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Phenyl, naphthyl, polyarylphenyl, coronene, and other aromatic and polyaromatic moieties primarily influence the final materials’ properties. One of the synthetic tools used to implement (hetero)aromatic moieties into final structures is Diels–Alder cycloaddition (DAC), typically combined with Scholl dehydrocondensation. Substituted 2-pyranones, 1,1-dioxothiophenes, and, especially, 1,3-cyclopentadienones are valuable substrates for [4 + 2] cycloaddition, leading to multisubstituted derivatives of benzene, naphthalene, and other aromatics. Cycloadditions of dienes can be carried out with extrusion of carbon dioxide, carbon oxide, or sulphur dioxide. When pyranones, dioxothiophenes, or cyclopentadienones and DA cycloaddition are aided with acetylenes including masked ones, conjugated or isolated diynes, or polyynes and arynes, aromatic systems are obtained. This review covers the development and the current state of knowledge regarding thermal DA cycloaddition of dienes mentioned above and dienophiles leading to (hetero)aromatics via CO, CO2, or SO2 extrusion. Particular attention was paid to the role that introduced aromatic moieties play in designing molecular structures with expected properties. Undoubtedly, the DAC variants described in this review, combined with other modern synthetic tools, constitute a convenient and efficient way of obtaining functionalized nanomaterials, continually showing the potential to impact materials sciences and new technologies in the nearest future.

NˆCˆN cyclometalated iridium(III) acetylide complexes in the 3 + 2+1 ligand mode were obtained and characterized. Cyclometalating ligands were bis(pyridyl)phenyl, bis(benzothiazolyl)phenyl and 2-phenylpyridine derivatives, while acetylene ligands represented 2-ethynylfluorene and 3-ethynylcarbazole derivatives. The HOMOs of the ethynyl iridium complexes are located on the ethynyl ligand and the iridium atom, whereas the LUMO is located exclusively on the NˆCˆN-cyclometalating ligand. All compounds showed phosphorescent properties, where the change of ligands significantly affects the wavelength of emission. Acetylide complexes emit light from the blue (∼ 400 nm) to orange (∼ 560 nm) range. Emission occurs from the mixed state 3MLCT/3LC, with a predominance of junction depending on the structure of the ligands.

A series of 2,2′:6′,2″-terpyridine (terpy), 2,6-di(thiazol-2-yl)pyridine (dtpy), and 2,6-di(pyrazin-2-yl)pyridine (dppy) derivatives with electron donating amino groups (dimethylamine, piperidine, morpholine and diphenylamine) connected to the terpy/dtpy/dppy skeleton via phenylene linkage have been thoroughly investigated in order to get an insight into the impact of amine donors and nitrogen-based π-deficient heterocycles on the thermal, redox, UV–Vis absorption and emission properties. All the compounds melted without thermal decomposition and the presence of di(pyrazin-2-yl)pyridine skeleton increased the melting temperature and prevented formation of amorphous material. The obtained compounds undergo electrochemical reduction and oxidation processes and show electrochemically estimated Eg in the range of 2.30–2.83 eV. The lowest values of Eg were confirmed for the compounds bearing 2,6-di(pyrazin-2-yl)pyridine core and dimethylamine or piperidine substituents. Structure-dependent fluorescence properties of the synthesized compounds were evidenced in both solution and solid state. The use of 2,2′:6′,2″-terpyridine as acceptor unit gives opportunity to obtain more efficient emitters, while 2,6-di(pyrazin-2-yl)pyridine derivatives display the largest Stokes shifts. The dramatic decrease in the fluorescence quantum yield with the increasing polarity was attributed to ICT→TICT, while dual emission behavior was assigned to LE to ICT emissions. The effect of protonation and viscosity on the emission properties was also examined and it was found to be dependent on the nature of the acceptor moiety. Under external voltage the 2,6-di(pyrazin-2-yl)pyridine derivatives, except for dtpy with diphenylamine, did not exhibit light emission, contrary to the functionalized terpy and dppy.

PAHs (polycyclic aromatics hydrocarbons), the compound group that contains perylene and its derivatives, including functionalized ones, have attracted a great deal of interest in many fields of science and modern technology. This review presents all of the research devoted to modifications of PAHs that are realized via the Diels–Alder (DA) cycloaddition of various dienophiles to the bay regions of PAHs, leading to the π-extension of the starting molecule. This type of annulative π-extension (APEX) strategy has emerged as a powerful and efficient synthetic method for the construction of polycyclic aromatic hydrocarbons and their functionalized derivatives, nanographenes, and π-extended fused heteroarenes. Then, [4 + 2] cycloadditions of ethylenic dienophiles, -N=N-, i.e., diazo-dienophiles and acetylenic dienophiles, are presented. This subject is discussed from the organic synthesis point of view but supported by theoretical calculations. The possible applications of DA cycloaddition to PAH bay regions in various science and technology areas, and the prospects for the development of this synthetic method, are also discussed.

Diels-Alder cycloaddition of various dienophiles to the bay region of polycyclic aromatic hydrocarbons (PAHs) is a particularly effective and useful tool for the modification of the structure of PAHs and thereby their final properties. The Diels-Alder cycloaddition belongs to the single-step annulative π-extension (APEX) reactions and represents the maximum in synthetic efficiency for the constructions of π-extended PAHs including functionalised ones, nanographenes, and π-extended fused heteroarenes. Herein we report new applications of the APEX strategy for the synthesis of derivatives of 1,2-diarylbenzo[ghi]perylene, 1,2-diarylbenzo[ghi]perylenebisimide and 1,2-disubstituted-benzo[j]coronene. Namely, the so far unknown cycloaddition of 1,2-diarylacetylenes into the perylene and perylenebisimide bay regions was used. 1,2-Disubstituted-benzo[j]coronenes were obtained via cycloaddition of benzyne into 1,2-diarylbenzo[ghi]perylenes by using a new highly effective system for benzyne generation and/or high pressure conditions. Moreover, we report an unprecedented Diels-Alder cycloaddition-cycloaromatisation domino-type reaction between 1,4-(9,9-dialkylfluoren-3-yl)-1,3-butadiynes and perylene. The obtained diaryl-substituted core-extended PAHs were characterised by DFT calculation as well as electrochemical and spectroscopic measurements.

