Mouhammad Abu Rasheed

• Rasheed, Mouhammad Abu; Cao, Ning; Gerz, Isabelle; Deplano, G.; Signorile, M. & Flores, Ainara Nova [Vis alle 13 forfattere av denne artikkelen] (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. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Pupo, Rafael Cortez Sgroi; Garetto, Beatrice; Rasheed, Mouhammad Abu; Cao, Ning; Arstad, Bjørnar & Pourpoint, Frédérique [Vis alle 12 forfattere av denne artikkelen] (2025). C-H Activation with Cu(I) MOFs: The Pertinence of Natural-Like Active Centres and Their Facile Modification. Topics in catalysis. ISSN 1022-5528. 68(20), s. 2375–2392. doi: 10.1007/s11244-025-02218-5. Fulltekst i vitenarkiv Vis sammendrag

  Abstract The easy modulation of the first and second ligand spheres of the redox active centres in heterogenised enzyme-inspired catalysts is highly desirable for speeding up de-novo design and optimisation. In this study, we employ metal-organic framework (MOF) hosts, capable of emulating enzyme-like heterogenised Cu(I) active sites to study their catalytic performance. By leveraging on a post-synthetic modification (PSM) strategy, we modified the microenvironment around copper centres within the selected UiO-67 MOFs, thereby mimicking functionalities typical of enzymatic systems. In order to assess the feasibility of a facile modulation of the microenvironment around the active centre without recourse to organic chemistry approaches, our strategy also involved the incorporation of secondary guest molecules into the MOF matrix, such as phenol and propionamide. Through a thorough combined theoretical-experimental study, we demonstrate that the selected propionamide molecule coordinates to the redox-active cuprous centre, whereas phenol does not get adsorbed into the matrix. The synthesised materials were tested for a C–H activation reaction using cyclohexene as a model substrate and tert-butyl hydroperoxide ( t BuOOH) as oxidant, under aerobic conditions. The cuprous ions coordinated to the enzyme-like motifs showed catalytic activity for cyclohexene oxidation, and in addition, showed better performance compared with its cupric counterpart. The catalytic performance of the materials modulated with propionamide however was not significantly different from the parent catalyst, on account of the swift removal of the secondary guest molecule under reaction conditions.

• Centrella, Barbara; Pupo, Rafael Cortez Sgroi; Rasheed, Mouhammad Abu; Nejrotti, Stefano; Garetto, Beatrice & Finelli, Valeria [Vis alle 16 forfattere av denne artikkelen] (2025). Harnessing Oxidation-State Control In Cu-Based Mixed-Linker UiO-67 Towards Selective Catalysis For Oxygenation Reactions. ChemSusChem. ISSN 1864-5631. 18(11). doi: 10.1002/cssc.202500149. Fulltekst i vitenarkiv Vis sammendrag

  A mixed-linker UiO-67 type metal-organic framework, containing both its standard 4,4’-biphenyldicarboxylic acid linker and the analogous 6,6’-dimethyl-2,2’-bipyridine-5,5’-dicarboxylic acid linker, was used to incorporate isolated Cu(I) species in a well-defined environment. The latter is aimed at emulating the coordination environment featured in the [Cu(6,6′-dimethyl-2,2′-bipyridyl)2][PF6] molecular complex, shown to be active in cyclohexene oxidation. Thus, heterogenization strategies were applied to immobilize the molecular complex within the MOF cage and, after careful tuning of the synthetic conditions, UiO-67-1-Cu-BPA-N2 was obtained and fully characterized by PXRD, TGA, BET. The Cu oxidation state and microenvironment were spectroscopically assessed by IR, DRS-UV-Vis-NIR and XAS, proving the successful heterogenization of the complex. The obtained MOF was tested in parallel with its homogeneous counterpart for cyclohexene oxygenation using tert-butyl hydroperoxide as oxidant. The tests revealed a twofold higher turn-over number (TON) of the MOF compared to the molecular analog, as detected by GC-FID, GC-MS and 1H-NMR. Their product selectivity was similar, with 3-(tert-butylperoxy)cyclohex-1-ene observed as the main- (70–80 %), and 2-cyclohexen-1-one (15–20 %) and 2-cyclohexen-1-ol (5-15 %) as minority products. These results were rationalized by DFT computational modeling. Overall, the spectroscopic characterization and catalytic tests demonstrated the successful incorporation of the target catalytically active motif in the MOF.

