The Branco Weiss Fellowship, formally known as the Society in Science program, is designed precisely for ideas of this kind. It supports postdoctoral researchers from any discipline who want to pursue unconventional, potentially transformative research questions at the academic institution of their choice, and it accepts no more than ten new fellows each year. With funding of up to CHF 600,000, roughly €635,000, over five years, the fellowship gives its recipients an unusual degree of freedom at a career stage when most researchers are still working within the frameworks of their senior colleagues. Mateo becomes only the second Spanish researcher to receive the award and one of the first to carry out the fellowship in Spain, a milestone that highlights the growing visibility of Spanish molecular science on the international stage.

For Mateo, the award represents more than financial security. It provides the opportunity to begin building his own research team and to establish an independent research programme at the Universidade de Santiago de Compostela, where he has worked since 2021 as a postdoctoral researcher in the groups of Diego Peña and Dolores Pérez. In a statement accompanying the announcement, he described the fellowship as an exceptional opportunity to explore a high-risk idea with the freedom and time needed to develop it, noting that carrying out the project at CiQUS, an environment that brings together synthetic chemistry, nanoscience and molecular materials, would allow questions to be addressed that would be difficult to tackle from a single discipline.

The scientific problem at the core of his project, named PhthalocyanYnes, begins with a paradox familiar to anyone who works with functional materials. Phthalocyanines are among the most chemically robust molecules in modern chemistry. These large, flat, nitrogen-rich macrocycles have optical properties that made them commercially valuable as pigments decades before anyone spoke of molecular electronics, and today they are regarded as highly attractive building blocks for functional materials ranging from organic semiconductors to catalysts. Their celebrated stability, however, is a double-edged sword. Once a phthalocyanine has been synthesised, its structure is remarkably difficult to modify, which means that exploring new variants typically requires designing and building each target molecule from scratch, a laborious process that limits how quickly new materials can be discovered.

Mateo’s proposed solution is to weaponise instability against stability. The project aims to introduce an aryne, an extremely reactive molecular intermediate that exists for only a fraction of a second, into these highly stable molecular systems. Arynes are among the most energetic species a synthetic chemist can generate in a reaction flask; they are so short-lived that they are never isolated but instead captured in situ by nearby molecules. The central challenge of the PhthalocyanYnes project is to tame this fleeting reactivity and harness it to selectively transform the phthalocyanine framework, for example through cycloaddition reactions, in which the aryne forms new rings by adding across the stable molecular scaffold. If the strategy works, it would effectively turn the molecules’ greatest weakness, their inertness, into a design opportunity.

The payoff, if the chemistry can be controlled, would be a fundamentally new way of accessing families of phthalocyanine-based structures. Rather than synthesising each member of a molecular family individually, researchers could prepare a common advanced precursor and then diversify it at a late stage of synthesis, a philosophy that has transformed drug discovery in medicinal chemistry but remains largely unexplored for these pigment-derived materials. Late-stage functionalisation of phthalocyanines would make the molecules substantially more versatile and programmable, allowing optical and electronic properties to be tuned almost modularly, in the way that software engineers modify code rather than rebuilding a program from first principles.

To reach that goal, the project will combine several techniques that rarely converge in a single laboratory programme. Synthetic chemistry will provide the molecular scaffolds and the aryne chemistry needed to modify them. Advanced spectroscopy will be used to characterise the products and follow the reactions as they unfold. Computational modelling will help predict which aryne additions are feasible and what properties the resulting structures will have. Single-molecule characterisation, a specialty that has grown rapidly at CiQUS in recent years, will allow individual molecules to be imaged and probed directly, revealing whether the intended structures have actually been achieved at the atomic scale. Together, these approaches will be applied to molecular architectures that are currently difficult to access, including asymmetric phthalocyanine–carbon nanostructure hybrids, extended molecular networks and nanographenes with tunable optical, electronic and magnetic properties.