Three novel perylene diimide derivatives with bulky aromatic moieties (fluorene, carbazolyl-fluorene, and anthracyl-fluorene) connected via triple bonds with perylene core were successfully designed and synthesized. The chemical structure of prepared compounds was confirmed by 1H and 13C NMR and mass spectrometry. Their optimized ground-state geometry and frontier molecular orbitals were theoretically estimated based on density functional theory. The compounds undergo the reversible electrochemical reduction process and exhibit very low energy band gaps (1.56–1.98 eV) being promising for electronic applications. They also display excellent solubility, high thermal stability and luminescence in solution and in the solid state as a film in the red spectral region. The highest photoluminescence quantum yield (79% in solution and 28% in the film) was found for perylene diimide bearing fluorene unit. All molecules showed the ability for light emission under an applied voltage. The fabricated diodes with structure ITO/PEDOT:PSS/compound/Al exhibited electroluminescence with maximum emission band located between 685 and 732 nm. The most intense electroluminescence, which was additionally plasmonically enhanced by incorporating silver nanowires, was observed for the device based on molecules with anthracene structure.

Six novel fluoranthene derivatives, namely, three terminally substituted and three bis(fluoranthene) units with fluorene, bithiophene, and carbazole spacers, were obtained through [2+2+2] cycloaddition and characterized completely. Based on the conducted studies, the obtained derivatives can be classified as donor-acceptor (D-A) and acceptor-donor-acceptor (A-D-A) systems, in which the fluoranthene unit acts as an electron-withdrawing unit. The optical results revealed that novel fluoranthene derivatives absorb light in the range λ=236-417 nm, which originates from a π→π* transition within the conjugated system. The compounds exhibit fluorescence that range from deep blue to green, which mainly arises from intramolecular charge transfer (ICT) states. High Stoke shifts and high quantum yields in solution (ϕ=0.22-0.57) and in the solid state (ϕ=0.18-0.44) have been observed for fluoranthene derivatives. All the derivatives display multistep oxidation processes at low potentials. The electronic structure of the presented compounds is additionally supported by time-dependent DFT computations.

A series of solution-processable tetrasubstituted naphthalene derivatives bearing thiophene or carbazole units were synthesized using the tandem cycloaddition [2+1+2+1] and Diels–Alder reaction[4+2]. Thermal, electrochemical, absorption, and emission properties of synthesized compounds were studied. They can be considered as molecular glasses with glass transition temperature ranging from 37 to 122 °C with high thermal stability up to 300 or 400 °C. The naphthalene derivatives were electrochemically active and showed low energy band gap between 1.64 and 1.85 eV. All derivatives were luminescent and emitted light with maximum emission band located at 379–436 nm with photoluminescence quantum yield in the range of 9.5–19.8% in solution. They photo- and electroluminescence ability in solid state as thin film and blends with poly(9-vinylcarbazole) (PVK) and mixture PVK with (2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole) (PBD) were tested. Together with increase of compound content from 2 to 15 wt% in binary matrix, the increase of electroluminescence intensity was observed. Diodes with guest-host configuration showed electroluminescence with maximum of emission band from 593 to 637 nm. The most intense emission of light under applied voltage characterized devices based on compound bearing carbazole derivatives and one methyl group.

Novel derivatives of 4'-phenyl-2,2':6′,2″-terpyridine (tpy) with ethynyl ( T1 ), 2-ethynyl-9,9-dioctylfluorene ( T2 ), 9,9-dioctylfluorene ( T3 ), 9-ethynyl-10-decyloxyanthracene ( T4 ) substituents were obtained via Sonogashira or Suzuki-Miyaura coupling reactions, respectively, and thoroughly characterized. The presence of ethynyl bridge impacts photophysical properties of novel compounds by shifting absorption and emission spectra towards longer wavelengths as compared to T3 , where fluorene is connected with tpy via a single bond. TGA measurements showed that among the new terpyridines those obtained as solids exhibited high thermal stability as opposed to those which were oils (tpy containing fluorene motif). Due to the fact that high thermal stability of 4'-phenyl-2,2':6′,2″-terpyridine derivatives showed photoluminescence (PL) quantum yield (Φ) in the range of 27–84% in solution, their electroluminescence ability was tested in diodes with guest-host configuration. For the compounds dispersed in a matrix consisting of poly(9-vinylcarbazole) (PVK) (50 wt %) and (2- tert -butylphenyl-5-biphenyl-1,3,4-oxadiazole) (PBD) (50 wt %) radiation with maxima between 374 and 531 nm and characterized with Φ in the range of 8–12% was observed. They exhibited green or violet electroluminescence. The results confirmed the substantial role of aryl groups and the linker in the presented terpyridines in terms of their thermal, electrochemical, optical and electroluminescence properties. In addition, density functional theory (DFT) and time-dependent-density functional theory (TD-DFT) calculations were performed to provide an independent support and deeper insight into the experimental results.

Five novel derivatives of pyrene, substituted at positions 1,3,6,8 with 4-(2,2-dimethylpropyloxy)pyridine (P1), 4-decyloxypyridine (P2), 4-pentylpyridine (P3), 1-decyl-1,2,3-triazole (P4), and 1-benzyl-1,2,3-triazole (P5), are obtained through a Suzuki-Miyaura cross-coupling reaction or CuI -catalyzed 1,3-dipolar cycloaddition reaction, respectively, and characterized thoroughly. TGA measurements reveal the high thermal stability of the compounds. Pyrene derivatives P1-P5 all show photoluminescence (PL) quantum yields (Φ) of approximately 75 % in solution. Solid-state photo- and electroluminescence characteristics of selected compounds as organic light-emitting diodes are tested. In the guest-host configuration, two matrixes, that is, poly(N-vinylcarbazole) (PVK) and a binary matrix consisting of PVK and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) (50:50 wt %), are applied. The diodes show red, green, or blue electroluminescence, depending on both the compound chemical structure and the actual device architecture. In addition, theoretical studies (DFT and TD-DFT) provide a deeper understanding of the experimental results.

