Tags:
Catalysis,
Organic chemistry,
Energy,
SMN,
Chemistry
Publications
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Rasheed, Mouhammad Abu; Cao, Ning; Gerz, Isabelle; Deplano, G.; Signorile, M. & Flores, Ainara Nova
[Show all 13 contributors for this article]
(2026).
Unraveling cyclohexane peroxidation pathways over a pMMO-inspired Cu-N4 complex: combined experimental and computational study.
Journal of Catalysis.
ISSN 0021-9517.
457.
doi:
10.1016/j.jcat.2026.116813.
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The reactivity of a Cu–N4 complex with an imidazole-based ligand, inspired by the mono-CuB site suggested for particulate methane monooxygenase (pMMO), has been studied by catalytic testing, UV–Vis and XAS spectroscopies and DFT methods. The Cu–N4 complex was synthesized in Cu(I) and Cu(II) initial oxidation states, referred to as 1 and 2, respectively. Both were tested for cyclohexane (CyH) oxidation in acetonitrile (MeCN) at 25 °C and ambient pressure, using H2O2 as co-substrate. 1 showed higher activity in CyH oxidation than 2, with both forming cyclohexyl hydroperoxide (Cy–OOH) as the main product. In situ ultraviolet–visible (UV–Vis) and X-ray absorption (XAS) spectroscopies support a Cu(I)/Cu(II) redox cycle triggered by the excess amount of H2O2. Starting from 2, a slow reduction to Cu(I) and distinct Cu(II) signals, compared to those observed with 1, were detected using operando UV–Vis spectroscopy. Density functional theory (DFT) results suggest both Fenton- (via •OH and •OOH) and Cu(II)–oxyl-mediated reactions from 1 leading to C–H oxidation and H2O2 disproportionation. Kinetic data at 30 min of reaction indicate a ∼1st order reactivity with respect to H2O2 and Cu concentrations, and a fractional (∼0.5) order with respect to CyH, in line with the mechanism proposed by DFT calculations. These reaction orders change at 240 min of reaction, indicating catalyst decomposition by ligand oxidation, hydrolysis, or aggregation. This study highlights the importance of preventing the reaction of Cu(II)–oxyl with H2O2 and Fenton-type chemistry for efficient and selective oxidation of C–H to alcohol, providing hints for further catalyst design.
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Gerz, Isabelle; Aunan, Erlend; Finelli, Valeria; Rasheed, Mouhammad Abu; Deplano, Gabriele & Pupo, Rafael Cortez Sgroi
[Show all 15 contributors for this article]
(2024).
Enabling a bioinspired N,N,N-copper coordination motif through spatial control in UiO-67: synthesis and reactivity.
Dalton Transactions.
ISSN 1477-9226.
53,
p. 8141–8153.
doi:
10.1039/d3dt03096b.
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Metal–organic frameworks (MOFs) featuring zirconium-based clusters are widely used for the development of functionalized materials due to their exceptional stability. In this study, we report the synthesis of a novel N,N,N-ligand compatible with a biphenyl dicarboxylic acid-based MOF. However, the resulting copper(I) complex exhibited unexpected coordination behaviour, lacking the intended trifold coordination motif. Herein, we demonstrate the successful immobilization of a bioinspired ligand within the MOF, which preserved its crystalline and porous nature while generating a well-defined copper site. Comprehensive spectroscopic analyses, including X-ray absorption, UV/Vis, and infrared spectroscopy, were conducted to investigate the copper site and its thermal behaviour. The immobilized ligand exhibited the desired tridentate coordination to copper, providing access to a coordination motif otherwise unattainable. Notably, water molecules were also found to coordinate to copper. Upon heating, the copper centre within the MOF exhibited reversible dehydration, suggesting facile creation of open coordination sites. Furthermore, the copper site displayed reduction at elevated temperatures and subsequent susceptibility to oxidation by molecular oxygen. Lastly, both the molecular complexes and the MOF were evaluated as catalysts for the oxidation of cyclohexane using hydrogen peroxide. This work highlights the successful immobilization of a bioinspired ligand in a zirconium-based MOF, shedding light on the structural features, thermal behaviour, and catalytic potential of the resulting copper sites.
