Mariola Siwy

Synthesis, characterization, and study of photoinduced optical anisotropy in polyimides containing side azobenzene units.

In this paper, novel processable aromatic polymers with imide rings and attached as side-chain azobenzene units are presented. Polymers differ in the chemical structures of chromophores and polymer backbones. Azopolymers were obtained by a two-step synthetic approach. This includes the preparation of a precursor poly(esterimide) and poly(etherimide) with pendant phenolic hydroxyl groups, followed by the covalent bonding of NLO chromophores onto the polyimide backbone by the Mitsunobu reaction. The degree of functionalization of polymers was estimated by UV-vis spectroscopy. Polymers were characterized and evaluated by FT-IR, (1)H NMR, X-ray, UV-vis, DSC, and TGA methods. The synthesized polymers exhibited glass transition temperatures in the range of 167-228 degrees C, thermal stability with decomposition temperatures in the range of 275-446 degrees C, and excellent solubilities in common organic solvents. The light-induced optical anisotropy was studied in obtained azopolymers with the help of a holographic grating recording technique. Two polarization geometries were applied for the grating inscription s-s and p-p. The influence of the polarization geometry on the diffraction efficiency dynamics and on the depth of the surface modulation was not observed, which is different from results reported in the literature. Surface relief gratings, which appeared after the light exposure, were observed by atomic force microscopy. Additionally, the optical anisotropy in poly(esterimide)s was investigated by photoinduced birefringence measurements. For the first time, in polyimide with covalently bonded azobenzene derivatives, the high photoinduced birefringence (Delta n = 0.01) was measured.

Comparative studies of structural, thermal, optical, and electrochemical properties of azines with different end groups with their azomethine analogues toward application in (opto)electronics.

Two series of azines and their azomethine analogues were prepared via condensation reaction of benzaldehyde, 2-hydroxybenzaldehyde, 4-pyridinecarboxaldehyde, 2-thiophenecarboxaldehyde, and 4-(diphenylamino)benzaldehyde with hydrazine monohydrate and 1,4-phenylenediamine, respectively. The structures of given compounds were characterized by FTIR, (1)H NMR, and (13)C NMR spectroscopy as well as elemental analysis. Optical, electrochemical, and thermal properties of all compounds were investigated by means of differential scanning calorimetry (DSC), UV-vis spectroscopy, stationary and time-resolved photoluminescence spectroscopy, and cycling voltammetry (CV). Additionally, the electronic properties, that is, orbital energies and resulting energy gap were calculated theoretically by density functional theory (DFT). Influence of chemical structure of the compounds on their properties was analyzed.

Complexes of silver(I) ions with tetrapyrrolidinyl- and tetramorpholinyl-PNP-lariat ethers in acetonitrile and methanol solutions

This work concerns the investigation of stability constants of silver(I) ions with the tetrapyrrolidinyl-PNP-lariat ether L1 in acetonitrile solution and tetramorpholinyl-PNP-lariat ether L2 in acetonitrile and methanol solutions. The new tetramorpholinyl-PNP-lariat ether L2 was synthesized on the basis of the procedure described in a previous publication. Stability constants of complexes with silver ions were determined using a simple potentiometric titration. Furthermore, NMR spectra were obtained to investigate how the complexation of silver(I) ions by the investigated macrocyclic ligand occurs. Spectrometric data analyses and potentiometric measurements indicate that complexation of Ag+ involves participation of the endocyclic nitrogen atom of the cyclophosphazene ring and polyether oxygen donors. As regards L1 the stability of the obtained complex is influenced by pyrrolidinyl groups. On the other hand, L2 includes the morpholinyl subunits attached to the exocyclic P atom, having in their structure the oxygen atom, which pulls out the electrons of the cyclophosphazene ring and thereby destabilizes the formation of a coordination system.

New Molecular Receptors with Cyclophosphazene Subunits: Synthesis, Reactivity, and Structure-Property Relationships

A series of hydrophopic ( 2 and 3) and new hydrophilic ( 4– 7) molecular receptors of the PNP-lariat ether with tetra-substituted cyclotriphosphazene subunits have been prepared by the complete nucleophilic substitution of chlorine atoms in the reactive PNP-crown precursor 1 with the respective sodium cation-paired oxyanions (phenoxy → 2, β-naphthoxy → 3, and methoxytrioxyethylenoxy → 4) and aliphatic amines (n-propylamine → 5 aziridine → 6, and pyrrolidine → 7). Their structures were established by MS and 31P NMR spectroscopy and their metal ion complexing properties tested by a TLC method. Comparison of the complexation behaviour for ligands 1– 7 shows that the affinity for particular cations is strongly substituent-dependent and, in general, is significantly enhanced by cooperation of the side arm donor atoms (O or N) with the parent PNP-crown structure in the binding process. The remarkable affinity of some ligands for selected cations, in particular lithium, cesium, and silver ions, is interpreted in terms of structure-property relationships.

Polycyclic aromatic hydrocarbons connected with Schiff base linkers: Experimental and theoretical photophysical characterization and electrochemical properties.

