Драматургический ремейк – ответ на поп­-культуру

Uniwersytet w Białymstoku23324

Spectroscopic characterization of chloride and pseudohalide ruthenium (II) complexes with 4-(4-nitrobenzyl) pyridine

Chloride, isocyanate and isothiocyanate hydride carbonyl ruthenium(II) complexes of 4-(4-nitrobenzyl)pyridine were synthesized from the precursor complex [RuHCl(CO)(PPh3)3] and characterized by IR, NMR, UV-Vis spectroscopy and X-ray crystallography. The electronic structures of the complexes were investigated by means of DFT calculations, based on their crystal structures. The spin-allowed singlet-singlet electronic transitions of the complexes were calculated by time-dependent DFT, and the UV-Vis spectra are discussed on this basis. The emission properties of the complexes were studied at ambient temperature, and the quantum yields of fluorescence, the lifetimes and nature of the excited states are discussed. The chloride and isothiocyanate complexes are practically nonemissive, with quantum yields under 0.01 %. Interpretation of spectra, supported by TD-DFT calculations, indicates that in this energy region, the transitions have MLCT character with admixture of LLCT (chloride and isothiocyanate complexes). The dominant LLCT character was visible in the case of the most emissive (isocyanate) complex. The low values of the lifetimes and quantum yields for these complexes indicate the influence of the metal center in the emission process

Właściwości luminescencyjne fosfinowych związków koordynacyjnych rutenu(II) z ligandami N-heteroaromatycznymi

This PhD thesis is a summary of my research, which I have achieved since 2011r in Department of Crystallography Institute of Chemistry University of Silesia under supervision of Prof. Jan Grzegorz Małecki. Research conducted by me in this area has focused on structural and spectroscopic characterization of phosphine ruthenium(II) complexes, obtained on the basis of the precursors [RuHCl(CO)(PPh3)3] and [RuCl2(PPh3)3] with N-heteroaromatic ligands. As part of the work, I obtained 30 coordination compounds of ruthenium(II), which can be divided into three groups: pseudohalide derivatives of the starting compounds [RuH(X)(CO)(PPh3)3] (where X = N3−, NCO−); [RuH(X)(CO)(PPh3)2(MeCN)] and [Ru(X)2(PPh3)2(MeCN)2] (where X = N3−, NCS−); complexes with bidentate N,X-donor (X = N, O) ligands with general formula [RuH(CO)(L)(PPh3)2] and [Ru(L)2(PPh3)2] (where L – bidentate N,O- or N,N-donor ligands); chloride and pseudohalide ruthenium(II) with N-heteroaromatic monodentate N-donor ligands with general formula [RuHX(CO)(L)(PPh3)2] (with X = Cl, NCO, N3, NCS, L = monodentate N-heterocyclic ligand). The resulting compounds were characterized by structural and spectroscopic study with particular emphasis on electron emission spectra. The discussion of the experimental results was expanded to include the results of quantum-mechanical calculations. The crystal and molecular structure of coordination compounds was uniquely determined by X-ray structural analysis. The study on emission spectra of the compounds [RuH(X)(CO)(PPh3)2(MeCN)] and [Ru(X)2(PPh3)2(MeCN)2] (where X = N3−, NCS−) at both ambient and low temperature showed the mixed nature of the emissive excited state (LLCT/MLCT) and the effect of thermal deactivation process of the excited states to the MC, which is characteristic also for the other two groups of received complexes. In contrast, lack of luminescence characteristic for [RuH(X)(CO)(PPh3)3] (wherein X = N3─, NCO─) can be related to the deviations from an ideal octahedral geometry due to steric hindrance caused by the presence of three triphenylphosphine ligands. The second group of received complexes are compounds with bidentate N,O- and N,N-donor ligands. Among them large group are compounds with general formulas [RuH(CO)(L)(PPh3)2] and [Ru(L)2(PPh3)2] (where L – carboxylate derivative N-heteroaromatic). On the basis of the electronic structure of these compounds, excited states was identified as MLCT with an admixture of ILCT. Excitation in the ultraviolet range result in emission bands including the range from the near ultraviolet and blue color of visible light. In contrast, excitation and emission spectra of [RuH(CO)(L)(PPh3)2] (wherein L - derivatives of 8-hydroxyquinoline) relative to the emission spectra in the previous group are bathochromic shifted, which extends the spectral range of emission in the study compounds to green and red-orange color. Moreover, in this group of compounds the fluorescence resonance energy transfer (FRET) between the states IL and MLCT have place. Chloride and pseudohalide complexes with monodentate N-heteroaromatic ligands was also obtained and characterized. In a series of compounds with 4-pyrrolidinpyridine, impact of π* triphenylphosphine on the electronic transitions corresponding to the excited wavelengths was detected, and for compounds with 4-(4-nitrobenzyl)pyridine share of π* pyridine ligand was visible. The influence of pseudohalide ligands to the HOMO was illustrated by density of state diagrams, and on this basis it has been found that character of emissive excited state in chloride complexes can be defined as MLCT, however in the case of pseudohalide derivatives excited state are MLLCT or LLCT. Quantum yields in the obtained compounds are in the range from a few to several percent, with higher emission quantum yields determined for compounds with bidentate ligands than for chloride and pseudohalide coordination compounds with monodentate ligands. Nanosecond lifetimes of excited states (at room temperature) show significant share of thermal deactivation of MLCT excited states. One of the aspects which are characteristic for most of known from the literature coordination compounds of ruthenium (II) is that the luminescence of such systems is usually limited to the range of red and orange. One of the undertaken research problem was to check whether it is possible to obtain emission maxima in a wider spectral range. Phosphine ruthenium (II) complexes with N-heteroaromatic ligands show emissions in higher field of energy, thus extending the spectral range of emission of coordination compounds of this element