New mono- and bisruthenium, symmetrical and unsymmetrical complexes bridged by new cyclometalating 1,3,6,8-tetra(4-subsituted-2-pyridyl)pyrene derivative containing solubilizing group - 2,2-dimethylpropyloxy with the terminal 4'-phenyl-2,2':6',2''-terpyridine ligands containing diethylamine and 2-ethynyl-9,9-dioctylfluorene moiety were synthesized and thoroughly characterized. Thermal studies showed that obtained complexes retain high thermal stability. Spectroscopic studies showed the metal-to-ligand-charge-transfer (MLCT) excitation. What is more, the electrochemical studies showed delocalization of the electronic charge (mixed-valance). In addition, density functional theory (DFT) and time-dependent-density functional theory (TD-DFT) calculations were performed to provide more details about structural properties and deeper understanding of the experimental results. All obtained results showed the considerable differences between mono- and bisruthenium and symmetrical and unsymmetrical complexes.

The highly active, reusable and regioselective crown ethers bases catalytic systems, especially 15-Crown-5/NaOH, 18-Crown-6/KOH, dibenzo-18-Crown/6-t-BuOK, and 18-Crown-6/t-BuOK, for double bond migration in various allyl and diallyl compounds have been presented. Allyl and/or diallyl: arenes and heteroarenes, ethers, acetal, sulfides, selenide, sulfoxides, imines, phosphine, and phosphine oxide were smoothly converted into their corresponding 1-propenyl derivatives under very mild conditions. Some of the C,O- and O,S-diallyl compounds were fully regioselectively isomerized to allyl-(1-propenyl) derivatives. An unprecedented and significant effect of increasing the reaction rate and shortening the quantitative reaction conversion time without decreasing the selectivity under ultrasound-assisted conditions was observed. Various solvents, including low-boiling point ones containing only C, H and/or O atoms, such as DMFL, DME, THF, Et2O, toluene, and 1,4-dioxane, can be used instead of the most frequently used DMSO. Remarkably highly effective recycling of 18-Crown-6/t-BuOK and dibenzo-18-Crown-6-t-BuOK catalytic systems for isomerization of low-boiling or high-boiling point allyl compounds respectively and crown ethers from all examined catalytic systems was developed. The opportunity to effectively combine the double bond migration with in situ generation of nitrile oxide and finally 1,3-DC-cycloaddition into one pot variant synthesis of isoxazolines from Qallyl has also been announced.

First report of π-conjugated push-pull copolymer systems with 4,4′-bipyridine moieties in the main macromolecular chain is presented. C-substitution pattern of electropolymerisable bithiophene pendants at the 4,4′-bipyridine unit offered the versatility to retain the latter as free amine, or convert it into bipyridylium salt. Both structures have been prepared and investigated, delivering the first example of a polymer with viologen unit making up the extended π-bond. Detailed electrochemical, spectroelectrochemical and quantum chemical study of these new polymer systems and their 2,2′-bipyridine analogues has shown that while linear structure and extended conjugation in the latter help it to accommodate charge carriers characteristic for heavily doped polythiophene, the conjugation break afforded by the meta substitution pattern across the 4,4′-pirydyl unit makes the polymer behave like an ensemble of shorter oligomeric segments with better defined electron transitions and sharper, and faster electrochromic response. Effective π-π interchain coupling between α,ω-bis(2-pyridyl)quaterthiophene repeating units was observed, whereas intramolecular interactions were found to dominate in the linear 2,2′-bipyridyl based polymer. While the bithiophene derivative of methyl viologen electropolymerised less easily than its corresponding non-quaternised derivative, the resulting polymer films demonstrated decent stability when subject to subsequent p- and n-doping, featuring pronounced charge trapping/detrapping signatures. Furthermore, ion pairing between the viologen and weakly basic PF 6 − and CF 3 SO 3 − counterions has been found to impact the redox chemistry of bithiophene functionalised viologen structure. Experimental findings have been confronted with results of quantum chemical computations helping to elucidate the electrochemical and spectroelectrochemical observations made. Presented study delivers insights into the doping processes taking place in conjugation disrupted 4,4'-bipyridine core copolymers, helping to evaluate their potential as substrates for new tuneable π-conjugated polymeric systems.

Platinum(II) coordination compounds with formulas [PtCl(L)]Cl, (where L=4’-(2,2’-bithiophen-5-yl)-2,2′:6′,2”-terpyridine (L1), 4’-(4-dimethylaminophenyl)-2,2′:6′,2”-terpyridine (L2), 4’-(2,4-difluorophenyl)-2,2′:6′,2”-terpyridine (L3)), were synthesized from K2[PtCl4] precursor and characterized by X-ray crystallography, FT-IR, NMR, UV-Vis spectroscopy and electrochemical studies. The emission properties of the compounds were studied in solutions and in solid state at ambient temperature and in methanol : ethanol frozen glass matrix at 77 K. The quantum yields of fluorescence, the lifetimes and the nature of excited states were described on the basis of the molecular properties. Theoretical calculations, with usage of DFT method, were undertaken to elucidate the structural, spectroscopic and bonding properties of the synthesized coordination compounds.

