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121.
Gajda J Pacholczyk J Bujacz A Bartoszak-Adamska E Bujacz G Ciesielski W Potrzebowski MJ 《The journal of physical chemistry. B》2006,110(51):25692-25701
L-selenomethionine 1 crystallizes in P2(1) space group with two molecules in the asymmetric unit. Solid-state NMR spectroscopy is used for searching of structure and dynamics of 1 in the crystal lattice. The distinct molecular motion of side chains for A and B molecules of 1 is apparent from measurements of relaxation parameters (1H 1rho, 13C T1) and analysis of CSA data (2D-PASS experiment). The 13C delta(ii) and 77Se delta(ii) parameters are correlated with theoretical shielding parameters obtained by means DFT GIAO calculations. Attempt to explain the mechanism of phase transition of crystals of 1 at 313K is presented. 相似文献
122.
Szymczak JJ Urban J Roszak S Leszczynski J 《The journal of physical chemistry. A》2006,110(48):13099-13105
The presence of solvent molecules, even inert, may significantly influence processes taking place in the gas phase. The reason for the solvent activity may be found in studies of complexes originating from microsolvation. The structure, thermodynamics, and vibrational properties of NH(4)(+)Ar(n) (n = 0-5) and NH(3)Ar(n) (n = 0-4) complexes are presented in this work with the aim to elucidate the effect of microsolvation on protonation/deprotonation processes. The relation between the nature of interactions in cationic and neutral clusters and the proton affinity is studied as a function of the number of ligands in complexes. 相似文献
123.
Isomerization and Decomposition of a Criegee Intermediate in the Ozonolysis of Alkenes: Dynamics Using a Multireference Potential
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Jaroslaw Kalinowski Prof. Markku Räsänen Dr. Petri Heinonen Prof. Ilkka Kilpeläinen Prof. R. Benny Gerber 《Angewandte Chemie (International ed. in English)》2014,53(1):265-268
The isomerization and decomposition dynamics of the simplest Criegee intermediate CH2OO have been studied by classical trajectory simulations using the multireference ab initio MR‐PT2 potential on the fly. A new, accelerated algorithm for dynamics with MR‐PT2 was used. For an initial temperature of 300 K, starting from the transition state from CH2OO→CH2O2 , the system reaches the dioxirane structure in around 50 fs, then isomerizes to formic acid (in ca. 2800 fs), and decomposes into CO+H2O at around 2900 fs. The contributions of different configurations to the multiconfigurational total electronic wave function vary dramatically along the trajectory, with diradical contributions being important for transition states corresponding to H‐atom transfers, while being only moderately significant for CH2OO. The implications for reactions of Criegee intermediates are discussed. 相似文献
124.
Anna W. Sobanska Karolina Derecka Jaroslaw Pyzowski 《Central European Journal of Chemistry》2013,11(2):133-136
The water-soluble sunscreen 2-phenylbenzimidazole-5-sulfonic acid (PBS) was quantified in a sun-care product and water samples by thin layer chromatography followed by densitometric scanning in fluorescence mode (cut-off filter 370 nm, wavelength of excitation — 300 nm). Normal phase TLC was performed on silica gel 60 as stationary phase. Mobile phase used was ethyl acetate-ethanol-water 70:35:30 (v/v/v). The limit of detection (LOD) was 0.0004 μg spot-1, and the limit of quantification (LOQ) was — 0.001 μg spot?1 without any sample pre-concentration. 相似文献
125.
Jaroslaw Buczynski 《Transformation Groups》2007,12(4):631-646
We give the full classification of smooth toric Legendrian subvarieties in P2n-1. We also prove that under some minor assumptions the group of linear automorphisms preserving a given Legendrian subvariety
preserves the contact structure of the ambient projective space. 相似文献
126.
Robert Musiol Barbara Podeszwa Jacek Finster Halina Niedbala Jaroslaw Polanski 《Monatshefte für Chemie / Chemical Monthly》2006,118(2):1211-1217
Aromatic aldehydes undergo condensation with quinaldines under microwave irradiation to afford structurally diverse styrylquinolines
in high yields under solvent-free conditions. A comparison with the conventional method clearly indicates the advantages of
the new protocol. 相似文献
127.
Jaroslaw Wlodarczyk 《Transactions of the American Mathematical Society》1997,349(1):373-411
We prove that a toric birational map between two complete
smooth toric varieties of the same dimension can be decomposed in a sequence of equivariant blow-ups and blow-downs along smooth centers.
smooth toric varieties of the same dimension can be decomposed in a sequence of equivariant blow-ups and blow-downs along smooth centers.
128.
Moldoch J Szajwaj B Masullo M Pecio L Oleszek W Piacente S Stochmal A 《Natural product communications》2011,6(11):1627-1630
A new C-6 flavone glycoside (6), together with seven known compounds, cryptochlorogenic acid (1), chlorogenic acid (2), 2-O-trans-caffeoylhydrocitric acid (3), isovitexin 7-beta-D-glucopyranoside (4), 7,4'-dihydroxy-5-methoxyflavone-6-C-beta-D-glucopyranoside (5), 3,5-O-dicaffeoylquinic acid (7) and 4,5-O-dicaffeoylquinic acid (8), were isolated from the aerial parts of Knautia arvensis. Their structures were elucidated by extensive spectroscopic methods including 1D- (1H, 13C and TOCSY) and 2D-NMR (DQF-COSY, HSQC, HMBC) experiments, as well as ESIMS analysis. Compounds 1, 3-5 and 8 are reported for the first time in Knautia arvensis. 相似文献
129.
Barbatti M Szymczak JJ Aquino AJ Nachtigallová D Lischka H 《The Journal of chemical physics》2011,134(1):014304
Ab initio surface hopping dynamics calculations were performed for the biologically relevant tautomer of guanine in gas phase excited into the first ππ? state. The results show that the complete population of UV-excited molecules returns to the ground state following an exponential decay within ~220 fs. This value is in good agreement with the experimentally obtained decay times of 148 and 360 fs. No fraction of the population remains trapped in the excited states. The internal conversion occurs in the ππ? state at two related types of conical intersections strongly puckered at the C2 atom. Only a small population of about 5% following an alternative pathway via a nπ? state was found in the dynamics. 相似文献
130.
Tomasz Goslinski Jaroslaw PiskorzDawid Brudnicki Andrew J.P. WhiteMaria Gdaniec Wojciech SzczolkoEwa Tykarska 《Polyhedron》2011,30(6):1004-1011
Novel tribenzoporphyrazines possessing peripherally annulated tetrahydrodiazepine and diazepine rings were synthesized and characterized, and the substituent effects on their absorption spectra in various solvents and on singlet oxygen generation were studied. Solvatochromic effects of tribenzoporphyrazines dissolved in a range of protic and aprotic solvents were evaluated by monitoring the changes in the UV-Vis spectra. The correlation between the Q-band shift towards longer wavelengths and the refractive index of the solvent indicated that the solvatochromic effects are mainly a result of solvation rather than coordination processes. The potential photosensitizing activity of novel tribenzoporphyrazines was evaluated by measuring the ability of singlet oxygen production, which is the result of the interaction between an activated photosensitizer and oxygen. This experiment proves promising photosensitizing activity of novel styryldiazepinotribenzoporphyrazine, which is an efficient singlet oxygen generator with a ΦΔ value of 0.44, although this value is a little lower than that of zinc phthalocyanine. 相似文献