Metallocene-catalyzed olefin polymerizations using triphenylcyclopropenium tetrakis(pentafluorophenyl)borate as the activator

2003 ◽  
Vol 81 (6) ◽  
pp. 758-763 ◽  
Author(s):  
Huiying Li ◽  
Douglas C Neckers
Keyword(s):  
Ethylene Polymerization ◽  
Bathochromic Shift ◽  
Propylene Polymerization ◽  
Styrene Polymerization ◽  
Coordination Polymerization ◽  
Polymerization Mechanism ◽  
H Nmr ◽  
Carbonium Ion ◽  
Vis Spectroscopy ◽  
Olefin Polymerizations

Triphenylcyclopropenium (TPCP) tetrakis(pentafluorophenyl)borate activates bis(cyclopentadienyl)dimethyl titanium resulting in a highly reactive initiating system for the polymerization of styrene. In contrast to triphenylmethyl tetrakis(pentafluorophenyl)borate which is quite active in the absence of the metallocene, TPCP borate shows no activity for styrene polymerization in the absence of bis(cyclopentadienyl)dimethyl titanium. TPCP is the most efficient activator in the carbonium ion – borate class. We propose, based on 1H NMR evidence that reaction of Cp2TiMe2 and TPCP borate leads to the formation of the cationic Ti complex [Cp2TiMe]+B(C6F5)4–. Evidence for the latter is also provided by UV–vis spectroscopy in that we found a bathochromic shift of the Cp2TiMe2 LMCT absorption band from 361 to 482 nm in CH2Cl2 and 487 nm in toluene, respectively. Thermal decomposition of the cationic complex [Cp2TiMe]+B(C6F5)4– leads to less activity. The systems are good catalysts for ethylene polymerization as well, but are less active when using propylene. A conventional Ziegler–Natta coordination polymerization mechanism accounts for ethylene and propylene polymerization while a carbocationic polymerization mechanism is proposed for styrene.Key words: triphenylcyclopropenium tetrakis(pentafluorophenyl)borate, bis(cyclopentadienyl)dimethyl titanium, activator, olefin polymerization.

scholarly journals Synthesis, Characterization, and BSA-Binding Studies of Novel Sulfonated Zinc-Triazine Complexes

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Nalin Abeydeera ◽  
Inoka C. Perera ◽  
Theshini Perera
Keyword(s):  
Bathochromic Shift ◽  
Binding Constants ◽  
Disodium Salt ◽  
Water Soluble ◽  
Disulfonic Acid ◽  
Binding Studies ◽  
H Nmr ◽  
Acid Sodium Salt ◽  
Vis Spectroscopy ◽  
Chemical Formulas

Four Zn(II) complexes containing a pyridyl triazine core (L1 = 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5′,5″-disulfonic acid disodium salt and L2 = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4′,4″-disulfonic acid sodium salt) were synthesized, and their chemical formulas were finalized as [Zn(L1)Cl2]·5H2O·ZnCl2 (1), [Zn(L1)2Cl2]·4H2O·2CH3OH (2), [Zn(L2)Cl2]·3H2O·CH3OH (3), and [Zn(L2)2Cl2] (4). The synthesized complexes are water soluble, making them good candidates for biological applications. All four complexes have been characterized by elemental analysis and 1H NMR, IR, and UV-Vis spectroscopy. The IR stretching frequency of N=N and C=N bonds of complexes 1–4 have shifted to lower frequencies in comparison with free ligands, and a bathochromic shift was observed in UV-Vis spectra of all four complexes. The binding studies of ligands and complexes 1–4 with bovine serum albumin (BSA) resulted binding constants (Kb) of 3.09 × 104 M−1, 12.30 × 104 M−1, and 16.84 × 104 M−1 for ferene, complex 1, and complex 2, respectively, indicating potent serum distribution via albumins.

Semi-Hydrogenated, Asymmetric Metallocene Catalysts for the Propylene Polymerization

2003 ◽  
Vol 58 (6) ◽  
pp. 533-538
Author(s):  
Martin Schloegla ◽  
Carsten Trolla ◽  
Ulf Thewaltb ◽  
Bernhard Riegera
Keyword(s):  
Molecular Weight ◽  
Elevated Temperatures ◽  
Catalyst Activity ◽  
Propylene Polymerization ◽  
Metallocene Catalysts ◽  
Polymerization Mechanism ◽  
X Ray ◽  
H Nmr