Nine rhenium(i) complexes possessing three carbonyl groups together with a bidentate coordinated 2,6-di(thiazol-2-yl)pyridine derivative were synthesized to examine the impact of structure modification of the triimine ligand on the photophysical, thermal and electrochemical properties of [ReCl(CO)3(4-Rn-dtpy-κ2N)]. The Re(i) complexes were fully characterized using IR, 1H and 13C, HRMS-ESI and single crystal X-ray analysis. Their thermal properties were evaluated using DSC and TGA measurements. Photoluminescence spectra of [ReCl(CO)3(4-Rn-dtpy-κ2N)] were investigated in solution and in the solid state, at 298 and 77 K. Both emission wavelengths and quantum yields of [ReCl(CO)3(4-Rn-dtpy-κ2N)] were found to be structure-related, demonstrating a crucial role of the substituent attached to the 2,6-di(thiazol-2-yl)pyridine skeleton. In order to fully understand the photophysical properties of [ReCl(CO)3(4-Rn-dtpy-κ2N)], density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed. Furthermore, the complexes which showed appropriate solubility in chloroform were tested as an emissive active layer in OLED devices.

The novel cyclometalated NCN platinum(II) acetylide complexes were synthesized. As precursors of acetylide ligands were used 9,9-dibutyl-2-ethynylfluorene, 9-butyl-3-ethynylcarbazole, and 5-ethynyl-2,2′-bithiophene, whereas 1,3-di(2-pirydyl)benzene derivatives were cyclometalating NCN ligands. Variable character of ligands allowed to prepare a series of novel platinum(II) complexes, which showed light emission in a wide wavelength range from 410 to 625 nm. The optical and electrochemical properties of new complexes were examined and compared with theoretical DFT calculations. Complexes containing fluorenyl and carbazyl motif were used as emitters in an organic light-emitting diodes. The applicability of these Pt(II) complexes for electroluminescence was examined.

Novel symmetrical anthracene derivatives with bulky carbazolyl-fluorene, diphenylamino-fluorene, or carbazolyl-carbazole units connected to the anthracene frame through an ethynyl bridge were synthesized in excellent yield by using Sonogashira cross-coupling. The ethynyl bridge in the anthracene dyes increases π-electron conjugation and the bulky substituents considerably attenuate intermolecular interactions. The dyes possess high thermal stability, tremendous solubility in common organic solvents, and especially high photoluminescence quantum yield (Φf) in solution in the range of 77–98 %. OLED devices were fabricated. The AFM images of thin films and blends prepared from all compounds show a uniform and flat surface, indicating excellent film-forming properties. Devices incorporating the anthracene derivative with diphenylamino-fluorene end-capping groups exhibited the highest value of current density (J). All of the fabricated OLED devices emitted yellowish-orange light under applied voltage.

A series of novel, highly phosphorescent cyclometalated iridium(III) complexes of type [(X2C^N)2Ir(Q2bpy)]+PF6– (where X2C^N is 2-phenylpyridine or 2-(2,4-difluorophenyl)pyridine anion and Q2bpy are 4,4′-bifunctionalized 2,2′-bipyridines) is presented. The complexes were fully characterized by means of NMR spectroscopy, high-resolution mass spectrometry (HRMS), cyclic voltammetry, and UV–vis. For several compounds also the crystallographic structures were obtained. The cyclometalates exhibited efficient photoluminescence at 298 K both in solution and in the solid state with good intensity and color purity. The emission wavelength range covered almost the whole visible spectrum and was strongly correlated with the EWG/ERG character of the Q substituent in the ancillary ligand. For further insight into the electronic structure of the complexes, a comprehensive electrochemical support (CV) was introduced, and finally, it was confronted with theoretical background using a density functional theory approach to...

The paper contains a comprehensive study regarding the new possibilities of using 2-pyranone derivatives. In this work, six compounds of this type (including three electropolymerisable bithiophenyl's monomers) were synthesized in a one-step reaction with high yields ranging from 57% to 81%. The synthesized monomers of Bt-py-Bt (where Bt = 2,2′-bithiophene-5-yl, py = pyranone moiety) type were transformed into conducting polymers in an electrochemical oxidation process. The influence of the pyranone bridge on the stability, luminescent and (spectro)electrochemical behaviour was thoroughly studied. The polymers present extraordinary stability during both multiple n- and p-doping. The experimental results were also investigated theoretically, using the DFT approach. Calculations of the frontier orbital energies and the corresponding Eg value were done for each polymer using periodic boundary conditions. Finally, the electrochemical impedance spectroscopy measurements of polymeric films were done and evaluated.

Structural, spectroscopic and electrochemical properties of six complexes [AuCl(L1)](PF6)2·CH3CN (1), [AuCl(L2)](PF6)2 (2), [PtCl(L1)](BPh4)·CH3CN (3), [PtCl(L2)](SO3CF3) (4), [CuCl2(L1)] (5) and [CuCl2(L2)]·CH3CN (6) with modified 2,2':6',2''-terpyridine ligands, 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (L1) and 4'-(4-methoxynaphthalen-1-yl)-2,2':6',2''-terpyridine (L2) were thoroughly investigated and a significant role of the substituent (4-methoxyphenyl or 4-methoxynaphthalen-1-yl) and the metal center was demonstrated. The naphthyl-based substituent was found to increase the emission quantum yield of the luminescent Au(iii) and Pt(ii) complexes. Furthermore, the antiproliferative potential of the reported complexes was examined towards human colorectal (HCT116) and ovarian (A2780) carcinoma cell lines as well as towards normal human fibroblasts. The Au(iii) complex 2 and Cu(ii) complex 5 were found to have a higher antiproliferative effect on HCT116 colorectal and A2780 ovarian carcinoma cells when compared with the Pt(ii) complex with the same ligand (4). The order of cytotoxicity in both cell lines is 2 > 6 > 1 > 3 > 4. Complex 2 seems to be more cytotoxic towards HCT116 and A2780 cancer cell lines with IC50 values 300× and 130× higher in normal human fibroblasts compared to the respective cancer cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and the typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation and flow cytometry assay. The induction of apoptosis correlates with the induction of reactive oxygen species (ROS). Fluorescence microscopy analysis indicates that after 3 h of incubation, complexes 1-4 are localized inside HCT116 cells and the high levels of internalization correlate with their cytotoxicity.

