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1

Crystal structures and conformers of CyMe4-BTBP

Lyczko K., Ostrowski S.

Nukleonika

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2015

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Vol. 60, No. 4, part 2

853--857

EN

The crystal structure of new conformation of the CyMe4-BTBP ligand (ttc) has been presented. The ttt conformer of this compound in a form of THF solvate has been also crystallized. The geometries of six possible conformations (ttt, ttc, tct, tcc, ctc and ccc) of the CyMe4-BTBP ligand have been modeled in the gas phase and in solutions (MeOH and H2O) by DFT calculations using B3LYP/6-31G(d,p) method. According to the calculations, in the three different media the conformers with trans orientation of the N atoms in the bipyridyl moiety are the most stable.

2

N-winyloformamid - nowy ekologiczny monomer wodorozpuszczalny

Bortel E., Witek E., Pazdro M., Kochanowski A.

Polimery

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2007

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T. 52, nr 7-8

503-510

PL

Opisano trzy różne metody syntezy N-winyloformamidu (NVF) - nietoksycznego, izomerycznego w stosunku do akryloamidu monomeru rozpuszczalnego w wodzie, od niedawna produkowanego na skalę przemysłową. Są to technologie realizowane w koncernach BASF (Niemcy), Mitsubishi (Japonia) i Air Products & Chemicals (USA). Scharakteryzowano strukturę cząsteczki NVF, która w wyniku silnego sprzężenia może przybierać postaci czterech różnych konformerów. Opierając się na wynikach własnych badań spektroskopowych i obliczeń kwantowo-mechanicznych uzasadniono przyczynę występowania w widmach NMR sygnałów pochodzących tylko od dwóch konformerów (trans-cis i trans-trans, brak cis-trans i cis-cis). Przedstawiono reakcje towarzyszące rodnikowej i jonowej polimeryzacji NVF. Wskazano na możliwości zastosowania poli(N-winyloformamidu) i otrzymywanej z niego na drodze hydrolizy poliwinyloaminy.

EN

N-vinylformamide (NVF) is a nontoxic water-soluble monomer, isomeric in relation to acrylamide, until recently introduced into the industrial scale of production. Three various methods of N-vinylformamide synthesis were described, according to the technologies realized in BASF (Germany), Mitsubishi (Japan) and Air Products & Chemicals (USA) companies. There was described the structure of NVF molecule which can form four various conformers because of strong coupling. The reason of the presence of signals of just two conformers in NMR spectra (trans-cis and trans-trans only, cis-cis and cis-trans not present) has been justified on the basis of the results of own spectroscopic investigations (Fig. 1 and 2) and quantum-mechanical calculations (Fig. 3 and 4). The reactions accompanying the radical or ionic NVF polymerizations were presented. Possible applications of poly(N-vinylformamide) as well as of polyvinylamine, obtained by its hydrolysis, were pointed.

3

Rotation of PRODAN in excited state

Tomin V I

Optica Applicata

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2006

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Vol. 36, nr 4

s. 523--528

EN

Instant spectra and anisotropy kinetics of PRODAN luminescence in different ranges of spectra has been studied upon excitation by picosecond pulses. Instant spectra of luminescence reveal time dependent Stokes shift having intermolecular nature as its characteristic time correlates with dielectric relaxation time of solvent. The mean Brownian rotation time for the curves obtained shows complex character of spectral dependence with maximum ~39 ns near maximum of luminescence intensity and drops down to 15 ns on the edges of the spectrum. An explanation is based on a treatment of intermolecular energy conversion into thermal movement of molecules during relaxation in excited state. Calculations using hydrodynamic model show “stick” boundary conditions for solutes: rotational volumes correspond to solute together with molecules of the first coordinative sphere filled by solvent.

4

Anomalous broadening of DMABN electronic spectra in solutions

Tomin V, Hubisz K

Optica Applicata

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2006

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Vol. 36, nr 4

s. 475--481

EN

The results of spectral broadening study of electronic bands of an archetype molecule with intramolecular charge transfer in the excited state, n-dimethylaminobenzonithrile (DMABN), in polar solvents are discussed. The broadening is anomalously large, it amounts to 8000 cm–1, and manifests itself in both luminescence and excitation spectra. The explanation of the results obtained is based on treating a solution as a set of chemically identical solvates with solute in the centre, which have different energies of the pure electronic transitions. The inhomogeneity is likely to arise due to both the intermolecular effect of luminophor environment on its spectra in polar solvents and the existence of various conformers of DMABN.