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Gerz, Isabelle; Jannuzzi, Sergio Augusto Venturinelli; Hylland, Knut Tormodssønn; Negri, Chiara; Wragg, David Stephen & Øien-Ødegaard, Sigurd
[Show all 10 contributors for this article]
(2021).
Structural Elucidation, Aggregation, and Dynamic Behaviour of N,N,N,N-Copper(I) Schiff Base Complexes in Solid and in Solution: A Combined NMR, X-ray Spectroscopic and Crystallographic Investigation.
European Journal of Inorganic Chemistry (EurJIC).
ISSN 1434-1948.
doi:
10.1002/ejic.202100722.
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A series of Cu(I) complexes of bidentate or tetradentate Schiff base ligands bearing either 1-H-imidazole or pyridine moieties were synthesized. The complexes were studied by a combination of NMR and X-ray spectroscopic techniques. The differences between the imidazole- and pyridine-based ligands were examined by 1H, 13C and 15N NMR spectroscopy. The magnitude of the 15Nimine coordination shifts was found to be strongly affected by the nature of the heterocycle in the complexes. These trends showed good correlation with the obtained Cu−Nimine bond lengths from single-crystal X-ray diffraction measurements. Variable-temperature NMR experiments, in combination with diffusion ordered spectroscopy (DOSY) revealed that one of the complexes underwent a temperature-dependent interconversion between a monomer, a dimer and a higher aggregate. The complexes bearing tetradentate imidazole ligands were further studied using Cu K-edge XAS and VtC XES, where DFT-assisted assignment of spectral features suggested that these complexes may form polynuclear oligomers in solid state. Additionally, the Cu(II) analogue of one of the complexes was incorporated into a metal-organic framework (MOF) as a way to obtain discrete, mononuclear complexes in the solid state.
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Rotunno, Giuseppe; Kaur, Gurpreet; Lazzarini, Andrea; Buono, Carlo & Amedjkouh, Mohamed
(2021).
Symmetry Breaking and Autocatalytic Amplification in Soai Reaction Confined within UiO-MOFs under Heterogenous Conditions.
Chemistry - An Asian Journal.
ISSN 1861-4728.
16(16),
p. 2361–2369.
doi:
10.1002/asia.202100419.
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Symmetry breaking is observed in the Soai reaction in a confinement environment provided by zirconium-based UiO-MOFs used as crystalline sponges. Subsequent reaction of encapsulated Soai aldehyde with Zn(i-Pr)2 vapour promoted absolute asymmetric synthesis of the corresponding alkanol. ATR-IR and NMR confirm integration of aldehyde into the porous material, and a similar localization of newly formed chiral alkanol after reaction. Despite the confinement, the Soai reaction exhibits significant activity and autocatalytic amplification. Comparative catalytic studies with various UiO-MOFs indicate different outcomes in terms of enantiomeric excess, handedness distribution of the product and reaction rate, when compared to pristine solid Soai aldehyde, while the crystalline MOF remains highly stable to action of Zn(iPr)2 vapour. This is an unprecedented example of absolute asymmetric synthesis using MOFs.
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Thoresen, Eirik Mydske; Øien-Ødegaard, Sigurd; Kaur, Gurpreet; Tilset, Mats; Lillerud, Karl Petter & Amedjkouh, Mohamed
(2020).
Strongly visible light-absorbing metal-organic frameworks functionalized by cyclometalated ruthenium(ii) complexes.
RSC Advances.
10(15),
p. 9052–9062.
doi:
10.1039/c9ra06984d.
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Four different ruthenium(II) complexes were incorporated into the metal–organic framework (MOF) UiO-67 using three different synthetic strategies: premade linker synthesis, postsynthetic functionalization, and postsynthetic linker exchange. One of these complexes was of the type (N–N)3Ru2+, and three of the complexes were of the type (N–N)2(N–C)Ru+, where N–N is a bipyridine-type ligand and N–C is a cyclometalated phenylpyridine-type ligand. The resulting materials were characterized by PXRD, SC-XRD (the postsynthetic functionalization MOFs), N2 sorption, TGA-DSC, SEM, EDS, and UV-Vis spectroscopy, and were digested in base for subsequent 1H NMR analysis. The absorption profiles of the MOFs that were functionalized with cyclometalated Ru(II) complexes extend significantly further into the visible region of the spectrum compared to the absorption profiles of the MOFs that were functionalized with the non-cyclometalated reference, (N–N)3Ru2+.