Platinum(II) complexes with the formula [PtCl(L)]CF3O3S (where L = 4′-(4-chlorophenyl)-2,2′:6′,2′′-terpyridine (L1), 4′-(4-bromophenyl)-2,2′:6′,2′′-terpyridine (L2), and 4′-(benzothiophene-2-yl)-2,2′:6′,2′′-terpyridine (L3)) were synthesized from precursor [Pt(PhCN)2Cl2] and characterized by FT-IR, NMR, UV-vis spectroscopy, X-ray crystallography and electrochemical studies. The emission properties of the coordination compounds were studied in solution and in the solid state at ambient temperature and in methanol : ethanol frozen glass matrices at 77 K. The quantum yields of fluorescence, lifetimes and the nature of the excited states were described on the basis of the molecular properties of the compounds. To elucidate the structural, spectroscopic and bonding properties of the obtained compounds, calculations at the DFT level were undertaken. Coordination compounds are emissive in both solution and solid states. Emission energies and the character of excited states in solution are governed by the donor–acceptor properties of the 4′ substituent of the terpyridine core. The emission properties in the solid state are attributed to the aggregation induced phenomenon. Moreover, the compounds [PtCl(L1)]CF3O3S and [PtCl(L2)]CF3O3S display a bathochromic shifted emission corresponding to J-aggregation (head-to-head Pt⋯Pt interactions), while in the case of compound [PtCl(L3)]CF3O3S a hypsochromic shifted emission compared to that in solution is characteristic of the H-aggregation process (head-to-tail Pt⋯π interaction). The coordination compounds display a strong rigidochromic effect with decay times changing from the ps/ns scale at ambient conditions to the μs domain in frozen glass matrices.

Several new rhenium(I) complexes [ReCl(CO)3(4′-R-terpy-κ2N)] incorporating 2,2′:6′,2′′-terpyridine-based ligands were successfully synthetized and characterized by IR, NMR (1H and 13C), UV-vis spectroscopy and single crystal X-ray analysis. The luminescent properties of [ReCl(CO)3(4′-R-terpy-κ2N)] were studied in solution and solid state, at 298 and 77 K. To better understand the photophysical properties of [ReCl(CO)3(4′-R-terpy-κ2N)], density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed. Preliminary studies towards application of these complexes in organic light emitting diodes (OLEDs) were carried out, including testing the possibility of electroluminescence intensity increase by including metallic nanowires in the structure design.

Several 2,2':6',2''-terpyridines substituted in the 4'-position were synthesized and their photophysical properties were investigated by absorption and photoluminescence spectroscopy in dilute solutions and solid state. The studies confirmed that the absorption and emission wavelengths, fluorescence quantum yields and lifetimes of 1-R(1-16) are strongly structure-related, demonstrating a decisive role of the nature of the substituent in determining the photophysical properties of 4'-functionalized terpyridines. Additionally, the density functional theory (DFT) calculations were performed for 1-R(1-16) to get insight into their electronic structure and spectroscopic properties.

Six new Re(i) complexes of the general formula [ReCl(CO)3(4'-R-terpy-κ(2)N)] with 2,2':6',2''-terpyridine-based ligands have been synthesized and characterized by IR, NMR ((1)H and (13)C), UV-Vis spectroscopy and single crystal X-ray analysis. The luminescent properties of [ReCl(CO)3(4'-R-terpy-κ(2)N)] were studied in solution and solid state, at 298 and 77 K, respectively. To obtain detailed insight into the electronic structures and spectroscopic properties of [ReCl(CO)3(4'-R-terpy-κ(2)N)], the density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed. Also, the suitability of this class of materials for being applied in organic light emitting diodes (OLEDs) has been preliminarily tested.

A new small molecule, with D-A-D framework was prepared in good yield by using a [2+1+2+1] cycloaddition followed by the [4+2] Diels–Alders reaction. Additionally, tetra-substituted naphthalene derivatives were also prepared from in situ generated benzyne (using 2-trimethylsilylphenyl triflate and cesium fluoride). All of this compounds exhibit strong 2D-π-conjugation. The influence of this type of interactions on photophysical properties with the aid of DFT calculations was examined. The preliminary tests of application possibility of synthesized compounds in devices for optoelectronics were carried out as well.

Four novel cyclometalated iridium(III) complexes: [Ir(q-bt-Ph) 2 (phen)]PF 6 , [Ir(q-bt-Ph) 2 (acac)], [Ir(q-bt-Me) 2 (bpy)]PF 6 and [Ir(q-bt-Me) 2 (acac)] (where q-bt-Ph, q-bt-Me correspond to 2-(2,2’-bithien-5-yl)-4-phenylquinoline and 2-(2,2’-bithien-5-yl)-4-methylquinoline), are reported. The complexes were characterized by NMR, FTIR and HRMS. The optical, electrochemical properties and thermal stability of novel iridium(III) complexes were thoroughly investigated. The complexes emit a light in the narrow range of 693–707 nm. The optical study showed that replacement of fragment in the main quinoline ligand did not affect wavelength of the emitted light. On the other hand, the modification of the ancillary ligand and substituent in the quinoline ring caused the increase of the photoluminescence quantum yields. Electrochemical experiments demonstrate that the oxidation process for complexes [Ir(q-bt-Ph) 2 (phen)]PF 6 and [Ir(q-bt-Ph) 2 (acac)] was reversible (or quasi-reversible) and well detectable whereas for complexes with quinoline substituted by methyl group was irreversible, even at low temperature (−70 °C). The electrochemical and photophysical studies have been well confirmed by density functional theory (DFT) calculations. In addition, bulk heterojunction polymer solar cells based on complexes [Ir(q-bt-Ph) 2 (phen)]PF 6 and [Ir(q-bt-Ph) 2 (acac)] were fabricated. Only the solar cell incorporating [Ir(q-bt-Ph) 2 (acac)] exhibited a photovoltaic effect. The architecture of the cell was ITO/PEDOT:PSS/P3HT:PCBM:[Ir(q-bt-Ph) 2 (acac)]/Al. A power conversion efficiency of 0.25% was measured under 1 sun illumination using an AM 1.5G filter to simulate the solar spectrum.