A series of polyaromatic hydrocarbons with anthracene, phenanthrene and pyrene units connected with Schiff base junctions were synthesized via condensation of p-phenylenediamine and hydrazine with selected aldehydes. The effect of both hydrocarbon structures and presence of N-N- or phenyl- linked diimines on properties of the prepared azines and azomethines was analyzed. The obtained compounds were soluble in common organic solvents and melted in the range of 226-317°C. Their photophysical and electrochemical properties were investigated by UV-vis, photoluminescence spectroscopies and cyclic voltammetry (CV), respectively. Moreover, a density functional theory (DFT) was applied for calculation of their electronic and geometric structures as well as absorption and emission spectra. Additionally, their electron acceptor activity was preliminary tested in photovoltaic experiment.

Single and double crown macrocyclic derivatives of cyclotriphosphazene as receptors of silver(I) ions

We report the preparation of new single and double PNP-lariat ether derivatives. L1 was synthesized from a MONO-ANSA precursor and L2 was synthesized from a BIS-ANSA precursor by subsequent substitution of the chlorine atoms. The reactive chlorine atoms were substituted by piperidinyl groups. Their structures were established by elemental analysis, MS, 1H NMR, 31P NMR and 13C NMR spectroscopy. Furthermore, this work includes an investigation of the complexation of silver(I) ions by the two new ligands in methanol and acetonitrile solutions. 1H NMR, 31P NMR and 13C NMR spectra were recorded to investigate how the complexation of silver(I) ions by the investigated macrocyclic ligands occurs.

Synthesis and mesomorphism of 2,5-bis(3,4-bis(n-alkoxy)phenyl)thiazolo[5,4-d]thiazole tetracatenar liquid crystals

A series of new symmetrical 2,5-bis(3,4-bis(n-alkoxy)phenyl)thiazolo[5,4-d]thiazoles (TTn) prepared via condensation of dithiooxamide with six different 3,4-di-n-alkoxybenzaldehydes were characterized by 1H NMR, FTIR, UV-Vis, and photoluminescence spectroscopy. Moreover, one compound lack of aliphatic chains, i.e., 2,5-diphenylthiazolo[5,4-d]thiazole (TT) was synthesized and characterized. The investigated TTn compounds emitted blue light. The effect of length of n-alkoxy (i.e., OC n H2 n +1, n = 8, 10, 12, 14, 16, and 18) peripheral groups on thermal and mesomorphic behavior was investigated by means of differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. Variable heating and cooling rates were used to study the liquid-crystalline properties of TTn. All compounds exhibited liquid-crystalline properties which self-organize into one or two smectic mesophases (SmB and SmE).

Structure–alkali metal cation complexation relationships for macrocyclic PNP-lariat ether ligands

Water-insoluble, mono- and diarmed PNP-lariat ethers containing various aryloxy and regioisomerically-positioned binaphthylylenedioxy substituents linked to the phosphorus atoms of the cyclophosphazene ring via oxygen atoms are synthesized by regioselective, sodium ion-assisted arylolysis of tetrachloro-16-PNP-6 crown ether 1. Heterogeneously-substituted, mixed aryloxy-amino PNP-lariat ethers and bis-lariat ethers with two different substituents linked to the PNP-macrocycle via an oxygen and a nitrogen atom are prepared by stepwise arylolysis and aminolysis reactions of 1. The alkali-metal cation complexation behavior of the PNP-lariat ethers is evaluated in solvent polymeric membrane electrodes. The PNP-lariat and bis-lariat ethers exhibit pronounced selectivity for large alkali metal cations (Rb+ and Cs+) over small ones (Li+ and Na+). The selectivity is influenced by the configuration of the crown ether ring and the number of oxygen donor atoms in the ligand. For some PNP-lariat ethers, evidence for formation of 2 : 1 (ligand–metal ion) complexes with Rb+ and Cs+ is provided by ESI-MS.

New anthracene-based Schiff bases: theoretical and experimental investigations of photophysical and electrochemical properties

The new Schiff bases bearing anthracene unit were synthesized from 2-aminoanthracene and various aldehydes such as: benzaldehyde, 4-(diphenylamino)benzaldehyde, 9-phenanthrenecarboxaldehyde, 9-anthracenecarboxaldehyde, and biphenyl-4-carboxaldehyde, 2-naphthaldehyde. Resulted azomethines were characterized by IR, NMR (1H and 13C), elemental analysis and UV-vis spectroscopy. The imine consists of anthracene and biphenyl moieties exhibited liquid crystal properties and their nematic phase showed Schlieren texture. The photoluminescence measurements carried out in solution and in solid state as blend with PMMA revealed the ability of the imines to emission of the blue light with quantum yield efficiency in the range of 2.18-6.03% in blend. Based on the electrochemical experiment they showed value of energy gap (Eg) in the range of 2.5-2.7eV. Additionally, density functional theory (DFT) was applied for calculations of both electronic structure and spectroscopic properties of synthesized Schiff bases. Moreover, the results obtained from preliminary tests of application of the azomethines in organic photovoltaic (OPV) devices confirmed their electron acceptor character.

NCN-Coordinating Ligands based on Pyrene Structure with Potential Application in Organic Electronics

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.