Phenylene Units Research Articles

Insights into the Structural Modification of Selenium-Doped Derivatives with Narrowband Emissions: A Theory Study.

The research on boron/nitrogen (B/N)-based multiresonance thermally activated delayed fluorescence (MR-TADF) emitters has been a prominent topic due to their narrowband emission and high luminous efficiency. However, devices derived from the common types of narrowband TADF materials often experience an efficiency roll-off, which could be ascribed to their relatively slow triplet-singlet exciton interconversion. Since inserting the heavy Se atom into the B/N scheme has been a proven strategy to address the abovementioned issues, herein, extensive density functional theory (DFT) and time-dependent DFT (TD-DFT) simulations have been employed to explore the effects of the structural modification on a series of structurally modified selenium-doped derivatives. Furthermore, the two-layered ONIOM (QM/MM) model has been employed to study the pressure effects on the crystal structure and photophysical properties of the pristine CzBSe. The theoretical results found that the introduced tert-butyl units in Cz-BSeN could result in a shorter charge transfer distance and smaller reorganization energy than the parent CzBSe. In contrast to directly incorporating the o-carborane (Cb) unit to CzBSe, incorporating the bridged phenyl units is important in order to achieve narrowband emissions and high luminous efficiency. The lowest three triplet excited states of CzBSe, Cz-BSeN and PhCb-BSeN all contribute to their triplet-singlet exciton conversions, resulting in a high utilization of triplet excitons. The pressure has an evident influence on the photophysical properties of the aggregated CzBSe and is favored for obtaining narrowband emissions. Our work is promised to provide a feasible strategy for designing selenium-doped derivatives with narrowband emissions and rapid triplet-singlet exciton interconversions.

Tuning the Properties of Hydrazone/Isosorbide-Based Switchable Chiral Dopants.

The long-range supramolecular interactions in liquid crystals (LCs) can be used to amplify and subsequently propagate microscopic structural changes into macroscopic events. Here, we report on a systematic structure-property analysis using 16 chiral photoswitchable dopants composed of bistable hydrazones and chiral isosorbide moieties. Our findings showcase the relationship between the dopant's structure and its helical twisting power (β), and hence, the photophysical properties of the host LC. We show that an increase in the hydrazone CNNH dihedral angle results in an increase in the β value, while alkoxy chains do not lead to such an increase. These results contradict established rules of thumb, stating that structural rigidity and long alky chains are needed for high β values. We also found that the position of the substitution, whether at the 2' or 5' positions of the isosorbide unit, or the attachment of the chiral unit to the rotor or stator phenyl units can have negative or positive additive effects that can either increase or decrease the β values. These results made us hypothesize that unsymmetrically functionalized dopants should result in large Δβ values, which we corroborated experimentally. Moreover, a fluorine-functionalized dopant resulted in higher overall β values, most likely because of π-π interactions. Finally, the dopants were used in modulating and locking in the reflective properties of LC films, yielding multicolor LC canvases that can reflect light from the ultraviolet to the infrared range (i.e., a manipulation of up to ca. 1500 nm of reflected light).

Size-Increased All-Phenylene Molecular Spoked Wheels - A Combined Theoretical and Experimental Approach.

A lateral expansion of molecular spoked wheels (MSWs) based on an all-phenylene backbone is described. The MSWs contain a central hub, six spokes, and a rim that is formed by a sixfold Yamamoto coupling of the respective non-cyclized dodecabromo precursor yielding MSWs with up to 30 phenylene rings in the perimeter. Attempts to prepare compounds of such size without flexible side groups at the spokes were unsuccessful, most probably due to an aggregation and accompanying oligomerization of the precursors during the cyclization. To overcome these problems, fluorene units are inserted into the spokes. These contain additional alkyl chains and lead to a curvature of the wheels. Quantum chemical calculations on the mechanism of the Yamamoto coupling lead to geometry and strain-related criteria for the successful rim closure to the respective MSW. Subsequently, MSWs are prepared with four and even six phenylene units at each edge of the hexagonal wheels. The resulting MSWs are characterized by spectroscopic methods, and additionally some of them are visualized via scanning tunneling microscopy (STM).