The potential applications extend well beyond the laboratory curiosity that such exotic molecules might otherwise remain. Phthalocyanines and their derivatives already play important roles in organic photovoltaics, organic light-emitting diodes, sensors and catalysis, and their rigid, planar geometry makes them natural candidates for molecular components in next-generation devices. The chemistry developed in the PhthalocyanYnes project could open new opportunities for the development of functional molecular materials for applications in optoelectronics and quantum technologies, fields in which the ability to fine-tune the electronic structure of individual molecules is becoming increasingly important. Molecular networks and nanographenes with precisely controlled shapes and electronic properties are also of intense interest for quantum information research, where the behaviour of single molecules and single spins can carry information in ways that conventional materials cannot.

Mateo’s path to this award reflects the kind of interdisciplinary training that such ambitious projects demand. He joined CiQUS in 2021 as a postdoctoral researcher within the ERC Synergy Grant MolDAM project, supervised by Diego Peña, and has since continued his research at the centre, developing expertise at the intersection of organic chemistry, molecular design, nanoscience, molecular materials and surface chemistry. That combination, spanning the design of new reactions, the study of molecules on surfaces and the construction of functional materials, is precisely the skill set needed to attempt late-stage aryne chemistry on scaffolds as demanding as phthalocyanines. His independent programme will strengthen CiQUS’s ability to attract and support emerging scientific talent and to pursue high-risk research with transformative potential, according to the centre.

CiQUS itself holds the María de Maeztu Unit of Excellence accreditation, one of the highest recognitions available to research centres in Spain, along with the CIGUS recognition awarded by the Xunta de Galicia, and it receives financial support from the European Union through the Galicia FEDER 2021–2027 Programme. For the wider European research community, the award of a Branco Weiss Fellowship to a researcher based in Spain, and the decision to develop the project there rather than relocating to a northern European hub, signals a shift in where unconventional early-career science can flourish. If Mateo’s fleeting arynes can indeed be captured and put to work on some of the most stable molecules known to chemistry, the result could be a new generation of programmable molecular materials whose properties are written into their structures one selective reaction at a time.

Subject of Research: Late-stage aryne-based modification of phthalocyanine molecules for programmable functional molecular materials

Article Title: Luis M. Mateo awarded Branco Weiss Fellowship to develop new approach to molecular design at CiQUS

Article References: Luis M. Mateo awarded Branco Weiss Fellowship to develop new approach to molecular design at CiQUS. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Branco Weiss Fellowship, Luis M. Mateo, CiQUS, phthalocyanines, aryne chemistry, late-stage functionalisation, molecular design, nanoscience, optoelectronics, quantum technologies, ETH Zurich, Universidade de Santiago de Compostela

The materials at the centre of the study are covalent organic frameworks, or COFs, a class of substances that has captivated chemists for the better part of two decades. COFs are constructed from organic molecules stitched together by strong covalent bonds into extended, ordered lattices riddled with pores measured in nanometres. This marriage of crystalline precision and internal void space makes them tantalising candidates for everything from electronic devices and chemical sensors to energy storage systems. Yet there has always been a catch. In their pristine form, most COFs are electrical insulators, and the standard remedy has been post-synthetic doping, in which external substances are introduced to supply the electrons or holes needed for conduction. That remedy comes at a price, because dopants can disrupt the framework’s structure, diminishing its crystallinity, its porosity and its long-term stability.

The CiQUS researchers, working across three groups led by Manuel Souto, Diego Peña and Francisco Rivadulla, proposed a fundamentally different route. Rather than injecting charge carriers after the framework has been assembled, they designed the building blocks to carry them from the outset. The key ingredients are neutral trioxotriangulene radicals, often abbreviated TOT, a family of organic molecules distinguished by a highly delocalised spin and a remarkable resistance to degradation. Because these radicals are stable in their neutral state, they can be woven into the framework as genuine structural components rather than added later as guests, and their unpaired electrons stand ready to serve as charge carriers without the need for counterions or any other external chemical species.

The results reported in the journal Angewandte Chemie International Edition are striking on several fronts. The radical-embedded framework crystallised into an ordered lattice and exhibited genuine semiconducting behaviour, with room-temperature electrical conductivity ranking among the highest values ever recorded for a neutral, non-doped COF. Crucially, the material did not sacrifice the property that makes COFs so attractive in the first place. The framework retained a specific surface area exceeding 1,200 square metres per gram, a figure that speaks to an internal landscape of pores preserved intact despite the electronic functionality now built into its walls.

