Search results for "Suzuki"
showing 10 items of 80 documents
Solid-state cis–trans isomerism in bis(oxamato)palladate(ii) complexes: synthesis, structural studies and catalytic activity
2014
A new generation of bis(oxamato)palladate(II) monomeric complexes has been prepared by using N-2,6-dimethylphenyloxamate (2,6-Me2pma) as the ligand. Four alkaline salts of the complex, namely {[Na(H2O)]2trans-[PdII(2,6-Me2pma)2]}n (1a), {[Na4(H2O)2]cis-[PdII(2,6-Me2pma)2]2}n (1b), {[K4(H2O)3]cis-[PdII(2,6-Me2pma)2]2}n (2), {[Rb4(H2O)3]cis-[PdII(2,6-Me2pma)2]2}n (3) and {[Cs6(H2O)7]trans-[PdII(2,6-Me2pma)2]2cis-[PdII(2,6-Me2pma)2]}n·3nH2O (4), were obtained and structurally characterized by single crystal X-ray diffraction. Both the cis and trans stereoisomers of the [PdII(2,6-Me2pma)2]2− complex anion were isolated in the solid state, in a cation-dependent manner. The trans-isomer as the so…
Synthesis and stereochemical properties of "extended" biphenols bridged by ortho-, meta-, and para-phenylene spacers
2009
A series of isomeric biphenols based on para- (1), meta- (2), and ortho- (3) terphenyl backbones was synthesized. Suzuki cross-coupling methodology was employed for the construction of the terphenyl backbone of their methyl-protected precursors (respectively 8, 13, and 16). Using K2CO3 as the base, the best reaction conditions involved DMF at 100 °C as solvent. Anhydrous conditions greatly improved the yields of the sterically crowded systems (particularly 16). ortho-Terphenyls 3 and 16 exist as mixtures of syn/anti atropisomers in solution. Compound 16 crystallizes in the anti-in form. DFT calculations at the B3LYP/6-311+G(d,p) level indicate that for both compounds the anti-in form is mor…
Evidences of release and catch mechanism in the Heck reaction catalyzed by palladium immobilized on highly cross-linked-supported imidazolium salts
2014
Abstract Palladium (10 wt%) on a highly cross-linked imidazolium-based material was used as catalyst in 0.1 mol% in the Heck reaction between several alkenes and aryl iodides. Products were obtained from good to high yields. Deeper investigations showed a release of Pd species in solution and their capture by the imidazolium-based support. When a sixfold amount of support was employed the re-captured Pd species (0.5–0.6 wt%) were not anymore catalytically active. This result represents a new interesting aspect of this work since the highly cross-linked imidazolium-based material can act also as Pd scavenger avoiding the release of the metal in solution. Important differences between Heck an…
Fixed point results on metric-type spaces
2014
Abstract In this paper we obtain fixed point and common fixed point theorems for self-mappings defined on a metric-type space, an ordered metric-type space or a normal cone metric space. Moreover, some examples and an application to integral equations are given to illustrate the usability of the obtained results.
Some new extensions of Edelstein-Suzuki-type fixed point theorem to G-metric and G-cone metric spaces
2013
Abstract In this paper, we prove some fixed point theorems for generalized contractions in the setting of G -metric spaces. Our results extend a result of Edelstein [M. Edelstein, On fixed and periodic points under contractive mappings, J. London Math. Soc., 37 (1962), 74–79] and a result of Suzuki [T. Suzuki, A new type of fixed point theorem in metric spaces, Nonlinear Anal., 71 (2009), 5313–5317]. We prove, also, a fixed point theorem in the setting of G -cone metric spaces.