Boosted electro-optic performance in second-order nonlinear optical chromophores featuring thiophen-2-amine-derived donor groups

Two innovative second-order nonlinear optical chromophores, designated as B–C, have been synthesized, featuring thiophene-derived donors and a tricyanovinyldihydrofuran bridge as acceptors. These chromophores have undergone comprehensive characterization. Notably, the donor components of chromophores B–C were (methyl(phenyl)amino)thiophene and (4-methoxyphenylamino)thiophene, respectively, in contrast to the diethylamino phenyl unit present in chromophore A. Density functional theory calculations suggested that the first hyperpolarizability of chromophore C, with a (methoxyphenyl amino) thiophene donor, was approximately 60 % higher than that of chromophores A and B. This indicates that merely substituting the benzene ring with thiophene does not significantly enhance the electron-donating ability of the donor. Polymeric thin films doped with 25 wt% of chromophores A-C exhibited r33 values of 39 p.m./V, 46 p.m./V, and 76 p.m./V, respectively. The electro-optic coefficients of chromophores B and C were 18 % and 95 % higher than that of chromophore A, respectively. These findings confirm that thiophene-derived donors, particularly those with multiple heteroatoms, can effectively enhance the electro-optical coefficient of chromophores.

Dihedral Angles and Photoluminescence Quantum Yields: An NMR Analysis.

The synthesis of two different series of donor-acceptor (D-A) molecules is reported, consisting of a series of four structurally related donors and two different acceptors. The subtle differences in the electron density of these D-A-D and D-A compounds are clearly reflected in the different chemical shifts of certain donor protons in the 1H NMR spectra. These shifts show a cosine squared correlation of the dihedral angle between the donor units and the neighbouring phenyl unit of the acceptor. This correlation is also related to optical properties such as the photoluminescence quantum yield, which shows a similar trend due to the different degree of charge transfer during excitation and relaxation processes. In this way, it is possible to directly correlate a molecular structural parameter with a material property on a purely experimental basis, which should be applicable to many donor-acceptor systems.

Reactivity of Tetrel-Functionalized Heptaphosphane Clusters toward Azides.

In this work, the reactivity of tetrel-functionalized phosphorus clusters toward organoazides is probed. Clusters (Me3Si)3P7 (1) and (Me3Ge)3P7 (2) were reacted with benzyl azide, phenyl azide, and 4-bromophenyl azide, and it was found that the [RN] (R = benzyl, phenyl, and 4-bromophenyl) unit from the azide inserted into the phosphorus-tetrel bonds on the cluster, accompanied by N2 elimination. Through control of the azide stoichiometry, the mono-, bis-, and tris-inserted products could be observed, consistent with these insertions proceeding in a stepwise manner. The bonding between the amine moieties and clusters was further investigated by computational chemistry, and the findings were consistent with the phosphorus cluster having undergone a formal oxidation. These insertion reactions are a convenient means of accessing Zintl clusters functionalized with exo-nitrogen-bonded moieties, which, to the best of our knowledge, were previously unknown.

Lithiophilic Dibenzamide Linkages to Impart Lithium Storage Capacity in Porous Polybenzamides.

Polymer-based organic cathode materials have shown immense promise for lithium storage, owing to their structural diversity and functional group tunability. However, designing appropriate high-performance cathode materials with a high-rate capability and long cycle life remains a significant challenge. It is quintessential to design polymer-based electrodes with lithiophilic linkages. Herein, we design a bifurcated dibenzamide (DBA) linkage having lithiophilic functionalities. 1H NMR has been used as an experimental tool to understand the lithiophilic nature of the DBAs. Considering the strong Li+ affinity of DBAs, a series of polybenzamides have been designed as lithium storage systems. The design of porous polybenzamides consists of amides as only redox-active functionalities, and the rest are inactive phenyl units. Porous polybenzamides, when tested as cathodes against a Li-metal anode, displayed high capacity and rate performance, demonstrating their redox activity. The most efficient polybenzamide (TAm-TA) delivered a specific capacity of 248 mA h g-1 at 1C. TAm-TA retained 63% of its specific capacity at a very high rate of 10C (157 mA h g-1). Notably, polybenzamides displayed a capacity enhancement during long cycling, tending to achieve their theoretical capacity. Long cycling stability tests over 3000 cycles at a rate of 1.3C and over 6000 cycles at elevated rates (5C to 40C) demonstrate the electrochemical robustness of dibenzamide linkages. Finally, two full-cell experiments using TAm-TA as both cathode and anode were conducted, which delivered high capacity, demonstrating that TAm-TA is a promising candidate for Li+-ion batteries (LIBs). Furthermore, the ex situ Fourier transform infrared (FT-IR), X-ray photoemission spectroscopy (XPS), and density functional theory (DFT) studies revealed the stepwise lithiation/delithiation mechanism for polybenzamides.