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Romagnoli, Carlo; Sieng, Bora & Amedjkouh, Mohamed
(2020).
Kinetic relationship in parallel autocatalytic amplifications of pyridyl alkanol and chiral trigger pyrimidyl alkanol.
Chirality.
ISSN 0899-0042.
32(9),
p. 1143–1151.
doi:
10.1002/chir.23256.
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Experimental and kinetic analysis of a chemical system combines autocatalytic amplification of 2‐alkynyl‐5‐pyrimidyl alkanol 2 and 6‐alkynyl‐3‐pyridyl akanol 4 in which 2 acts as a chiral trigger and 4 being the subsequent autocatalyst. Starting from a very low initial ee, both alkanols are produced with high enantiopurity in one single cycle. This provides insight into a dual nonlinear amplification of chirality observed with amplifying trigger 2 and accelerated amplification of autocatalyst 4. These kinetic studies reveal a five‐fold magnitude superior amplification rates of 4 associated with trigger's enantiopurity at the outset.
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Rotunno, Giuseppe; Petersen, Dirk & Amedjkouh, Mohamed
(2020).
Absolute Autocatalytic Amplification under Heterogenous Phase Conditions Involving Subsequent Hydride Transfer and a Hemiacetal Intermediate.
ChemSystemsChem.
2(5).
doi:
10.1002/syst.201900060.
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In contrast to the homogenous phase, absolute asymmetric amplification of pyridine alkanol is observed under heterogenous conditions. The reaction of iPr2Zn vapor on a solid powder of pyridine carbaldehyde induced autocatalytic
amplification of chirality providing the alkanol product with an enantiopurity up to 90 % ee. In this study, side products were identified and their formation is traced back to redox pathways involving hydride transfer, namely a chiral ester resulting most probably from a disproportionation of the starting aldehyde into a hemiacetal and subsequent hydride loss following a Claisen-Tishchenko mechanism. These observations provide new perspectives in the elucidation of the mechanism of
amplification of chirality in the Soai reaction.
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Wåhlander, Jakob Karl Kristoffer; Amedjkouh, Mohamed & Balcells, David
(2019).
A DFT Perspective on Diels-Alder Organocatalysts Based on Substituted Phosphoramides.
European Journal of Organic Chemistry.
ISSN 1434-193X.
2019(2-3),
p. 442–450.
doi:
10.1002/ejoc.201800844.
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Phosphoramides are an interesting alternative to the thiourea motif that has long been used in organocatalysis. In the R1N(H)-P(O)(R3)-N(H)R2 formulation, phosphoramides give the advantage of having a third variable substituent, R3, compared to the two available in thioureas, and the possibility of introducing chirality with an asymmetric phosphorous center. In this work, we present a systematic computational study on the catalytic properties of these underexplored compounds. These studies show the catalytic potential of a series of substituted phosphoramides in Diels-Alder reactions, including the asymmetric [4+2] cycloaddition of pro-chiral substrates. The nature of the phosphorous-bound R3 substituent has a significant impact both on catalytic activity and enantioselectivity. Remarkably, several of the phosphoramides studied are predicted to be more active than the Schreiner’s thiourea organocatalyst.
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Wåhlander, Jakob Karl Kristoffer; Amedjkouh, Mohamed & Gundersen, Lise-Lotte
(2019).
Synthesis directed towards trans-clerodanes employing an exo-selective Diels Alder reaction as a key-step.
Monatshefte für Chemie.
ISSN 0026-9247.
150(1),
p. 49–58.
doi:
10.1007/s00706-018-2277-9.
