Concentration-dependent spectral changes in functional dyes are critical for optoelectronic applications yet remain poorly quantified. Here, we introduce a physically meaningful metric system based on UV-Vis spectroscopic data that translates spectral behavior into compact descriptors by decoupling underlying amplification and attenuation processes. Systematic extinction studies on six novel 2,3-dibenzyloxy-tert-butyl-substituted phthalocyanines (3a-f) with varied central ions (metal-free, Mg, Zn, Cu, Ni, Co) reveal three distinct types of concentration behavior predicted by the electronic structure of the central ions: (i) classical H-aggregation with intensity transfer for Ni (ENI = 55,316, DPI = +0.971 at Q-band and - 0.990 at H-band, NC = 4.14); (ii) a sharp, cooperative hyperchromic effect for Co (RWI = 0.50, NC = 5.10); and (iii) weak, non-specific attenuation for Mg, Zn, Cu, and the ligand (NC = 0.73-3.43). Our metrics quantitatively resolve these behaviors, with the composite Normalized Cooperativity index (NC) successfully ranking the compounds; thus, Ni (NC = 4.14) and Co (NC = 5.10) show an order of magnitude higher cooperativity than the other dyes (NC = 0.73-1.31). Crucially, the CORRELATO algorithm was employed as an unbiased validator, autonomously identifying stable high-correlation relationships (rxy > 0.95) and selecting the composite NC index as the key classifying parameter. This provides rigorous proof that our metrics are objective physical measures, not arbitrary constructs. By offering a validated, quantitative framework covering both synthesis prediction and property analysis, this work transforms aggregation analysis from a descriptive art into a predictive science.

Statistical cross-cyclization of two different phthalonitriles typically gives A3B-type phthalocyanines in low yields and requires tedious empirical screening. Here we show that machine learning can turn this inefficient process into a predictable, data-driven synthesis. Using the CORRELATO algorithm on only 16 experiments, we derive an interpretable model (R2 = 0.84, MAE = 4.13%) that quantifies the influence of reagent ratio, temperature, and time. This work provides a validated starting template that any chemist working in synthesis can adapt to their own system, as long as a new experimental dataset is collected for the specific reaction conditions of interest.

Recently (Photochem Photobiol. 2023;100:1277-1289. doi:10.1111/php.13898), we described the anti-Kasha effect in tribenzo-6H-1,4-diazepinoporphyrazins with C2v symmetry, where the ultrafast spin changes successfully compete with the internal conversion. In this study, we show the presence of this effect in 2 (3),9 (10),16(17),23(24)-tetra-tert-butyl-29H,31H-phthalocyanine (1) and 1,4-di-[2-(2-methoxyethoxy)ethoxy]-29H,31H-phthalocyanine (2), which also possess reduced molecular symmetry and do not bear 6H-1,4-diazepine fragments. The anti-Kasha effect in 1 and 2 supplemented by Mg(II) tribenzo-6H-1,4-diazepinoporphyrazinates 3 and 4 exhibits a close-to-linear dependence on energy gap value between the zero vibrational levels of two lowest singlet excited states S1 0 and S2 0 (these states are degenerate in D4h symmetry) and enhances with increase. The theoretical kinetic model of excited state dynamics, which takes into account the observed effects and follows Fermi's golden rule, predicts the presence of an additional excited state with enhanced spin-orbit coupling compared to S1 0, S2 0 and the corresponding triplet states, which is not predicted by TDDFT calculations in the Born-Oppenheimer approximation. The combination of the above indicates that the key role in the observed anti-Kasha effect and the mechanism of dissipation of the excited state in porphyrazines and their analogs is played by vibronic excited states, which requires theoretical research methods beyond the Born-Oppenheimer approximation.