New catalytically or high pressure activated reactions and routes, including coupling, double bond migration in allylic systems, and various types of cycloaddition and dihydroamination have been used for the synthesis of novel bithiophene derivatives. Thanks to the abovementioned reactions and routes combined with non-catalytic ones, new acetylene, butadiyne, isoxazole, 1,2,3-triazole, pyrrole, benzene, and fluoranthene derivatives with one, two or six bithiophenyl moieties have been obtained. Basic sources of crucial substrates which include bithiophene motif for catalytic reactions were 2,2'-bithiophene, gaseous acetylene and 1,3-butadiyne.

Here we report the preparation of 3,6- bis(bithenyl)-N-decylcarbazole with low oxidation potential due to extended conjugation that underwent facile electrochemical polymerization to form stable electroactive polymer. We extended the conjugation of the monomers in comparison to the carbazole and large decrease were observed in the oxidation potential at which polymerization occurs. To lower the oxidation potential of the monomer and control the optical and electronic properties of the polycarbazole, we attached the thiophene, bithiophene and 3,4-ethylenedioxythiophene (EDOT) at both the 3 and 6 positions of N-substituted carbazole. The monomers and their polymers were compared through electron paramagnetic resonance (EPR) and UV-Vis-NIR spectroelectrochemistry resulting in interesting properties. As optically active materials the CIE L*a*b chromaticity and other optical properties were observed.

Two gold(iii) complexes incorporating 2,2':6',2''-terpyridine derivatives have been synthesised and characterized, and the possibility of tuning the cytotoxic activity by structural modifications of a terpy ligand has been examined. Both complexes [AuCl(4'-R1-terpy)](PF6)2 (1) and [AuCl(4'-R2-terpy)](PF6)2 (2), where R1 is 2-pyridyl and R2 is 3-pyridyl, show good anti-proliferative activities against HCT116, which are higher in relation to those of the free ligands, [AuCl(terpy)](PF6)2 and standard anticancer drug cisplatin. The cytotoxic properties of the gold complexes were examined by MTS assay, cell cycle and apoptosis analysis, ROS measurements, determination of mitochondrial membrane potential and mass, and staining of phosphatidylserine with Annexin-V antibody FITC-conjugated together with PI.

Six new copper(II) complexes with 2,2’:6’,2’’-terpyridine (4’-Rn-terpy) [1 (R1 = furan-2-yl), 2 (R2 = thiophen- 2-yl), and 3 (R3 = 1-methyl-1H-pyrrol-2-yl)] and 2,6-di(thiazol-2-yl)pyridine derivatives (Rn-dtpy) [4 (R1), 5 (R2), and 6 (R3)] have been synthesized by a reaction between copper(II) chloride and the corresponding ligand. The complexes have been characterized by UV-vis and IR spectroscopy, and their structures have been determined by X-ray analysis. The antiproliferative potential of copper(II) complexes of 2,2’:6’,2’’-terpyridine and 2,6-di(thiazol-2-yl)pyridine derivatives towards human colorectal (HCT116) and ovarian (A2780) carcinoma as well as towards lung (A549) and breast adenocarcinoma (MCF7) cell lines was examined. Complex 1 and complex 6 were found to have the highest antiproliferative effect on A2780 ovarian carcinoma cells, particularly when compared with complex 2, 3 with no antiproliferative effect. The order of cytotoxicity in this cell line is 6 > 1 > 5 > 4 > 2 ≈ 3. Complex 2 seems to be much more specific towards colorectal carcinoma HCT116 and lung adenocarcinoma A549 cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation. The specificity towards different types of cell lines and the low cytotoxic activity towards healthy cells are of particular interest and are a positive feature for further developments. Complexes 1–6 were also tested in the oxidation of alkanes and alcohols with hydrogen peroxide and tert-butyl-hydroperoxide (TBHP). The most active catalyst 4 gave, after 120 min, 0.105 M of cyclohexanol + cyclohexanone after reduction with PPh3. This concentration corresponds to a yield of 23% and TON = 210. Oxidation of cis-1,2-dimethylcyclohexane with m-CPBA catalyzed by 4 in the presence of HNO3 gave a product of a stereoselective reaction (trans/cis = 0.47). Oxidation of secondary alcohols afforded the target ketones in yields up to 98% and TON = 630.

The article contains a comprehensive study regarding the synthesis and properties of novel polythiophenes, where bithiophene units are linked with either ethynyl or bisethynylarylenyl bridges. A convenient and selective method for lithiation of 2,2′-bithiophene, with the aid of n-butyllithium in dialkyl ether/n-hexane solution under mild conditions (−5 to 5 °C), is also presented. The lithiation, followed by the addition of iodine solution at room temperature constituted a robust method towards the synthesis of 5-iodo-2,2′-bithiophene, which was then used as a key substrate in the Sonogashira-type cross-coupling reactions. The coupling of 5-ethynyl-2,2′-bithiophene with 5-iodo-2,2′-bithiophene, mediated by [PdCl2(PPh3)2]/CuI couple, resulted in the formation of 1,2-bis(2,2′-bithiophene-5-yl)ethyne. The synthesized monomers of Bt–A–Bt (where Bt = 2,2′-bithiophene-5-yl) type, namely: 1,2-bis(2,2′-bithiophene-5-yl)ethyne, 1,4-bis(2,2′-bithiophene-5-yl)buta-1,3-diyne and 1,4-bis(2,2′-bithiophene-5-ylethynyl)benzene were transformed into conducting polymers in an electrochemical oxidation process. The influence of the A bridge on the stability, luminescent and electrochemical behavior was thoroughly studied. The polymers present an extraordinary stability during multiple n- and p-doping. The experimental results were also investigated theoretically, using DFT approach. For each polymer calculations of the frontier orbital energies and the corresponding Eg value were done using periodic boundary conditions. For polythiophene derived from 1,2-bis-(2,2′-bitiophene-5-yl)ethyne the value of the band gap was also estimated using an oligomeric approximation. Furthermore, the presented compounds revealed an enhanced fluorescent activity, especially in the case of a monomer with bisethynylphenylene bridge and the corresponding polymer.