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A potential intermediate in the synthesis of several trans-clerodane natural products has been constructed employing a Diels Alder reaction as a key-step. Two epimeric exo adducts were formed in a 4:3 ratio in an EtAlCl2 mediated cycloaddition of O-silylated 2-vinylcyclohex-2-enol and N-tigloylisoxazolidinone. Both isomers were converted to the trans-clerodane intermediate in four steps; reductive removal of the oxazolidinone, followed by O-benzylation, removal of the silyl protecting group and finally a Dess-Martin oxidation of the deprotected alcohol to the corresponding ketone. It was possible to transform both isomers from the cycloaddition into the final target, but the major isomer was converted at greater yields. An interesting discovery made during the work was that the desilylation demanded significantly different conditions depending on which isomer was deprotected. The fact that the cycloaddition not only resulted in an excellent exo selectivity, but also that the alkene to a large extent approached from the least hindered side, opens the possibility for enantioselective synthesis of the target compound from (R) or (S) diene starting materials in the future.
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Thoresen, Eirik Mydske; Balcells, David; Øien-Ødegaard, Sigurd; Hylland, Knut Tormodssønn; Tilset, Mats & Amedjkouh, Mohamed
(2018).
Cyclometalated Ruthenium Complexes with Carboxylated Ligands from a Combined Experimental/Computational Perspective.
Dalton Transactions.
ISSN 1477-9226.
47(8),
p. 2589–2601.
doi:
10.1039/c7dt03935b.
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Sieng, Bora; Maldonado, Matias Funes; Romagnoli, Carlo & Amedjkouh, Mohamed
(2018).
One-Pot Alkynylation of Azaaryl Aldehydes and Spontaneous Base-Free Rearrangement into Enone Esters: an Autoinductive Mechanism.
European Journal of Organic Chemistry.
ISSN 1434-193X.
2018(12),
p. 1491–1495.
doi:
10.1002/ejoc.201701566.
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Maldonado, Matias Funes; Sieng, Bora & Amedjkouh, Mohamed
(2016).
Asymmetric autocatalysis as a relay for remote amplification of chirality of target molecules used as triggers.
Organic Letters.
ISSN 1523-7060.
18(11),
p. 2536–2539.
doi:
10.1021/acs.orglett.6b00742.
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Fredriksen, Kim Alex & Amedjkouh, Mohamed
(2016).
Investigation of reactive intermediates and reaction pathways in the coupling agent mediated phosphonamidation reaction.
European Journal of Organic Chemistry.
ISSN 1434-193X.
2016(3),
p. 474–482.
doi:
10.1002/ejoc.201501244.
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Maldonado, Matias Funes; Sieng, Bora & Amedjkouh, Mohamed
(2015).
Enabling asymmetric alkynylation of azaaryl aldehydes with soai autocatalyst.
European Journal of Organic Chemistry.
ISSN 1434-193X.
2015(19),
p. 4081–4086.
doi:
10.1002/ejoc.201500507.
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Romagnoli, Carlo; Sieng, Bora & Amedjkouh, Mohamed
(2015).
Asymmetric Amplification Coupling Enantioselective Autocatalysis and Asymmetric Induction for Alkylation of Azaaryl Aldehydes.
European Journal of Organic Chemistry.
ISSN 1434-193X.
2015(19),
p. 4087–4092.
doi:
10.1002/ejoc.201500508.
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Gerz, Isabelle; Olsbye, Unni; Tilset, Mats & Amedjkouh, Mohamed
(2019).
Biomimetic Copper Complexes for Incorporation into MOFs.
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Wåhlander, Jakob Karl Kristoffer; Balcells, David; Gundersen, Lise-Lotte & Amedjkouh, Mohamed
(2017).
A New Phosphonamide-framework as Catalyst in Diels-Alder Reactions.
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Thoresen, Eirik Mydske; Amedjkouh, Mohamed; Tilset, Mats; Lillerud, Karl Petter; Øien-Ødegaard, Sigurd & Balcells, David
(2016).
Novel Ruthenium Functionalized Linkers for Photosensitization of Metal-Organic Frameworks.
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Thoresen, Eirik Mydske; Tilset, Mats; Lillerud, Karl Petter & Amedjkouh, Mohamed
(2015).
