Synthesis and Characterisation of Unsymmetrical Porphyrazines Containing Bis(hydroxyethylthio) Substituents

Summary. Unsymmetrical porphyrazines bearing a single peripheral bis(hydroxyethylthio) moiety were synthesised by mixed condensation of bis(2-hydroxyethylthio)maleonitrile and phthalonitrile. Complexation of the thioether groups of metal-free porphyrazine with PdCl₂ further lowered the intensity of the Q-band absorption of the porphyrazine core. The new compounds were characterised by elemental analyses, IR, ¹H NMR, UV-Vis, and mass spectra.     

Metallophthalocyanines with rod-shaped substituents

4-(4′-Dioctylaminocarbonylbiphenyloxy) phthalonitrile was synthesized from 4-(4′-carboxybiphenyloxy)phthalonitrile and dioctylamine in the presence of Et₃N. Metallophthalocyanines (Zn, Co and Cu) substituted with four dioctylaminocarbonyl biphenyloxy groups on the peripheral positions were prepared from 4-(4′-dioctylaminocarbonylbiphenyloxy)phthalonitrile and the corresponding divalent metal salts (Zn(CH₃COO)₂, CoCl₂ and CuCl₂). The new phthalocyanines are soluble in common organic solvents. These compounds were characterised by ¹H-NMR, ¹³C-NMR, FT-IR, UV-Vis and mass spectroscopies.     

Unsymmetrical phthalocyanines with alkynyl substituents

The synthesis of unsymmetrically substituted metallophthalocyanines (M = Zn, Ni, Co) bearing two phenylethyl moieties and six alkythio substituents was achieved by co-cyclotetramerization of two different phthalonitrile derivatives, namely 4,5-di(hexylthio)phthalonitrile and 4,5-di(phenylethynyl)phthalonitrile in the presence of zinc, cobalt or nickel salts. In contrast to the totally alkyne substituted phthalocyanines, these partially alkyne-containing derivatives are more soluble and their Q band absorptions are red-shifted when compared with all alkylthio phthalocyanines. Electrochemical properties of the phthalocyanines were studied by cyclic voltammetry.     

Prospects of Producing Hydrogen-Ammonia Fuel Based on Lithium Aluminum Amide

Russian Physics Journal - The paper presents the development of the statistical theory of phase transformation of lithium aluminum amide with the formation of ammonia. Free energies of phases are...     

Thermoelectric properties of stannite-phase CuZn2AS4 (CZAS; A=Al,Ga and In) nanocrystals for solar energy conversion applications

The current study aimed to comprehensively investigate structural, electronic, optical and transport properties of quaternary semiconductor CuZn₂AS₄ (CZAS; A=Al, Ga and In) nanocrystals (NCs). Based on energy considerations, the stannite structure (I-42m; No. 121) is found to be more stable than the kesterite (I-4; No.82) and wurtzite (P6₃mc; No.186) type structures. By means of hybrid functional calculations, these nanocrystals have direct band gap of 0.81–1.71 eV with a high absorption coefficient of >10⁴ cm^?1, which are well-suited for use in solar energy-conversion applications. Some of the latest advances in applications of these nanocrystals in thermoelectric applications are also highlighted in the current study. It is observed that transport coefficients of these materials are found to be nearly direction independent and isotropic. All three samples are p-type conductors at room temperature. Especially, the Seebeck coefficient of CuZn₂AlS₄ is even larger than that of CuZn₂GaS₄ and CuZn₂InS₄ under the studied carrier concentration and temperature region. The maximum figure of merit (ZT) reaches 0.982 (0.977), 0.984 (0.974) and 0.53 (0.955) for p-type (n-type) CuZn₂AlS₄, CuZn₂GaS₄, and CuZn₂InS₄, respectively, at 300 K. The high Seebeck coefficients, high figure of merit and low thermal conductivities make these systems good candidates for high-efficiency thermoelectric conversion applications.     