The first covalently linked dimer has been prepared for cyclazine systems by regioselective oxidative homocoupling of 1,2-dicarbomethoxy-3-phenylcycl[3.2.2]azine. The regioselectivity of this reaction at 4-position, having been confirmed by X-ray diffraction analysis and NMR spectroscopy, has been also reliably predicted within the model of average local ionization energy on the molecular surface of the starting monomer at the BP86/def2-TZVP level of theory. Due to the planar it-it interaction of the cycl[3.2.2]azine subunits, the dimer is a green fluorophore (tem = 527 nm, toluene), characterized by a bathochromic shift of the main bands in the UV-vis and fluorescence spectra relative to the monomer by 41 and 71 nm, respectively. Furthermore, the dimer demonstrates an increased fluorescence quantum yield relative to the monomer (55 % vs. 35 % in toluene), and according to the data of X-ray diffraction analysis, DFT calculations and variable temperature 1D and 2D 1H NMR spectroscopy, is characterized by hindered rotation of the S1-state-involved cycl[3.2.2]azine cores along the C4-C4 ' bond axis. Such prerequisites determine good application potential of the 4-4 ' coupled cycl[3.2.2]azine derivatives as turn-on fluorescent, i.e. fluorogenic probes for advanced bioimaging in living systems. Finally, unlike the monomer, the dimer shows reversibility of both one- and two-electron reduction and oxidation processes, and therefore can become the basis of both n- and p-type semiconductors.

A series of tribenzo[g,l,q]-6H-1,4-diazepino[2,3-b]porphyrazines has been synthesized. A temperature-dependent steric effect was applied in the mixed Linstead macrocyclization of phthalonitrile and 5,7-bis(2'-arylethenyl)-6-propyl-6H-1,4-diazepine-2,3-dicarbonitrile to achieve high yield of low-symmetry A3B-type Mg(II) tribenzo[g,l,q]-6H-1,4-diazepino[2,3-b]porphyrazinate. The analysis of photophysical and photochemical properties of the obtained complexes showed the anti-Kasha effect: the ultrafast spin changes successfully compete with the IC. TD-DFT calculations showed that the presence of 1,4-diazepine heterocycle in the porphyrazine structure leads to the formation of additional charge-transfer triplet state T2. We propose, it could participate in the pumping of T1x state alongside with T1y state (these states are degenerate in D4h symmetry) and, therefore, increase singlet oxygen (1Δg) generation. Stable micellar nanoparticles have been obtained based on the tribenzo[g,l,q]-6H-1,4-diazepino[2,3-b]porphyrazine Mg(II) and Zn(II) complexes using polyvinylpyrrolidone. The nanoparticles effectively interact with model biological structures (FBS and brain homogenate), leading to disaggregation of the macrocycles. They also exhibit pronounced phototoxic effects in MCF-7 cells upon red light irradiation. We propose that enhancement in PDT activity could be explained by their increased resistance to aggregation due to the presence of n-propyl substituent directly attached to the C6 position of the 1,4-diazepine moiety. The demonstrated results show the promising potential of tribenzo-6H-1,4-diazepinoporphyrazines as heavy atom-free photosensitizers.

This work is devoted to studying the aggregation effect on the nonlinear optical (NLO) and charge transport (CT) properties of low-symmetry phthalocyanines bearing a cyclotriphosphazene moiety, a monomer, and clamshell-type bis-phthalocyanine. FE-SEM and AFM studies revealed ordered nanoaggregation in these compounds, represented as repeating objects of regular configuration, globules (340–480 nm), which contain small aggregates inside their cavity, similar to smoothed polygons (ca. 40 nm). Such specificity is not characteristic of other functionalized phthalocyanines, which we dealt with earlier. A new spectral method for estimating the aggregation threshold based on the change in extinction with increasing concentration of solutions was also implemented, and the effect of aggregation on optical limiting was demonstrated. The behavior of isomers and rotamers of bis-phthalocyanine in the presence of electric fields of various strengths was investigated with the DFT calculations, and that partially corresponds to the impact of laser radiation on molecules. It was shown that the unusual behavior of the trans-isomer in FF-DFT calculations is the reason for the worsening of the NLO and CT characteristics of bis-phthalocyanine, in which the macrocycles are strapped through a phosphazene spacer. An advanced method of multiparametric analysis has been implemented to evaluate the NLO and CT properties of the dyes in general.