Functionalized linkers as photosensitizers in UiO-67 MOFs
for photocatalytic CO2 reduction.
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Thoresen, Eirik Mydske; Tilset, Mats; Lillerud, Karl Petter & Amedjkouh, Mohamed
(2015).
Metal organic frameworks (MOFs) with functionalized linkers
as photosensitizers for photocatalytic CO2 reduction.
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Wåhlander, Jakob Karl Kristoffer; Balcells, David; Gundersen, Lise-Lotte & Amedjkouh, Mohamed
(2015).
Computational Study of Phosphonamides for use in Diels-Alder Reactions.
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Thoresen, Eirik Mydske; Tilset, Mats; Lillerud, Karl Petter & Amedjkouh, Mohamed
(2015).
Metal organic frameworks (MOFs) with functionalized linkers as photosensitizers for photocatalytic CO2 reduction.
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Wåhlander, Jakob Karl Kristoffer; Amedjkouh, Mohamed; Balcells, David & Gundersen, Lise-Lotte
(2014).
Synthesis directed towards asmarine fragments and development of Lewis acid Diels-Alder catalysts.
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Wåhlander, Jakob Karl Kristoffer; Amedjkouh, Mohamed; Balcells, David & Gundersen, Lise-Lotte
(2014).
Synthesis of Asmarine Fragments and Development of Lewis Acid Diels-Alder Catalysts.
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Amedjkouh, Mohamed; Sieng, Bora; Maldonado, Matias Funes & Romagnoli, Carlo
(2014).
Intelligent organozinc reagents for propagation of chirality in relevant chemical transformations.
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Romagnoli, Carlo; Maldonado, Matias Funes; Sieng, Bora & Amedjkouh, Mohamed
(2014).
Propagation of chirality in asymmetric alkylation.
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Maldonado, Matias Funes; Sieng, Bora; Romagnoli, Carlo & Amedjkouh, Mohamed
(2014).
One-step Synthesis of γ-Oxo-α,β-Unsaturated Esters from Heteroaromatic Aldehydes.
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Romagnoli, Carlo; Sieng, Bora; Maldonado, Matias Funes & Amedjkouh, Mohamed
(2014).
Propagation of Chirality in Asymmetric alkylation of Pyridyl Aldehydes.
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Maldonado, Matias Funes; Sieng, Bora & Amedjkouh, Mohamed
(2014).
Propagation of chirality in asymmetric alkynylation.
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Amedjkouh, Mohamed; Romagnoli, Carlo; Maldonado, Matias Funes & Sieng, Bora
(2014).
Efficient remote asymmetric amplification in synergistic autocatalytic systems.
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Sieng, Bora; Amedjkouh, Mohamed; Maldonado, Matias Funes & Romagnoli, Carlo
(2014).
One-step Synthesis of γ-Oxo-α,β-Unsaturated Esters from Heteroaromatic Aldehydes.
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Maldonado, Matias Funes; Sieng, Bora & Amedjkouh, Mohamed
(2014).
Propagation of chirality in asymmetric alkynylation.
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Jacobsen, Øyvind & Amedjkouh, Mohamed
(2014).
Synthesis and Structural Studies of Oligopeptides Comprising Non-Stereogenic α,α-Disubstituted Amino Acid Residues.
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Sagstad, Paul Arne & Amedjkouh, Mohamed
(2024).
Synthesis and attempted MOF incorporation of dipyrido[3,2-a:2',3'-c]phenazine-10,13-dicarboxylic acid.
Universitetet i Oslo.
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In this work a route for the synthesis of dipyrido[3,2-a:2',3'-c]phenazine-10,13-dicarboxylic acid (4b) was developed. Using this route, 4b was synthesized from o-diaminobenzene in 6 steps and extensively characterized. 4b was attempted incorporated into a UiO-66 Metal Organic Framework (MOF) structure. The resulting materials were characterized by powder x-ray diffraction (PXRD), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and Brunauer-Emmett-Teller (BET) surface area analyses. Although the results from these analyses show that some 4b remains after synthesis, unequivocal conformation of successful incorporation into the framework structure was not obtained. Single crystals of UiO-66 containing 4b were also attempted synthesized for structural elucidation by single crystal x-ray diffraction (SCXRD), unsuccessfully.