Investigation of cholinesterase and α-glucosidase enzyme activities, and molecular docking and dft studies for 1,2-disubstituted cyclopentane derivatives with phenyl and benzyl units.

Six known products (4-9) were prepared from reaction of adipoyl chloride with 1,2,3-trimethoxybenzene according to the literature. From (2,3,4-trimethoxyphenyl)(2-(2,3,4-trimethoxyphenyl)cyclopent-1-en-1-yl)methanone (4) of them, four new 1,2-disubstituted cyclopentane derivatives (10-13) with phenyl and benzyl units were synthesized by reactions such as hydrazonation, catalytic hydrogenation and bromination. The obtained compounds 4-13 were examined for their in vitro inhibitory activity against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and α-glucosidase enzymes. All compounds 4-13 showed inhibition at nanomolar level with Ki values in the range of 45.53 ± 7.35-631.96 ± 18.88nM for AChE, 84.30 ± 9.92-622.10 ± 35.14nM for BChE, and 25.47 ± 4.46-48.87 ± 7.33 for α-Glu. In silico molecular docking studies of the potent compounds were performed in the active sites of AChE (PDB: 1E66), BChE (PDB: 1P0I), and α-glucosidase (PDB: 5ZCC) to compare the effect of bromine atom on the inhibition mechanism. The optimized molecular structures, HOMO-LUMO energies and molecular electrostatic potential maps for the compounds were calculated by using density functional theory with B3LYP/6-31 + G(d,p).

Thiourea-functionalized aminoglutethimide derivatives as anti-leishmanial agents.

Aim: We aim to develop new anti-leishmanial agents against Leishmania major and Leishmania tropica.Materials & methods: A total of23 thiourea derivatives of (±)-aminoglutethimide were synthesized and evaluated for in vitro activity against promastigotes of L. major and L. tropica.Results & conclusion: The N-benzoyl analogue 7p was found potent (IC50=12.7μM) against L. major and nontoxic to normal cells. The docking studies, indicates that these inhibitors may target folate and glycolytic pathways of the parasite. The N-hexyl compound 7v was found strongly active against both species, and lacked cytotoxicity against normal cells, whereas compound 7r, with a 3,5-bis-(tri-fluoro-methyl)phenyl unit, was active against Leishmania, but was cytotoxic in nature. Compound 7v was thus identified as a hit for further studies.

Comprehensive investigations of four ratiometric fluorescent chemosensors based on 4-(1H-imidazol-2-yl)benzaldehyde skeleton for malononitrile detection

Malononitrile is a very important chemical material and has wide application fields in production of medicines, pesticides, and extraction of gold. However, its nonnegligible hypertoxicity inspired researchers to develop more efficient analysis techniques to sensitively and selectively detect malononitrile. Nopinone derivatives initiated by our research group have been developed as a class of organic fluorescent chemosensors for identifying multiple analytes in recent years. Different heterocyclic compounds based on nopinone were designed and synthesized to be applied in the fields of environmental analysis, food detection and bioimaging. Nevertheless, the comparison research on the optical properties of fluorescent compounds containing the nopinyl matrix with other structural analogs including alkyl, cyclohexyl and phenyl groups was deficient. Herein, four 4-(1H-imidazol-2-yl)benzaldehyde-based ratiometric fluorescent chemosensors based on o-dimethyl cyclohexyl, phenyl and nopinyl units for recognizing malononitrile were designed and developed, and their differences in the optical properties and detection performances were investigated by using spectral analysis combined with theoretical calculations. Moreover, the nopinone-based 4-(1H-imidazol-2-yl)benzaldehyde fluorescent chemosensor NMZQ was successfully applied in the dual channel fluorescence bioimaging of malononitrile in living HeLa cells and zebrafish, which attributed to its outstanding spectral property and detection performance.

