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101.
Poriel C Ferrand Y le Maux P Raul-Berthelot J Simonneaux G 《Chemical communications (Cambridge, England)》2003,(9):1104-1105
Anodic oxidation of tetraspirobifluorene-manganese porphyrin lead to the coating of the working electrode by insoluble electroactive poly(9,9'-spirobifluorene-manganese porphyrin) films for which electrochemical behaviour and physicochemical properties are described; these polymeric materials are able to catalyze the heterogeneous epoxidation of styrene with iodobenzene diacetate and iodosylbenzene. 相似文献
102.
Francis P. Gasparro Paola Gattolin Gerard A. Olack Lawrence I. Deckelbaum Bauer E. Sumpio 《Photochemistry and photobiology》1993,57(S1):1007-1009
Abstract— The formation of 8-methoxypsoralen-DNA monoadducts and cross-links is presumed to be responsible for the efficacy of photochemotherapies that employ 8-methoxypsoralen activated with long-wavelength ultraviolet radiation (UVA,320–400 nm). In this report it is shown that 8-methoxypsoralen can also be activated with visible light (419 nm). Bovine aorta smooth muscle cells were treated with 8-methoxypsoralen (1000 ng/mL) and 419 nm light (up to 12 J/cm2 ). Cellular DNA was isolated, hydrolyzed using nucleolytic enzymes and then analyzed by reversed-phase high-performance liquid chromatography. The primary effect of using visible light instead of long-wavelength ultraviolet radiation is a more than 10-fold reduction in the extent of cross-link formation. Because the extent of monoadduct and cross-link formation has not been routinely measured in experiments in which cellular assays have been performed, it is difficult to correlate cell response to the presence of a particular type of 8-methoxypsoralen photoadduct (monoadduct or cross-link). Thus, the use of visible light allows the study of cells containing nearly 100% monoadducts. In addition, the reduction in cross-link formation when visible light is used to activate the compound may also reduce the mutagenicity of 8-methoxypsoralen and hence enhance its therapeutic efficacy. 相似文献
103.
Gerard de Leeuw John S. Field Raymond J. Haines Beth McCulloch Elsie Meintjies Christiaan Monberg Gillian M. Olivier Praveen Ramdial Clifford N. Sampson Beate Sigwarth Nick D. Steen Kandasamy G. Moodley 《Journal of organometallic chemistry》1984,275(1):99-111
Reaction of [Fe2(CO)9] with a half molar amount of R2PYPR2 (Y = CH2, R = Ph, Me, OMe or OPri; Y = N(Et), R = OPh, OMe or OCH2; Y = N(Me), R = OPri or OEt) leads to the ready formation of a product which on irradiation with ultraviolet light rapidly decarbonylates to the heptacarbonyl derivative [Fe2(μ-CO)(CO)6{μ-R2PYPR2}]. Treatment of the latter with a slight excess of the appropriate ligand results, under photochemical conditions, in the formation of the dinuclear pentacarbonyl complex [Fe2(μ-CO)(C))4{μ-R2PYPR2}2] but under thermal conditions in the formation of the mononuclear species [Fe(CO)3{R2PYPR2}]. Reaction of [Ru3(CO)12] with an equimolar amount of (RO)2PN(R′)P(OR)2 (R′ = Me, R = Pri or Et; R′ = Et, R = Ph or Me) under either thermal or photochemical conditions produces [Ru3(CO)10{μ-(RO)2PN(OR)2}] which reacts further with excess (RO)2PN(R′)P(OR)2 on irradiation with ultraviolet light to afford the dinuclear compound [Ru2(μ-CO)(CO4{μ-(RO)2PN(R′)P(OR)2}2]. The molecular structure of [Ru2(μ-CO)(CO)4{μ-(MeO)2PN(Et)P(OMe)2}2], which has been determined by X-ray crystallography, is described. 相似文献
104.
Michael W. Winkley Gerard F. Judd Roland K. Robins 《Journal of heterocyclic chemistry》1971,8(2):237-240
The first synthesis of a purine nucleoside analog containing a bridgehead nitrogen atom is here reported. The direct glycosylation of the trimethylsilyl derivative of s-triazolo[2,3-a] pyrimid-7-one has been shown to give 3-(β-D-ribofuranosyl)-s-triazolo[2,3-a]pyrimid-7-one (V) and 4-(β-D-ribof'uranosyl)-s-lriazolo[2,3-α]pyrimid-7-one (VII). The nueleoside V may he considered a close analog of inosine in which the nitrogen N1 and C5 of inosine have been interchanged. Bro-minalion of the tri-O-acelyl derivative IV gave, after deblocking, 6-bromo-3-(β-D-ribofurnaosyl)-s-triazolo[2,3-a] pyrimid-7-one (IX). Structural assignments of the nucleosides were made on the basis of comparison of the ultraviolet absorption spectral characteristics with 3-methyl-s-triazolo-[2,3-a]pyrimid-7-one (XI) and 4-methyl-s-lriazolo[2,3-a Jpyrimid-7-one (XII) prepared by a standard procedure from 7-methoxy-s-triazolo(2,3-a] pyrimidine (X). 相似文献
105.
