Absorption Bands Of Compounds Research Articles

Вивчення електронної будови та реакційної здатності похідних 5-(адамантан -1-іл)-4r-1,2,4-тріазол-3-тіолів

<p>Резюме. Вивчено електронні спектри поглинання 5-(адамантан-1-іл)-4-феніл-1,2,4-тріазол-3-тіолу (І) і 5-(адамантан-1-іл) -4-метил-1,2,4-тріазол-3-тіолу (ІІ) в розчинниках різної полярності (вода, 95 % етанол, 0,1 М HCl, 0,1 М H<sub>2</sub>SO<sub>4</sub>, 0,1 М NaOH, н-гексан). Встановлено, що смуга поглинання сполуки І характеризується наявністю одного максимуму середньої інтенсивності в межах від 250 до 262 нм, а сполуки ІІ – в межах від 236 до 255 нм. Враховуючи хімічну будову досліджуваних сполук і характер їх спектрів поглинання, можна зробити висновок, що смуга поглинання сполуки І є результатом накладення p → p<sup>x</sup> – переходів 1,2,4-тріазолового циклу на <sup>1</sup>L<sub>b</sub> – смугу фенільного радикала. Смуга поглинання сполуки ІІ зумовлена лише π→π<sup>x</sup> – переходами в родоначальному хромофорі, а саме в 1,2,4-тріазолі. Використання методу Extended Hückel на підставі лінійної комбінації атомних орбіталей відповідно до програми Chemoffice Free Trial 11.0.1 дозволило нам провести прогнозування реакційної здатності досліджуваних сполук на основі квантово-хімічних розрахунків зарядів їх атомів. Проведені розрахунки дозволили зробити висновок, що 1,2,4-тріазоловий цикл сполуки І є π – надлишковим за рахунок впливу субстітуєнтів, які знаходяться у положеннях 3-SH – (-Ι, + М), 4-феніл – (-Ι, + М), 5-адамантил – (+ І). Кислотний характер SH-центру виникає за рахунок електронакцепторного впливу тріазолового кільця. Атом сірки при цьому проявляє негативний індуктивний ефект (-І), а мезомерний ефект є позитивним (+ М) і + М ˃ -І. На атомі сірки спостерігається дефіцит електронної густини (+ 0,0314774), а на атомі водню тіольного угрупування зосереджено заряд (+0,0232612), в результаті чого реакція алкілування (SF) відбувається за SH-кислотним центром. Враховуючи квантово-хімічні розрахунки зарядів атомів сполуки ІІ, можна зробити висновок, що наявність метильного субстітуєнта в положенні 4 впливає на розподіл її електронної щільності. Таким чином, метильний радикал проявляє позитивний індуктивний ефект (+І).</p><p><strong>Ключові слова:</strong> УФ-спектри, електронна будова, рекційна здатність, похідні 5-(адамантан-1-іл)-4R-1,2,4-тріазол-3-тіолів</p>