A series of 5,7-disubstituted 1,4-diazepinoporphyrazinato magnesium(II) and nickel(II) complexes, including two novel compounds, were obtained by metal-templated macrocyclization. A combination of X-ray diffraction, 1H NMR, UV-vis, and electrochemical analyses allowed us to study their tendency towards H-type dimerization and trace the influence of structural and solvation factors on dimer stability. Based on the physicochemical and theoretical DFT calculation data, it was found that the main binding forces between 6H-1,4-diazepinoporphyrazine decks in the dimers were efficient π-π donor-acceptor interactions induced by the interdeck C-H⋯N hydrogen bonds. Furthermore, the metal-ligand (Pz2- → M2+) electronic interactions have a key influence on the π-π stacking of the porphyrazine cores. It was shown that the displacement of the metal ion out of the macrocycle plane induced by coordinating agents can trigger the dissociation of the dimer, since the resulting enhancement of the donor-acceptor electronic interaction between the metal ion and the π-system of the ligand leads to a subsequent weakening of the π-π stacking of the porphyrazine cores. The TD-DFT calculations predicted the non-degeneracy of the HOMO-1 → LUMO and HOMO → LUMO+1 transitions in the 6H-1,4-diazepinoporphyrazine H-dimers, which explains the Q-band splitting in their UV-vis spectra.

The family of 3-arylcycl[3.2.2]azine-1,2-dicarboxylic acids has been extended with a series of 4-alkylsubstituted derivatives. The corresponding water-soluble sodium salts were synthesized as well. The obtained compounds are characterized by intense light absorption up to 450 nm (lg epsilon 4-4.5), pronounced blue-green fluorescence in 430-550 nm region (phi F 10-30 %), good cellular uptake with the values of experimentally determined log D7.4 distribution coefficients ranging from-0.5 to 1.3, and cytotoxicity in HeLa cells classified as weak to moderate (for most of the compounds, IC50 >= 100 mu M) and being at levels typical of most fluorophores already widely used in molecular imaging. Moreover, a good correlation of cytotoxicity and log D7.4 values has been established implying that cytotoxicity tends to decrease with increasing hydrophilicity of the compounds. Finally, the compounds retain fluorescence after penetration into living cells, distributing discretely in the cytoplasm and perinuclear space, which characterizes them as promising blue-green fluorophores for biomedical applications.

The electrochemical properties of a covalently linked conjugate (Dyad) composed of methyl pheophorbide a (Pheo a) and zinc(II) 2-(2-hydroxymethylbenzyloxy)-9(10),16(17),23(24)-tri-tert-butylphthalocyaninate (ZnPc) were studied. Cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements revealed three reductions at -1.59, 1.78 and -2.03 V vs. [Formula: see text]/Fc and four oxidations at 0.06, 0.47, 0.57 and 0.87 V vs. [Formula: see text]/Fc in [Formula: see text]-DCB containing 0.05 M TBAPF 6 . The first reduction included two overlapped processes, the reduction of Pheo a followed by the reduction of ZnPc, separated byca. 0.08 V. Compared to individual components, the ZnPc subunit in Dyad undergoes the first oxidation more easily with a cathodic shift of potential by 0.08 V, while Pheo a subunit, on the contrary, is more difficult to oxidize showing an anodic potential shift of 0.14 V. This indicates a certain interaction between the two subunits in Dyad, which is additionally confirmed by a slight bathochromic shift of the Q band positions in the UV-vis spectra of Dyad relative to its components. Moreover, the cathodic shift of the second oxidation potential of the ZnPc subunit concerning individual ZnPc reaches 0.35 V, indicating an intensification of the electronic interaction between [Formula: see text] and Pheo a in Dyad. The spectroelectrochemical experiment showed that the reversible first oxidation of the ZnPc subunit is followed by its irreversible second oxidation, which proceeds slightly ahead of the first oxidation of the Pheo a fragment. Thus, both electrochemical and spectroelectrochemical studies support the conclusion on the enhanced interaction between [Formula: see text] and Pheo a in Dyad, which even leads to a change in the order of their further oxidations.

The selective synthesis of clamshell-type bis-phthalocyanine was performed using cyclotriphosphazene as a peripheral spacer. The spectral characteristics of the target dye are similar to those of most H-dimers, and the reaction can be considered conditionally selective with respect to the cis-isomer

An interaction of 2-hydroxy-9(10),16(17),23(24)-tri-tert-butyl-29H,31H- phthalocyanine (1) with hexachlorocyclotriphosphazene (phosphonitrilic chloride trimer) produced, along with the A(3)B type low-symmetry monophthalocyanine (monomer 2), a bis-derivative 3 with spectral characteristics such as that of most clamshell-type phthalocyanines (typically, H-dimers). The reaction can be considered conditionally selective. DFT calculations showed the possibility of the existence of several isomers. Based on the UV-Vis, fluorescent and NMR studies, we found that 3 was obtained as an inseparable mixture of three diastereomers-achiral cis-isomer and two chiral trans-isomers. DFT analysis has also shown that cis-isomer can exist as two rotamers-parallel and oblique, by an analogy with the cofacial J-type dimers that we obtained earlier.