Chloride and pseudohalide hydride-carbonyl ruthenium(II) complexes with 4-pyrrolidinopyridine as co-ligand

Chloride and pseudohalide (N3 -, NCS-) hydride-carbonyl ruthenium(II) complexes with 4-pyrrolidinopyridine as co-ligand were synthesized and characterized by IR, 1H, and 31P NMR, electronic absorption and emission spectroscopy and X-ray crystallography. The electronic structures of the complexes were calculated by density functional theory (DFT) on their crystal structures. The spin-allowed singlet–singlet electronic transitions of the complexes were calculated by time-dependent DFT, and the UV–Vis spectra have been discussed on these basis. The emission properties of the complexes were also studied

Interactions of amino acids with aluminum octacarboxyphthalocyanine hydroxide. Experimental and DFT studies

The influence of albumin and amino acids (l-serine, glycine, l-histidine, l-tryptophan, l-cysteine) on the properties of aluminum octacarboxyphthalocyanine hydroxide (Al(OH)PcOC) was investigated in a phosphate buffer (pH 8.0). Particular attention was paid to the spectroscopic properties and photostability of Al(OH)PcOC. The effect of albumin or amino acids on the photodegradation of Al(OH)PcOC was examined in water using red light: 685 nm and daylight irradiation. Analysis of kinetic curves indicated that interaction with those molecules increases the photostability of Al(OH)PcOC. The molecular structure of Al(OH)PcOC complexes (in vacuum and in water) with axially or equatorially coordinated amino acids was studied by the B3LYP/6-31G* method, and the effects on molecular structure and electronic absorption spectrum were investigated on the basis of the density functional theory. The calculation results revealed that axial coordination significantly reduces the non-planarity of the phthalocyanine ring, and, thus, alters the electronic structure. On the other hand, hydrogen bonding of phthalocyanine side COOH groups with amino acids, in equatorial complexes, does not change the structure within the center of the phthalocyanine, and causes only a slight increase in UV–vis bands intensity, which is in perfect agreement with experimental data. [Figure not available: see fulltext.

A copper(I) phosphine complex with 5,7-dinitro-2-methylquinolin-8-ol as co-ligand

5,7-Dinitro-2-methylquinolin-8-ol has been synthesized, and its copper(I) complex has been prepared. Both the free 2-MequinNO2 ligand and its complex were characterized by IR, NMR, and UV–Vis spectra. The structure of the [Cu(2-MequinNO2)(PPh3)2] complex has been determined by single-crystal X-ray analysis. The free 2-MequinNO2 ligand reveals luminescence in contrast to the complex. For 2-MequinNO2, the quantum yield, lifetime of the excited state, and the rate constants of both radiative and non-radiative decay have been determined. The lack of luminescence for the complex has been explained with the use of a quantum chemical study

From red to green luminescence via surface functionalization. Effect of 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno[3,4-c]pyrrole-4,6-dione ligands on the photoluminescence of alloyed Ag-In-Zn-S nanocrystals

A semiconducting molecule containing a thiol anchor group, namely 2-(5-mercaptothien-2-yl)-8-(thien-2-yl)-5-hexylthieno- [3,4-c]pyrrole-4,6-dione (abbreviated as D-A-D-SH), was designed, synthesized, and used as a ligand in nonstoichiometric quaternary nanocrystals of composition Ag1.0In3.1Zn1.0S4.0(S6.1) to give an inorganic/organic hybrid. Detailed NMR studies indicate that D-AD- SH ligands are present in two coordination spheres in the organic part of the hybrid: (i) inner in which the ligand molecules form direct bonds with the nanocrystal surface and (ii) outer in which the ligand molecules do not form direct bonds with the inorganic core. Exchange of the initial ligands (stearic acid and 1-aminooctadecane) for D-A-DSH induces a distinct change of the photoluminescence. Efficient red luminescence of nanocrystals capped with initial ligands (λmax = 720 nm, quantum yield = 67%) is totally quenched and green luminescence characteristic of the ligand appears (λmax = 508 nm, quantum yield = 10%). This change of the photoluminescence mechanism can be clarified by a combination of electrochemical and spectroscopic investigations. It can be demonstrated by cyclic voltammetry that new states appear in the hybrid as a consequence of D-A-D-SH binding to the nanocrystals surface. These states are located below the nanocrystal LUMO and above its HOMO, respectively. They are concurrent to deeper donor and acceptor states governing the red luminescence. As a result, energy transfer from the nanocrystal HOMO and LUMO levels to the ligand states takes place, leading to effective quenching of the red luminescence and appearance of the green one

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

Indium(II) chloride as a precursor in the synthesis of ternary (Ag–In–S) and quaternary (Ag–In–Zn–S) nanocrystals

A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag−In−S and quaternary Ag−In−Zn−S nanocrystals. This new precursor, being in fact a dimer of Cl2In−InCl2 chemical structure, is significantly more reactive than InCl3, typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO3) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7−6.2 nm) Ag−In−Zn−S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9−10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5−10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag−In−S and Ag−In−Zn−S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag−In− S) and quaternary (Ag−In−Zn−S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols

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