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4,4‐Difluoro‐4‐borata‐3a‐azonia‐4a‐aza‐s‐indacene (BODIPY) dyes are extensively used in various applications of their triplet states, ranging from photoredox catalysis, through triplet sensitization to photodynamic therapy. However, the rational design of BODIPY triplet chromophores by ab initio modelling is limited by their strong interactions of spin, electronic and vibrational dynamics. In particular, spin‐vibronic coupling is often overlooked when estimating intersystem crossing (ISC) rates. In this study, a combined experimental and theoretical approach using spin‐vibronic coupling to correctly describe ISC in BODIPY dyes was developed. For this purpose, seven π‐extended BODIPY derivatives with iodine atoms in different positions were examined. It was found that the heavy‐atom effect of iodine atoms is site specific, causing high triplet yields in only some positions. This site‐specific ISC was explained by El‐Sayed rules, so both the contribution and character of the molecular orbitals involved in the excitation must be considered when predicting the ISC rates. Overall, the rational design of BODIPY triplet chromophores requires using (i) the high‐quality electronic structure theory, including both static and dynamical correlations; and (ii) the two‐component wave function Hamiltonian, and rationalizing; and (iii) ISC based on the character of the molecular orbitals of heavy atoms involved in the excitation, expanding El‐Sayed rules beyond their traditional applications. [ABSTRACT FROM AUTHOR]

In this work, we developed a water‐soluble caging group based on a π‐extended BODIPY scaffold able to release carboxylate‐containing cargo upon red light illumination (λirr=633 nm). We performed mechanistic studies showing new insights into the principles of the photoreactivity of these cages and demonstrated a significant influence of the structure of a carboxylate cargo on the rate and efficiency of the uncaging process and its side reactions. We used it for selective delivery, visualisation, and photorelease of a signaling lipid in cell plasma and internal membranes. With this approach, we successfully induced Ca2+ release in cells expressing the GPR40 receptor. [ABSTRACT FROM AUTHOR]

In this work, we developed a water‐soluble caging group based on a π‐extended BODIPY scaffold able to release carboxylate‐containing cargo upon red light illumination (λirr=633 nm). We performed mechanistic studies showing new insights into the principles of the photoreactivity of these cages and demonstrated a significant influence of the structure of a carboxylate cargo on the rate and efficiency of the uncaging process and its side reactions. We used it for selective delivery, visualisation, and photorelease of a signaling lipid in cell plasma and internal membranes. With this approach, we successfully induced Ca2+ release in cells expressing the GPR40 receptor. [ABSTRACT FROM AUTHOR]

Abstract A new series of photosensitive azo materials possessing a chiral alkyl lactate moiety and terminal n-alkyl carboxylate unit close to the azo group has been synthesized and studied. The length of the n-alkyl carboxylate chain has been systematically varied in order to establish the effect of the molecular structure on the self-assembling behaviour. Two series of materials possessing hexyl and dodecyl alkyl chains in the chiral part of the molecule have been studied. It has been shown that the length of both the alkyl chains strongly influences the mesomorphic behaviour, however, each chiral/achiral chain has different utility to tune the mesomorphic properties. With exception of the compound with the longest chains, all studied compounds exhibited the chiral tilted ferroelectric smectic C* phase. Based on the combination of terminal alkyl chains, chiral nematic, orthogonal smectic A*, and twist grain boundary smectic A* phases have been detected on cooling beyond the SmC* phase. The presence of the photosensitive functional N=N group in the molecular core allowed further tuning of the material properties by UV light illumination. The E -to- Z photoisomerization of the azo group and subsequent thermal back-isomerisation have been studied in solution by nuclear magnetic resonance and most importantly in the mesophases on bulk samples. We report on UV-induced isothermal switching from chiral smectic and nematic mesophases into the isotropic phase, respectively, and differences in the textures of mesophase upon restoration of the ordered liquid. Highlights • Photosensitive chiral liquid crystals exhibiting a broad SmC* phase as well as SmA*, TGBA* and N* phases are presented. • Low-energy UV light induces isothermal phase transition from SmC* over TGBA* (SmA*) and N* phases into the isotropic phase. • Fast isothermal transition from any mesophase to isotropic phase is enabled by high-energy UV light. [ABSTRACT FROM AUTHOR]

Hexagonal phase ultrafine nanoparticles of NaY(Gd)F 4 were synthesized using chloride precursors and sodium acetate to provide liquid environment for ionic transportand as a source of sodium ions. Prepared ultrafine nanocrystals were analysed by XRD, laser Doppler electrophoresis and TEM measurements. Absence of fluoroacetic acid was confirmed by NMR of wash water obtained by dispersion centrifugation. Synthesized nanocrystals were 8.9 nm in diameter and had a hexagonal crystal structure. The method is appropriate for further experimental development, e.g. the synthesis of luminescent fluorides based on NaY(RE)F 4 system, and for possible industrial application because of its ability to prepare large amounts of nanocrystals and due to the fact that the process is affordable and environmental friendly. [ABSTRACT FROM AUTHOR]