The hydrogenation of rac-[1-(9-η5-fluorenyl)-2-(5,6-cylopenta-2-methyl-1-η5-indenyl)ethane] metallocene dichlorides (1a: Zr, 1b: Hf) with PtO2/H2O/H2 is reported. The diastereoselective formation of exclusively rac-[1-(2,3,4,5,6,7,8,9-octahydro-η5-fluorenyl)-2-(2-methyl- 1,4,4a(R;S),5,6,7,7a(S;R),8-octahydro-s-η5-indacenyl)ethane]metallocene dichlorides (2a: Zr, 2b: Hf) was shown by 1H-NMR and by X-ray analysis of 2a. Both compounds were activated in situ with triisobutylaluminum/PhC+3 [B(C6F5)4]D and tested as catalysts in propylene polymerization reactions. Comparison to the non-hydrogenated complexes revealed a decrease in molecular weight of the polymer and in catalyst activity. Experiments at elevated temperatures resulted in a lower stereospecificity and reduced isotacticity values indicating a polymerization mechanism analogous to C2-symmetric catalysts.

Synthesis and spectral characterization of bis(β-diketonato)zirconium(IV) and -hafnium(IV) phthalocyaninates

2002 ◽  
Vol 06 (02) ◽  
pp. 114-121 ◽  
Author(s):  
L. A. Tomachynski ◽  
V. Ya. Chernii ◽  
S. V. Volkov
Keyword(s):  
Organic Solvents ◽  
Elemental Analysis ◽  
Central Atom ◽  
Spectral Characterization ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Cl Atoms

The reaction of PcMCl 2 ( M = Zr , Hf ) with β-diketones is reported. 1 H NMR and elemental analysis suggest the substitution of two Cl atoms for two β-diketone fragments takes place as a result of this reaction and the complexes PcM(β-dik)2 are formed. All obtained complexes are stable and highly soluble in most organic solvents. The data from 1 H and 19 F NMR, and UV-vis spectroscopy suggest the coordination of two β-diketone ligands in a cis geometry about the central atom of the macrocycle. It was shown bis(β-diketonato)zirconium(IV) and hafnium(IV) phthalocyanines containing β-diketones with donor or acceptor groups or with bulky substituents can be obtained.

Gemischte Alkalimetall-Oxidosulfidomolybdate A2[MoOxS4– x] (x = 1, 2, 3; A = K, Rb, Cs, NH4). Synthesen, Kristallstrukturen und Eigenschaften / Mixed Alkali Oxidosulfidomolybdates A2[MoOxS4−x] (x = 1, 2, 3; A = K, Rb, Cs, NH4).Synthesis, Crystal Structure and Properties

2012 ◽  
Vol 67 (2) ◽  
pp. 127-22
Author(s):  
Anna J. Lehner ◽  
Korina Kraut ◽  
Caroline Röhr
Keyword(s):  
Bathochromic Shift ◽  
Structure Type ◽  
Structure Theory ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Coordination Numbers ◽  
Preparation Conditions ◽  
Vis Spectroscopy ◽  
Type Orthorhombic

Mixed sulfido/oxidomolybdate anions [MoOxS4−x]2− (x = 1, 2, 3) have been prepared by passing H2S gas through a solution of oxidomolybdates. The alkali salts of K+, Rb+, Cs+, and NH+4 precipitate as crystalline salts from these solutions depending on the pH, the polarity of the solvent, the educt concentrations and the temperature. Their structures have been determined by means of X-ray single-crystal diffraction data. All trisulfidomolybdates A2[MoOS3] (A = NH4/K/Rb/Cs) are isotypic with the tetrasulfido salts, exhibiting the β -K2[SO4] type (orthorhombic, space group Pnma, Z = 4; for A = Rb: a = 940.62(4), b = 713.32(4), c = 1164.56(5) pm, R1 = 0.0281). In contrast, the disulfidomolybdates exhibit a rich crystal chemistry, forming three different structure types depending on the preparation conditions and the size of the A cation: All four cations form salts crystallizing with the (NH4)2[WO2S2] structure type (monoclinic, space group C2/c, Z = 4, for A = Rb: a = 1144.32(11), b = 732.60(4), c = 978.99(10) pm, β = 120.324(7)°, R1 = 0.0274). For the three alkali metal cations a second polymorph with a new structure type (monoclinic, space group P21/c, Z = 4) is observed in addition (for A = Rb: a = 674.83(2), b = 852.98(3), c = 1383.10(9) pm, β = 115.19(1)°, R1 = 0.0216). The cesium salt also crystallizes with a third modification of another new structure type (orthorhombic, space group Pbcn, Z = 4, a = 915.30(6), b = 777.27(7), c = 1120.02(7) pm, R1 = 0.0350). Only for K, an anhydrous monosulfidomolybdate could be obtained (K2[MoO4] structure type, monoclinic, space group C2/m, Z = 4, a = 1288.7(3), b = 615.7(2), c = 762.2(1) pm, β = 109.59(1)°, R1 = 0.0736). The intramolecular chemical bonding in the molybdate anions is discussed and compared with the respective vanadates. Hereby aspects like bond lengths, bond strengths and force constants derived from Raman spectroscopy, are taken into account. Especially for the polymorphic disulfido salts, in-depth analyses of the local coordination numbers and the packing of the ions are presented. The gradual bathochromic shift of the crystal color with increasing S content and increasing size of the counter cations A and molar volumes (for the polymorphic forms), respectively, is in accordance with the increase of the experimental (UV/Vis spectroscopy) and calculated (FP-LAPW band structure theory) band gaps.

