ABAB Homoleptic Bis(phthalocyaninato)lutetium(III) Complex: Toward the Real Octupolar Cube and Giant Quadratic Hyperpolarizability

Phthalocyanines prepared from 4,5-dihexylthiophthalonitrile, a popular building block

Phthalocyanines are tetrapyrrolic artificial porphyrinoids that play major roles in advanced biological and technological applications. Research on this family of dyes is particularly active in Türkiye, with many derivatives being prepared from 4,5-dihexylthiophthalonitrile DiSHexPN, which is one of the most popular noncommercially available building blocks for phthalocyanines. This review summarizes the phthalocyanines and their versatile properties and applications that have been published since 1994, when the synthesis of DiSHexPN was first described, to emphasize the importance of this building block in plentiful applications, all with biomedical or technological impact.

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

This review summarises advances in chemistry of tetrapyrrole sandwiches with rare earth elements and highlights the current state of their use in single-molecule magnetism, organic field-effect transistors, conducting materials and nonlinear optics.

Synthesizing and evaluating the photodynamic efficacy of asymmetric heteroleptic A7B type novel lanthanide bis-phthalocyanine complexes

In this study heteroleptic A₇B type novel Lu(iii) and Eu(iii) lanthanide phthalocyanines (LnPc(Pox)[Pc′(AB₃SH)]) with high extinction coefficients have been synthesized as candidate photosensitizers with reaction yields higher than 33%. The singlet oxygen quantum yields of LuPc(Pox)[Pc′(AB₃SH)] and EuPc(Pox)[Pc′(AB₃SH)], respectively, were measured 17% and 1.4% by the direct method in THF. The singlet oxygen quantum yield of LuPc(Pox)[Pc′(AB₃SH)] in THF is the highest among lutetium(iii) bis-phthalocyanine complexes to date. The photodynamic efficacy of the heteroleptic lanthanide phthalocyanines was evaluated by measuring cell viabilities of A549 and BEAS-2B lung cells, selected to representing in vitro models for testing cancer and normal cells against potential drugs. The cell viabilities demonstrated concentration dependent behavior and were varied by the type of phthalocyanines complexes. Irradiation of the cells for 30 minutes with LED array at 660 nm producing flux of 0.036 J cm⁻² s⁻¹ increased cell death for LuPcPox-OAc, LuPc(Pox)[Pc′(AB₃SH)] and ZnPc. The IC₅₀ concentrations of LuPc(Pox)[Pc′(AB₃SH)] and ZnPc were determined to be below 10 nM for both cell lines, agreeing very well with the singlet oxygen quantum yield measurements. These findings suggest that LuPc(Pox)[Pc′(AB₃SH)] and particularly LuPcPox-OAc are promising drug candidates enabling lowered dose and shorter irradiation time for photodynamic therapy.

Novel bis-lanthanide Lu(iii) and Eu(iii) phthalocyanine complexes have been designed/synthesized and tested their photodynamic efficacy for A549 and BEAS-2B cells in vitro conditions as candidate photosensitizers in PDT.

Lu(iii) bis-phthalocyanines containing carbazole moieties: synthesis, characterization, electrochemical properties and sensor applications

In this study, the synthesis and characterization of sandwich type Lu(iii) bis-phthalocyanines bearing electropolymerizable carbazole groups were evaluated and their electrochemical sensing properties studied towards DA, UA and AA.

Nonlinear optical behavior of n-tuple decker phthalocyanines at the nanosecond regime: investigation of change in mechanisms

The coordination system of rare-earth n-tuple decker phthalocyanines would be better suited with appropriate metal ions with the correct coordination number and the solvent system of the reaction, amongst other reasons, for the formation of n-tuple decker phthalocyanines. As a result, these complexes are very rare. In this manuscript, we present new n-tuple decker phthalocyanines in the form of double- (complex 2), quadruple- (complex 3a) and sextuple-decker phthalocyanines (complex 3b), all of which contain neodymium and cadmium metal ions. The primary focus is the investigation of the nonlinear optical (NLO) mechanisms responsible for the observed reverse saturable absorption. While the extension of the π-electron system has been found to enhance the nonlinear optical behavior of complexes 3a and 3b, a change in the NLO mechanisms has been observed, with complex 2 lacking the triplet state population, as revealed by a laser flash photolysis technique. It has also been established that the excited state absorption cross sections follow a clear order of magnitude for the complexes under investigation: σ 23 (for 3b) > σ 23 (for 3a) > σ 1m (for 2). This trend evidences the effects of the extension of the π-electron system.

