Results 1 to 10 of about 370 (171)

The kerogen vanadyl porphyrins: Incorporation during catagenesis [PDF]

Journal of the Serbian Chemical Society, 1999
Natural vanadyl (VO 2+)-deoxophylloerythroetioporphyrins (DPEP) have been shown to be capable of reacting and quantitatively incorporating into immature kerogen model materials (torbanite, lignites, subbituminous coal and immature lacustrine ...
Premović Pavle I., Tonsa Ivana R., Đorđević Dragan M., Premović Miroslav P.   +3 more
doaj   +5 more sources

Air oxidation of the kerogen/asphaltene vanadyl porphyrins: An electron spin resonance study [PDF]

Journal of the Serbian Chemical Society, 2000
The thermal behavior of vanadyl porphyrins was studied by electron spin resonance during heating of kerogens, isolated from the La Luna (Venezuela) and Serpiano (Switzerland) bituminous rocks, at 250ºC for 1 to 20 days in the presence of air ...
Premović Pavle I., Tonsa Ivana R., Đorđević Dragan M., Pavlović Mirjana S.   +3 more
doaj   +5 more sources

Postdiagenetic Bacterial Transformation of Nickel and Vanadyl Sedimentary Porphyrins of Organic-Rich Shale Rock (Fore-Sudetic Monocline, Poland) [PDF]

Frontiers in Microbiology, 2021
Nickel and vanadyl porphyrins belong to the so-called fossil geo- or sedimentary porphyrins. They occur in different types of organic matter-rich sediments but mostly occur in crude oils and their source rocks, oil shales, coals, and oil sands.
Robert Stasiuk, Renata Matlakowska
doaj   +2 more sources

Radicals on the silica surface: probes for studying dynamics by means of fast field cycling relaxometry and dynamic nuclear polarization [PDF]

Magnetic Resonance Letters, 2023
Determining the dynamics of adsorbed liquids on nanoporous materials is crucial for a detailed understanding of interactions and processes on the solid-liquid interface in many materials and porous systems.
Bulat Gizatullin, Carlos Mattea, Siegfried Stapf   +2 more
doaj   +2 more sources

Magnetic expression in kerogen reveals impact on fluid transport [PDF]

Magnetic Resonance, 2022
How can the transport of fluids in a confined and complex mixed organic/inorganic matrix be far below the expected value from a topological aspect? A good example of this situation is oil shales.
B. Nicot, J.-P. Korb, I. Jolivet, H. Vezin, D. Gourier, A.-L. Rollet   +5 more
doaj   +2 more sources

ENDOR study of nitrogen hyperfine and quadrupole tensors in vanadyl porphyrins of heavy crude oil [PDF]

Magnetic Resonance in Solids, 2016
We report the observation of pulsed electron-nuclear double resonance (ENDOR) spectrum caused by interactions of the nitrogen nuclei 14N with the unpaired electron of the paramagnetic vanadyl complexes VO2+ of vanadyl porphyrins in natural crude oil.
Gracheva I.N., Gafurov M.R., Mamin G.V., Biktagirov T.B., Rodionov A.A., Galukhin A.V., Orlinskii S.B.
doaj   +3 more sources

Light-Activated Qubit Coupling in a Vanadyl Porphyrin Trimer. [PDF]

J Am Chem Soc
Molecules provide a modular and chemically tunable platform for quantum information science. In recent years, significant advances have been made in enabling optical spin initialization, coherent control, and both optical and electrical readout of molecular qubits.
Privitera A, Chiesa A, Santanni F, Ranieri D, Sahu PP, Krzyaniak MD, Caneschi A, Young RM, O Senge M, Totti F, Wasielewski MR, Carretta S, Sessoli R.   +12 more
europepmc   +3 more sources

V-Porphyrins Encapsulated or Supported on Siliceous Materials: Synthesis, Characterization, and Photoelectrochemical Properties. [PDF]

Materials (Basel), 2022
Metalloporphyrin-containing mesoporous materials, named VTPP@SBA, were prepared via a simple anchoring of vanadyl porphyrin (5,10,15,20-Tetraphenyl-21H,23H-porphine vanadium(IV) oxide) through a SBA-15-type mesoporous material.
Myltykbayeva ZK, Seysembekova A, Moreno BM, Sánchez-Tovar R, Fernández-Domene RM, Vidal-Moya A, Solsona B, López Nieto JM.   +7 more
europepmc   +2 more sources

Nutation Spectroscopy of a Weakly Interacting Heterobimetallic Spin System. [PDF]

Chemistry
An heterobimetallic VIV−CuII complex is synthesized by a modular process involving external coordination sites of a porphyrinato ligand and a PdII linker. Pulsed Electron Paramagnetic Resonance experiments, in particular spin nutation spectroscopy at variable microwave powers or magnetic fields, reveals weak but non‐negligible magnetic interactions and
Appleton JL, Le Breton N, Choua S, Ruppert R, Boudalis AK.   +4 more
europepmc   +2 more sources

Conclusive Insight into the Coordination Complexes of a Flexible Bis(β-diketonato) Ligand and Their Phase-Dependent Structure: A Multi-Technique Approach. [PDF]

Chemistry
Complexes of flexible bis(β‐diketonato) ligand bdhb2− are dimeric in the crystalline state but rearrange to monomeric in organic solution. The transformation, first detected on paramagnetic VO2+ and Co2+ derivatives, is conclusively proved through the preparation of diamagnetic [Zn2(bdhb)2(py)2] and its investigation by high‐resolution 1H NMR ...
Imperato M, Nicolini A, Mironova O, Benassi E, Demitri N, Gigli L, Mucci A, Cornia A.   +7 more
europepmc   +2 more sources