Polypeptides containing a basic amino acid close to their single tryptophan residue were irradiated with monochromatic 302 nm radiation. Tryptophan photolysis was monitored by absorption and fluorescence spectroscopy. Amino acid loss was evaluated by amino acid analysis. Only the protonated residues adjacent to tryptophan in the sequence were destroyed upon tryptophan excitation. This reaction is probably due essentially to direct interaction between the excited tryptophan and the neighbouring residue without electron solvation. 相似文献
106.
107.
Pot experiments were conducted to study the efficacy of a slow sulfur-releasing fertilizer, sulfur glass fritz (SGF 1), on
growth, photosynthesis, and sulfur, and nitrogen assimilation potentials of brown mustard (Brassica juncea L. Czern. & Coss. cv. Pusa Jaikisan). Growth as indicated by biomass accumulation slowed down in response to the application
of sulfur glass fritz. A similar trend was observed in the case of photosynthesis rate. The activity of two marker enzymes,
ATP-sulfurylase and nitrate reductase, showed very low levels of activity, indicating poor assimilation of sulfur and nitrogen
by the plant under sulfur glass fritz. It is therefore concluded that the release of sulfur by sulfur glass fritz is too slow
and that the initial nonavailability of sulfur to the plants could lead to suboptimization of both sulfur- and nitrogen-assimilating
enzymes. These factors may contribute to low rates of photosynthesis and poor growth. 相似文献
108.
Polylactide (PLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) blends were prepared at different compositions by melt mixing. First, the rheological properties of each individual component are briefly presented focusing on the most important aspects to be taken into account during blends preparation and investigation. The kinetics of PHBV viscosity decrease due to strong polymer degradation in the molten state was recorded. This helped making a choice of the blending parameters and of the way of performing the rheological frequency sweeps. DSC showed that components are immiscible in the whole range of compositions studied. Blends morphology was studied using high-resolution scanning electron microscope and optical microscopy in reflection mode. Nodular and co-continuous morphologies were observed depending on the composition, and minor phase size was roughly estimated. The rheology of PLA/PHBV blends was investigated in the dynamic mode and correlated with the morphology observed. The results showed an important role of the interfaces between PLA and PHBV and a peculiar behaviour of the viscosity of some mixtures at low frequencies. At medium and high frequencies mixture dynamic viscosity follows the mixing law. 相似文献
109.
Reaction of [Nb(NMe(2))(5)] with 10 equiv of 2,6-Me(2)C(6)H(3)SH in toluene results in the formation of red crystals of [Nb(SC(6)H(3)Me(2)-2,6)(5)]. Crystal structure analysis of [Nb(SC(6)H(3)Me(2)-2,6)(5)] showed that the niobium center adopts a distorted trigonal bipyramidal geometry. Niobium disulfide, NbS(2), has been successfully prepared via a thio "sol-gel" process using [Nb(SC(6)H(3)Me(2)-2,6)(5)] as the metal source. In contrast, vapor phase thin-film studies revealed that [Nb(SC(6)H(3)Me(2)-2,6)(5)] functions as a single-source precursor to NbS films. 相似文献
110.
Timothy S. Keizer Lauren J. De Pue Sean Parkin David A. Atwood 《Journal of Cluster Science》2002,13(4):609-620
Various Salen ligands (Salen(
t
Bu)H2=N, N-ethylenebis(3,5-di-tertbutyl(2-hydroxy)benzylidenimine) were used to prepare borosilyl and -O bridged borosilyl compounds having the formula, L{B(OSiMe3)2}2 (L=Salen(
t
Bu) (1), Salpen(
t
Bu) (2), Salben(
t
Bu) (3), Salhen(
t
Bu) (4) and L(BOSiMe3)2(-O) (L=Salen(
t
Bu) (5) and Salben(
t
Bu) (6)). In the case of 5 and 6 the formation of the B–O–B linkage takes precedence over the formation of a B–O–Si linkage. All of the compounds were characterized by Mp, elemental analysis, 1H and 11B NMR, IR, MS and in the case of 1, 2, and6 by X-ray crystallography. 相似文献