Alkyl-halogen-dipyrromethene (Dpm) ligands coordinated with boron(III), zinc(II), and cadmium(II) were studied experimentally and theoretically to elucidate and compare influence of the coordination centers and halogen substituents ("heavy" atom effect) on observable photophysical properties. Novel and recently published experimental data were summarized and analyzed using quantum-mechanical calculations which revealed specific of the electronic structures and photo-induced dissipations in the molecular complexes. Halogenation of the Dpm difluoroborates (BODIPY) increases the intersystem spin crossing (ISC) and the triplet harvest whereas halogen atoms play no crucial role in fluorescence quenching of the systems with Zn(II) and Cd(II) complexing agents. Low fluorescence intensities of double Dpm moieties coordinated with the transition metal ions are provided by radiationless internal conversion suppressing photoemission with following ISC which is intensified in presence of halogens. BODIPY fluorescence undergoes direct ISC competition and quenching intensity depend on the kind and the number of halogens.

An analysis and interpretation of experimental and theoretical data on the spectral-luminescent, photophysical, and photochemical properties of dipyrromethenates are presented depending on the structure of the ligand, the complexing agent type, and the solvent and its phase state (temperature). The special features of photonics related to the violation of the physicochemical properties in the series of substituted dipyrromethenates in heteroatoms and heavy atoms (their nature, location, and the number of such substituents) are discussed.

Photonics of complexes of p- and d-elements with dipyrromethenates is investigated. The role of substituents (their type and localization in the ligand) and of the medium in which dipyrromethenates are placed (solvents, gas mixtures, or solid matrices) is discussed as well as the effect of complexing agents on photonics of the examined complexes. The possibilities for dipyrromethenates application as liquid and solid state laser active media, sensor media for determining the oxygen concentration in a gas mixture, and photosensitizers for singlet oxygen generation in optical devices are presented.

Abstract The spectral-luminescence characteristics of binuclear bis(BODIPY) complexes in cyclohexane and ethanol, which exhibit different photophysical and photochemical properties in these solvents, have been investigated. It has been shown that the difference in spectroscopic properties is due to intermolecular interaction of the excited molecules with solvation shell. The possibilities of practical use are discussed.

The spectral luminescent properties of a series of zinc dipyrromethenate [Zn(dpm) 2 ] with alkyl-, phenyl-, meso-aza-, and halogen substituents in the ligand are studied in solutions in ethanol (neutral and acidified with hydrochloric acid). The stability of the complexes in proton-donor solvents in the ground and excited states is investigated, and quantum yields of laser-induced phototransformations are measured. In a number of cases, a relationship between the photochemical stability of the investigated dipyrromethenates and their properties in proton-donor media is found and discussed.

Experimental study of photonics of selected complexes was presented. Electronic absorption and luminescence spectra in different solutions at room temperature (298 K) were shown. For dipyrromethene complexes with zinc phosphorescence was observed in ethanol solution at liquid nitrogen temperature (77 K). Also quantum yield of transformation under excitation of Nd:YAG laser was received. Their values are enough for successful use in modern optical devices. For one of the studied complex the theoretical calculations were made by Gaussian 09. Discussion of features relationships of the structure with the properties using quantum chemical calculations was carried out.

Spectral, photophysical, photochemical characteristics for mononuclear and binuclear dipyrromethenes in complexes with BF2 (BODIPY), bis-BODIPY and bis-helicates ([Zn-2(L)(2)]) are described. The role of substituents (type and location in the ligand) and the medium in which dipyrromethene complexes are placed (solvents, solid-state matrices), the effect of different complexing agents (p- and d-elements) on the photonics of the complexes are discussed. The results of studying the lasing and photochemical properties of complexes under the action of laser irradiation are presented. In addition, for the described complexes the stability in the ground and excited states in protic media are estimated. Based on the analysis of the results discussed possibilities of practical application of these compounds to creating various optical devices.

In the present paper spectral-luminescent, lasing, photochemical, sensory, and photosensitized characteristics of a number of Zn(II) and B(III) coordination complexes of dipyrrins with different structures are investigated. The results show that alkyl-, phenyl-, and propargylamino-derivatives of dipyrrin core in these complexes have excellent luminescent characteristics and can be used as active media for tunable liquid and solid-state lasers. Zinc (Zn-dpm(2)) and boron fluoride complexes of dipyrrins (BODIPYs) with halogen atoms and aza-substitution in meso-position in their ligands do not exhibit effective fluorescence, but some of them have long-lived emission due to increased nonradiative intersystem processes in an excited state proceeding by the mechanism of heavy atom and the presence of low-lying n pi- and sigma pi-states of different natures and multiplicities. The reason for the short wavelength shift of the Zn-dpm(2) spectra compared to the corresponding BODIPY is studied using quantum-chemical calculation. For solid samples based on halogenated complexes, a dependence of the long-lived emission intensity on the oxygen concentration in the surrounding gas mixture is established that indicates the possibility of application of these complexes for the creation of optical oxygen sensors. Moreover, results of investigations of halogen-substituted tetraphenyl-aza-BODIPY complexes as photosensitizers of singlet oxygen production are presented. Such complexes are promising for creating media for generation of singlet oxygen, which is important for photodynamic therapy and oxidation catalysis. In addition, data on the stability of these compounds in different electronic states are presented. (C) 2017 Elsevier B.V. All rights reserved.