Synthesis, optical properties, and dual‐color halochromic fluorescence of novel π‐conjugated polymers bearing coumarin unit in the main chain

AbstractA series of novel π‐conjugated polymers bearing alternating coumarin and phenylene units in the main chain backbone was synthesized via Sonogashira coupling reaction. The red‐shifts in the absorption maxima of the polymers indicate the expansion of π‐conjugated system in the polymer main chains. These polymers exhibited strong green fluorescence in organic solvents. Clearly perceptible dual‐color halochromic fluorescence was confirmed for the polymers by the significantly reversible changes of emission color from green to blue during alkalization and acidification processes. The lactone ring opening and closing property in the coumarin molecule functioned as a controllable switch, broadening the applications of the coumarin‐based π‐conjugated polymers as acid–base responsive fluorescence materials.

Diruthenium complexes incorporating carboxylated chalcones with phenyl or ferrocenyl units: Synthesis, structural, electrochemical and DNA binding studies

A total of eight diruthenium sawhorse and cationic complexes incorporating carboxylated chalcones with phenyl or ferrocenyl units have been synthesized and characterized. The electrochemical behavior of the sawhorse and cationic complexes incorporating the ferrocenyl moiety have been studied by cyclic voltammetry. For the cationic complexes both the diruthenium core and the ferrocenyl unit undergo oxidation, in contrast only the ferrocenyl moieties for the sawhorse complexes were oxidized. The enhanced solubility of the cationic complexes over the neutral sawhorse compounds in aqueous medium enabled DNA binding studies to be undertaken for the former. All of the cationic complexes could bind to DNA, and displayed better selectivity for quadruplex over duplex DNA. These results indicate that diruthenium cationic complexes are able to bind to quadruplex DNA and have the potential to function as telomerase inhibitors.

Strategic design of a rare trigonal symmetric luminescent covalent organic framework by linker modification

We designed a trigonal symmetric imine-linked covalent organic framework (COF), TFPC-DAB, with control over the angularity of the building units, where a bent C2-symmetric diamine, such as 1,3-diaminobenzene (1,3-DAB or DAB), with an exo-angle of 120° was used instead of those with an exo-angle of 180°, in combination with a C3-symmetric trialdehyde, such as tri(4-formylphenoxy)cyanurate (TFPC). Its synthesis was accomplished by reacting the building units in a mixture of mesitylene/dioxane/6 M acetic acid under solvothermal conditions. The phase purity, thermal stability, and porosity of TFPC-DAB were established by various analytical techniques. Utilizing the Density Functional Tight Binding (DFTB+) simulation and Pawley refinement, the best fit of the small angle x-ray pattern was found to have an AA stacking of TFPC-DAB in the trigonal space group P3 with low refinement parameters. Such smart materials are in huge demand to detect hazardous corrosive chemicals, such as HCl and NH3. The dual features of electron deficient π-acidic triazine moiety and heteroatoms (N/O) from TFPC and electron rich phenyl units from DAB embodied in the framework enhance its luminescent property and thereby make it suitable for solvent-based HCl and NH3 sensing. The detection limits for HCl and NH3 in methanol were found to be 14 and 82 ppb, respectively. The effect of solvent polarity on the sensing studies was observed with much lower detection limits in dioxane: 2.5 and 11 ppb for HCl and NH3, respectively. A detailed theoretical calculation using density functional theory and configurational bias Monte Carlo modules was conducted for understanding interactions between the COF and HCl or NH3 analytes.