scholarly journals Protected Gold Nanoparticles with Thioethers and Amines As Surrogate Ligands

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
M. Rafiq H. Siddiqui
Keyword(s):  
Gold Nanoparticles ◽  
Variable Temperature ◽  
Size Control ◽  
Analytical Techniques ◽  
High Resolution Electron Microscopy ◽  
Phase Method ◽  
Two Phase ◽  
H Nmr ◽  
Resolution Electron ◽  
Vis Spectroscopy

Dodecyl sulfide, dodecyl amine, and hexylamine were shown to act as surrogate ligands (L) via metastable gold nanoparticles. By collating analytical and spectroscopic data obtained simultaneously, empirical formula Au24L was assigned. These impurity-free nanoparticles obtained in near quantitative yields showing exceptional gold assays (up to 98%Au) were prepared by a modification of the two-phase method. Replacement reactions on the Au24L showed that Au:L ratios may be increased (up to Au55:L (L= (H25C12)2S)) or decreased (Au12:L (L= H2NC12H25and H2NC6H13)) as desired. This work encompassing the role of analytical techniques used, that is, elemental analysis, variable temperature1H NMR, FAB mass spectrometry, UV-Vis spectroscopy, thin film X-ray diffraction, and high-resolution electron microscopy (HREM) has implications in the study of size control, purity, stability, and metal assays of gold nanoparticles.

scholarly journals A multi-colorimetric probe to discriminate between heavy metal cations and anions in DMSO–H2O with high selectivity for Cu2+ and CN−: study of logic functions and its application in real samples

RSC Advances ◽  
2021 ◽  
Vol 11 (47) ◽  
pp. 29466-29485
Author(s):  
Eunike Hamukwaya ◽  
Johannes Naimhwaka ◽  
Veikko Uahengo
Keyword(s):  
Heavy Metal ◽  
Schiff Base ◽  
Reaction Mechanism ◽  
High Selectivity ◽  
Colorimetric Probe ◽  
Real Samples ◽  
Heavy Metal Cations ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Logic Functions

A ditopic multi-colorimetric probe based on the phenylpridyl-thioic moiety (EN) was synthesized via a Schiff base reaction mechanism and characterized using 1H NMR and UV-vis spectroscopy.

scholarly journals Experimental and Theoretical Studies of Novel Azo Benzene Functionalized Conjugated Polymers: In-vitro Antileishmanial Activity and Bioimaging

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Neetika Singh ◽  
Mohd. Arish ◽  
Prabhat Kumar ◽  
Abdur Rub ◽  
Ufana Riaz
Keyword(s):  
Atomic Orbital ◽  
Uv Spectra ◽  
Basis Set ◽  
Fluorescence Studies ◽  
H Nmr ◽  
Transmission Electron ◽  
B3lyp Method ◽  
Vis Spectroscopy ◽  
Experimental Findings

AbstractTo study the effect of insertion of azobenzene moiety on the spectral, morphological and fluorescence properties of conventional conducting polymers, the present work reports ultrasound-assisted polymerization of azobenzene with aniline, 1-naphthylamine, luminol and o-phenylenediamine. The chemical structure and polymerization was established via Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H-NMR) spectroscopy, while the electronic properties were explored via ultraviolet-visible (UV-vis) spectroscopy. Theoretical IR and UV spectra were computed using DFT/B3LYP method with 6–311G basis set while theoretical 1H-NMR spectra was obtained by gauge independent atomic orbital (GIAO) method. The theoretically computed spectra were found to be in close agreement with the experimental findings confirming the chemical as well as electronic structure of the synthesized polymers. Morphology was investigated by X-ray diffraction and transmission electron microscopy studies. Fluorescence studies revealed emission ranging between 530–570 nm. The polymers also revealed high singlet oxygen (1O2) generation characteristics. In-vitro antileishmanial efficacy as well as live cell imaging investigations reflected the potential application of these polymers in the treatment of leishmaniasis and its diagnosis.

