Manuel Melle-Franco

University of Aveiro | UA · CICECO - Centre for Research in Ceramics and Composite Materials

Controlling the edge morphology and terminations of graphene nanoribbons (GNR) allows tailoring their electronic properties and boosts their application potential. One way of making such structures is encapsulating them inside single‐walled carbon nanotubes. Despite the versatility of Raman spectroscopy to resolve strong spectral signals of these s...

In this study, we report the synthesis of a series of planar and helical dinaphthophenazines by cyclocondensation reactions between the newly developed 9,10-bis((triisopropylsilyl)ethynyl)anthracene-1,2-dione and different diamines. Their optoelectronic and electrochemical properties are studied by ultraviolet-visible (UV-vis) spectroscopy, fluores...

Molecular nanoribbons are a class of atomically‐precise nanomaterials for a broad range of applications. An iterative approach that allows doubling the lenght of the longest pyrene‐pyrazoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach –with a 60 linearly‐fused ring backbone (14.9 nm) and a 324‐a...

Molecular nanoribbons are a class of atomically‐precise nanomaterials for a broad range of applications. An iterative approach that allows doubling the lenght of the longest pyrene‐pyrazoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach –with a 60 linearly‐fused ring backbone (14.9 nm) and a 324‐a...

The quality of crystalline two-dimensional (2D) polymers1–6 is intimately related to the elusive polymerization and crystallization processes. Understanding the mechanism of such processes at the (sub)molecular level is crucial to improve predictive synthesis and to tailor material properties for applications in catalysis7–10 and (opto)electronics1...

Investigations of clathrate structures have gained a new impetus with the recent discovery of room-temperature superconductivity in metal hydrides. Here we report the finding, through density functional theory calculations, of a clathrate phase in the fullerite C60 system. Intermolecular bonds of the type 5/5 2 + 3 cycloaddition are induced between...

Molecular conformation has an important role in chemistry and materials science. Molecular nanoribbons can adopt chiral twisted helical conformations. However, the synthesis of single-handed helically twisted molecular nanoribbons still represents a considerable challenge. Herein, we describe an asymmetric approach to induce single-handed helicity...

Several antitumor drugs base their cytotoxicity on their capacity to intercalate between base pairs of DNA. Nevertheless, it has been established that the mechanism of intercalation of drugs in DNA starts with the prior groove binding mode of interaction of the drug with DNA. Sometimes, for some kind of flat small molecules, groove binding does not...

Two-dimensional fused aromatic networks (2D FANs) have emerged as a highly versatile alternative to holey graphene. The synthesis of 2D FANs with increasingly larger lattice dimensions will enable new application perspectives. However, the synthesis of larger analogs is mostly limited by lack of appropriate monomers and methods. Herein, we describe...

Two‐dimensional fused aromatic networks (2D FANs) have emerged as a highly versatile alternative to holey graphene. The synthesis of 2D FANs with increasingly larger lattice dimensions will enable new application perspectives. However, the synthesis of larger analogs is mostly limited by lack of appropriate monomers and methods. Herein, we describe...

Herein we report the synthesis of covalently functionalized carbon nano-onions (CNOs) via a reductive approach using unprecedented alkali-metal CNO intercalation compounds. For the first time, an in situ Raman study of the controlled intercalation process with potassium has been carried out revealing a Fano resonance in highly doped CNOs. The inter...

Investigations of clathrate structures have gained a new impetus with the recent discovery of room-temperature superconductivity in metal hydrides. Here we report the finding, through density functional theory calculations, of a clathrate phase in the fullerite C60 system. Intermolecular bonds of the type 5/5 2+3 cycloaddition are induced between e...

The effect of polypropylene (PP) on the Seebeck coefficient (S) of carbon nanofibers (CNFs) in melt-extruded PP composites filled with up to 5 wt. % of CNFs was analyzed in this study. The as-received CNFs present an electrical conductivity of ~320 S m⁻¹ and an interesting phenomenon of showing negative S-values of −5.5 μVK⁻¹, with 10⁻² µW/mK² as t...

The synthesis of three molecular nanoribbons with a twisted aromatic framework is described. The largest one shows a 53 linearly fused rings backbone (12.9 nm) and 322 conjugated atoms in its aromatic core (C296N24S2). This new family of nanoribbons shows extremely high molar absorptivities, reaching 986 100 M–1 cm–1, and red-emitting properties.

Synthesis of covalent organic frameworks (COFs) is well-advanced but understanding their nanoscale structure and interaction with other materials remains a significant challenge. Here, we have developed a methodology for the detailed imaging and analysis of COF crystallites using carbon nanotube substrates for COF characterisation. Detailed investi...

A new wavy 2D covalent organic framework shines light on the structural factors that dominate charge transport.

