific biological targets. Among the various photosensitizers, phthalocyanines (Pc) have attracted particular attention due to their excellent photophysical properties, most of which meet the therapeutic requirements. The statement that aggregation of Pc-based photosensitizers is undesirable because it suppresses ROS generation has become commonplace in PDT.

Nanostructured Aluminum Oxyhydroxide-A Prospective Support for Functional Porphyrin-Based Materials.

A method for the grafting of unsymmetrical ABC-type 5,15-bis(4-butoxyphenyl)-10-(4-carboxyphenyl)-20-(phenanthrenoimidazolyl)-porphyrin onto the surface of nanostructured aluminum oxyhydroxide modified with a single SiO layer (NAOM) was successfully developed. A straightforward procedure towards surface modification of NAOM allowed us to prepare a new porphyrin-containing hybrid material. The obtained 3D heterostructure was extensively characterized using XPS, TEM and diffuse reflectance spectroscopy.

Solvation-Induced Conformational Switching of Trisphthalocyanates for Control of Their Magnetic Properties.

Stabilization of different conformers of sandwich phthalocyaninates by changing the solvation environment has been demonstrated with the examples of new heteroleptic yttrium(III) and terbium(III) triple-decker complexes (where M = Y or Tb, [(BuO)Pc] = octa--butoxyphthalocyaninato ligand, and [(15C5)Pc] = tetra-15-crown-5-phthalocyaninato ligand). To this end, we have performed a comprehensive crystallographic characterization of two solvates formed by the Y(III) complex with either toluene or dichloromethane. In the solvate with toluene, both pairs of Pc ligands are in staggered conformations, providing both metal cations with a square-antiprismatic environment.

Site-Selective Solvation-Induced Conformational Switching of Heteroleptic Heteronuclear Tb(III) and Y(III) Trisphthalocyaninates for the Control of Their Magnetic Anisotropy.

In the present work, we report the synthesis of isomeric heteronuclear terbium(III) and yttrium(III) triple-decker phthalocyaninates (M = Tb, M* = Y or M = Y, M* = Tb, [(BuO)Pc]-octa--butoxyphthalocyaninato-ligand, [(15C5)Pc]-tetra-15-crown-5-phthalocyaninato-ligand). We show that these complexes undergo solvation-induced switching: the conformers in which both metal centers are in square-antiprismatic environments are stabilized in toluene, whereas in dichloromethane, the metal centers M and M* are in distorted prismatic and antiprismatic environments, respectively. This conclusion follows from the detailed analysis of lanthanide-induced shifts in H NMR spectra, which makes it possible to extract the axial component of the magnetic susceptibility tensor χaxTb and to show that this term is particularly sensitive to conformational switching when terbium(III) ion is placed in the switchable "M" site.

Antimicrobial activity of photosensitizers: arrangement in bacterial membrane matters.

Porphyrins are well-known photosensitizers (PSs) for antibacterial photodynamic therapy (aPDT), which is still an underestimated antibiotic-free method to kill bacteria, viruses, and fungi. In the present work, we developed a comprehensive tool for predicting the structure and assessment of the photodynamic efficacy of PS molecules for their application in aPDT. We checked it on a series of water-soluble phosphorus(V) porphyrin molecules with OH or ethoxy axial ligands and phenyl/pyridyl peripheral substituents.

An anionic porphyrinylphosphonate-based hydrogen-bonded organic framework: optimization of proton conductivity through the exchange of counterions.

Hydrogen-bonded organic frameworks (HOFs) possessing high crystallinity, simple synthetic procedure and easy regeneration provide high efficiency as multifunctional systems, including applications as proton conductors. Porphyrinylphosphonates having acidic moieties, which can form multiple hydrogen bonds, together with tunable physical-chemical properties of a macrocycle may significantly improve the proton conductivity of such materials. Herein, the synthesis, characterization and proton-conducting properties of a novel anionic HOF based on a new complex of palladium(II) with -tetrakis(4-(phosphonatophenyl))porphyrin, HOF-IPCE-1Pd, are reported.

