- How N-(pyridin-4-yl)pyridin-4-amine and its methyl and nitro derivatives are arranged in the interlayer space of zirconium sulfophenylphosphonate: a problem solved by experimental and calculation methods
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Classical molecular simulation methods were used for a description of an arrangement of intercalated molecules N-(pyridin-4-yl)pyridin-4-amine (AH) and its derivatives, 3-methyl-N-(pyridin-4-yl)pyridin-4-amine (AMe), and 3-nitro-N-(pyridin-4-yl)pyridin-4-amine (ANO2) within a layered structure of zirconium 4-sulfophenylphosphonate. The intercalated molecules were placed between SO3H groups of the host layers. Their mutual positions and orientations were solved by molecular simulation methods and compared with the presented experimental results. Final calculated data showed differences of partially disordered arrangement of the intercalated molecules between zirconium 4-sulfophenylphosphonate layers. The calculation results revealed a dense net of hydrogen bonds connecting water molecules and the guests in the interlayer space and the sulfo groups of the host layers. We calculated the dipole moments of the AH, AMe and ANO2 guests in the final models in order to illustrate potential use of these materials in non-linear optics.
- Ková?, Petr,?koda, Jakub,Pospí?il, Miroslav,Melánová, Klára,Svoboda, Jan,Bene?, Ludvík,Kutálek, Petr,Zima, Vítězslav,Bure?, Filip
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- Can Remote N-Heterocyclic Carbenes Coordinate with Main Group Elements? Synthesis, Structure, and Quantum Chemical Analysis of N+-Centered Complexes
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Remote N-heterocyclic carbenes (rNHCs), such as N-methyl-4-pyridylidene, are known to form coordination complexes with TMs. Herein, it is established that rNHCs can also coordinate to the N+ centre. Synthesis of some novel divalent NI complexes with the general formula (rNHC)→N+←(NHC) and (rNHC)→N+←(rNHC) was achieved, and X-ray diffraction studies supported the coordination bond character between the rNHCs and the N+ centre. Quantum chemical analysis established the presence of divalent NI character at the central nitrogen in these systems.
- Patel, Neha,Arfeen, Minhajul,Sood, Radhika,Khullar, Sadhika,Chakraborti, Asit K.,Mandal, Sanjay K.,Bharatam, Prasad V.
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- Effect of intercalation and chromophore arrangement on the linear and nonlinear optical properties of model aminopyridine push-pull molecules
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Three push-pull aminopyridine derivatives having D-π-A, D-(π-A)2, and D-(π-A)3 arrangements were examined as model organic chromophores capable of intercalation into inorganic layered materials (alpha modification of zirconium hydrogen phosphate, zirconium 4-sulfophenylphosphonate, and gamma modification of titanium hydrogen phosphate). The fundamental properties of these dyes, their methylated analogues as well as their intercalates were studied by X-ray analysis, electrochemistry, UV/Vis absorption spectra, TGA, IR spectra, SHG, and were completed by DFT calculations. The synthesis of tripodal tris(pyridin-4-yl)amine is given for the first time. The HOMO-LUMO gap, the position of the longest-wavelength absorption maxima, and the dipole moment of aminopyridines can easily be tuned by attaching/removing pyridin-4-yl electron withdrawing units and their quaternization (pyridine vs. pyridinium acceptors). Their intercalation proved to be feasible affording novel inorganic-organic hybrid materials. The intercalation is accompanied by protonation of the guest, which enhances its ICT and strongly anchors the aminopyridines into the confined space of the layered host. Moreover, this process results in ordering of the organic chromophores and also brings improved thermal and chemical robustness. As a result, the measured SHG efficiencies of the intercalates are larger than those observed for the pure organic push-pull chromophores. Hence, the methodology of intercalation turned out to be very useful strategy for property tuning of NLO-active organic molecules.
- Bure?, Filip,Cvejn, Daniel,Melánová, Klára,Bene?, Ludvík,Svoboda, Jan,Zima, Vítězslav,Pytela, Old?ich,Mikysek, Tomá?,R??i?ková, Zdeňka,Kityk,Wojciechowski, Artur,Alzayed, Nasser
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- Use of the graebe-ullmann reaction in the synthesis of 8-methyl-γ- carboline and isomeric aromatic aza-γ-carbolines
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Two variants of the Graebe-Ullmann reaction were used to obtain 8-methyl-5H-pyrido[4,3-b]indole (8-methyl-γ-carboline) and the conditions for this reaction were optimized. The feasibility of using this method was studied for the synthesis of a series of isomeric aromatic aza-γ- carbolines from the corresponding 1-(pyridyl)-1H-1,2,3-triazolo[4,5-c]pyridines under thermal and microwave irradiation conditions.
- Alekseev,Kurkin,Yurovskaya
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p. 1235 - 1250
(2013/03/13)
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