Keywords: BODIPY; Photocages; Selective Delivery; Signaling Lipids; Uncaging EN BODIPY Photocages Selective Delivery Signaling Lipids Uncaging 1 1 1 08/19/22 20220822 NES 220822 B Tissue-transparent red light b is used to release oleic acid, a signaling lipid, into cells, which induces Ca SP 2+ sp oscillations accompanied by a turn-on fluorescence response. Inside Cover: Red-Shifted Water-Soluble BODIPY Photocages for Visualisation and Controllable Cellular Delivery of Signaling Lipids (Angew. BODIPY, Signaling Lipids, Photocages, Selective Delivery, Uncaging. [Extracted from the article]

Keywords: BODIPY; Photocages; Selective Delivery; Signaling Lipids; Uncaging EN BODIPY Photocages Selective Delivery Signaling Lipids Uncaging 1 1 1 08/18/22 20220822 NES 220822 B Gewebetransparentes rotes Licht b wird verwendet, um Ölsäure, ein signalgebendes Lipid, innerhalb von Zellen freizusetzen, was Ca SP 2+ sp -Oszillationen auslöst, die mit einer Fluoreszenzantwort einhergehen. Innentitelbild: Red-Shifted Water-Soluble BODIPY Photocages for Visualisation and Controllable Cellular Delivery of Signaling Lipids (Angew. BODIPY, Photocages, Selective Delivery, Signaling Lipids, Uncaging. [Extracted from the article]

We present two isomeric series of photosensitive bent-core liquid crystals possessing a lateral chlorine atom in the central resorcinol unit and various linking units in the side arms. With the aim to tune properties of the nematic phase, we have varied the type of the linking unit in the lengthening arm with rising rigidity from benzoate ester, biphenyl, cinnamate, Schiff base to stilbene moieties. In addition to that, we have changed the position of the lateral substituent (chlorine) as well. The mesomorphic properties of the materials have been determined from differential scanning calorimetry, polarizing optical microscopy, dielectric spectroscopy and X-ray studies. We show that synergy of the linking unit with the effect of the lateral substituent gives rise to broad temperature range of mesophases — the nematic phase as well as a SmCP phase. Thanks to the presence of the photosensitive group in the molecular structure, we have been able to transform both mesophases to the isotropic phase under UV light. The chemical structure–mesomorphic properties relationships are discussed with the aid of ab initio calculations and the results presented in context with experimental data. • Two series of 4-chlororesorcinol-based photosensitive bent-core nematogens are presented. • Mutual position of chlorine atom on the central core and the azo group is crucial for mesomorphic behaviour. • Broad stable nematic phase below 100 °C and switchable SmC A P A phase are observed. • Photosensitivity of bulk mesophases is documented by X-ray profile and polarizing microscopy measurements. [ABSTRACT FROM AUTHOR]

Liquid crystals (LCs) are among the most prominent materials of the current information age, mainly due to their well-known application in liquid crystal displays (LCDs). Their unique electro-optical properties stem from their ability to form organised structures (mesophases) on the transition from solid state to isotropic liquid. Molecules of LCs in a mesophase still maintain the anisotropy of solid crystals, while simultaneously exhibiting the fluidity of liquids, which gives the system the ability to react immediately to external stimuli such as electric or magnetic fields, light, mechanical stress, pressure and, of course, temperature. For the proper function of LC-based devices, not only chemical, but also optical purity of materials is strongly desirable, since any impurity could be detrimental to the self-assembly of the molecules. Therefore, in this study we aimed to verify synthetic methods published in the literature, which are used nowadays to prepare chiral building blocks based on lactic acid, for their enantioselectivity. Moreover, we have focused on the development of an analytical chiral separation method for target liquid crystalline materials. Using a chiral polysaccharide-based column operated in liquid chromatography mode, we show that not all published methods of LC synthesis are enantioselective, which could lead to significant differences in the properties of the resulting materials. We show that high-performance liquid chromatography with UV detection and supercritical fluid chromatography with UV and mass spectrometry detection enable full control over the chemical and optical purity of the target LCs and the corresponding chiral building blocks. For the first time, we utilise supercritical fluid chromatography with mass detection for the direct chiral analysis of liquid crystalline materials and impurities formed during the synthesis. [ABSTRACT FROM AUTHOR]

A new photoresponsive bent‐core nematic (BCN) material, which exhibits flexoelectric domains (FDs) driven by electric field, is reported. Unexpectedly, it is found that the morphologies of FDs can be controlled by irradiation with light fields. This light tunability is ascribed to the photoisomerization effect of the azo moiety within the BCN molecules, where the ratio of trans and cis isomers changes according to the parameters of the light field, resulting in adjustable electric threshold and periodicity of FDs. Based on this principle, a prototype of controllable optical grating is assembeled, whose operation can be manipulated by the wavelength or intensity of light. Due to the easy, instant, and remote operation by light, this optical, contactless tunability has a great advantage over traditional electric control in tunable photonic devices. [ABSTRACT FROM AUTHOR]