Doubly-bridged PNP-lariat ethers and their complexes with silver(I) ions in methanol solution

Publikacja w ramach programu Royal Society of Chemistry "Gold for Gold" 2013 finansowanego przez Uniwersytet ŁódzkiWe report the preparation of four new double-bridged PNP-lariat etherderivatives L1 – L4 synthesized from precursor 1 by the subsequent substitution of chlorine atoms. The process consists of two steps. In the fi rst one two reactive chlorine atoms of the – PCl 2 exocyclic moiety are substituted with respective nucleophiles: 2,2 0 -thiodiethanethiol 2 and 2,2 0 -oxydiethanethiol 3 . In the second step the other chlorine atoms are substituted by aziridynyl 6 and pyrrolidinyl 7 groups, respectively. Their structures were established by MS, 1 H NMR, 31 P NMR, 13 C NMR spectroscopy. Furthermore, this work includes the investigation of complexation of silver( I ) ions with the new ligands L1 – L4 in methanol solution. The formation of the novel tetra-nuclear silver( I ) complexes were observed. Stability constants were determined using a simple potentiometric titration. 1 H NMR, 31 P NMR, 13 C NMR spectra were recorded to investigate how the complexation of silver( I ) ions by the investigated macrocyclic ligands occur

Symmetrical and unsymmetrical azomethines with thiophene core : structure - properties investigations

Unsymmetrical and symmetrical azomethines were obtained using the condensation reaction of diamino-thiophene-3,4 dicarboxylic acid diethyl ester with 4-(1-pyrrolidino)benzaldehyde, fluorene-2-carboxaldehyde, 1-methylindole-3-carboxaldehyde, and benzothiazole-2-carboxaldehyde. Their thermal, optical, and electrochemical properties were investigated, and the results were supported by calculations using the density functional theory. The studied compounds melted in the range of 170–260 °C and can be converted into amorphous materials with high glass transition temperatures between 76 and 135 °C. They were thermally stable up to 220–300 °C. All imines were electrochemically active and exhibited low energy band gaps below 2 eV (except for one imine with Eg = 2.39 eV) determined on the basis of cyclic voltammetry. Most of the azomethines were emissive in solution and in the solid state. Some of them showed both S1 (first excited state) emission and S2 (second excited state) emission or only fluorescence from higher excited state, which is first time observed for azomethines. The imine with the most promising properties was tested in a light-emitting diode, and its ability for emission of light under external voltage was demonstrated

Photoelectrochemical and thermal characterization of aromatic hydrocarbons substituted with a dicyanovinyl unit

Seven aromatic hydrocarbons bearing a dicyanovinyl unit were prepared to determine the relationship between both the number of aromatic rings and location of acceptor substituent on their thermal and optoelectronic properties. Additionally, the density functional theory calculations were performed. The obtained compounds showed temperatures of the beginning of thermal decomposition in the range of 137 – 289 °C, being above their respective melting points found between 88 and 248 °C. They were electrochemically active and showed quasi-reversible reduction process (except for 2-(phen-1- yl)methylene)malononitrile). Electrochemically estimated energy band gaps were below 3.0 eV, in the range of 2.10 – 2.50 eV. The absorption and emission spectra were recorded in CHCl3 and NMP and in solid state. All compounds strongly absorbed radiation with absorption maximum ranging from 307 to 454 nm ascribed to the intramolecular charge transfer between the donor and acceptor units. The aromatic hydrocarbons were luminescent in all investigated media and exhibited higher photoluminescence quantum yields in the solid state due to the aggregation induced emission phenomena. Electroluminescence ability of selected compounds was tested in a diode with guest-host configuration. Additionally, the selected compound together with a commercial N719 was applied in the dye-sensitized solar cell

Facile production of ultra-fine silicon nanoparticles

A facile procedure for the synthesis of ultra-fine silicon nanoparticles without the need for a Schlenk vacuum line is presented. The process consists of the production of a (HSiO1.5)n sol–gel precursor based on the polycondensation of low-cost trichlorosilane (HSiCl3), followed by its annealing and etching. The obtained materials were thoroughly characterized after each preparation step by electron microscopy, Fourier transform and Raman spectroscopy, X-ray dispersion spectroscopy, diffraction methods and photoluminescence spectroscopy. The data confirm the formation of ultra-fine silicon nanoparticles with controllable average diameters between 1 and 5 nm depending on the etching time