Supramolecular hybrids based on Ru(II) porphyrin and octahedral Mo(II) iodide cluster.

The coordination-driven design and synthesis of new stable supramolecular cluster-porphyrin (CP) hybrids based on an A-type ruthenium porphyrin 5,15-bis[(-tolyl)porphyrinato(2-)]ruthenium(carbonyl)(aqua) [RuDTolP(CO)H2O] and an octahedral molybdenum(II) iodide cluster with six terminal isonicotinate ligands (BuN)[{MoI}(OOC-CHN)] (PyMoC) are reported. The stepwise supramolecular assembly of the PyMoC "superoctahedron" with RuDTolP(CO)H2O has been studied by H NMR and 2D H-H COSY, H-N HMBC and DOSY techniques, as well as by UV-vis spectroscopy and HR-ESI mass spectrometry. The formation of discrete cluster-porphyrin CPn adducts with different numbers of coordinated porphyrins ( = 1-6), including the geometrical isomers of CP2, CP3 and CP4, has been observed.

Tuning Photochemical and Photophysical Properties of P(V) Phthalocyanines.

The ability of P(V) phthalocyanines (Pcs) for efficient singlet oxygen (SO) generation was demonstrated for the first time by the example of unsubstituted and α- and β-octabutoxy-substituted P(V)Pcs with hydroxy, methoxy and phenoxy ligands in the apical positions of the octahedral P centre. Variation of substituents in Pc ring and P(V) axial ligands allows careful tuning of photophysical and photochemical properties. Indeed, a combination of BuO groups in the β-positions of the Pc ring and PhO groups as axial ligands provides significant SO generation quantum yields up to 90%; meanwhile, the values of SO generation quantum yields for others investigated compounds vary from 27 to 55%.

Switchable Nanozyme Activity of Porphyrins Intercalated in Layered Gadolinium Hydroxide.

In this study, organo-inorganic nanohybrids with enzyme-like activity were prepared by in situ intercalation of anionic 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin and its complexes with Zn(II) and Pd(II) (, M = 2H, Zn(II) and Pd(II)) into gadolinium layered hydroxide (). The combination of powder XRD, CHNS analysis, FT-IR, EDX, and TG confirmed the layered structure of the reaction products. The basal interplanar distances in samples were 22.

Substitution pattern in ruthenium octa-n-butoxyphthalocyanine complexes influence their reactivity in N-H carbene insertions.

Ruthenium phthalocyanine complexes bearing -OBu substituents in the peripheral or non-peripheral positions are efficient catalysts for the selective double or single carbene insertion to the amine N-H bonds. This complementary reactivity of two Ru complexes can be used for the synthesis of asymmetric tertiary amines and diamines bearing different substituents and has been demonstrated by two examples of readily available primary amines using different carbene precursors in successive reactions.

Structure Determination of Binuclear Triple-Decker Phthalocyaninato Complexes by NMR via Paramagnetic Shifts Analysis Using Symmetry Peculiarities.

The detailed knowledge about the structure of multinuclear paramagnetic lanthanide complexes for the targeted design of these compounds with special magnetic, sensory, optical and electronic properties is a very important task. At the same time, establishing the structure of such multinuclear paramagnetic lanthanide complexes in solution, using NMR is a difficult task, since several paramagnetic centers act simultaneously on the resulting chemical shift of a particular nucleus. In this paper, we have demonstrated the possibility of molecular structure determination in solution on the example of binuclear triple-decker lanthanide(III) complexes with tetra-15-crown-5-phthalocyanine Ln[(15C5)Pc] {where Ln = Tb () and Dy ()} by quantitative analysis of the pseudo-contact lanthanide-induced shifts (LIS).

Rare-earth based tetrapyrrolic sandwiches: chemistry, materials and applications.

