Cobalt(II) Porphyrins Supported on Crosslinked Polymer Matrix as Model Compounds

1999 ◽  
Vol 03 (04) ◽  
pp. 316-321 ◽  
Author(s):  
TESSYMOL MATHEW ◽  
SUNNY KURIAKOSE
Keyword(s):  
Electronic Properties ◽  
Polymer Matrix ◽  
Spectral Methods ◽  
Binding Capacity ◽  
Cobalt Complexes ◽  
Systematic Variation ◽  
Spectroscopic Methods ◽  
Model Compounds ◽  
Solid Polymers ◽  
Crosslinked Polymer

Polymer-bound cobalt(II) porphyrins were studied for their dioxygen—binding capacity. Tetra—aminoporphyrins were anchored on a divinylbenzene (DVB)-crosslinked chloromethyl polystyrene network. The crosslinked, solid polymers were swelled in chloroform and the swollen polymers were used for the entire studies. Ortho-, meta- and para-substituted porphyrin systems were developed by adjusting the bonding position with the help of suitably substituted aminoporphyrins. The products were characterized by chemical and spectroscopic methods. Cobalt(II) complexes of polymeric porphyrins were synthesized and characterized by electronic and ESR spectral methods. The spectra gave evidence for the systematic variation of electronic properties in ortho, meta and para compounds and for the dioxygen-binding capacity of cobalt complexes. These results are discussed.

Numerical Modeling of Macroscopic Behavior of Particulate Composite with Crosslinked Polymer Matrix

2011 ◽  
Vol 465 ◽  
pp. 129-132
Author(s):  
Luboš Náhlík ◽  
Bohuslav Máša ◽  
Pavel Hutař
Keyword(s):  
Young’S Modulus ◽  
Polymer Matrix ◽  
Young's Modulus ◽  
Numerical Models ◽  
Strain Curve ◽  
Particulate Composite ◽  
Material Behavior ◽  
Particulate Composites ◽  
Stress Strain ◽  
Crosslinked Polymer

Particulate composites with crosslinked polymer matrix and solid fillers are one of important classes of materials such as construction materials, high-performance engineering materials, sealants, protective organic coatings, dental materials, or solid explosives. The main focus of a present paper is an estimation of the macroscopic Young’s modulus and stress-strain behavior of a particulate composite with polymer matrix. The particulate composite with a crosslinked polymer matrix in a rubbery state filled by an alumina-based mineral filler is investigated by means of the finite element method. A hyperelastic material behavior of the matrix was modeled by the Mooney-Rivlin material model. Numerical models on the base of unit cell were developed. The numerical results obtained were compared with experimental stress-strain curve and value of initial Young’s modulus. The paper can contribute to a better understanding of the behavior and failure of particulate composites with a crosslinked polymer matrix.

A SERIES OF MODEL COMPOUNDS FOR THE STUDY OF AROMATIC REACTIONS

1965 ◽  
Vol 43 (2) ◽  
pp. 337-342
Author(s):  
S. Safe ◽  
R. Y. Moir
Keyword(s):  
Nitro Group ◽  
Systematic Variation ◽  
Model Compounds ◽  
Group A ◽  
Methylene Group

A series of halogenated phthalides was prepared in which there was a systematic variation in the identity, position, and degree of activation of the halogen, and in the activation of the methylene group. A study was made of the selective reductive removal of halogen in the presence of another halogen, or of a nitro group.

Structure and Content of Dicyclopentadiene in Ethylene Propylene Dicyclopentadiene Terpolymers

1967 ◽  
Vol 40 (2) ◽  
pp. 563-568
Author(s):  
R. J. de Kock ◽  
A. Veermans
Keyword(s):  
Double Bond ◽  
Polymer Chain ◽  
Spectroscopic Methods ◽  
Double Bonds ◽  
Model Compounds ◽  
Ethylene Propylene ◽  
Infrared Spectroscopic ◽  
Polymerization Mixture ◽  
Derivatives Of

Abstract With the aid of model compounds—derivatives of endo- and exo-dicyclopentadiene—it has been established that a) the 9, 10-double bond (the double bond in the norbornane ring) is involved in the polymerization of dicyclopentadiene with ethylene and propylene, b) dicyclopentadiene, present in the polymerization mixture in the endo-configuration, occurs in the exo-configuration in the polymer chain. The same model compounds enable the dicyclopentadiene content of ethylene propylene dicyclopentadiene terpolymers to be determined by infrared spectroscopic methods. Use is made of the 3045 cm−1 band, which is characteristic of endo-cyclic double bonds in five-membered rings.

Interactions of nitric oxide and organic nitroso compounds with metalloporphyrins and heme

2000 ◽  
Vol 04 (04) ◽  
pp. 354-357 ◽  
Author(s):  
GEORGE B. RICHTER-ADDO
Keyword(s):  
Nitric Oxide ◽  
Excited State ◽  
Electronic Properties ◽  
Ground State ◽  
Bond Formation ◽  
Metal Center ◽  
Nitroso Compounds ◽  
Model Compounds ◽  
Axial Ligands ◽  
Metal Nitrosyls

The chemistry of nitric oxide (NO) has taken on new dimensions since the discovery, about a decade ago, of a myriad of biological events that NO participates in. Many of the foundations of metal-NO chemistry were laid out earlier by inorganic chemists and biochemists investigating the structures and electronic properties of the heme-NO moiety or its model compounds. Certainly, the persistent work over the last three decades by chemists working with metal nitrosyls has paid off. Current areas of research in heme-NO chemistry include (i) how the NO group approaches and binds to the metal center (or how it dissociates from the metal center); (ii) the ground state and excited state geometries of the metal-NOfragment; (iii) effects of the trans axial ligands on NO orientation and/or dissociation; and (iv) N-N bond formation from NO molecules catalyzed by heme groups.

scholarly journals Imido Cobalt Complexes with Imidyl Character

2021 ◽  
Author(s):  
alexander Reckziegel ◽  
Manjinder Kour ◽  
Beatrice Battistella ◽  
Stefan Mebs ◽  
Katrin Beuthert ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
High Spin ◽  
Bond Activation ◽  
High Spin State ◽  
Cobalt Complexes ◽  
Spectroscopic Methods ◽  
Computational Studies ◽  
Ancillary Ligand ◽  
Unpaired Spin

We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L<sub>2</sub>)<sup>–</sup>, (L = N(Dipp)SiMe<sub>3</sub>), Dipp = 2,6-diisopropylphenyl) bearing very long Co–NAryl bonds of around 1.75 Å. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from C–H bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me<sub>3</sub>Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular C–H bond activation.<br>

scholarly journals Imido Cobalt Complexes with Imidyl Character

2021 ◽  
Author(s):  
alexander Reckziegel ◽  
Manjinder Kour ◽  
Beatrice Battistella ◽  
Stefan Mebs ◽  
Katrin Beuthert ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
High Spin ◽  
Bond Activation ◽  
High Spin State ◽  
Cobalt Complexes ◽  
Spectroscopic Methods ◽  
Computational Studies ◽  
Ancillary Ligand ◽  
Unpaired Spin

We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L<sub>2</sub>)<sup>–</sup>, (L = N(Dipp)SiMe<sub>3</sub>), Dipp = 2,6-diisopropylphenyl) bearing very long Co–NAryl bonds of around 1.75 Å. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from C–H bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me<sub>3</sub>Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular C–H bond activation.<br>

Sign in / Sign up

Export Citation Format

Share Document