Electrochemical Study of Tricarbonyl(η6-cyclooctatetraene)metal(0) Complexes of the Group 6 Elements

1998 ◽  
Vol 53 (8) ◽  
pp. 875-880
Author(s):  
Giirkan Atinç Yilmaz ◽  
Ahmet M. Önal ◽  
Saim Özkar
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Supporting Electrolyte ◽  
Energy Levels ◽  
Dichloromethane Solution ◽  
Reduction Potentials ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Constant Potential ◽  
Uv Visible

Abstract Tricarbonyl(η6-cyclooctatetraene)metal(0) complexes of the group 6 elements were prepared by using the procedures described in the literature with some minor modifications and identi­fied by IR and NMR spectroscopy. Their electrochemical behavior was studied by using cyclic voltammetry in dichloromethane solution containing 0.1 M tetrabutylammonium tetrafiuorob-orate as supporting electrolyte. Their oxidation and reduction potentials were measured and discussed in terms of the frontier energy levels in connection with the UV-Visible electronic ab­ sorption spectral data. In order to elucidate the mechanism of electrooxidation of the complexes, constant potential electrolysis was performed for one representative example, tricarbonyl(η6-cyclooctatetraene)chromium(O). The IR monitoring of the reaction showed that it is gradually converted to hexacarbonylchromium(O) upon electrolysis at constant potential.

Spectroelectrochemical Investigation of Pentacarbonyl(pyrazine)metal(0) (Metal = Cr, Mo, W) Complexes of Group 6 Elements

2002 ◽  
Vol 57 (1) ◽  
pp. 92-98 ◽  
Author(s):  
Şeniz Özalp Yaman ◽  
Emren Esentürk ◽  
Ceyhan Kayran ◽  
Ahmet M. Önal
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behaviour ◽  
Reference Electrode ◽  
Constant Current ◽  
Oxidation Peak ◽  
Group 6 ◽  
Constant Potential ◽  
Electrochemical Mechanism ◽  
Temperature Constant

The electrochemical behaviour of pentacarbonyl(pyrazine)metal(0) complexes of the group 6 elements was studied by cyclic voltammetry in dichloromethane-(n-Bu)4NBF4 solventelectrolyte couple at -20°C vs. Ag/Ag+ or SCE reference electrode. Constant potential electrolyses of the complexes were carried out at their first oxidation peak potentials and monitored in situ by UV-Vis spectrometry. Electrolysis of W(CO)5pz produces [W(CO)5pz]+ and a similar electrochemical mechanism is expected both for Cr(CO)5pz and Mo(CO)5pz complexes. In situ low temperature constant current ESR electrolysis also confirmed the production of [W(CO)5pz]+ after the electron transfer.

Cycloaddition Reactions of (η6-Tropone)tricarbonylmetal(0) Complexes of Group 6 Metals with Alkynes

2002 ◽  
Vol 67 (11) ◽  
pp. 1635-1646
Author(s):  
Izzet Amour Morkan ◽  
Ayşe Uztetik Morkan
Keyword(s):  
Nmr Spectroscopy ◽  
Ammonium Nitrate ◽  
Crystalline Solids ◽  
Cycloaddition Reactions ◽  
Terminal Alkynes ◽  
Uv Photolysis ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Cerium Iv Ammonium Nitrate ◽  
And Tungsten

(η6-Cyclohepta-2,4,6-trien-1-one)tricarbonylmetal(0) complexes of chromium (2a), molybdenum (2b), and tungsten (2c) are formed when tris(acetonitrile)tricarbonylchromium(0), -molybdenum(0), and -tungsten(0), respectively, are treated photochemically with tropone (cyclohepta-2,4,6-trien-1-one) 1. UV photolysis of 2a-2c and RC≡CR' (R = R' = Ph, Me3Si, Et; R = Ph, R' = Me3Si) in toluene gives the [6+2] cycloadducts, (η4,η2-8,9-diphenylbicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 3a-3c, (η4,η2-8,9-bis(trimethylsilyl)bicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 4a-4c, (η4,η2-8,9-diethylbicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 5a-5c, and (η4,η2-8-phenyl-9-(trimethylsilyl)bicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 6a-6c. Compounds 2a-2c, 3a-3c, 4a-4c, 5a-5c, and 6a-6c were purified by chromatography, recrystallized and isolated as analytically pure crystalline solids in moderate yields and characterized by mass, IR, and NMR spectroscopy. Pure organic heterobicyclotriene ligands 7a, 8a, 9a, and 10a were isolated from 3a, 4a, 5a, and 6a, respectively, by treatment with cerium(IV) ammonium nitrate (R = R' = Me3Si; R = Ph, R' = Me3Si) or by heating in toluene (R = R' = Ph, Et). It was not possible to isolate the bicyclic complexes resulting from the reactions of 2a-2c with terminal alkynes like phenylacetylene.

Determination of Nanomaterial Energy Levels for Organic Photovoltaics by Cyclic Voltammetry

2007 ◽  
Vol 1031 ◽  
Author(s):  
Robert Ann DiLeo ◽  
Annick Anctil ◽  
Brian Landi ◽  
Cory Cress ◽  
Ryne P Raffaelle
Keyword(s):  
Cyclic Voltammetry ◽  
Polymer Composites ◽  
Organic Solar Cells ◽  
Energy Levels ◽  
Reduction Potentials ◽  
Fundamental Understanding ◽  
Cv Measurements ◽  
The Individual ◽  
The Relationship

AbstractA wide variety of nanomaterials and associated nanomaterial/polymer composites are being developed in an effort to produce higher efficiency organic solar cells. This development requires a fundamental understanding of the energy levels for the individual materials, and their composites, to enable device designs which posess appropriate energy level matching. Cyclic voltammetry (CV) allows for the determination of the band gaps (Eg) and energy levels of these various nanomaterials and composites by measuring their oxidation and reduction potentials. These potentials correspond to a given material's ionization potential (IP) and electron affinity (EA), respectively. The results for the EA, IP, and Eg have been determined by CV for derivatized fullerenes and CdSe quantum dots (QD), measured in isolation, and in conjugated polymer composites with MEH-PPV. In addition, CV measurements conducted under dark and illuminated conditions were used to investigate the relationship between energy levels within the composites.

