Search results for "ASIS"

Physiologische Erythrozyten-Protektionslösung (PEP)

2001

1,3-Di(hetero)aryl-7-substituted Pyrenes—An Undiscovered Area of Important Pyrene Derivatives

2019

Despite the pyrene derivatives have been covered extensively by scientists during the last years, many interesting properties and applications of pyrene derivatives have been presented, nowadays there are still areas of pyrenes’ chemistry that need to be fulfilled. Most of the described in literature pyrenes are 1,3,6,8-tetrasubstituted followed by 4,5,9,10-tetrasubstituted, 2,7-, and 1,6-, and 1,8-disubstituted pyrene derivatives. In the case of 1,3-di(hetero)aryl-7-substituted, there are only a few examples of derivatives containing at position 7 - tert-butyl group. In this work, the necessity of synthesis of 1,3-di(hetero)aryl-7-substituted pyrenes is presented based on the results of th…

Synthesis and Conformational Analysis of Saturated3,1,2-Benzoxazaphosphinine 2-Oxides

2005

N-Unsubstituted, N-methyl and N-benzyl cis- and trans-2(hydroxymethyl)cyclohexylamines were subjected to ring closure with phenylphosphonic dichloride, phenyl dichlorophosphate and bis(2-chloroethyl)phosphoramidic dichloride in order to synthesize P-epimeric diastereomers of the corresponding unsubsituted and N-substituted 2-phenyl-, 2phenoxy- and 2-[bis(2-chloroethyl)amino]octahydro-2H3,1,2-benzoxazaphosphinine 2-oxides. The stereochemistry and conformations of the prepared compounds were analyzed mainly by variable-temperature 1 H, 13 C and 31 P NMR spectroscopy. Geometry optimizations were performed for some trans-fused molecules by utilizing the B3LYP DFT method and a locally dense basi…

ChemInform Abstract: A Theoretical Determination of the Dissociation Energy of the Nitric Oxide Dimer.

2010

Multi-reference CI methods have been applied to determine the dissociation energy and structure of thecis-N2O2 molecule. The convergence of the theoretical result has been checked with respect to a systematic expansion of the one-electron basis set and the multi-reference CI wave function. The best calculated value, 13.8 kJ/mol, is in agreement with the experimental value, 12.2 kJ/mol. It has been obtained with an extended ANO-type basis set [6s5p3d2f], including the effect of the basis set superposition error (BSSE) in the geometry optimization, and additional effects, such as the electron correlation of core electrons and relativistic corrections, using the average coupled pair functional…

Rotational spectra of isotopic species of silyl fluoride. Part II: theoretical and empirical equilibrium structure

2010

Abstract The equilibrium structure of silyl fluoride, SiH 3 F, has been reinvestigated using both theoretical and experimental data. With respect to the former, quantum-chemical calculations at the coupled-cluster level have been employed together with extrapolation to the basis set limit, consideration of higher excitations in the cluster operator, and inclusion of core correlation as well as relativistic corrections ( r (Si–F) = 1.5911 A, r (Si–H) = 1.4695 A, and ∠FSiH = 108.30°). A semi-experimental equilibrium structure has been determined based on the available rotational constants for the various isotopic species of silyl fluoride ( 28 SiH 3 F, 28 SiD 3 F, 29 SiH 3 F, 29 SiD 3 F, 30 S…

Interpretation of the electronic absorption spectrum of free base porphin by using multiconfigurational second-order perturbation theory

1998

Abstract Multiconfigurational second-order perturbation (CASPT2) calculations have been performed on the low-lying optically allowed valence excited states of the free base porphin molecule in order to assign the four lowest bands of the spectrum. The low-lying triplet states have also been characterized. A basis set of the atomic natural orbital type of split-valence plus polarization quality for first-row atoms has been employed. Polarization functions are important for an accurate description of the transitions. These CASPT2 results provide a consistent picture of the experimental spectrum. Each band of the spectrum up to 4.5 eV is composed of a pair of states, which become degenerate in…

Comparison of the molecular structure and spectra of benzene and borazine

1970

Ab initio SCF MO and CI calculations for two different gaussian basis sets are carried out for the isoelectronic molecules benzene C6H6 and borazine B3N3H3 in order to investigate the effect of increasing the flexibility in the representation of their respective π systems. In the process it is found from comparison of orbital charge density contour diagrams and inner shell orbital energies of borazine with analogous data for other systems that the BN bonds of this compound are considerably less polar (B+N−) than that of ammonia borane BNH6 (B−N+). CI calculations employing the larger basis set produce generally better agreement with the experimental transition energies of benzene than do th…

Excited State N−H Tautomer Selectivity in the Singlet Energy Transfer of a Zinc(II)-Porphyrin-Truxene-Corrole Assembly

2017

International audience; An original corrole-containing polyad for S-1 energy transfer, in which one zinc(II)-porphyrin donor is linked to two free-base corrole acceptors by a truxene linker, is reported. This polyad exhibits a rapid zinc(II)-porphyrin*free-base corrole transfer (4.83x10(10)s(-1); 298K), even faster than the tautomerization in the excited state processes taking advantage of the good electronic communication provided by the truxene bridge. Importantly, the energy transfer process shows approximately 3-fold selectivity for one corrole N-H tautomer over the other even at low temperature (77K). This selectivity is due to the difference in the J-integral being effective in both t…

Zinc and inflammatory/immune response in aging

2007

Life-long antigenic burden determines a condition of chronic inflammation, with increased lymphocyte activation and proinflammatory cytokine production. A large number of studies have documented changes in zinc metabolism in experimental animal models of acute and chronic inflammation and in human chronic inflammatory conditions. In particular, modification of zinc plasma concentration, as well as intracellular disturbance of antioxidant intracellular pathways, has been found in aging and in some age-related diseases. Zinc deficiency is diffused in aged individuals in order to avoid meat and other high zinc content foods due to fear of cholesterol. Rather, they increase the consumption of r…

Oral Candidiasis in children and adolescents with cancer. Identification of Candida spp

2007

Oral candidiasis represents a serious problem for children with cancer. The mortality rate of this infection has increased due to fungal septicemia, associated with a primary buccal infection. Objective: Identify the Candida spp. in buccal lesions of patients with cancer, establish the predominant species and correlate them to age and sex of the patient, clinical presentation, type of neoplasic disease and cytostatic therapy received. Study design: 62 patients, between 0-16 years, were investigated in a cross sectional study. Sample inclusion criteria: Patients with malignant neoplasic disease that were receiving cytostatic treatment and had suspicious lesions of oral candidiasis. Patients …