Search results for "kompleksi"
showing 10 items of 201 documents
Catalytic epoxidation using dioxidomolybdenum(VI) complexes with tridentate aminoalcohol phenol ligands
2019
Reaction of the tridentate aminoalcohol phenol ligands 2,4-di-tert-butyl-6-(((2 hydroxyethyl)(methyl)amino)methyl)phenol (H2L1) and 2,4-di-tert-butyl-6-(((1-hydroxybutan-2-yl)amino)methyl)phenol (H2L2) with [MoO2(acac)2] in methanol solutions resulted in the formation of [MoO2(L1)(MeOH)] (1) and [MoO2(L2)(MeOH)] (3), respectively. In contrast, the analogous reactions in acetonitrile afforded the dinuclear complexes [Mo2O2(μ-O)2(L1)2] (2) and [Mo2O2(μ-O)2(L2)2] (4). The corresponding reactions with the potentially tetradentate ligand 3-((3,5-di-tert-butyl-2-hydroxybenzyl)(methyl)amino)propane-1,2-diol (H3L3) led to the formation of the mononuclear complex [MoO2(L3)(MeOH)] (5) in methanol whi…
Interactions of a Diplumbyne with Dinuclear Transition Metal Carbonyls to Afford Metalloplumbylenes
2020
The metathesis reactions of the diplumbyne AriPr6PbPbAriPr6 (AriPr6 = −C6H3–2,6-(C6H2–2,4,6-iPr3)2) with the dinuclear metal carbonyls Mn2(CO)10, Fe2(CO)9, and Co2(CO)8 under mild conditions afforded the complexes Mn(CO)5(PbAriPr6) (1), Fe(CO)4(PbAriPr6)2 (2), and Co4(CO)9(PbAriPr6)2 (3), respectively. Complexes 1–3 were structurally characterized by single-crystal X-ray diffraction and spectroscopically characterized by 1H, 13C{1H}, 59Co{1H}, and 207Pb{1H} NMR; UV–vis; and IR methods. They are rare examples of species formed by the direct reaction of a group 14 dimetallyne with transition metal carbonyls. Complexes 1 and 2 feature Mn–Pb or Fe–Pb single bonds, whereas in 3 a Co–Pb cluster i…
Halogen bonds in 2,5-dihalopyridine-copper(II) chloride complexes
2018
Ten coordination complexes obtained through a facile reaction between 2,5-dihalopyridines and copper(II) chloride (CuCl2) are characterized using single crystal X-ray diffraction. Two series of dihalopyridine complexes based on 2-chloro-5-X-pyridine and 2-bromo-5-X-pyridine (X = F, Cl, Br and I) were prepared to analyze the C–X2/X5⋯Cl–Cu halogen bonds (XB). The influence of X2- and X5-substituents on the respective interactions was examined by comparing them to the X2/X3⋯Cl–Cu XBs found in mono-substituted halopyridine complexes, (n-X-pyridine)2·CuCl2 (n = 2, 3 and X = Cl, Br and I). Varying the X5-halogens in (2,5-dihalopyridine)2·CuCl2, the C5–X5⋯Cl–Cu XBs follow the order F5 1 and they c…
Effects of Remote Ligand Substituents on the Structures, Spectroscopic, and Magnetic Properties of Two-Coordinate Transition-Metal Thiolate Complexes
2018
The first-row transition-metal(II) dithiolates M(SAriPr4)2 [AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2; M = Cr (1), Mn (3), Fe (4), Co (5), Ni (6), and Zn (7)] and Cr(SArMe6)2 [2; ArMe6 = C6H3-2,6-(C6H2-2,4,6-Me3)2] and the ligand-transfer reagent (NaSAriPr4)2 (8) are described. In contrast to their M(SAriPr6)2 (M = Cr, Mn, Fe, Co, Ni, and Zn; AriPr6 = C6H3-2,6-(C6H2-2,4,6-iPr3)2) congeners, which differ from 1 and 3-6 in having p-isopropyl groups on the flanking aryl rings of the terphenyl substituents, compounds 1 and 4-6 display highly bent coordination geometries with S-M-S angles of 109.802(2)° (1), 120.2828(3)° (4), 91.730(3)° (5), and 92.68(2)° (6) as well as relatively close metal-flanking …
Enantiomeric Resolution of Asymmetric-Carbon-Free Binuclear Double-Stranded Cobalt(III) Helicates and Their Application as Catalysts in Asymmetric Re…
2018
A series of double-stranded binuclear helicates [Co2(H1)2]4+, [Co2(H2)2]4+, and [Co2(H3)2]4+, derived from monodeprotonated bis-pyridyl hydrazine-based ligands of H21, H22, and H23 with one, two, and three -CH2 spacers, were obtained. These asymmetric-carbon-free racemic helicates were separated into their ΔΔ and ΛΛ enantiomers. The resolved helicates were examined for the first time as enantioselective catalysts in asymmetric benzoylation and nitroaldol reactions.