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Tangevold, Ingeborg Braskerud; Szilagyi, Petra Agota; Amedjkouh, Mohamed & Pupo, Rafael Cortez Sgroi
(2024).
Synthesis of bioinspired bidentate N-ligands and their incorporation into UiO-67.
Universitetet i Oslo.
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Atmospheric methane is one of the main drivers of global warming today. Transforming methane to methanol has been suggested as a strategy to lower the anthropogenic release of methane, since methanol is more easily handled as a fuel and more versatile as chemical feedstock. Thus, a catalyst that can oxidise methane to methanol directly and selectively has been sought after for years. Particulate methane monooxygenases (pMMOs) and lytic polysaccharide monooxygenases (LPMOs) are two groups of enzymes that can activate C-H bonds to selectively form alcohols; both utilise N-ligated copper as cofactor, and can be used as blueprints for designing novel catalysts for selective methane oxidation. This work sought to synthesise ligands inspired by the active sites of pMMOs and LPMOs and immobilising them in the tunable and robust UiO-67 metal-organic framework (MOF). Specifically, three bidentate N-ligands were synthesised in this work, all were designed in a manner that let them double as functionalised linkers for the UiO-67 framework, and two of the ligands were also added hydrophobic functionality. The ligands were formed through synthetic routes of four to six steps with total yields of 28-51 %. Methods such as the Suzuki coupling, reductive amination and ester hydrolysis were employed. Through their ability to act as functionalised linkers for UiO-67, all three ligands were also incorporated into crystalline, porous and thermally stable mixed-linker UiO-67 type MOFs, in which 16.7-19.7 % of the linkers were functionalised. Incorporation of the functionalised linkers led to some decrease in the thermal stability and porosity of the MOFs, but not detrimentally. MOF integration of the ligands was done through post-synthetic linker exchange (PSLE), since the ligands decomposed during attempts at direct synthesis of the mixed-linker UiO-67 MOFs. Due to the increased bulkiness of ligands containing hydrophobic functionality, PSLE with these had to be performed at elevated temperatures to obtain the desired degree of linker exchange.
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Amoakwah, Melchizedek & Amedjkouh, Mohamed
(2023).
Synthesis and structural characterization of heteroleptic dipyridophenazine–based [Cu(N^N)(P^P)]+ complexes.
Universitetet i Oslo.
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For the purposes of solar–induced multi–electron storage and charge transfer reactions, heteroleptic [Cu(N^N)(P^P)]+ type copper(I) complexes where (N^N)= diimine ligand and (P^P)= bulky diphosphine ligand, have become promising and viable alternatives to noble metal photosensitizers. In this thesis, the synthesis, structural and geometrical configurations of a series of electron–withdrawing para–substituted dipyrido–[3, 2–a: 2’, 3’–c]phenazine(dppz) copper complexes (inclusive of the non-substituted) are studied. With bromo, cyano and 4-methoxycarbonyl nitrophenyl as the substituents and (9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos), 1,1'-Bis (diphenylphosphino)ferrocene (dppf) and ([1,1′-Binaphthalene]-2,2′ diyl)bis(diphenylphosphane) (binap) as the (P^P) ligands, the corresponding complexes were synthesized via a one–pot two–step method and characterized using multinuclear NMR, DOSY, FTIR and UV–Vis DR spectroscopy. The dppz ligands were obtained in quantitative yields via bromination, cyanation and Suzuki–type coupling reactions conducted on an intermediate benzothiadiazole scaffold. The cyano and alkyl benzoate derivatives were chosen for the prospective aim of incorporating the complexes into Zr–based MOFs UiO–66 and UiO–68 respectively. The free bromo– and cyano–dppz ligands exhibited severe solubility issues, with NMR characterization being possible upon strong acid addition. The complexes showed satisfying stability upon exposure to air and water with DOSY studies in N–donor solvents showing the fortunate absence of dissociative speciation and ligand exchange reactions leading to the formation of homoleptic species. Through–space correlations and solid– state structures defined by NOESY/ROESY NMR and SC–XRD indicated π–stacking properties among the complexes caused by a distorted tetrahedral coordination sphere around the Cu(I) metal. From the UV-Vis DRS studies, it was inferred that the presence of parasubstituted EWGs on the distal benzenoid ring promoted red-shifting of the absorption properties for both the ligands and complexes within the visible region.