Pyridone substituted phthalocyanines: Photophysico-chemical properties and TD-DFT calculations

4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and [Formula: see text]H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.

Sandwich rare earth complexes simultaneously involving aromatic phthalocyanine and antiaromatic hemiporphyrazine ligands showing a predominantly aromatic nature

Two mixed (phthalocyaninato)(hemiporphyrazinato) and two homoleptic bis(hemiporphyrazinato) rare earth double-decker complexes have been synthesized and structurally characterized. The EPR and NMR results clarified the protonated nature of these sandwich double-deckers. Spectroscopic and theoretical calculation results clearly reveal the predominantly aromatic nature of the mixed ring sandwich double-deckers.

First Example of Nonlinear Optical Materials Based on Nanoconjugates of Sandwich Phthalocyanines with Quantum Dots

We report original, selective, and efficient approaches to novel nonlinear optical (NLO) materials, namely homoleptic double- and triple-decker europium(III) complexes 2 and 3 with the A₃ B-type phthalocyanine ligand (2,3-bis[2'-(2''-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-n-butoxyphthalocyanine 1) bearing two anchoring diethyleneglycol chains terminated with OH groups. Their covalently linked nanoconjugates with mercaptosuccinic acid-capped ternary CdSeTe/CdTeS/ZnSeS quantum dots are prepared in the presence of an ethyl(dimethylaminopropyl)carbodiimide activating agent. Optical limiting (OL) properties of the obtained low-symmetry complexes and their conjugates with quantum dots (QDs) are measured for the first time by the open-aperture Z-scan technique (532 nm laser and pulse rate of 10 ns). For comparison, symmetrical double- and triple-decker Eu^III octa-n-butoxyphthalocyaninates 5 and 6 and their mixtures with trioctylphosphine oxide-capped QDs are also synthesized and studied. It is revealed that both lowering of molecular symmetry and expansion of the π-electron system upon moving from double- to triple-decker complexes significantly improves the OL characteristics, making the low-symmetry triple-decker complex 3 the most efficient optical limiter in the studied family of sandwich complexes, affording 50 % lowering of light transmittance below 0.5 J cm^-2 input fluence. Conjugation (both covalent and noncovalent) with QDs affords further enhancement of the OL properties of both double- and triple-decker complexes. Altogether, the obtained results contribute to the development of novel nonlinear optical materials for future nanoelectronic and optical device applications.

Synthesis, characterization and metal ion sensing properties of novel pyridone derivatives phthalocyanines

The design of novel substituted phthalocyanines closely follows the requirement of their planned applications. In this study, synthesize of novel pyridone derivatives metal-free and symmetrical cobalt(II) phthalocyanines was carried out to improve brightness. For this purpose; starting with 4-nitrophthalonitrile and 4-hydroxy-6-methyl-3-nitro-2-pyridone, 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile was prepared. Then 2(3),9(10),16(17),23(24)-tetrakis[6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy] metal-free phthalocyaninato and 2(3),9(10), 16(17),23(24)-tetrakis[6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy] phthalocyaninato Co(II) were synthesized by using 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile, lithium metal and cobalt(II) acetate tetrahydrate in amyl alcohol, respectively. The sensing behavior of the film of derivatives metal-free and symmetrical cobalt(II) phthalocyanines for the online detection of heavy metal ions in water samples was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the analytes on the coating surface cause a reversible negative frequency shift of the resonator. Quartz crystal microbalance (QCM) functionalized with phthalocyanine, derivatives metal-free and symmetrical cobalt(II) phthalocyanines, are demonstrated to be sensors for the detection of heavy metal ions like Cd[Formula: see text], Zn[Formula: see text], Cu[Formula: see text], Cr[Formula: see text] and Co[Formula: see text]. Thus, QCM based sensor arrays are considered a promising platform for the direct analysis of aqueous samples.

An octupolar bis(porphyrinato) terbium(iii) complex with the highest off-resonant hyperpolarizability

A novel bis(porphyrinato) terbium double-decker complex HTb(DADAPor)₂ with the octupolar molecular exhibits the large off-resonant first hyperpolarizability.