The influence of molecular shape on reorientation dynamics of sizable glass-forming isomers at ambient and elevated pressure

We used dielectric spectroscopy to access the molecular dynamics of three isomers with a structure based on a sizable, partially rigid, and non-polar core connected to a polar phenylene unit differing in the position of the polar group, and, consequently, the direction and magnitude of the dipole moment to address the question how unique molecular properties, in particular large size and elongated shape, affect the dynamics. The position of the polar group differentiates the molecular shape and isomer’s anisotropy and leads to different thermal and dynamic properties of the isomers. The shape of permittivity loss spectra was governed by magnitudes of the longitudinal and transverse components of dipole moment to a large extent. For para isomer with negligible traverse component of dipole moment, the narrowest loss peak was found while for meta isomer, the bimodal loss peak was observed at high temperatures. Its shape evolved on cooling limiting the possibility of individual mode separation near glass transition where the dynamics were more cooperative. High-pressure dielectric studies showed that sizable isomers were characterized by the pronounced sensitivity of glass transition temperature, Tg, to compression. Observed high activation volumes, such as 735 cm3/mol at Tg for para isomer, were found to correlate with the length scale of dynamic cooperativity. The number of dynamically correlated molecules depended on molecular shape and varied among isomers while the determined values were much smaller than that reported for other glass-forming liquids. We discussed here the obtained results in the context of the specific properties of the systems studied showing the overriding role of anisotropy.

Study on phenyl series of polymers wrapping of different diameters of semiconducting single-walled carbon nanotubes for ammonia gas sensors

In this study, the fluorene-alt-benzene (PFOB), fluorene-alt-bisbenzene (PFDB), and fluorene-alt-tribenzene (PFTB) were synthesized via Suzuki coupling. The phenyl units in PFDB and PFTB are linked by imine bonds (-CH=N-). These three polymers were employed to selectively sort the semiconducting single-walled carbon nanotubes (sc-SWCNTs) from two types of single-walled carbon nanotubes (SWCNTs) with different tube diameters (Plasma (0.9–1.7 nm) and Hipco (0.8–1.2 nm)). The six polymer/sc-SWCNTs composites were prepared for chemiresistor devices via a simple drop-coasting method for detecting the ammonia vapor. The results indicate that all six devices based on polymer/sc-SWCNTs composites demonstrate excellent sensitivity to ammonia vapor. Additionally, they exhibit a low theoretical detection limit and good reproducibility. The PFTB and PFOB showed higher efficiency of selection of plasma and Hipco, respectively. The corresponding sensors showed a good response to ammonia vapor at 3 ppm (PFTB/sc-SWCNTs (Plasma): 5.8% and PFOB/sc-SWCNTs (Hipco): 5.0%). The results suggest that the specific type of polymer needs to be designed for effectively sort sc-SWCNTs from different SWCNTs. This will enable the fabrication of polymer/sc-SWCNTs composite sensors with better response to ammonia.

Narrowband emission from fully-bridged triphenylamine derivatives: insights into effects of structure modification and pressure.

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors.

Salt-induced Fmoc-tripeptide supramolecular hydrogels: a combined experimental and computational study of the self-assembly.

Delving into the mechanism behind the molecular interactions at the atomic level of short-sequence peptides plays a key role in the development of nanomaterials with specific structure-property-function relationships from a bottom-up perspective. Due to their poor water solubility, the self-assembly of Fmoc-bearing peptides is usually induced by dissolution in an organic solvent, followed by a dilution step in water, pH changes, and/or a heating-cooling process. Herein, we report a straightforward methodology for the gelation of Fmoc-FFpY (F: phenylalanine; Y: tyrosine; and p: PO42-), a negatively charged tripeptide, in NaCl solution. The electrostatic interactions between Fmoc-FFpY and Na+ ions give rise to different nanofibrillar hydrogels with rheological properties and nanofiber sizes modulated by the NaCl concentration in pure aqueous media. Initiated by the electrostatic interactions between the peptide phosphate groups and the Na+ ions, the peptide self-assembly is stabilized thanks to hydrogen bonds between the peptide backbones and the π-π stacking of aromatic Fmoc and phenyl units. The hydrogels showed self-healing and thermo-responsive properties for potential biomedical applications. Molecular dynamics simulations from systems devoid of prior training not only confirm the aggregation of peptides at a critical salt concentration and the different interactions involved, but also corroborate the secondary structure of the hydrogels at the microsecond timescale. It is worth highlighting the remarkable achievement of reproducing the morphological behavior of the hydrogels using atomistic simulations. To our knowledge, this study is the first to report such a correspondence.

