www.iciq.cat https://hdl.handle.net/2072/300912 2026-04-08T08:41:51Z 2026-04-08T08:41:51Z Terry, Lane M. Leversee, River A. Aragay, Gemma Ballester, Pablo McCoy, Anne B. Weber, J. Mathias https://hdl.handle.net/2072/489416 2026-04-08T08:27:49Z 2026-03-17T00:00:00Z

Dissecting halide-receptor interactions in “four wall” aryl-extended calix[4]pyrrole complexes: the role of the aromatic walls Terry, Lane M.; Leversee, River A.; Aragay, Gemma; Ballester, Pablo; McCoy, Anne B.; Weber, J. Mathias We report cryogenic ion vibrational spectroscopy of chloride, bromide, and iodide complexes with octa-methyl calix[4]pyrrole (omC4P) and with the tetra-α “four wall” 4-nitroaryl-extended calix[4]pyrrole (AEC4P). Experimental infrared spectra are compared with those obtained using density functional theory calculations to elucidate the binding motifs of these receptor-halide complexes. For both receptors, halide binding is mainly driven by symmetric interactions between the halide ion and the receptor's four pyrrole NH groups. These interactions lock the receptor in cone conformation and are encoded in the NH stretching region of their infrared spectra. For the “four wall” AEC4P, the cone conformation defines a deep, polar, aromatic cavity closed at one end by the converging pyrrole NH groups. Halide binding (Cl−, Br−, or I−) redistributes negative charge from the bound anion onto the meso-p-nitroaryl substituents, generating an electrostatic field that drives the ion deeper into the cavity. In contrast, the anionic complexes of the omC4P receptor, which lacks meso-aryl substituents, feature a shallower binding geometry for the bound halide.

2026-03-17T00:00:00Z Ruiz-Ferrando, Andrea Mitchell, Sharon López, Núria Pérez-Ramírez, Javier https://hdl.handle.net/2072/489415 2026-04-07T07:56:54Z 2026-04-03T00:00:00Z

Toward Predictive Theory in Single-Atom Catalysis Ruiz-Ferrando, Andrea; Mitchell, Sharon; López, Núria; Pérez-Ramírez, Javier Single-atom catalysis has become a central framework for experiment-theory integration, as catalytic performance is highly sensitive to the environment of individual metal atoms, a feature that electronic structure calculations are well-suited to analyze. Yet much of current theoretical practice relies on simplified single-site models and narrow reactivity windows, overlooking the intrinsic site diversity and evolution of single-atom catalysts (SAC). This Perspective discusses how SAC modeling can be reframed through a lifecycle-oriented view that integrates synthesis, activity, stability, and safety. By adopting ensemble-based descriptions and modular thermodynamic descriptors, we show how theory can be used systematically in line with the level of structural definition accessible experimentally. Using acetylene hydrochlorination as a prominent SAC application with exceptional data coherence for examining the theory-experiment interplay, wedemonstrate that site formation and evolution under synthesis and reaction conditions, as well as ensemble-driven activity trends consistent with experimental yields, can be treated quantitatively. In contrast, stability and safety are more effectively addressed through comparative, pathway-resolved analyses. More broadly, this perspective points toward a shift in how SAC modeling is framed across reactions, enabling theory to move beyond post-rationalization toward disciplined prediction.

2026-04-03T00:00:00Z Rigo, Davide Lamparelli, David H. Buonerba, Antonio Capacchione, Carmine Kleij, Arjan W. https://hdl.handle.net/2072/489413 2026-04-01T09:28:46Z 2026-03-10T00:00:00Z

Depolymerization and Reuse of Polycarbonates: Emerging Classes, Mechanisms and Challenges Rigo, Davide; Lamparelli, David H.; Buonerba, Antonio; Capacchione, Carmine; Kleij, Arjan W. The efficient recycling of plastics and polymers is a focal point within the development of circular chemistry. In this realm, the development of new types of recyclable-by-design polymers plays a crucial role in answering a growing need for plastic formulations that can build on this intrinsic feature while using renewable resources. Within the large and diverse family of engineering polymers, polycarbonates (PCs) play an essential role as modular components for many consumer products. Challenges related to a more sustainable production of PCs and their end-of-life disposal have created incentives towards a more responsible use and reuse of these macromolecules. This review focuses on key aspects that should guide future PC development, with both a mechanistic understanding of controlled degradation and identifying efficient depolymerization approaches being the major outcomes. In addition, emerging classes of polycarbonates, such as heteroatom-containing ones are highlighted and discussed.

2026-03-10T00:00:00Z Scopano, Angelo Potenza, Nicole Berluti, Giovanni Havenith, Remco W. A. Kleij, Arjan W. Pescarmona, Paolo P. https://hdl.handle.net/2072/489412 2026-04-01T09:19:43Z 2026-03-03T00:00:00Z

A one-pot organocatalytic process for the synthesis of cyclic carbonates from CO2 and alkenes using cumene hydroperoxide as a green oxidant Scopano, Angelo; Potenza, Nicole; Berluti, Giovanni; Havenith, Remco W. A.; Kleij, Arjan W.; Pescarmona, Paolo P. Cyclic carbonates are usually obtained from coupling of carbon dioxide and epoxides. The latter are generally prepared through the selective oxidation of alkenes or other compounds containing a double bond. However, a one-pot route in which an alkene is directly converted into a cyclic carbonate would be preferable as it would circumvent the handling of generally toxic epoxides and would increase process efficiency in terms of energy, solvent and reagents usage. Here, we present an attractive strategy combining a recyclable oxidant (cumene hydroperoxide, CHP) with an inexpensive, metal-free organic halide salt as catalyst. These components act cooperatively promoting the oxidation of the chosen model substrate (styrene) and the cycloaddition of CO2 to the generated epoxide intermediate. Tetrabutylammonium bromide exhibited the best catalytic performance, providing a 55% styrene carbonate yield after 6 h at 10 barg of CO2 and 80 °C using 1.5 equivalents of oxidant; and 67% in the presence of 4 equivalents of oxidant. These cyclic carbonate yields are significantly higher than those obtained with other oxidants (tert-butyl hydroperoxide and hydrogen peroxide). A scope of substrates was converted into their respective cyclic carbonates including a new bio-based methylisoeugenol-derived product and a cyclic carbonate attained from bio-based methyl oleate (having a disubstituted double bond). From mechanistic control experiments, we determined that the oxidation step proceeds through a radical mechanism, with an active involvement of CHP in epoxide activation via hydrogen-bonding, demonstrating a dual role of the oxidant. Our strategy offers a practical proof of concept of a direct approach to cyclic carbonates with a simple organocatalyst that could be reused in four consecutive runs with a similar performance, and using a recyclable oxidant.

2026-03-03T00:00:00Z