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21.
Ruta Lazauskaite Maryte Daskeviciene Vytautas Getautis Juozas V. Grazulevicius 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):565-571
Abstract Photoinitiated cationic polymerizations of various epoxy monomers bearing a carbazole moiety, 9-[3-(allyloxy)-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[3-methoxy-2-(oxiran-2-ylmethoxy)propyl]-9H-carbazole, 9-[2-(oxiran-2-ylmethoxy)ethyl]-9H-carbazole, as well as a composition of 3,6-dibromo-9-(oxiran-2-ylmethyl)-9H-carbazole with 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate were investigated in bulk using triphenyl carbenium
salts having anions such as BF4
−, SnCl5
−, and SbCl6
−. Dark polymerizations of the carbazolyl monomers in the presence of the initiators are studied. These photoinduced polymerization
reactions give oligomers of degree of polymerization 4-22. The effect of the anion of the photoinitiator and polymerization
time on the polymerization reaction is discussed.
Graphical abstract
相似文献
22.
Kapre R Ray K Sylvestre I Weyhermüller T DeBeer George S Neese F Wieghardt K 《Inorganic chemistry》2006,45(9):3499-3509
Two oxo-bis(benzene-1,2-dithiolato)chromate(V) complexes, namely, [CrO(L(Bu))2]1- and [CrO(L(Me))2]1-, have been synthesized and studied by UV-vis, EPR, magnetic circular dichroism (MCD), and X-ray absorption spectroscopy and by X-ray crystallography; their electro- and magnetochemistries are reported. H2L(Bu) represents the pro-ligand 3,5-di-tert-butylbenzene-1,2-dithiol, and H2L(Me) is the corresponding 4-methyl-benzene-1,2-dithiol. A structural feature of interest for both the complexes is the folding of the dithiolate ligands about the S-S vector providing Cs symmetry to the complexes. Geometry optimizations using all-electron density functional theory with scalar relativistic corrections at the second-order Douglas-Kroll-Hess (DKH2) and zeroth-order regular approximation (ZORA) levels result in excellent agreement with the experimentally determined structures and electronic and S K-edge X-ray absorption spectra. From DFT calculations, the Cs instead of C2v symmetry for the complexes is attributed to the strong S(3p) --> Cr(3d(x2-y2)) pi-donation in Cs geometry providing additional stability to the complexes. 相似文献
23.
24.
Archive of Applied Mechanics - The series expansions in Eq. (16) of [1] for trigonometric functions depending on a small evolution parameter shall be corrected. 相似文献
25.
Van Zandt LL 《Physical review letters》1986,57(16):2085-2087
26.
We investigate inner shearing constraints for a direct one-dimensional beam model coarsely describing warping. In particular, we study how they affect the field equations for the elastic buckling of open thin-walled beams. We show that the distinction between the axes of the shear centres and of the centroids is crucial for the kinematics of the beam, and to derive expression of reactive actions, hence of buckling critical conditions. We also show how a suitable definition of the warping inertial action and properly introduced inner shearing constraints yield the field equations of the literature for the beam in a general dynamic setting. 相似文献
27.
Meccanica - Local stiffeners affect the behaviour of thin-walled beams (TWBs). An in-house code based on a one-dimensional model proved effective in several instances of compressive buckling of... 相似文献
28.
Mihaela Matache Cristian Dobrota Niculina D. Bogdan Lavinia L. Ruta Ileana C. Farcasanu Daniel P. Funeriu 《Tetrahedron》2009,65(31):5949-3817
A new efficient approach for the synthesis of functionalized dihydro-pyrimido[4,3-d]coumarins is described. Use of benzyl- or tert-butyl acetoacetate and various salicyl aldehydes in typical Biginelli multicomponent reactions provides esters that can be easily deprotected to yield the corresponding hydroxy acids. Annelation of the latter leads to the target dihydro-pyrimido[4,3-d]coumarins. Formation of some unexpected oxo-bridged tetrahydro-pyrimidines is also described. Spectral properties of the synthesized dihydro-pyrimido[4,3-d]coumarins indicate the necessity to revisit some compounds previously reported as products of direct one-pot Biginelli condensation involving 4-hydroxycoumarin as dicarbonyl component. 相似文献
29.
Lavinia L. Ruta Ileana C. Farcasanu Mihaela Bacalum Mina Rileanu Arpad Mihai Rostas Constantin Daniliuc Mariana Carmen Chifiriuc Luminia Mruescu Marcela Popa Mihaela Badea Emilia Elena Iorgulescu Rodica Olar 《Molecules (Basel, Switzerland)》2021,26(22)
Novel complexes of type [Cu(N-N)(dmtp)2(OH2)](ClO4)2·dmtp ((1) N-N: 2,2′-bipyridine; (2) L: 1,10-phenantroline and dmtp: 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine) were designed in order to obtain biologically active compounds. Complexes were characterized as mononuclear species that crystallized in the space group P-1 of the triclinic system with a square pyramidal geometry around the copper (II). In addition to the antiproliferative effect on murine melanoma B16 cells, complex (1) exhibited low toxicity on normal BJ cells and did not affect membrane integrity. Complex (2) proved to be a more potent antimicrobial in comparison with (1), but both compounds were more active in comparison with dmtp—both against planktonic cells and biofilms. A stronger antimicrobial and antibiofilm effect was noticed against the Gram-positive strains, including methicillin-resistant Staphylococcus aureus (MRSA). Both electron paramagnetic resonance (EPR) and Saccharomyces cerevisiae studies indicated that the complexes were scavengers rather than reactive oxygen species promoters. Their DNA intercalating capacity was evidenced by modifications in both absorption and fluorescence spectra. Furthermore, both complexes exhibited nuclease-like activity, which increased in the presence of hydrogen peroxide. 相似文献
30.
It was found out that semiconductor CdS nanoparticles (NPs) are able to catalyze photooxidation of the well known chromogenic enzymatic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by oxygen. The photocatalytical oxidation of TMB does not require hydrogen peroxide and its rate is directly proportional to the quantity of CdS NPs produced in situ through the interaction of Cd2+ and S2− ions in an aqueous medium. This phenomenon was applied to development of colorimetric sensitive assays for glucose oxidase and glutathione reductase based on enzymatic generation of CdS NPs acting as light-powered catalysts. Sensitivity of the developed chromogenic assays was of the same order of magnitude or even better than that of relevant fluorogenic assays. The present approach opens the possibility for the design of simple and sensitive colorimetric assays for a number of enzymes using inexpensive and available TMB as a universal chromogenic compound. 相似文献