Tailored synthesis of nanographenes, and especially graphene nanoribbons (GNR), has been achieved on metal substrates via a bottom-up approach from organic precursors, which paves the way to their application in nanoelectronics and optoelectronics. Since quantum confinement in nanographenes leads to the creation of peculiar band structures, strongl...

Three‐dimensional covalent organic frameworks (3D COFs) with a pcu topology have been obtained from distorted polycyclic aromatic hydrocarbons acting as triangular antiprismatic (D3d) nodes. Such 3D COFs are six‐fold interpenetrated as the result of interframework π‐stacking, which enable charge transport properties that are not expected for 3D COF...

Three‐dimensional covalent organic frameworks (3D COFs) have been obtained from distorted polycyclic aromatic hydrocarbon nodes. Interframework π‐stacking enables charge transport properties that are not expected for 3D COFs. Abstract Three‐dimensional covalent organic frameworks (3D COFs) with a pcu topology have been obtained from distorted poly...

Metal-free carbon-based catalysts have gained much attention during the last 15 years as an alternative toward the replacement of platinum-based catalysts for the oxygen reduction reaction (ORR). However, carbon-based catalysts only show promising catalytic activity in alkaline solution. Concurrently, the most optimized polymer electrolyte membrane...

Herein, we report the synthesis of mechanically interlocked nitrogenated nanographenes. These systems have been obtained by clipping different tetralactam macrocycles around a 1.9 nm dumbbell-shaped nitrogenated nanographene. Thermal, optoelectronic, and electrochemical characterization of the different mechanically interlocked nanographenes eviden...

The originality of phosphorene is suppressed by its structural defects, irreproducibility, and sensitivity to the ambient environment. To preserve phosphorene's essential characteristics, for example, influencing the charge redistribution and generating the formation of active centers, noble-metal decoration is found to be an efficient approach. He...

Vapor grown carbon nanofiber (CNF) based ink dispersions were used to dip-coat woven cotton fabrics with different constructional parameters, and their thermoelectric (TE) properties studied at room temperature. Unlike the positive thermoelectric power (TEP) observed in TE textile fabrics produced with similar carbon-based nanostructures, the CNF-b...

The Clar Goblet, the first radical bowtie nanographene proposed by Erich Clar nearly 50 years ago, was recently synthesized. Bowtie nanographenes present quasi-degenerate magnetic ground states which make them so elusive as unique. We present a thorough analysis of the spin states energetics of Clar Goblet and bowtie nanographenes by a battery of e...

A new strategy to obtain distorted pyrene-fused azaacenes is reported.

Electroactive organic molecules exhibiting electrical conductivity, redox‐activity, optical or magnetic properties have emerged in recent years as promising building blocks for the design of crystalline porous frameworks, such as metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), with numerous functions in electronics. In this...

Producing crystals of the desired form (polymorph) is currently a challenge as nucleation is yet to be fully understood. Templated crystallisation is an efficient approach to achieve polymorphs selectivity; however, it is still unclear how to design the template to achieve selective crystallisation of specific polymorphs. More insights into the nan...

The motion of molecular fragments in close contact with atomically flat surfaces is still not fully understood. Does a more favourable interaction imply a larger barrier towards motion even if there are no obvious minima? Here, we use mechanically interlocked rotaxane-type derivatives (MINTs) of single-walled carbon nanotubes (SWNTs) featuring four...

A straightforward method for the synthesis of two dibenzo[a,h]anthracene-5,6,12,13-diquinone building blocks is reported. To showcase their usefulness, a series of dibenzo[a,h]anthracene nitrogenated derivatives have been synthesized that show different optoelectronic, redox, and charge transport properties, illustrating their potential as organic...

Graphene quantum dots (GQDs) possess excellent optical properties, high photostability, aqueous solubility and bio-compatibility. The presence of carboxyl and hydroxyl groups on GQDs surface and edges provides an excellent opportunity to explore them as anchoring units for covalent functionalization. In addition, the nonlinear optical response of G...

We use mechanically interlocked rotaxane-type derivatives of SWNTs (MINTs) featuring four different types of macrocycles with significantly different affinities for the SWNT thread as models to study this problem. Using molecular dynamics, we find that there is no direct correlation between the interaction energy of the macrocycle with the SWNT and...

Electroactive organic molecules have received a lot of attention in the field of electronics because of their fascinating electronic properties, easy functionalization and potential low cost towards their implementation in electronic devices. In recent years, electroactive organic molecules have also emerged as promising building blocks for the des...

Herein, we describe a series of three sterically congested nitrogenated benzodipentaphenes, one of which shows a highly distorted aromatic backbone with an unprecedented double π-expanded helicene structure.

The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)...

Fullerene derivatives are used in a wide range of applications including as electron acceptors in solution-processable organic photovoltaics. We report agglomeration of fullerene derivatives in optically opaque solutions of PC 61 BM and PC 71 BM, with concentrations ranging from 30 mg mL À1 up to 90 mg mL À1 , in different solvents with relevance t...