ГОСТРА ТОКСИЧНІСТЬ Б-АЛКІЛПОХІДНИХ 5-(АДАМАНТАН-1-ІЛ)-4Р-1,2,4- ТРІАЗОЛ-З-ТІОНУ

<p align="center"><strong><span>THE </span></strong><strong><span>STUDYOFTHEELECTRONICSTRUCTURE ANDREACTIVITYOF 5-(ADAMANTANE-1-YL)-4R-1,2,4-TRIAZOLE-3-THIOLES DERIVATIVES</span></strong></p><p align="center"><span>V. M. Odyntsova</span></p><p align="center"><span>Zaporizhzhуa State Medical University,Zaporizhzhуa</span></p><p><strong><span>Summary:</span></strong><span>The electronic absorption spectra of 5-(adamantane-1-yl)-4-phenyl-1,2,4-triazole-3-thiole (I) and 5-(adamantane-1-yl)-4-methyl-1,2,4-triazole-3-thiole (II) in solvents of different polarity (water, 95 % ethanol, 0.1 M HCl, 0.1 M H2SO4, 0.1 M NaOH, n-hexane) are studied. It is established that the absorption band of compound I is characterized by the presence of only one maximum of the average intensity in the range from 250 to 262 nm, while compound II is in the range from 236 to 255 nm.</span></p><p><strong><span>Key</span></strong><strong></strong><strong><span>words:</span></strong><span> UV spectra, electronic structure, reactivity, derivatives of 5-(adamantane-1-yl)-4R-1,2,4-triazole-3-thioles.</span></p><p><strong><span>Introduction.</span></strong><span> The study of UV spectra of organic compounds that are derivatives of 1,2,4-triazole, untilrecently, little attention had been paid. In scientific publications to date there aren’t theoretical conclusions on the impact of the substitutes on the nature of the UV spectra of various derivatives of 1,2,4-triazole, and some publication sare devoted only to the study of the existence of the thion-thiole tautomerism derivatives of 1,2,4-triazole-3(5)-thione. We have investigated the change in the UV absorption spectra and the positions of maxima of the investigated substances, depending on the polarity of the used solvents. Additionally, we have studied the reactivity’s ability of the compounds І and II in order to predict the possible directions of the reaction.</span></p><p><strong><span>The aim</span></strong><span> of our study was to study the absorption’s spectra of 5-(adamantane-1-yl)-4R-1,2,4-triazole-3-thiolеs derivatives, namely: 5-(adamantane-1-yl)-4-phenyl-1,2,4-triazole-3-thiolе (І) and 5-(adamantane-1-yl)-4-methyl-1,2,4 - triazole-3-thiolе (ІІ) in the solvents of different polarity (water, 95 % ethanol, 0,1 M solutions of hydrochloric and sulphuric acids, 0,1 M solution of sodium hydroxide and n-hexane).</span></p><p><strong><span>Methods.</span></strong><span> To investigate the purity of the compounds І and II, we used a thin-layer chromatography method, and the identity of the intended composition of compounds – their actual composition was checked by elemental analysis using elemental GmbHanalyzer, from Germany. All used solvents and reagents were the qualification</span></p><p><span>«chemically pure» and fully complied with the requirements of pharmacopoeial analysis. UV spectra were measured with a spectrophotometer «Specord 200».</span></p><p><strong><span>Results and discussion.</span></strong><span> Taking into account the chemical structure of the studied compound sand their absorption’s spectra is shown that the absorption band of the compound I is the result of applying π → πx transitions 1,2,4-triazole cycleon 1Lb– band of the phenyl radical. The absorption band of compound II is caused only by π→πx – transitions in parental chromophor, namely in 1,2,4-trizole. The use of the Extended Hückel method is based on the linear combination of atomic orbitals according to the program Chem office 11.0.1 Free Trial allowed us to predict the reactivity of the investigated compounds on the basis of quantum-chemical calculations of their atoms’ charges. The calculations indicate that 1,2,4-trіasole cycle of the compound I is π redundant due to the impact of the substitutes which are in the positions 3-SH – (-Ι, + M), 4-phenyl – (-Ι, + M), 5-adamantyl – (+ І). The acidic nature of SH-centre occurs due to the electron capture’s influence of the triazole ring. The sulphur atom shows a negative inductivee ffect (-I), but mesomeone effect is positive (+ M) + M > I. A deficiency of electron density (+ 0,0314774) is noted on the sulfur atom, and the charge (+0,0232612) is focused on the hydrogen atom of thiole group, resulting in the reaction of alkylation (SF) is gone according to the SH-acidic center.</span></p><p><strong><span>Conclusions.</span></strong><span> The absorption band of the compound І is the result of applying π→πх– transition triazole cycle on 1Lb– band of the phenyl radical and the absorption band of compound II is caused by π→πх– transitions only in the triazole cycle. The study of the results of quantum-chemical calculations of the compound I shows that 1,2,4-triazoline cycle is π redundant due to the impact of the substitutes inposition of 3-SH – (-I,+M), 4-phenyl – (-I,+M), 5-adamantyl – (+І).</span></p><p><span>On the basis of quantum chemical calculations of compound II on Heukelem is found that the presence of a methyl radical inposition 4 has an impact on the distribution of electron density. In this case a methyl radical shows a positive inductivee ffect (+I).</span></p>

A novel electrochemical and chromogenic guest-responsive anisidine-based chemosensor for transition metallic cations

A new family of N,N-disubstituted p-anisidine-based electroactive ligands bearing dipyridinylamino- (1), difuranylamino- (2) and dithiophenylamino- (3) binding sites has been prepared by reductive alkylation of anisidine. The electrochemical investigations, in 0.1mol/dm−3 LiClO4 acetonitrile solution, showed that upon the addition of metallic cations, the redox features of 1 underwent drastic changes due to the cation chelation. The chemosensor complexation with Ni(II), Zn(II), Cd(II) and Pb(II) led to large anodic shifts of the oxidation potential peaks up to 700mV depending on the metal cation. A particularly high sensitivity toward nickel(II) with a higher selectivity to zinc(II) were observed. However, in the same conditions, thiophenyl- and furfuranyl- derivatives showed no sensitivity for any of the investigated cations. Moreover, UV–visible spectroscopy studies of 1 showed that the compound can act as a chromogenic guest-responsive and in presence of metallic cations, the absorption bands of compound 1 shifted due to a participation of the nitrogen lone pairs in the cation complexation. UV–visible spectroscopy did also allow to distinguish between the Ni(II) and Zn(II) complexes. Electrochemical and UV–visible spectroscopic investigations showed that the complexes have 1:2 stoichiometry [M(1)2]2+ (M: Zn, Ni, Cd and Pb).

Photochromism and Its Application to a High-density Optical Memory

In order to solve problems of photochromic memory, a super-low power readout method and a crosstalk reduction method for multi-wavelength recording were proposed. In the demonstration of 2-wavelength recording using photochromic diarylethenes, the crosstalk between multiplexed channels, which is caused from broad absorption bands of compounds, was effectively reduced by the method. A new high density optical memory, a super-resolution disk with a photochromic mask layer, was also introduced. The super-resolution method has enabled us to increase the recording density of conventional optical disks.