An excellent, selective and very convenient method for the synthesis of hydroxyalkyl vinyl ethers of HO–A–O–CH CHCH3 type via isomerization of appropriate readily available allylic substrate of HO–A–O–CH2CH CH2 type mediated by various soluble ruthenium complexes under solvent-free conditions has been presented. Our research has demonstrated that (CH2)n or (CH2CH2O)n or ortho-phenylene, but neither –CH2C CCH2– nor –CH2CH CHCH2– can play a role of an A linker. The use of detailed screening experiments allowed discovering new, efficient catalysts for a highly selective isomerization of allyloxyalcohols such as [RuH2(CO)(PPh3)3], [RuH2(PPh3)4] or [Ru(CO)3(PPh3)2]. For these ruthenium complexes, the only reaction products were enol ethers, and an intra- and/or intermolecular addition of an OH group to the double bond has not been observed. The use of the complexes containing Cl ligand as catalysts precursors ([RuClH(CO)(PPh3)3], [RuCl2(PPh3)3], RuCl3·3H2O and other) and surprisingly also [Ru3(CO)12] led to a consequent cyclization and/or polymerization of enol ethers. The addition to the catalytic system of trialkyl amines, K2CO3, CaH2 and others as scavengers of HCl (generated in situ from Ru–Cl complexes) has also allowed to eliminate fully consequent reactions. The scale-up of the selected method of isomerization has been successfully performed and the best results were obtained for [RuH2(CO)(PPh3)3] and [RuCl2(PPh3)3] + 5 K2CO3. Finally, several pathways of the reaction between allyloxyalcohols and the ruthenium complexes of various structures have been proposed. The double bond migration and addition of the OH group to the allyl or the vinyl ether moiety could proceed according to the transition metal catalysis mechanisms and tandems the transition metal catalysis-Lewis acid catalysis or the transition metal catalysis-Bronsted acid catalysis.

The hydridecarbonyl ruthenium(II) [RuH(CO)(MeImCOO)(PPh3)2]·CH3OH 1 and [RuH(CO)(BImCOO)(PPh3)2] 2 complexes were synthesized and characterized by IR, 1H, 31P NMR, UV–Vis spectroscopy and X-ray crystallography. The experimental studies were completed by quantum chemical calculations which were used to identify the nature of the interactions between the ligands and the central ion and the orbital compositions in the frontier electronic structures. Based on a molecular orbital scheme, the calculated results allowed the interpretation of the UV–Vis spectra obtained at an experimental level. The luminescence properties of the complexes were determined. The catalytic activity for both of the complexes was tested in the reaction of the double bond migration in O-allyl systems. Complex 1 was significantly more active than complex 2, because of the longer Ru–H bond distance in complex 1 in comparison with complex 2.

The ruthenium(II) complexes [RuH(CO)(6-OH-py-2-COO)(PPh 3 ) 2 ] ( 1 ) and [Ru(3-OH-py-2-COO) 2 (PPh 3 ) 2 ] ( 2 ) have been prepared in the reactions of [RuHCl(CO)(PPh 3 ) 3 ] and [RuCl 2 (PPh 3 ) 3 ] with 6-hydroxy- and 3-hydroxypyridine-2-carboxylic acids. The complexes have been characterized by IR, UV–Vis, NMR spectroscopy and X-ray crystallography. Based on the crystal structures, computational investigations were carried out in order to determine the electronic structures of the complexes. The electronic spectra were calculated with the use of time-dependent DFT methods, and correlated with the molecular orbitals of the complexes. The emission properties of the complexes have been examined and quantum efficiencies equal to 0.084 for the hydride carbonyl complex ( 1 ) and 0.046 for complex ( 2 ) have been determined. The catalytic activity in the reaction of the double bond migration in 4-allyloxybutan-1-ol for both the complexes was tested. Under properly selected reaction conditions, complex ( 1 ) selectively catalyzes double bond migration leading to 1-propenyloxyalcohol.

A new strategy for the synthesis of 3-aryl-4-methyl-5-O-substituted isoxazolines via tandem catalytic isomerization of O-allyl systems to O-(1-propenyl) systemsd1,3-dipolar cycloaddition (1,3-DC) to nitrile oxides is presented. The influence of the heteroatom in Ph-X-CH]CHCH3 (X¼O, S, or Se) on the regioand stereoselectivity of ArCNO 1,3-cycloaddition to these dipolarophiles is analyzed as well. The dipolarophiles were obtained via [RuClH(CO)(PPh3)3]e, [RuH2(CO)(PPh3)]e or base (KOH/18-crown-6)-catalyzed double bond migration in corresponding allyl ethers, O-allyl acetals, PhSe and PhSeeallyl systems. Cycloadditions of nitrile oxides to O-(1-propenyl) systems were fully regioselective whereas in the reactions of ArCNO with the PhSe(1-propenyl) and PhSee(1-propenyl) systems both possible regioisomers were formed. It was established that within the majority of dipolarophiles of ROCH]CHCH3 type 1,3-DC is concerted, while for some dipolarophiles of RXCH]CHCH3 (X¼O and R¼Ph3C, 2,3-dihydroxypropyl, tetrahydropyran-2-yl; X¼S or Se and R¼Ph) type 1,3-DC turns into a two-step reaction with simultaneous rotation about CeC bond. The results of the experiments have been analyzed theoretically using DFT calculations. The results of these calculations agreed well with the experimental data.