Preparation, X-ray Structures, Spectroscopic, and Redox Properties of Di- and Trinuclear Iron-Zirconium and Iron-Hafnium Porphyrinoclathrochelates

The first hybrid di- and trinuclear iron(II)-zirconium(IV) and iron(II)-hafnium(IV) macrobicyclic complexes with one or two apical 5,10,15,20-tetraphenylporphyrin fragments were obtained using transmetalation reaction between n-butylboron-triethylantimony-capped or bis(triethylantimony)-capped iron(II) clathrochelate precursors and dichlorozirconium(IV)- or dichlorohafnium(IV)-5,10,15,20-tetraphenylporphyrins under mild conditions. New di- and trinuclear porphyrinoclathrochelates of general formula FeNx₃((Bn-Bu)(MTPP)) and FeNx₃(MTPP)₂ [M = Zr, Hf; TPP = 5,10,15,20-tetraporphyrinato(2-); Nx = nioximo(2-)] were characterized by one-dimensional (¹H and ¹³C{¹H}) and two-dimensional (COSY and HSQC) NMR, high-resolution electrospray ionization mass spectrometry, UV-visible, and magnetic circular dichroism spectra, single-crystal X-ray diffraction experiments, as well as elemental analyses. Redox properties of all complexes were probed using electrochemical and spectroelectrochemical approaches. Electrochemical and spectroelectrochemical data suggestive of a very weak, if any, long-range electronic coupling between two porphyrin π-systems in FeNx₃(MTPP)₂ complexes. Density functional theory and time-dependent density functional theory calculations were used to correlate spectroscopic signatures and redox properties of new compounds with their electronic structures.

Synthesis of an ABCD-Type Phthalocyanine by Intramolecular Cyclization Reaction

Unsymmetrical phthalocyanines with a low symmetry can exhibit unique and intriguing properties that can facilitate their applications in certain disciplines. The synthesis of these compounds, however, has posed a great difficulty. A novel and unprecedented approach for phthalocyanine synthesis is reported that involves intramolecular cyclization of prelinked tetrakisphthalonitriles. By using this strategy, the first ABCD-type phthalocyanine has been prepared in 7.2% yield.

Mechanism of the Zn(II)Phthalocyanines' Photochemical Reactions Depending on the Number of Substituents and Geometry

In this work, the synthesis and the nonlinear absorption and population dynamics investigation of a series of zinc phthalocyanines (ZnPcs) dissolved in chloroform are reported. In order to determine the relevant spectroscopic parameters, such as absorption cross-sections of singlet and triplet excited states, fluorescence relaxation times, intersystem crossing, radiative decay and internal conversion, different optical and spectroscopic techniques were used. By single pulse and pulse train Z-scan techniques, respectively, singlet and triplet excited states‘ absorption cross-section were determined at 532 nm. Furthermore, the intersystem crossing time was obtained by using both techniques combined with the fluorescence lifetime determined by time-resolved fluorescence. The radiative and internal conversion rates were determined from the fluorescence quantum yield of the samples. Such spectroscopy parameters are fundamental for selecting photosensitizers used in photodynamic therapy, as well as for many other applications.

ABAB-type phthalocyanines simultaneously bearing electron donating and electron accepting groups. Synthesis, spectroscopy, and structure

Mg(trans-TPTCPc) was successfully prepared and structurally characterized, representing the first structurally characterized ABAB-type phthalocyanine compound simultaneously bearing electron-donating and electron-accepting groups.

Synthesis of lutetium(iii)–porphyrin complexes: old problems and new excellent conditions found

A convenient high-yielding method for the preparation of very attractive lutetium(iii)–porphyrin complexes was developed (in sulfolane at reflux temperature, 0.5 h, up to 88%).

The optical characterization of metal-mediated aggregation behaviour of amphiphilic Zn(ii) phthalocyanines

Addition of Ag⁺ cations induces J-aggregation in ultrathin films of both symmetrically and asymmetrically substituted Zn(ii) phthalocyanines.

