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101.
In this report, we investigate the interactions of Me(x)MCl(3-x) (x = 0-3, M = Al, Ga) with various aromatic and alkyl-substituted 1,4-diaza-1,3-butadiene (R)DAB ligands (or α-diimine ligands) to give a variety of structures in solution and in the solid state. In combination with other previously reported structures, certain general trends of reactivity of these species can be deduced, although there are still some unexplained modes of reactivity. The methylated Al species react with aromatic-substituted (R)DAB ligands to provide final products that result from C═N insertion into the Al-CH(3) group followed by rearrangement reactions. The addition of methyl groups onto the backbone of the (R)DAB ligand is insufficient to stop the insertion and rearrangement processes from occurring. In the case of MeAlCl(2) with the bulky (DiPP)DAB ligand, the reaction could be followed spectroscopically from the monoadduct through the inserted/rearranged final product. Methylated Ga species, however, are much less predictable in their behavior with aromatic-substituted (R)DAB ligands. Depending on the exact species and ratios used, coordinated adducts can be formed and identified, or inserted/rearranged products similar to the aluminum reactions can be obtained. Quite interestingly, cation/anion pairs can also be formed in which GaCl(3) or MeGaCl(2) act as a chloride acceptors. This behavior was unique and substantially different from the analogous Al reactions which formed either a dicoordinated adduct or an inserted/rearranged complex. When the stronger-donating alkyl-substituted (R)DAB ligands were used with Me(2)GaCl, only cation/anion pairs were obtained. Surprisingly, when the same reactions were performed using Me(2)AlCl as a reagent, irreproducible results were obtained. 相似文献
102.
Long Giang BachMd. Rafiqul Islam Yeon Tae JeongYeong Soon Gal Kwon Taek Lim 《Applied Surface Science》2012,258(7):2816-2822
The synthesis of chemically anchored adenosine with biocompatible poly(2-hydroxylethyl methacrylate) grafted gold nanoparticles (Ado-i-PHEMA-g-AuNPs) was realized by employing a simple strategy. Disulfide-containing poly(2-hydroxylethyl methacrylate) (DT-PHEMA) was initially synthesized by atom transfer radical polymerization (ATRP). The formation of DT-PHEMA was confirmed by 1H-NMR and FT-IR. The molecular weight and molecular weight distribution were found to be 9.6 kg/mol and 1.40 from GPC analysis. DT-PHEMA was subsequently used for the synthesis of PHEMA-g-AuNPs by a grafting to protocol. The grafting of DT-PHEMA on the surface of AuNPs was confirmed by FT-IR, TGA, XPS, and EDX analyses. The particle size of the PHEMA-g-AuNPs was found to be ca. 5.0 nm from HR-TEM analysis. Boronic acid was used for functionalization of PHEMA-g-AuNPs, which was then subjected for covalent immobilization with adenosine via strong interaction between free hydroxyl groups of adenosine and boronic acid. Characterization and properties of the Ado-i-PHEMA-g-AuNPs were investigated by taking advantage from FT-IR, XPS, EDX, and UV-visible spectroscopy. The Ado-i-PHEMA-g-AuNPs nanocomposite exhibits a surface plasmon resonance peak at 586 nm which is red shifted from AuNPs (521 nm), indicating significant changes of surface property upon PHEMA-adenosine immobilization onto the surface of AuNPs. 相似文献
103.
An efficient method for ring-closing metathesis under solvent-free conditions and by microwave activation was established. Non-thermal microwave specific effects were evident. 相似文献
104.
Nguyen Tan Thanh Nguyen Ngoc Tuan Ping-Chung Kuo Doan Manh Dung Doan Lan Phuong Dinh Thi Truong Giang 《Natural product research》2018,32(20):2392-2397
A new tirucallane-type triterpenoid igniarine (1), and four known compounds meshimakobnol A (2), meshimakobnol B (3), ergosterol (4) and ergosterol peroxide (5), were purified from the methanol extracts of the fruiting bodies of Phellinus igniarius (DC. ex Fr.) Quél. The structure of 1 was elucidated using a combination of 1D and 2D NMR techniques and HR-ESI-MS analyses. In addition, the isolated compounds were examined for their cytotoxicity against several tumour cell lines and part of the tested compounds demonstrated weak cytotoxicity. 相似文献
105.
The synthesis of ortho-alkylated ketones through a chelation-assisted Rh (I) catalyzed ortho-alkylation reaction of aromatic imines under microwave activated solvent-free conditions in monomode reactors was performed. These conditions have been also applied to hydroacylation and ortho-alkylation reactions with aldimines. 相似文献
106.
Transport of tervalent REEs — Sc, Y, Ce, Eu, Gd, Tm, Yb — from nitrate medium through a liquid membrane containing TBP in n-dodecane, impregnated on a flat-sheet nucleoporous support, has been studied as a function of time and initial metal concentration, salting-out agent concentration and pH of the feed phase. Influences of various complexing agents dissolved in the strip phase was investigated, too. Adding a suitable amount of EDTA into the feed phase, separation of binary mixtures of REEs was experimentally achieved. 相似文献
107.
Significant improvements in the synthesis of pyrido-fused heterocycles were observed when performing the reaction under solvent-free conditions, applying the tert-amino effect as the key ring closure methodology. An unexpected cyclization of ortho-(1′-azacycloalkyl)benzaldehydes has been studied in water and on solid support. 相似文献
108.
Trung Ngo Viet 《Monatshefte für Mathematik》1980,90(4):331-337
The paper gives a criterion for Buchsbaum modules over a local ringR which depends only on a finite system of elements ofR. 相似文献
109.
Aphrons containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as an active substance were used for preconcentration of strontium from acetate buffers. Conditions for preparation of reasonably stable aphrons using non-ionic and anionic detergents in n-alkane and water mixture were found. After distribution of strontium, aphrons were separated from water solution by filtration with micro-filters. The separation efficiency was compared to the results obtained in liquid-liquid extraction of strontium with DEHPA in n-alkane. The results show that the preconcentration efficiency for strontium for aphrons is as good as for liquid-liquid extraction systems. 相似文献
110.
Twelve natural bis-spirolabdane-type diterpenoids, including eight new, named leoheteronones A-E, 15-epileoheteronones B, D, and E, and four known leopersin B, 15-epileopersin B, leopersin C, and 15-epileopersin C, together with hispanone and galeopsin were isolated from the aerial parts of the medicinal plant Leonurus heterophyllus SW. (Lamiaceae) grown in Vietnam. Their structures were determined by spectroscopic analyses. The current study emphasized the accumulation of C-15 oxygenated bis-spirolabdane-type diterpenoids of both 13R and 13S configurations in L. heterophyllus. 相似文献