Annotation. Study of complexes of dipyrromethene with different structure is one of the most successfully developing areas of modern chemistry. The demand for using a variety of optical devices in modern technology makes it necessary to explore the photonics of new organic luminophores (coordination complexes of dipyrromethene with pand d-elements) depending on their structure, intermolecular interactions, temperature, etc. In this work was researched dipyrromethene compounds, which can form stable complexes with ions of delements. The main advantage complexes of Zn(II) with dipyrromethens is easy to "self-assembly" in the "soft" conditions on complexing ions in solutions and in biological systems, as well as high sensitivity spectralluminescence characteristics to changes in the structure of the chromophore and the nature of the solvent. Systematic observation of photochemical and photophysical properties and establishment of their connection with structural features of the complexes are required for successful usage of dipyrromethene complexes and creation of various hi-tech optical devices which are based on them. Therefore, the purpose of the work is to study the spectral-luminescent, sensory properties of different complexes of dipyrromethenes with zinc, the optimal combination of which will indicate the direction of the most effective use of these dyes. In the study of a number of complexes of dipyrromethens found that the introduction of various substituents in the dye structure significantly affects on photonics of luminophores. For dipyrromethene complexes with zinc we obtained characteristics of the spectra of long-lived emission of frozen ethanol solutions. It was incorporated in solid samples based on methylcellulose, in order to decrease diffusion and nonradiative processes by the room temperature. The results obtained in this work can be used as the basis for the design of optical sensors for oxygen.

In this paper spectral-luminescent, lasing, photochemical, and sensory characteristics of a number of Zn(II) and B(III) coordination complexes with dipyrrinates with different structures are presented. We have discussed relations of the structure of investigated compounds and formed solvates with their optical characteristics. The results showed that alkyl substituted dipyrrinates derivatives have excellent luminescent characteristics and demonstrated effective lasing upon excitation of Nd:YAG-laser. They can be used as active media for liquid tunable lasers. Zinc and boron fluoride complexes of dipyrrinates with heavy atoms in structure don't have fluorescence but have long-lived emission due to increased nonradiative intersystem processes in the excited state by the mechanism of a heavy atom. For solid samples based on halogenated complexes was found dependency of the long-lived emission intensity of the oxygen concentration in gas flow. The presence of line segment indicates the possibility of the use of these complexes as a basis for creation of optical sensors for oxygen. Moreover, results of a study of halogen-substituted aza-complexes under irradiation are presented. Such complexes are promising for the creating media for generation of singlet oxygen (1O2), which is important for photodynamic therapy in medicine and photocatalytic reactions in the industry.

Optical properties of some boron dipyrromethene difluoro (III) (BF2-dipyrromethene) derivatives are studied depending on the ligand structure, the medium in which they are incorporated, irradiation time, and radiation wavelength. Prospects for application of the prepared solid-state media painted by the examined compounds in various optical devices used in modern technologies are demonstrated. These are active laser media in the range 550–565 nm based on three-component silicate matrices with high laser damage threshold and sensor media based on boron difluoride complexes of halogen-substituted dipyrromethenes incorporated into an organic polymer for the determination of oxygen concentration in a gas mixture. Spectral, energy, and resource characteristics of lasing of solid-state elements are presented. The effect of reversible dye photounpainting in three-component silicate matrices with subsequent restoration in the darkness is discovered. Possible reasons for this effect are discussed with allowance for which laser media with increased photostability can be prepared. A high sensitivity of the sensor medium based on diiodinated complex of BF2-dipyrromethene incorporated into polyvinyl butyral is obtained. Reasons for the increase in the response time to the change of the gas mixture when going over to neutral argon and possibilities of its elimination are discussed.

A comparative study of spectral, luminescent, and photophysical parameters has been carried out for a series of zinc(II) and boron(III) chelates with dipyrromethene ligands of a similar structure: tetramethyl- and tetraphenylpyrrodimethenes bearing the substituents on the pyrrole rings and tetraphenylazapyromethene. In some cases, the luminescence efficiency of the chelates depends on the excitation wavelength. The replacement of the central atom boron(III) by zinc(II) results in not only a twofold increase in the number of coordinated chromophoric ligands and the absorption coefficient, but also an increase in the contribution of nonradiative processes to excitation energy deactivation and, hence, a decrease in the yield of fluorescence. The efficiency of intersystem crossing is higher in the zinc(II) dipyrromethene complexes than in the corresponding boron-chelated dipyrromethenes (BODIPYs), resulting in the appearance of phosphorescence in frozen solutions. It has been found that the replacement of the meso-spacer in the dipyrromethene ligand by the nitrogen atom not only shifts the absorption and fluorescence band maximums to longer wavelengths, but also decreases the fluorescence efficiency and leads to the appearance of long-lived luminescence even in aza-BODIPY. An analysis of the results has shown that these behavior can be due to involvement of the nπ* (πσ*, σπ*) states localized on the meso-nitrogen in the deactivation of excitation energy.