Laser-power-limiting devices play a predominant role in photonics because of their potential for protecting human eyes and optical devices that are sensitive to intense laser beams. This paper describes a new methodology for predicting the efficiency of optical limiting based on electric-field-induced changes in absorption spectra calculated with the TDDFT quantum-chemical method. Analytical equations are derived to evaluate the optical thresholds and speed of switching on, the dynamic range, and the degree of nonlinear attenuation of the radiation fluxes for the case of two-photon absorption. Thus, the researcher does not need to conduct costly experiments to evaluate the suitability of nonlinear absorbers for the creation of optical limiters. The possibility of developing a forecasting model is demonstrated by an example of a series of stable slipped-cofacial phthalocyanine J-type dimers, which were synthesized and investigated previously.

Plasmonic enhancement of absorption in charge‐transfer (CT) complexes formed under NO 2 gas adsorption onto 2D hybrid structure, based on the metal–organic monolayer and gold nanoparticles (AuNPs), is demonstrated. By using Langmuir–Blodgett deposition of low‐symmetry zinc phthalocyanine (ZnPc) molecules, the metal–organic monolayer is fabricated with greatly suppressed intermolecular aggregation. Oxidation of the monolayer through coordination of NO 2 molecules with axial zinc ions of ZnPc molecules gives rise to the specific absorption band inherited to cation radical ZnPc + . The hybrid AuNPs–ZnPc structure is engineered to maximize exciton–plasmon interaction of CT complexes at the radical form of the metal–organic monolayer. Excellent spectral and spatial overlaps with plasmon resonance boost absorption of CT internal optical transition, so‐called “fingerprint” band, by a factor of six from 0.45% to 2.8% in total. The approach paves the way for efficient plasmonic control over photochemical reactions promoted by charge‐transfer complexes in metal–organic films. In particular, the plasmonic effect is harnessed to improve NO 2 gas sensing properties; the experimental study shows a 15‐fold increase of the detection efficiency in the specific band of CT complexes under the gas exposure.

In this work, we show for the first time that low-symmetry phthalocyanines of A3B-type can be readily obtained in one stage from the corresponding symmetric alkoxy-substituted A4-type precursors by cleavage of a single ether bond. Namely, two 2,3,9,10,16,17,23,24-octa-n-butoxyphthalocyanines (BuOPcM, where M = 2H, Cu) were selectively transformed to the corresponding 2-hydroxy-3,9,10,16,17,23,24-hepta-n-butoxyphthalocyanine derivatives in acidic conditions. The selectivity of the ether bond cleavage largely depends on the temperature and time of contact of sulfuric acid with toluene solutions of the starting A4-type compounds. The new method gives superior overall yields of A3B-type phthalocyanines (>70%) compared to the common approach, which implies statistical cyclization of two different phthalogens. The target compounds can be considered as precursors for polymacrocyclic structures, as well as the basis for optical materials.

The first covalently linked conjugate of metal phthalocyaninate and chlorin e 6 derivative has been obtained by transesterification of α-ketomethyl ester in methylpheophorbide a with zinc(II) 2-(2-hydroxymethylbenzyloxy)-9(10),16(17),23(24)-tri-tert-butylphthalocyaninate under mild conditions. The dyad exhibits a panchromatic nature revealing both the phthalocyanine and pheophorbide derived bands in the UV-Vis absorption spectrum. The 1 H NMR spectroscopy data combined with theoretical calculations indicate the presence of spatial intramolecular interactions between the phthalocyanine, pheophorbide and spacer fragments of the dyad allowing to forecast its enhanced nonlinear optical properties, as well as the characteristic energy transfer from the excited pheophorbide subunit to the phthalocyanine core. Indeed, when excited in the UV-Vis range, the conjugate shows red fluorescence with the spectral maximum at 686 nm, which is close to the one of the initial zinc phthalocyaninate. Furthermore, the dyad effectively generates singlet oxygen and, in the presence of polyvinylpyrrolidone (PVP) as biocompatible solubilizer, forms stable micellar saline solutions with the particles ranged in size between 40 and 100 nm. These nanoparticles represent promising third-generation photosensitizing systems for application in theranostics. lowing equation: [44] S R S R toluene f where G is the integrated emission area, n is the refractive index of the solvent, A λ is the absorbance at the excited wavelength, and Φ f is the fluorescence quantum yield. The indexes S and R correspond to the sample and the reference, respectively. The singlet oxygen ( 1 O 2 ) quantum yields ( Φ Δ ) were mea sured in freshly prepared solutions in toluene containing

We report novel heteroleptic lanthanide sandwich complexes (Ln = Lu, Eu, La) and their spectral, electrochemical and computational studies.