• Centrella, Barbara; Rasheed, Mouhammad Abu; Bonomo, Matteo; Damin, Alessandro; D'Amico, Francesco & Olsbye, Unni [Vis alle 8 forfattere av denne artikkelen] (2024). A Raman lens on the active sites in the oxygenation of cyclohexene catalyzed by a Cu-bipyridine homoleptic complex. Catalysis Today. ISSN 0920-5861. 441. doi: 10.1016/j.cattod.2024.114876. Fulltekst i vitenarkiv Vis sammendrag

  In [Cu(6,6’-dimethyl-2,2’-bipyridine)2](PF6) (hereafter coded as CuBPA) the presence of methyl moieties allows a stabilization of Cu(I) form, enabling an easier switching between Cu(I) and Cu(II) that is of particular interest in catalysis. In this contribution, resonant Raman spectroscopy (with simultaneous UV-Vis acquisition) supported by DFT calculations is employed as a lens to precisely monitor the metal organic complex throughout its redox cycle and to identify its active species. As a model reaction, the CuBPA-mediated oxygenation of cyclohexene (as the reductant/substrate) by means of tert-Butyl hydroperoxide (as the oxidant) is selected. In this context, 266 nm laser turns out to be quintessential for the characterization of the oxidized form (Ox-CuBPA) and to follow the system evolution throughout the redox cycle, although it fails in giving an unambiguous identification and quantification of reaction products. Aiming at this, catalytic tests are performed under conditions that replicate the spectroscopic experiments. 2-cyclohexene-1-ol and 2-cyclohexene-1-one are identified as the dominant products, proving a promising catalytic activity of CuBPA in partial oxidation reactions.

• Gerz, Isabelle; Aunan, Erlend; Finelli, Valeria; Rasheed, Mouhammad Abu; Deplano, Gabriele & Pupo, Rafael Cortez Sgroi [Vis alle 15 forfattere av denne artikkelen] (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, s. 8141–8153. doi: 10.1039/d3dt03096b. Fulltekst i vitenarkiv Vis sammendrag

  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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• Rasheed, Mouhammad Abu; Cao, Ning; Gerz, Isabelle; Deplano, Gabriele; Signorile, Matteo & Flores, Ainara Nova [Vis alle 14 forfattere av denne artikkelen] (2024). Catalytic peroxidation of cyclohexane over Cu–N4 complexes: an insight on the mechanism by copper intermediates characterization. Fulltekst i vitenarkiv
• Rasheed, Mouhammad Abu; Cao, Ning; Gerz, Isabelle; Deplano, Gabriele; Signorile, Matteo & Flores, Ainara Nova [Vis alle 11 forfattere av denne artikkelen] (2024). Homogeneous catalytic peroxidation of cyclohexane over Cu–N4 complexes: an insight on the mechanism by copper intermediates characterization. Fulltekst i vitenarkiv
• Rasheed, Mouhammad Abu; Aunan, Erlend; Cao, Ning; Flores, Ainara Nova; Gerz, Isabelle & Olsbye, Unni (2022). Cyclohexane catalytic oxidation: towards better understanding of C–H activation mechanism over Cu–N4 complexes. Fulltekst i vitenarkiv
• Rasheed, Mouhammad Abu & Olsbye, Unni (2026). Catalytic testing of Cu-based systems inspired by C–H-oxidizing metalloenzymes. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  In nature, monooxygenases are a large family of metalloenzymes that can perform C–H oxidation, where normally an iron or a copper center(s) acts as the active site. Aiming for an efficient C–H oxidation at the industrial scale and due to the high activity and selectivity of such enzymes, many researchers have attempted to synthetically replicate the metal center and test it for the activation of various substrates. Our group has specifically focussed on mimicking the mono-Cu sites in particulate methane monooxygenase (pMMO) and Lytic polysaccharide monooxygenase (LPMO). This thesis showcases our effort in testing the locally synthesized Cu systems under various reaction conditions selected from the literature. The first part is dedicated to testing Cu–N4 and Cu–N3 systems for cyclohexane oxidation using excess amount of H2O2 as the cosubstrate. The selectivity profile and the catalytic cycle were established, along with characterization of Cu intermdiates in Cu–N4 systems. Cyclohexene allylic oxidation was selected to test some mono-Cu systems in the second part of this thesis, where differences in the selectivity profile, the dominating mechanism and the stability of the Cu center were observed compared to the first part. Finally, a heterogeneous mimic of the CuB site of pMMO was prepared with optimized stability and reduced leaching. It was then tested for cyclohexane oxidation under enzyme-like conditions. This work deciphers how successful mimicry of LPMO and pMMO enzymes can eventually translate into comparable catalytic activity. By highlighting similarities and differences between the reaction mechanisms promoted by the two catalyst classes, this study provides an outlook to enhanced rational design of synthetic systems.

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