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Austenaa, Bjørn Terjei & Amedjkouh, Mohamed
(2023).
Synthesis and characterization of photosensitive ligand for copper complexation and functionalization of UiO-67 MOF.
Universitetet i Oslo.
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Denne masteroppgaven beskriver syntese og karakterisering av lysfølsomme ligander for metall kompleks og funksjonalisering av MOF. Oppgaven beskriver vellykket syntese av 2 ligander og et forsøk på et tredje. Det tredje ligandet ville hatt et forlenget pi-system sammenlignet med de to første. For å lage dette ble det forsøkt å sette på et alkyn i en Sonogashira reaksjon. Ligander og mellomprodukter ble karakterisert med NMR spektroskopi og massespektrometri analyse. Smeltepunkter ble også målt for de fleste mellomprodukter og ligandene.
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Gerz, Isabelle; Amedjkouh, Mohamed & Tilset, Mats
(2022).
Bioinspired Copper Complexes for Incorporation into UiO-67.
Universitetet i Oslo.
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In this thesis, copper complexes bearing bidentate, tridentate, and tetradentate N-ligands were synthesised and characterised. The ligands’ design draws inspiration from the histidine copper brace, a structural motif found in enzymes. The compounds were investigated, among other techniques, with nuclear magnetic resonance (NMR) spectroscopy and UV/Vis spectroscopy. A combination of Variable Temperature (VT) 1H NMR, Diffusion Ordered Spectroscopy (DOSY) and 1H-15N Heteronuclear Multiple-Bond Correlation (HMBC) allowed to study the aggregation behaviour of the compounds. Pyridine and imidazole bearing N,N,N,Ncopper( I) complexes both formed dimers, yet these dimers are of different constitution. 15N NMR coordination shifts were obtained for several copper(I) complexes, highlighting the interplay between imine and heterocycle. In UV/Vis experiments, the aggregation behaviour of a bispyridine copper(I) complex in solution led to deviation from the linear correlation between concentration and absorption given by the Lambert-Beer law. While exploring the synthetic scope of the protocol for the tetradentate ligands, the formation of dibenzo[d,f]-1,2- dihydro-[1,3]diazepines was observed. The formation of this side product was influenced by a delicate interplay of the substituents on the employed aldehyde and Lewis acidic reagents present in the reaction mixture. Additionally to the aforementioned copper complexes, two pentacoordinated salen-type copper(II) complexes were synthesised. Their ligands differ only by a nitro-substitution para to the oxygen binding copper, yet this had a strong effect on the coordination geometry around copper as seen by single crystal X-ray diffraction. The oxidation of a tetracoordinated bisimidazole copper(I) complex in acetonitrile solution upon air exposure was studied by UV/Vis spectroscopy. The majority of copper complexes were synthesised with the aim to incorporate them into metal organic frameworks. The incorporation was successfully shown for two of the complexes. Preliminary studies of the oxidation of the complexes and their catalytic performance suggest that the herein presented complexes are promising catalyst candidates for aliphatic C–H oxidation.
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Rotunno, Giuseppe; Amedjkouh, Mohamed & Tilset, Mats
(2022).
Vapour-solid interactions for SMSB and asymmetric amplification of pyrimidine and pyridine aldehydes.
Universitetet i Oslo.