Heterogeeniset katalyytit Suzuki-Miyaura -kytkennässä
2016
Suzuki-Miyaura kytkentä on yksi tärkeistä orgaanisen kemian työkaluista, jolla saadaan integroitua hiili-hiilisidoksia molekyyleihin. Tämä palladiumkatalysoitu reaktio on kiinnostanut tutkijoita sen helppouden ja käytännöllisyyden takia jo muutaman vuosikymmenen ajan. Reaktiossa on mahdollista käyttää mm. homogeenisiä katalyyttejä, eli katalyyttejä, jotka sekoittuvat reaktioseokseen eli ovat samassa faasissa (neste/neste) tai heterogeenisiä katalyyttejä, jotka eivät sekoitu reaktioseokseen eli ovat eri faaseissa (neste/kiinteä). Homogeeniset Pd-katalyytit ovat olleet käytössä pitkään mutta niiden käyttöä varjostaa mm. palladiumjäämät reaktioseokseen ja katalyytin erottamisen vaikeus samasta…
Jaunu tetratiafulvalēnu atvasinājumu sintēze
2019
Jaunu tetratiafulvalēnu atvasinājumu sintēze. Karpicka D., zinātniskais vadītājs Dr. Chem. Šubins K. Bakalaura darbs, 44 lappuses, 34 attēli, 3 tabulas, 36 literatūras avoti, 1 pielikumi. Latviešu valodā. Literatūras apskatā ir apkopota informācija par tetratiafulvalēnu atvasinājumu sintēzi, izmantojot palādija katalizētas šķērssametināšanas reakcijas, reakciju mehānismiem un visbiežāk izmantotiem reaģentiem. Bakalaura darbs ir veltīts jaunu tetratiafulvalēna atvasinājumu iegūšanai. Ir aprakstīti sintēžu mēginājumi un galvenās problēmas to veikšanā.
Palladium supported on Halloysite-triazolium salts as catalyst for ligand free Suzuki cross-coupling in water under microwave irradiation
2015
Abstract Environmental friendly halloysite-dicationic triazolium salts (second generation) obtained by subsequent click reactions of a diyne derivative in the presence of 2-azidopropyl-modified halloysite nanotubes, were used as supports for palladium catalyst. Thanks to the high triazolium loading (25%) these materials were able to support higher amount of the metal than that on the monocationic derivative (first generation). Such materials were characterized by thermogravimetric analysis, FT-IR spectroscopy and SEM investigations. The new catalytic system was employed in the ligand free Suzuki cross-coupling under microwave irradiation. A set of solvent, time and% loading of palladium was…
A new efficient, highly dispersed, Pd nanoparticulate silica supported catalyst synthesized from an organometallic precursor. Study of the homogeneou…
2018
[EN] A new Pd(0) catalyst supported on silica UVM-7 has been synthesized from the organometallic [Pd-2(mu-(C6H4) Pp(2))(2)(CH3CN)(4)](BF4)(2) precursor, characterized by the high dispersion, activity, and small size of the palladium nanoclusters fixed on the silica surface. The catalyst was tested for the Suzuki-Miyaura (SM) reaction of different 4-substitutedphenyl halides with phenylboronic acid. The kinetic study concurs with most of the catalytic action was carried out by Pd species originated by the partial solubilization of Pd immobilized on mesoporous silica. The Schmidt's analysis of differential selectivity (SADS) in several competitive SM reactions, together the STEM-HAADF and HRT…
Benzo[b]oksepīn-2(3H)-ona arilatvasinājumu sintēze
2018
Benzo[b]oksepīn-2(3H)-ona arilatvasinājumu sintēze. Pudnika L., zinātniskais vadītājs Dr. chem., vadošā pētniece Grandāne A., Dr. chem., asoc. prof. Prikšāne A. Bakalaura darbs, 43 lappuses, 22 attēli, 8 tabulas, 35 literatūras avoti. Latviešu valodā. Darbā tika sintezēti benzo[b]oksepīn-2(3H)-ona arilatvasinājumi. Sintezēto benzo[b]oksepīn-2(3H)-ona atvasinājumu struktūra tika pierādīta ar KMR spektroskopiju. Literatūras apskatā apkopota informācija par benzo[b]oksepīn-2(3H)-ona atvasinājumu sintēzes metodēm.