What distinguishes this approach from earlier attempts to electrify COFs is the intimate integration of function and structure. The TOT radicals are not additives suspended within the pores or molecules grafted onto the surface as an afterthought. They are part of the molecular backbone itself, positioned by design so that their unpaired electrons can participate in charge transport. The ordered arrangement of these radical units throughout the framework creates pathways along which charges can move, turning the entire crystalline edifice into a conduit for electricity. In conventional doped systems, by contrast, the charge carriers and the framework often coexist uneasily, with the dopant acting as an intruder whose presence is tolerated rather than celebrated.

The significance of the achievement lies in the simultaneous preservation of three properties that chemists have historically struggled to reconcile: electrical conductivity, crystallinity and porosity. Materials that conduct well tend to be dense and disordered; materials that are porous and crystalline tend to be insulating. By embedding stable radicals into the framework’s architecture, the Spanish team has demonstrated that these attributes need not be mutually exclusive. The study further shows that the framework can be modified by selecting different molecular components and linkages, offering chemists a tunable dial for adjusting the electronic properties of the resulting materials. That modularity is one of the great promises of COF chemistry, and the new work suggests it can now be extended into the semiconducting regime without compromise.

The practical implications stretch across a remarkably broad technological canvas. Conductive, porous and crystalline organic frameworks could serve in electronics, where their processability and structural diversity offer advantages over rigid inorganic semiconductors. They could underpin spintronics, a field that exploits electron spin rather than charge alone, since the embedded radicals carry intrinsic spin character. Their porosity makes them natural candidates for sensors, where target molecules can diffuse into the material and modulate its electrical response, and for electrochemical devices where ion and electron transport must be coordinated. Energy storage looms particularly large on the horizon, because the TOT units can reversibly accept electrons, a property that points toward their use as active materials in batteries. The researchers are careful to note that these applications remain prospects for future investigation rather than demonstrated realities, but the foundational chemistry is now in place.

Behind the paper lies a story of interdisciplinary synergy within a single research centre. Synthesising a COF is a synthetic chemist’s challenge, demanding the precise design of molecular building blocks and the control of polymerisation conditions; characterising its electronic behaviour is a physicist’s task, requiring careful measurement of conductivity and charge transport; and understanding how structure governs function demands expertise spanning both. The groups of Souto, Peña and Rivadulla contributed complementary perspectives on the design, synthesis, characterisation and property studies of the new materials. The collaboration also extended beyond Spain’s borders, drawing in scientists at the CICECO-Aveiro Institute of Materials at the University of Aveiro in Portugal, whose contributions helped complete the picture of the framework’s structure and behaviour.

The work has already attracted attention beyond the specialist literature. Chemical & Engineering News, the news magazine of the American Chemical Society, recently highlighted the study as a new route to producing semiconducting COFs without dopants, a signal that the broader chemistry community regards the strategy as more than an incremental advance. Published under the title Semiconducting Covalent Organic Frameworks Based on Spin-Delocalized Trioxotriangulene Neutral Radicals, the paper arrives at a moment when demand is surging for organic electronic materials that can be manufactured cheaply, tuned molecularly and deployed in applications where silicon cannot follow. CiQUS, which holds María de Maeztu Unit of Excellence accreditation and CIGUS recognition from the Xunta de Galicia, and receives support from the European Union through the Galicia FEDER 2021–2027 Programme, has positioned itself at the forefront of that effort. If the radical-embedded framework approach proves general, the era of doping organic semiconductors may be drawing to a close, replaced by materials that carry their own charge, pore by pore, bond by bond.

Subject of Research: Dopant-free semiconducting covalent organic frameworks based on spin-delocalized trioxotriangulene neutral radicals

Article Title: New strategy to produce porous organic semiconductors without doping

Article References: New strategy to produce porous organic semiconductors without doping. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: covalent organic frameworks, COFs, organic semiconductors, trioxotriangulene radicals, dopant-free conductivity, charge transport, porosity, crystallinity, energy storage, spintronics, CiQUS, Angewandte Chemie