Psychometric properties of the Polish adaptation of short form of the Empathy Quotient (EQ-Short)

Aim. The purpose of the present study was to analyze the psychometric properties of the Polish-language version of the EQ-Short questionnaire, designed to measure affective and cognitive empathy. Method. 940 subjects, aged 15-80, took part in the study. Subjects fluent in both Polish and English (N = 31) completed the questionnaire in the original English version and its Polish translation. The remaining subjects (N = 909) participated in a study designed to verify construct validity and reliability of the Polish version of the tool. Results. The Polish and English versions of the EQ-Short show linguistic equivalence at a satisfactory level (r = 0.80, p < 0.001). Tests of validity and reliability of the translated tool showed that the Polish-language EQ-Short has good psychometric properties (Cronbach’s α = 0.78), comparable to the original version. In all age groups there were statistically significant sex differences in EQ-Short scores: women scored higher than men. Conclusion. The Polish-language adaptation of EQ-Short is linguistically and psychometrically similar to the English original and meets the criteria of a reliable tool for measuring empathy

Luminescence and electrochemical activity of new unsymmetrical 3- imino-1,8-naphthalimide derivatives

A new series of 1,8-naphtalimides containing an imine bond at the 3-position of the naphthalene ring was synthesized using 1H, 13C NMR, FTIR, and elementary analysis. The impact of the substituent in the imine linkage on the selected properties and bioimaging of the synthesized compounds was studied. They showed a melting temperature in the range of 120–164 C and underwent thermal decomposition above 280 C. Based on cyclic and differential pulse voltammetry, the electrochemical behavior of 1,8-naphtalimide derivatives was evaluated. The electrochemical reduction and oxidation processes were observed. The compounds were characterized by a low energy band gap (below 2.60 eV). Their photoluminescence activities were investigated in solution considering the solvent effect, in the aggregated and thin film, and a mixture of poly(N-vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) (50:50 wt.%). They demonstrated low emissions due to photoinduced electron transport (PET) occurring in the solution and aggregation, which caused photoluminescence quenching. Some of them exhibited light emission as thin films. They emitted light in the range of 495 to 535 nm, with photoluminescence quantum yield at 4%. Despite the significant overlapping of its absorption range with emission of the PVK:PBD, incomplete Förster energy transfer from the matrix to the luminophore was found. Moreover, its luminescence ability induced by external voltage was tested in the diode with guest–host configuration. The possibility of compound hydrolysis due to the presence of the imine bond was also discussed, which could be of importance in biological studies that evaluate 3-imino-1,8-naphatalimides as imaging tools and fluorescent materials for diagnostic applications and molecular bioimaging

1,8-Naphthalimides 3-substituted with imine or β-ketoenamine unit evaluated as compounds for organic electronics and cell imaging

In this paper, we describe both new as well as described in our previous works 1,8- naphthalimide derivatives substituted at the 3-C position with imine or -ketoenamine unitin order to demonstrate a broader scope of research enabling of analysis between the structureproperties relationship relevant to the application of these compounds in organic electronics and cellular imaging. Thermal, physicochemical, optical, electrochemical, electroluminescence, and biological properties of a series of derivatives containing the 1,8-naphthalimideunit were tested and compared. This allowed the determination of impact of substituents in the imide part (hexylamine, phenylethyl, benzyl, fluorobenzyl, methylbenzyl), type of bond (imine or ketoenamine) as well as the substituent on the naphthalene ring (2-hydroxyphenyl, 5-bromo-2- hydroxyphenyl, 3,5-diodo-2-hydroxyphenyl, pyrimidines) on their properties. Moreover, the properties in the aggregating state were tested in the MeOH/PBS system. Imines are susceptible to the hydrolysis process and aggregation-caused photoluminescence quenching(ACQ). In turn,-ketoenamine shown excited-state intramolecular proton transfer promoted by aggregation (AIEE). Our studies can be helpful in the further design of compounds containing the 1,8- naphthalimide structure for various applications

New acceptor-donor-acceptor systems based on bis-(imino-1,8- naphthalimide)