The first 1,2‐dicarbonitriles have been prepared for cyclazine systems. In particular, a synthetic procedure to 1,2‐dicyano‐3‐arylcycl[3.2.2]azines has been developed. Unexpected chlorination of 3‐arylcycl[3.2.2]azine‐1,2‐dicarboxylic acid derivatives by thionyl chloride at 4‐position was found, which according to theoretical considerations can proceed by the electrophilic (S E Ar) mechanism. The compounds are blue fluorophores in 450–480 nm region with quantum yields in toluene of ca. 30 % for non‐chlorinated derivatives, which decrease to 3–4 % for chlorinated ones.

Novel synthetic approach to low-symmetry meso-phenylsubstituted tetrabenzoporphyrins (TPBs) by Zn(OAc)2 templated assembly of phthalonitrile in the presence of benzyltriphenylphosphonium chloride has been proposed affording two main products: 5-phenyl-21H,23H-TBP (1) and 5,10-diphenyl-21H,23H-TBP (2) with higher yield for compound 1. Procedure for isolation of 1 and 2 in individual high purity state has been developed supplemented with selection of an appropriate NMR solvent system (CDCl3 with 1% additive of CF3COOH) that allowed full signal assignment in 1Н and 13С spectra to be made utilizing homonuclear 1H–1H (COSY, NOESY, TOCSY) and heteronuclear 1H–13C (HSQC) correlation techniques. Isolation and physicochemical study of a mixture of monobenzylated co-products 1a−g were carried out as well involving 1D and 2D NMR spectroscopies, which for the first time allowed not only to find out their structure, but also to determine the ratio of the positional isomers formed.

Novel heteroleptic Er(iii) and Yb(iii) naphthalocyaninato-phthalocyaninates containing an octa-phenyl or octa-phenoxysubstituted naphthalocyanine deck were synthesised and identified by 1H NMR, EPR and high resolution MALDI-TOF/TOF mass spectrometry. Direct synthesis of novel homoleptic Yb(iii) bis (octa-phenylnaphthalocyaninate) was carried out. Downfield lanthanide induced shifts of the aromatic protons in target compounds were observed compared with the corresponding diamagnetic Lu(iii) complexes. In the near-IR absorption spectra, an increase in ionic radius from Lu(iii) to Er(iii) resulted in a bathochromic shift of the intervalence band up to 1473 nm. This work presents the first experimental EPR study of Yb(iii) bis naphthalocyaninate, where a set of magnetic parameters and properties (including spin, magnitude and sign of magnetic anisotropy parameter D, increased splitting in a crystal field, ferromagnetic f-π interaction etc.) were determined and interpreted by both EPR and SQUID techniques and supported by theoretical considerations.

A series of heteroleptic quadruple -decker bis[lanthanide(III)] complexes based on a flexible spacer -linked phthalocyanine ligand of clamshell -type, denoted sandwich -clamshell complexes, have been prepared. Complexation of 1,1 '- [benzene-1,2-cl iyIbis(methanediyloxy)] -bis (10),16 (17),23(24)- tri- tert-butylphthalocyanine] (cl'" Pc2H4, 1) with [2(3),9(10),16(17),23(24)-tetra-tert-butylphthalocyaninato] lanthanide(III) acetates [tB"PcLn0Ac, 2a d; Ln = Eu (a), Gd (b), Tb (c), Lu(d)] afforded quadruple -deckers clam, thuPc4Ln2 (3a d) with good to excellent yields. The complexes reveal intrinsic UV Vis NIR absorption by analogy to classical doubledecker phthalocyaninates, while demonstrating high thermal stability up to 350 C. At the same time, a combination of H-1 NMR, electrochemistry and SQUID magnetometry supported by DFT theoretical calculations indicates that bis(phthalocyanine) subunits in 3 are in close contact mainly governed by the spacer group and, in some extent, by the presence of bulky tert-butyl peripheral substituents in the four phthalocyanine decks.