Reaktionen von C(NMe2)4 mit Carbonylverbindungen der 6. Gruppe. Kristallstrukturen von [C(NMe2)3][(CO)5CrC(O)NMe2], [C(NMe2)3]2[Mo2(CO)10] und [C(NMe2)3][(CO)4Mo(O2CNMe2)] / Reactions of C(NMe2,)4 with Group 6 Carbonyl Compounds. Crystal Structures of [C(NMe2 )3 ][(CO)5 CrC(O)NMe2], [C(NMe2)3]2[Mo2(CO)10] and [C(NMe2)3][(CO)4 Mo(O2CNMe2)]

2001 ◽  
Vol 56 (3) ◽  
pp. 306-314 ◽  
Author(s):  
Wolfgang Petz ◽  
Bernhard Neumüller ◽  
Jörg Lorberth ◽  
Klaus Megges ◽  
Werner Massa
Keyword(s):  
Nmr Spectroscopy ◽  
Crystal Structures ◽  
Carbonyl Compounds ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Independent Molecules

Abstract The reaction of C(NMe2)4 (1) with M(CO)6 (M = Cr, W) in THF solution leads to the anionic carbamoyl complexes [C(NMe2)3][(CO)5MC(O)NMe2] (2a, M = Cr; 2c M = W). In the case of M = Mo the resulting complex 2b is not obtained; instead, the salts [C(NMe2)3]2[Mo2(CO)10] (3) and [C(NMe2)3][(CO)4Mo(O2CNMe2)] (4) are isolated. The crystal structures of 2a, 3, and 4 are presented. In the salt-like compounds no interatomic contacts between anion and cation exist, and the cations are disordered. The structure of 4 shows two independent molecules. The compounds were further characterized by IR and NMR spectroscopy.

Cyclic butadiyne-linked porphyrin(2.1.2.1) oligomers

2020 ◽  
Vol 24 (01n03) ◽  
pp. 489-497 ◽  
Author(s):  
Daiki Kuzuhara ◽  
Wataru Furukawa ◽  
Naoki Aratani ◽  
Hiroko Yamada
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Fluorescence Spectra ◽  
Theoretical Calculations ◽  
Cyclic Structure ◽  
Absorption And Fluorescence Spectra ◽  
H Nmr ◽  
Reduction Potentials ◽  
Cyclic Trimer ◽  
Tof Ms

Cyclic butadiyne-linked porphyrin(2.1.2.1) oligomers are synthesized from 5,16-diethynylporphyrin(2.1.2.1) by Glaser–Hay coupling. Porphyrin(2.1.2.1) forms a bent structure which gives advantages for making cyclic structure without templating molecules. We isolated cyclic trimer and tetramer and characterized them by MALDI-TOF-MS and [Formula: see text]H NMR spectroscopy, theoretical calculations, UV-vis absorption and fluorescence spectra and cyclic voltammetry. The cyclic structure mainly affects the reduction potentials because of expansion of [Formula: see text]-conjugations through butadiyne-linkages to stabilize their LUMOs.

Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles

2008 ◽  
Vol 59 (1) ◽  
pp. 41-44
Author(s):  
Maria-Daniela Sofei ◽  
Maria Ilici ◽  
Valentin Badea ◽  
Carol Csunderlik ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Ir And Nmr Spectroscopy

The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

TBAI Catalyzed Electrochemical C-H Bond Activation of 2-arylated-N-methoxyamides for the Synthesis of Phenanthridinones

Synlett ◽  
2021 ◽  
Author(s):  
Kripa Subramanian ◽  
Subhash L. Yedage ◽  
Kashish Sethi ◽  
Bhalchandra M. Bhanage
Keyword(s):  
Electrochemical Method ◽  
Bond Activation ◽  
Supporting Electrolyte ◽  
Bioactive Compound ◽  
Reaction Conditions ◽  
Redox Catalyst ◽  
Synthetic Utility ◽  
One Step ◽  
Constant Potential

An electrochemical method for the synthesis of phenanthridinones via constant potential electrolysis (CPE) mediated by <i>n</i>-Bu<sub>4</sub>NI (TBAI) has been reported. The protocol is metal and oxidant free and proceeds with 100% current efficiency. Here TBAI plays the dual role of the redox catalyst as well as supporting electrolyte. The intramolecular C-H activation proceeds under mild reaction conditions and short reaction time via electrochemically generated amidyl radicals. The reaction has been scaled up to gram level showing its practicability and the synthetic utility and applicability of the protocol has been demonstrated by the direct one-step synthesis of the bioactive compound Phenaglaydon.

scholarly journals Water-soluble β-aminobisulfonate building blocks for pH and Cu2+ indicators

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84712-84721 ◽  
Author(s):  
Maria A. Cardona ◽  
Marina Kveder ◽  
Ulrich Baisch ◽  
Michael R. Probert ◽  
David C. Magri
Keyword(s):  
Nmr Spectroscopy ◽  
Building Blocks ◽  
Water Soluble ◽  
Visible Absorption ◽  
H Nmr ◽  
Uv Visible

Two phenyl β-aminobisulfonate ligands characterised by UV-visible absorption, EPR and 1H NMR spectroscopy exhibit evidence for binding with Cu2+ in water and methanol.

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