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In the last 25 years, the addition of diisopropylzinc to pyrimidine carbaldehydes, known nowadays as the Soai reaction, has drawn the attention of many research groups, not only as it is to date the only chemical reaction offering the chance to study the phenomenon of asymmetric autocatalysis in conjunction with high amplification of enantiomeric excess, but also for the remarkable property to give rise to high ee% even under absolute conditions. Absolute asymmetric synthesis produces chiral molecules in absence of any chiral polarization and is often speculated as possible explanation for the origin of homochirality. This thesis work deepens the knowledge of the Soai reaction performed under absolute conditions and under the less explored heterogeneous vapour-solid reaction conditions. In order to gain information on the long-speculated Soai reaction mechanism, the Soai reagent was encapsulated in UiO Metal-Organic Frameworks (MOFs). The MOFs were used as nano-reactors to probe confinement effects on the catalytically active species. In addition, the vapour-solid reactions revealed some unreported side products, in particular a chiral ester. This observation provides evidence for some recent debated transient intermediates, and opens new perspectives in the elucidation of the mechanism of amplification of chirality in the Soai reaction.
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Wåhlander, Jakob Karl Kristoffer; Amedjkouh, Mohamed & Gundersen, Lise-Lotte
(2018).
Diels-Alder reactions in synthesis and method development.
University of Oslo.
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This thesis has got two parts within the common theme of Diels-Alder reactions. One part starts with the group of natural products called asmarines. These compounds, which were found in the red sea sponges, were believed to have anti-cancer properties. However a synthetic pathway to these compounds does as of yet not exist. A potential synthetic pathway for a fragment of the asmarines was devised, using a Diels-Alder reaction in a crucial step. The other part starts with thioureas, a class of compounds that act as Diels-Alder catalysts by way of hydrogen bond activation of and α,β-unsaturated carbonyl compound. A new, but similar, phosphordiamide based framework that was hypothesized to act in a similar manner to the thioureas. It was thought that a functioning phosphordiamide catalyst could be used in the crucial Diels-Alder reaction of the asmarine fragment. A more in detail description is found in Chapter 1.
In Chapter 2 the initial attempts at producing a functional phosphordiamide catalyst are presented. A few simple catalysts are produced and evaluated using several different systems. The compounds are however unsuccessful as Diels-Alder catalysts. Further studies of phosphordiamides can be found in Chapter 3 which deals with a computational study a new set of phosphordiamide catalysts, with more successful results. The Chapter 4 deals with the previously discussed synthetic pathway of an asmarine fragment. The idea of using a phosphordiamide as a catalyst was discarded in favor of a Lewis acid catalyst. Though the synthesis of the fragment was not complete, the main Diels-Alder step was eventually overcome and several more steps were completed with good yields. The final Chapter 5 describes a possible continuation to both projects.
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Fredriksen, Kim Alex; Bonge-Hansen, Tore & Amedjkouh, Mohamed
(2017).
Attempted Enantioselective Preparation of ∝-Aminophosphonic Acids and a Mechanistic Investigation of the Coupling Agent Mediated Phosphonamidation Reaction.
Universitetet i Oslo.
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The aim of the study was to advance the chemistry related to aminophosphonic acids. After reviewing the available literature, our attention was drawn towards the preparation of chiral ∝-aminophosphonic acids and derivatives thereof. The first objective was to investigate their preparation, with a special emphasis on enantioselective methods. This investigation prompted us to explore whether chiral phase-transfer catalysis could be used in the key step to prepare chiral ∝-aminophosphonic acids in an enantioselective manner (see Chapter 2). The second objective was to promote a phosphonamidation reaction between monoesters of phosphonic acids and amines via a coupling agent-mediated reaction. Upon the eventual establishment of such a method an extended goal would be to attempt a phosphonamidation reaction on adequately protected aminophosphonic acids attempting to form small peptides (see Chapter 3). The peptides themselves could be interesting targets to study by means of NMR spectroscopy and X-ray crystallography, to investigate how the geometry of the phosphonoamidate groups affects the folding of the peptide. Once a methodology for the synthesis of phosphonamidates had been developed it became an important objective to control the stereochemistry at the phosphorous atom. Different strategies to achieve stereoselective phosphonamidation reaction were investigated. This feature necessitated the development of a new subclass of coupling agents that were themselves chiral (see Chapter 4).
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Published
Nov. 11, 2010 9:00 AM
- Last modified
Feb. 14, 2017 8:48 PM