Study on Host-Guest Inclusion Complexation of a Drug in Cucurbit [6]uril

2018 ◽  
Vol 232 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Kanak Roy ◽  
Subhadeep Saha ◽  
Biswajit Datta ◽  
Lovely Sarkar ◽  
Mahendra Nath Roy
Keyword(s):  
Surface Tension ◽  
Specific Conductivity ◽  
Inclusion Complexation ◽  
Conductivity Measurements ◽  
Saline Environment ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
The Stability ◽  
Ft Ir Spectroscopy

AbstractAssembly of pyridine-2-aldoxime drug with cucurbit [6]uril (CB[6]) has been investigated by1H-NMR and 2D-ROESY NMR, UV-Vis spectroscopy, FT-IR spectroscopy, surface tension and conductivity measurements in aqueous saline environment. The distinct cationic receptor feature and the cavity dimension of the CB[6] emphasize that the macro-cyclic host molecule remain as complex with the nerve stimulus drug molecule. The results obtained from surface tension and specific conductivity measurements suggest 1:1 inclusion complex formation between drug and CB[6]. The stability constant evaluated by UV-Vis spectroscopic approach is 2.21×105M−1at 298.15 K, which indicates that the complex is sufficiently stable at physiological temperature.

Lyotropic liquid crystalline phthalocyanines containing 4-((S)-3,7-dimethyloctyloxy)phenoxy moieties

2017 ◽  
Vol 21 (01) ◽  
pp. 16-23 ◽  
Author(s):  
Sibel Eken Korkut ◽  
Hale Ocak ◽  
Belkıs Bilgin-Eran ◽  
Dilek Güzeller ◽  
M. Kasım Şener
Keyword(s):  
Liquid Crystalline ◽  
Spectroscopic Properties ◽  
The Novel ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
Ft Ir ◽  
Aggregation Behaviors ◽  
Mesomorphic Properties ◽  
Thermotropic Liquid Crystalline Behavior

The novel metal free phthalocyanine and its copper complex which are octa-substituted at the peripheral positions with 4-(([Formula: see text]-3,7-dimethlyoctyloxy)phenoxy moieties were synthesized and characterized by FT-IR, 1H NMR and mass spectroscopy. Their mesomorphic properties were studied by polarizing optical microscopy. The spectroscopic properties and aggregation behaviors of the novel phthalocyanines were also investigated by UV-vis spectroscopy in different solvents with same concentration as well as in a wide range of concentrations of chloroform. Both compounds with chloroform and [Formula: see text]-dodecane clearly show the lyotropic columnar mesophase in a wide temperature range whereas thermotropic liquid crystalline behavior for both compounds is not observed. Both of these novel compounds show no aggregation in toluene, tetrahydrofuran, dichloromethane and chloroform.

Synthesis, in vitro inhibition effect of novel phthalocyanine complexes as carbonic anhydrase and paraoxonase enzyme inhibitors

2020 ◽  
Vol 24 (08) ◽  
pp. 1047-1053
Author(s):  
Emre Güzel ◽  
Barış Seçkin Arslan ◽  
Kübra Çıkrıkçı ◽  
Adem Ergün ◽  
Nahit Gençer ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Enzyme Inhibitors ◽  
Inhibition Effect ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
First Time ◽  
Ft Ir Spectroscopy ◽  
C Nmr

The preparation and assessment of carbonic anhydrase and paraoxonase enzyme inhibition properties of 3-(2-(5-amino-4-(4-bromophenyl)-3-methyl-1H-pyrazol-1-yl)ethoxy)phthalonitrile (2) and its nitrogen-containing non-peripheral phthalocyanine derivatives (3 and 4) are reported for the first time. The new phthalonitrile and its phthalocyanine derivatives have been elucidated by FT-IR spectroscopy, 1H-NMR, [Formula: see text]C-NMR, mass and UV-vis spectroscopy. The results demonstrated that all synthesized compounds moderately inhibited carbonic anhydrase and paraoxonase enzymes. Among the compounds, the most active ones were found to be compound 4 for PON (Ki : 0.14 [Formula: see text]M), compound 3 for hCA I (Ki : 22.52 [Formula: see text]M) and compound 1 for hCA II (Ki : 13.62 [Formula: see text]M).

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