Room-Temperature Phosphorescence and Efficient Singlet Oxygen Production by Cyclometalated Pt(II) Complexes with Aromatic Alkynyl Ligands
2020
The synthesis of five novel cyclometalated platinum(II) compounds containing five different alkynyl-chromophores was achieved by the reaction of the previously synthesized Pt–Cl cyclometalated compound (1) with the corresponding RC≡CH by a Sonogashira reaction. It was observed that the spectral and photophysical characteristics of the cyclometalated platinum(II) complexes (Pt–Ar) are essentially associated with the platinum-cyclometalated unit. Room-temperature emission of the Pt–Ar complexes was attributed to phosphorescence in agreement with DFT calculations. Broad nanosecond (ns)-transient absorption spectra were observed with decays approximately identical to those obtained from the emi…
NIR-absorbing transition metal complexes with redox-active ligands
2020
Bench top stable transition metal (M = Co, Ni, Cu) complexes with a non-innocent ortho-aminophenol derivative were synthesized by the reaction of metal(II)acetates with a ligand precursor in 2:1 ratio. The solid-state structures reveal the formation of neutral molecular complexes with square planar coordination geometries. The Co(II) and Cu(II) complexes are paramagnetic, whereas the Ni complex is a diamagnetic square planar low-spin Ni(II) complex. All complexes, and Ni(II) complex in particular, show strong absorption in the near-IR region. Peer reviewed
Powered by assemblage : language for multiplicity
2021
Abstract Assemblage is one way to examine complexities in today’s world. In Deleuzian thinking, assemblage refers to both the act of assembling diverse elements and the arrangements of these elements for a specific purpose. Importantly, it is the interaction between elements that allows the assemblage to become more than the sum of its parts. Applying this concept to long-term research on Cold Rush – the transformation of the Arctic commons into commodities – I argue that examining the boom, bust, and buzz around the commons can be fruitfully conceptualised and studied with assemblage. This approach brings with it an ontological shift from binaries into multiplicities and multiple temporali…
Infekcija un imunitāte
1931
Nodaļas: I. Infekcija 1. Mācība par infekciju savā attīstības gaitā 2. Infekcijas slimību vispārējais raksturojums 3. Sīkbūtnes, kā infekciju slimība cēloņi, un viņu darbības veids organismā 4. Patogēno mikrobu virulence (patogenitāte) 5. Infekcijas slimību izplatīšanās un pielipšanas veidi 6. Infekcijas slimību dīgļu iekļūšanas ceļi organismā 7. Pašinfekcija 8. Jauktā un sekundārā infekcija 9. Inkubācijas laiks 10. Infekcijas dīgļu un viņu kaitīgo vielu izplatīšanās veidi organismā 11. Patogēnās sīkbūtnes II. Imunitāte 1. Organisma aizsargu un cīņas līdzekļi pret infekciju 2. Pretvielu rašanās 3. Antitoksīni 4. Aglutinīni 5. Precipitīni 6. Lizīni 7. Oposinini un bakteriotropini 8. Ehrlicha…
Ketonu asimetriskā pārneses hidrogenēšana rutēnija(II) katalizatoru klātbūtnē
2016
Ketonu asimetriskā pārneses hidrogenēšana rutēnija(II) katalizatoru klātbutnē. Kvasovs Ņ., zinātniskais vadītāji: mag. ķīm. Jurijs Ponomarjovs, Dr. ķīm. Jāzeps Logins. Bakalaura darbs, 52 lappuses, 39 attēli, 25 literatūras avoti, 33 pielikumi. Latviešu valodā. Literatūras apskatā ir veikta jaunāko informācijas avotu izpēte par asimetrisko pārneses hidrogenēšanu. Uzmanība galvenokārt ir veltīta metodes vispārīgam raksturojumam, teorētiskajām pamatojumam, eksperimentālajai realizācijai. Ir raksturoti katalizatori, to vispārīga struktūra, daudzveidība un izmantošanas iespējas. Eksperimentālajā daļā tika sintezēti jauni potenciāli ligandi rutēnija(II) katalizatoriem. Iegūtie ligandi tika lieto…