Towards Clarifying the Role of O2 during the Phthalocyanine Synthesis

The role of O2 within the synthesis of phthalocyanines (Pcs) has remained unclear in the past century. Here, we demonstrate that O2 , in cooperation with the solvent n-pentanol, participates in the cyclic tetramerization of phthalonitriles over the half-sandwich complex template [Lu(Pc)(acac)] (acac=acetylacetonate) and terminates the reaction at the stage of uncyclized isoindole oligomeric derivatives rather than the phthalocyanine chromophores, resulting in the isolation of the heteroleptic (phthalocyaninato)(triisoindole-1-one) lutetium double-decker complexes [(Pc)Lu(TIO-I)] (TIO-I=3,4,7,8,11,12-sexi(2,6-diisopropylphenoxy)-15-[4,5-di(2,6-diisopropylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) and [(Pc)Lu(TIO-II)] (TIO-II=3,4,7,8,11,12-sexi(2,6-dimethylphenoxy)-15-[4,5-di(2,6-dimethylphenoxy)-2-cyanobenzimidamido]triisoindole-1-one) with the help of bulky substituents at the phthalonitrile periphery and an unsubstituted phthalocyanine ligand in the double-decker skeleton. Nevertheless, the cyclic tetramerization of the phthalonitriles was revealed to be sensitive to O2 with the reaction progression also depending on the oxygen concentration/content, leading to the O2 -senstive and -dependent nature for the isolation of phthalocyanine derivatives.

Tetrathiafulvalene derivatives as cation sensor: density functional theory investigation of the hyper-Rayleigh scattering first hyperpolarizability

The hyper-Rayleigh scattering first hyperpolarizability of a series of extended tetrathiafulvalene (TTF) and TTF derivatives have been theoretically investigated using density functional theory to explore their use as potential cation sensor.

Synthesis, characterization and investigation of the photophysical and photochemical properties of highly soluble novel metal-free, zinc(ii), and indium(iii) phthalocyanines substituted with 2,3,6-trimethylphenoxy moieties

The synthesis, characterization and photophysicochemical properties of 2,3,6-trimethylphenoxy substituted metal-free, zinc(ii), and indium(iii)acetate phthalocyanines were described.

meso-Phenyltetrabenzotriazaporphyrin based double-decker lanthanide(iii) complexes: synthesis, structure, spectral properties and electrochemistry

A series of tetrabenzotriazaporphyrin half-sandwich and sandwich compounds, including unexpected meso-dearylated derivatives as well as the first triple-decker, have been prepared.

Density functional theory study of pure octupolar porphyrazines with second-order nonlinear optical activity

Delicately designed pure octupolar molecular compounds, tetra(triptycene)porphyrazine and its skeleton expanded derivatives have been studied on the basis of density functional theory. The pure octupolar contribution with better isotropy to the second-order nonlinear optical response for these compounds is revealed, with further investigation to the molecular size effects, as well as peripheral polarized substituent influences to the nonlinear optical response.

Lanthanide macrocyclic complexes: from molecules to materials and from materials to devices

In the present review, we show how the chemistry of lanthanide macrocyclic complexes, which began almost 50 years ago in Russia, is still very active. Additionally to bisphthalocyanines complexes, triple-decker, but also quadruple- and quintuple-decker complexes have been synthesized via new chemical routes. The driving force for the development of this chemistry arises from the wide range of possible applications. Owing to their very high conductivity, compared to that of monophthalocyanines, LnPc2 and Ln2Pc3 complexes are used as molecular semiconductors in electronic devices. The radical nature of LnPc2 complexes makes them easily oxidized and reduced. This is the reason why they are particularly promising materials for the development of new chemical sensors, associated with both conductimetric and optical transducers.

2,2,3,3-Tetrafluoropropoxy substituted oxo-titanium phthalocyanines axially ligated with common MALDI matrix materials

The synthesis of tetra and octa 2,2,3,3-tetrafluoropropoxy substituted oxo-titanium phthalocyanines (TiOPc) are reported. Using strongly chelating oxygen donor ligands, the reactions of TiOPc with catecholate (1a, 2a), 4-nitrocatecholate (1b, 2b) and caffeic acid (1c, 2c), ellagic acid (1d, 2d) and chlorogenic acid (1e, 2e) are described. The new compounds were characterized by mass, 1 H NMR, FT-IR, and UV-vis spectroscopic techniques as well as elemental analysis.