The unique properties of natural tetrapyrrolic compounds have inspired the rapid growth of research interest in the design and synthesis of artificial porphyrinoids and their metal complexes as a basis of modern functional materials. A special role in the design of such materials is played by sandwich complexes formed by tetrapyrrolic macrocycles with rare earth elements, especially lanthanides. The development of synthetic approaches to the functionalization of tetrapyrrolic compounds and their rare earth complexes has facilitated the intensive development of new applications over the last decade.

Redox-Triggered Switching of Conformational State in Triple-Decker Lanthanide Phthalocyaninates.

Double- and triple-decker lanthanide phthalocyaninates exhibit unique physical-chemical properties, particularly single-molecule magnetism. Among other factors, the magnetic properties of these sandwiches depend on their conformational state, which is determined via the skew angle of the phthalocyanine ligands. Thus, in the present work we report the comprehensive conformational study of substituted terbium(III) and yttrium(III) trisphthalocyaninates in solution depending on the substituents at the periphery of molecules, redox-states and nature of solvents.

Peripheral Groups of Dicationic Pyrazinoporphyrins Regulate Lipid Membrane Binding.

Photodynamic therapy (PDT) is a widely used technique for skin cancer treatment and antimicrobial therapy. An improvement in PDT efficiency requires not only an increase in quantum yield of photosensitizer (PS) molecules but also their applicability for biological systems. Recently, we demonstrated that the activity of porphyrin-based PSs in the lipid membrane environment depends on the nature of the cation in the macrocycle due to its interactions with the lipid phosphate moiety, as well as the orientation of the PS molecules inside the membrane.

Low-Symmetry Phthalocyanines Bearing Carboxy-Groups: Synthesis, Spectroscopic and Quantum-Chemical Characterization.

The synthesis and characterization of AB-type phthalocyanines, -, bearing bulky 2,6-diisopropylphenoxy-groups or chlorine atoms on isoindoline units "A" and either one or two carboxylic anchors on isoindoline unit "B" are reported. A comparison of molecular modelling with the conventional time dependent-density functional theory (TD-DFT) approach and its simplified sTD-DFT approximation provides further evidence that the latter method accurately reproduces the key trends in the spectral properties, providing colossal savings in computer time for quite large molecules. This demonstrates that it is a valuable tool for guiding the rational design of new phthalocyanines for practical applications.

Octopus-Type Crown-Bisphthalocyaninate Anchor for Bottom-Up Assembly of Supramolecular Bilayers with Expanded Redox-Switching Capability.

Achievement of information storage at molecular level remains a pressing task in miniaturization of computing technology. One of the promising approaches for its practical realization is development of nanoscale molecular switching materials including redox-active systems. The present work demonstrates a concept of expansion of a number of available redox-states of self-assembled monolayers through supramolecular approach.

Ion-Driven Self-Assembly of Lanthanide Bis-phthalocyaninates into Conductive Quasi-MOF Nanowires: an Approach toward Easily Recyclable Organic Electronics.

Controlled self-assembly and rapid disintegration of supramolecular nanowires is potentially useful for ecology-friendly organic electronics. Herein, a novel method exploiting the binding between crown-substituted double-decker lanthanide phthalocyaninates (ML, M = Lu, Ce, Tb) and K ions is applied for the one-step fabrication of macroscopically long conductive one-dimensional quasi-metal-organic frameworks. Their properties are controlled by the size of the lanthanide ion guiding the assembly through either intra- or intermolecular interactions.

Switchable Aromaticity of Phthalocyanine via Reversible Nucleophilic Aromatic Addition to an Electron-Deficient Phosphorus(V) Complex.

Reversible nucleophilic addition to a phthalocyanine core was observed for the first time for the electron-deficient cationic phosphorus(V) complex [PcP(OMe)], whose reaction with KOH afforded a highly distorted nonaromatic adduct bearing an OH group at one of the α-pyrrolic carbon atoms. This adduct was characterized by single-crystal X-ray diffraction, ESI HRMS, and NMR, and UV-vis spectroscopy, together with quantum-chemical modeling. The acidic treatment of this adduct restored aromaticity and recovered the starting cationic complex.