In the condensation reaction of nitromethane with glyoxal carried out in an aqueous solution of sodium hydroxide, 3,6-dinitro-cyclohexane-1,2,4,5-tetraol was obtained (the expected product, described in the literature) and, unexpectedly, also tricyclic nitro-triol (6b-nitrohexahydro-2H-1,3,5-trioxacyclopenta[cd]-pentalene-2,4,6-triol), which has been unknown until now, was obtained as the main product. The structure of the compound was confirmed with 1H NMR and 13C NMR spectroscopy, LR, and HR-MS techniques and with single-crystal X-ray diffractometry. The tricyclic triol (formally a hemiacetal) was transformed into 6b-nitrohexahydro-2H-1,3,5-trioxacyclopenta[cd]-pentalene-2,4,6-triyl trinitrate by reaction with 98 % HNO3. Some explosive properties of this compound were determined including: friction and impact sensitivity, activation energy, detonation velocity, heat of combustion in an oxygen atmosphere and enthalpy of formation. The nitrate ester is a powerful explosive with performance close to that of pentaerythritol tetranitrate (PETN).

A bis-bithiophenyl derivative of diquat, 3,10-bis(2,2′-bithiophene-5-yl)-6,7-dihydropyrido[1,2-a:2′,1′-c]pyrazinodiynium hexafluorophosphate (bt2dq), was synthesized by quaternization of 5,5″-bis(2,2′-bithiophene-5-yl)-2,2′-bipyridine with 1,2-dibromoethane. Its UV–vis absorption spectrum is explained by TD-DFT calculations. It shows the electrochemical properties characteristic for bipyridinium salts (viologens and diquats) and can be electropolymerized to form a conjugated polymer composed of alternating quaterthiophene and diquat blocks. The polymer has been characterised by cyclic voltammetry and UV–vis spectroelectrochemistry: it can be reversibly oxidized, with spectral signs of p-doping of the oligothiophene blocks, and reversibly reduced, with formation of viologen-like cation radicals, which dimerize or form π-stacks.

A ruthenium tetra- t -butylphthalocyanine bisaxially ligated with 3,5-bis(2,2′-bithiophene-5-yl)pyridine was synthesized from ruthenium tetra- t -butylphthalocyanine dimer. The complex was electropolymerized (in CH 2 Cl 2 and CH 3 CN, with and without addition of BF 3 ·Et 2 O) to yield an insoluble conjugated metallopolymer, which was characterized by cyclic voltammetry and UV–vis spectroelectrochemistry. The polymer combines the electrochemical and spectral properties of the phthalocyanine and of a polythiophene-type conjugated polymer. In the presence of BF 3 , the polymer can be reversibly p-doped and de-doped. Materials obtained in CH 2 Cl 2 (tested in the same solvent) and in CH 3 CN/BF 3 (tested in CH 3 CN) exhibit an unusual hysteresis of redox properties.

A complex from copper(II) perchlorate with 4-amino-1,2,4-triazole (4-AT, C2H4N4) was synthesized, and elemental composition, molecular structure, and explosive properties were determined. To this end, elemental and X-ray analyses were carried out, sensitivity to mechanical and thermal stimuli was measured, mechanism of thermal decomposition was investigated, and kinetic parameters of decomposition were determined. In the next step measurements of heat of combustion and detonation velocity were performed. Detonation parameters were also calculated. It was stated that the complex has slightly distorted square bipyramidal (4+2) coordination. The four basal bonds are formed by nitrogen atoms of four 4-AT molecules. The coordination of the metal is completed by two axial oxygen atoms, one of the perchlorate ion, and one of the water molecule. With respect to explosive properties, tetrakis(4-AT)copper(II) perchlorate monohydrate belongs to the group of sensitive secondary explosives.

The systems containing EHPG, EHPG-OCH 3 and EHPG-NH-Ac and Tb(III) ions were used to study chemiluminescence (CL) and electrochemiluminescence (ECL) processes. In the CL studies the Fenton system (Fe(II)/(III)-H 2 O 2 ) was used as a source of reactive oxygen species (ROS). Kinetic CL curves and CL spectral distributions were recorded. On the basis of the results obtained, it was demonstrated that Tb(III) acted as a sensitizer. Similarly obtained CL decays in the systems of Fe(II)/(III)-EHPG (or its derivatives)-H 2 O 2 and Fe(II)/(III)-EHPG (or its derivatives)-Tb(III)-H 2 O 2 , independently on the Tb(III) concentration, showed that the lanthanide ions did not influence the kinetics of the oxidation of EHPG (or its derivatives) in the Fenton systems. The CL intensity increased with the increasing concentration of Tb(III) ions, which were the main emitters in the reaction systems. Spectrophotometric and luminescent studies of the systems before and after the additions of hydrogen peroxide proved that the excitation of the lanthanide ion was a result of energy transfer from the excited products of the oxidation of EHPG or its derivatives to the uncomplexed Tb(III) ions. ECL was generated on the surface of a nonstructural modified aluminum electrode with the use of K 2 S 2 O 8 , H 2 O 2 or KN 3 as coreactants in aqueous solution. In these studies we employed Al electrodes covered with a 2-4 nm layer of Al 2 O 3 doted with Tb(III) or Dy(III) ions. The electrodes were polarized using cathodic and anodic pulses of various amplitude and frequency. The relative ECL efficiencies were determined as a function of electric pulse parameters, electrolyte compositions and the thickness of barrier or porous layer of the Al 2 O 3 electrode.