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space.

The concept of bioisostere replacement is of paramount importance in medicinal chemistry, as it can be employed as a rational to expand bioactive chemical space to tackle lead optimization issues like lack of potency, efficacy, and selectivity or pharmacokinetic/dynamic issues. One of the most important building blocks (in the sense of participating in a vast area of chemical space of biological importance) in medicinal chemistry is the 2-phenethyl moiety, a key component of diverse drug-like entities. Although the core 2-phenethylamine structure has been recognized by the drug discovery community, little attention has been given to the various ring-based rescaffolding procedures that can be conducted with this unit. In this regard, a review on the use of 2-heteroarylethylamines displaying pharmacological activity is reported. A detailed description of flexible, amine-opened motifs is provided, that describes therapeutic targets and other potent bioactive examples, which will be a valuable repository of phenyl, heteroaryl, and other replacement units of high value to the drug discovery community.

Theoretical elucidation of the effect of the linkage and orientation of carbazole and naphthalenediimide on the TADF and RTP propensities.

Thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) are most promising processes for harvesting triplet excitons in organic light-emitting diodes. In this work, the effect of the linkage between the carbazole (Cz) donor (D) and the naphthalenediimide (NDI) acceptor (A) on the TADF and RTP propensities is elucidated using density functional theory computations employing D-A, D-A-D, D-π-A, and D-π-A-π-D structural designs. The effects of the dihedral angle between the donor and acceptor units on the energy difference between the singlet and triplet excited states (ΔEST), the spin-orbit coupling (SOC) constants, and radiative (kr), intersystem crossing (kISC) and reverse intersystem crossing (kRISC) rates are unravelled. The molecules possessing a direct linkage between Cz and NDI exhibit large ΔEST values due to substantial overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). However, the insertion of a phenyl spacer between the Cz and NDI units led to disjoint HOMO and LUMO and consequently resulted in a small ΔEST. Furthermore, the presence of two donors with and without a phenyl spacer on NDI resulted in a high-lying triplet state (T2) that is energetically lower than the lowest singlet excited state (S1), hence providing additional channels to the TADF and RTP processes. Also, the orientation of Cz and NDI in the ortho-positions of the phenyl unit resulted in a T1 state with dominant LE character which led to moderate spin-orbit coupling constants and highest kr rates compared to the analogous meta- and para-linked derivatives. Thus, the ortho-derivatives possessed small ΔEST, charge transfer dominated S1, joint holes and electrons for the T1 state, characteristic of local excitation, high SOC, and promising rISC and kr rates. Overall, the phenyl linked derivatives possess TADF characteristics, while the directly linked analogues show RTP propensity.

Photochromic polymers: Structural engineering driving individual NLO response

Photochromic polymers have attracted a lot of attention in the last few decades because of their useful properties related to color change and optical data storage. In this contribution we present a macromolecular structure influence on the output spectroscopic properties in the manner of all-optical switching and harmonics of light generation. Slight chemical architecture changes make significant difference if we consider generated optical anisotropy magnitude and kinetics of photoinduced process but also force diversified nonlinear optical response. We have placed a strong electron acceptor unit, fluorine atom, in a few alternate substitution patterns. One of them (1,4-) activates the phenyl unit, the other one (1,3-) works opposite. Finally, a joined form was also investigated, which led to appealing results making materials engineering field of studies a useful tool dedicated for advanced functional materials fabrication. Moreover, experimental achievements presented here indicate that investigated materials are perfect candidates for opto-electronics, photonics and spectroscopy fields and can be easily implemented into individual optical processing solutions.