In this paper, six novel symmetrical bis-(imino-1,8-naphthalimides) differing in core and N-substituent structure were synthesized, and their thermal (TGA, DSC), optical (UV-Vis, PL), electrochemical (DPV, CV) properties were evaluated. The compounds were stable to 280 C and could be transferred into amorphous materials. Electrochemical investigations showed their ability to occur reductions and oxidations processes. They exhibited deep LUMO levels of about -3.22 eV and HOMO levels above -5.80 eV. The optical investigations were carried out in the solutions (polar and non-polar) and in films and blends with PVK:PBD. Bis-(imino-1,8-naphthalimides) absorbed electromagnetic radiation in the range of 243–415 nm and emitted light from blue to yellow. Their capacity for light emission under voltage was preliminarily tested in devices with an active layer consisting of a neat compound and a blend with PVK:PBD. The diodes emitted green or red light

Ground- and excited-state properties of Re(I) carbonyl complexes - effect of triimine ligand core and appended heteroaromatic groups

In this work, a series of six rhenium(I) complexes bearing 2,2′ :6′ ,2′′ -terpyridine (terpy), 2,6-di(thiazol-2-yl)pyridine (dtpy), and 2,6-di(pyrazin-2-yl)pyridine (dppy) with appended quinolin-2-yl and N-ethylcarbazol-3-yl groups were prepared and spectroscopically investigated to evaluate the photophysical consequences of both the trisheterocyclic core (terpy, dtpy and dppy) and the heterocyclic substituent. The [ReCl(CO)3(Ln-κ2N)] complexes are regarded as ideal candidates for getting structure–property relationships, while terpy-like framework represents an excellent structural backbone for structural modifications. The replacement of the peripheral pyridine rings of 2,2′ :6′ ,2′′ -terpyridine by thiazoles and pyrazines resulted in a significant red-shift of the absorption and emission of [ReCl(CO)3(Ln-κ2N)] due to stabilization of the ligand-centred LUMO orbital. Both quinoline and Nethylcarbazole are extended π-conjugation organic chromophores, but they differ in electron-donating abilities. The low-energy absorption band of Re(I) complexes with the triimine ligands bearing quinolin-2-yl group was contributed by the metal-to-ligand charge-transfer (MLCT) electronic transitions. The introduction of electrondonating N-ethylcarbazol-3-yl substituent into the triimine acceptor core resulted in the change of the character of the HOMO of Re(I) complexes and a significant increase of molar absorption coefficients of the longwavelength absorption, which was assigned to a combination of 1MLCT and 1ILCT (intraligand chargetransfer) transitions. Regardless of the appended heteroaromatic group, the emitting excited state of Re(I) terpy-based complexes was demonstrated to have predominant 3MLCT character, as evidenced by comprehensive studies including static and time-resolved emission spectroscopy along with ultrafast transient absorption measurements. The diodes with Re(I) complexes dispersed molecularly in a PVK:PBD matrix were emissive andeffects of the complex structure on colour of emitted light and its intensity was pronounced

In-depth studies of ground- and excited-state properties of Re(I) carbonyl complexes bearing 2,2′:6′,2′′-terpyridine and 2,6-bis(pyrazin-2-yl)pyridine coupled with π‑conjugated aryl chromophores

In the current work, comprehensive photophysical and electrochemical studies were performed for eight rhenium(I) complexes incorporating 2,2′:6′,2″-terpyridine (terpy) and 2,6-bis(pyrazin-2-yl)pyridine (dppy) with appended 1-naphthyl-, 2-naphthyl-, 9-phenanthrenyl, and 1-pyrenyl groups. Naphthyl and phenanthrenyl substituents marginally affected the energy of the MLCT absorption and emission bands, signaling a weak electronic coupling of the appended aryl group with the Re(I) center. The triplet MLCT state in these complexes is so low lying relative to the triplet 3ILaryl that the thermal population of the triplet excited state delocalized on the organic chromophore is ineffective. The attachment of the electron-rich pyrenyl group resulted in a noticeable red shift and a significant increase in molar absorption coefficients of the lowest energy absorption of the resulting Re(I) complexes due to the contribution of intraligand charge-transfer (ILCT) transitions occurring from the pyrenyl substituent to the terpy/dppy core. At 77 K, the excited states of [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-functionalized ligands were found to have predominant 3ILpyrene/3ILCTpyrene→terpy character. The 3IL/3ILCT nature of the lowest energy excited state of [ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] was also evidenced by nanosecond transient absorption and time-resolved emission spectroscopy. Enhanced room-temperature emission lifetimes of the complexes [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-substituted ligands are indicative of the thermal activation between 3MLCT and 3IL/3ILCT excited states. Deactivation pathways occurring upon light excitation in [ReCl(CO)3(4′-(1-naphthyl)-terpy-κ2N)] and [ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] were determined by femtosecond transient absorption studies