Protonated Dipeptide Losses from b 5 and b 4 Ions of Side Chain Hydroxyl Group Containing Pentapeptides

In this study, C-terminal protonated dipeptide eliminations were reported for both b ₅ and b ₄ ions of side chain hydroxyl group (–OH) containing pentapeptides. The study utilized the model C-terminal amidated pentapeptides having sequences of XGGFL and AXVYI, where X represents serine (S), threonine (T), glutamic acid (E), aspartic acid (D), or tyrosine (Y) residue. Upon low-energy collision-induced dissociation (CID) of XGGFL (where X?=?S, T, E, D, and Y) model peptide series, the ions at m/z 279 and 223 were observed as common fragments in all b ₅ and b ₄ ion (except b ₄ ion of YGGFL) mass spectra, respectively. By contrast, peptides, namely S_MeGGFL-NH₂ and E_OMeGGFL-NH₂, did not show either the ion at m/z 279 or the ion at m/z 223. It is shown that the side chain hydroxyl group is required for the possible mechanism to take place that furnishes the protonated dipeptide loss from b ₅ and b ₄ ions. In addition, the ions at m/z 295 and 281 were detected as common fragments in all b ₅ and b ₄ ion (except b ₄ ion of AYVYI) mass spectra, respectively, for AXVYI model peptide series. The MS⁴ experiments exhibited that the fragment ions at m/z 279, 223, 295, and 281 entirely reflect the same fragmentation behavior of [M?+?H]⁺ ion generated from commercial dipeptides FL-OH, GF-OH, YI-OH, and VY-OH. These novel eliminations reported here for b ₅ and b ₄ ions can be useful in assigning the correct and reliable peptide sequences for high-throughput proteomic studies.

Non-Direct Sequence Ions in the Tandem Mass Spectrometry of Protonated Peptide Amides—an Energy-Resolved Study

The fragmentation reactions of the MH⁺ ions of Leu-enkephalin amide and a variety of heptapeptide amides have been studied in detail as a function of collision energy using a QqToF beam type mass spectrometer. The initial fragmentation of the protonated amides involves primarily formation of b_n ions, including significant loss of NH₃ from the MH⁺ ions. Further fragmentation of these b_n ions occurs following macrocyclization/ring opening leading in many cases to b_n ions with permuted sequences and, thus, to formation of non-direct sequence ions. The importance of these non-direct sequence ions increases markedly with increasing collision energy, making peptide sequence determination difficult, if not impossible, at higher collision energies.

Interaction between green tea extract and 99mTc-pertechnetate on in vivo distribution

People drink various types of tea without knowing the side effects of biological and chemical contents and radiopharmaceutical interactions. In current study, it is aimed to evaluate the effects of green tea extract in different extraction solvents on the radiolabeling of the blood constituents with ^99mTc and on the biodistribution of radiopharmaceutical sodium pertechnetate (Na^99mTcO₄) in male Wistar Albino rats. The extraction of green tea was performed in different solvents. Biodistribution studies were performed on male rats which were treated via gavage with green tea extract in different extraction solvents or saline (0.9 % NaCl) as a control group for 7 days. The radiolabeling of blood constituents performed incubating with SnCl₂ and ^99mTc. According to experimental results, radiolabeling blood components with ^99mTc were not modified in the usage of the different extraction solvents for green tea extraction, but a significant alteration (P < 0.05) of biodistribution of Na^99mTcO₄ was observed after treatment with green tea extract in distilled water. Although there is no considerable effect on radiolabeling of blood components, there is an outstanding change on the biodistribution studies especially with green tea extract in distilled water. The identified change monitored in this study may cause to reduce the risk of misdiagnosis and/or avoid the repetition of the examinations in nuclear medicine.     

Synthesis,characterization and biodistribution of 99mTc-Bioquin-HMPAO (99mTc-BH) as a novel brain imaging agent

Recently, the development of novel brain imaging agents has aroused much interest thanks to limited number of brain cancer or diseases diagnosis agents. It is aimed to synthesize a novel brain imaging agent including a promise for further studies on AD diagnosis potential and investigate its bioaffinity with biodistribution studies on healthy Balb/c mice. A novel radiolabeled agent was synthesized and characterized. Quality control of ^99mTc-BH was performed utilizing solvent extraction and chromatographic (Radio TLC and Radio HPLC) methods. Bioaffinity of the ^99mTc-BH was investigated on male Balb/c mice at various time points (5, 30, 60, 120 min post-injection). Paper electrophoresis showed that ^99mTc-BH has a neutral structure. Radiochemical purity of ^99mTc-BH was over 95 % with appropriate stability for imaging period. Selected brain regions have uptakes over 4 % ID/g following intravenous injection. Hippocampus has uptake approximately 10 % ID/g. ^99mTc-BH has shown brain uptake, so it may prove to be valuable for brain imaging as a novel technetium-labeled agent. Further investigations with AD animal model are our on going effort to show that this agent has AD diagnosis potential.