We studied the key electronic properties of a family of 2D frameworks structurally convergent with holey graphenes. The bandgap of these materials decreases monotonically with size showing a common trend with anthracenes and kekulenes . This is rationalized by Clar’s sextet rule which reveals a direct relationship between the molecular systems and...

The fourth author’s name was unfortunately misspelled on the first page and the first page of the ESM. Instead of Susy Piovesana1, Daniel Iglesias2, Manuel Melle-Franco3, Slavo Kralj4, Chiara Cavaliere1, Michele Melchionna2, Aldo Laganà1,5, Anna L. Capriotti1 (✉), and Silvia Marchesan2 (✉) It should read Susy Piovesana1, Daniel Iglesias2, Manuel Me...

Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen‐doped pyrene‐fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic h...

Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen‐doped pyrene‐fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic h...

In the last decades, photocatalysis has arisen as a solution to degrade emerging pollutants such as antibiotics. However, the reduced photoactivation of TiO 2 under visible radiation constitutes a major drawback because 95% of sunlight radiation is not being used in this process. Thus, it is critical to modify TiO 2 nanoparticles to improve the abi...

Protein and peptide phosphorylation regulate numerous pathological processes, however, their characterization is challenging due to their low abundance and transient nature. Therefore, nanomaterials are being developed to address this demanding task. In particular, carbon nanostructures are attracting interest as scaffolds for functional nanocompos...

The elusive Clar goblet, a magnetic, bowtie shaped nanographene is now synthesized and its peculiar magnetic ground state is characterized.

Novel C 60 and C 70 N-methyl-fulleropyrrolidine derivatives, containing both electron withdrawing and electron donating substituent groups, were synthesized by the well-known Prato reaction. The corresponding highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels were determined by cyclic voltammetry, fro...

We present herein the development of a new polycationic cyclophane the “red box”, second in a series of hydrazone-based analogues of the well-known organic receptor cyclobis(paraquat-p-phenylene)cyclophane (“blue box”). The macrocycle has been prepared in an excellent yield in aqueous media, and shows both a remarkable pH-responsiveness and unusual...

Deep eutectic solvents (DES) present interesting properties, mostly connected to their solvation ability, and have been subject to much research in the recent past. Currently, the discovery of new eutectic solvents is accomplished by experimentally measuring the eutectic point of random systems, often using choline chloride as a hydrogen bond accep...

The design of advanced N-doped carbon materials towards oxygen reduction reaction (ORR) catalysis is only possible if the nature of the active sites is fully understood. There is an important piece of research seeking to overcome this challenge through experimental or theoretical results. However, the combination of both approaches is necessary to...

Four decades after the first (and only) reported synthesis of kekulene, this emblematic cycloarene has been obtained again through an improved route involving the construction of a key synthetic intermediate, 5,6,8,9-tetrahydrobenzo[m]tetraphene, by means of a double Diels-Alder reaction between styrene and a versatile benzodiyne synthon. Ultrahigh...

div> Supramolecular polymers have a lot of potential in the development of new materials because of their inherent recyclability and their self-healing and stimuli-responsive properties. Supramolecular conductive polymers are generally obtained by the assembly of individual disk-like π-conjugated molecules into columnar arrays that provide an opti...

A high degree of crystallinity is an essential aspect in two-dimensional covalent organic frameworks, as many properties depend strongly on the structural arrangement of the different layers and their constituents. We introduce herein a new design strategy based on core-twisted polycyclic aromatic hydrocarbon as rigid nodes that give rise to a two-...

Supramolecular polymers have a lot of potential in the development of new materials because of their inherent recyclability and their self‐healing and stimuli‐responsive properties. Supramolecular conductive polymers are generally obtained by the assembly of individual aromatic molecules into columnar arrays that provide an optimal channel for elec...

Die Sache hat einen Haken: Ein Ansatz zur Herstellung supramolekularer Polymere durch das Verhaken S‐förmiger Monomere in 1D‐Anordnungen π‐gestapelter Anthracen‐ und Acridin‐Einheiten wird vorgestellt. Die daraus resultierenden Mikrometer‐großen Fasern zeigen Pseudoleitfähigkeiten im Einklang mit anderen leitenden Materialien. Abstract Supramolecu...

A face-centered cubic (fcc) polymerized C60 phase has been synthesized at 9.5 GPa and 550 °C. The observed short lattice constant, 13.19 Å, indicates that a three-dimensional (3D) polymer with adjacent C60 molecules covalently bonded was obtained. Possible polymerized structures, with each molecule adopting one of the two standard orientations, hav...

We report the first Ru(II) coordination compounds that interact with DNA through a canonical minor groove insertion mode and with selectivity for A/T rich sites. This was made possible by integrating a bis‑benzamidine minor groove DNA-binding agent with a ruthenium(II) complex. Importantly, one of the enantiomers (Δ‑[Ru(bpy)2b4bpy]2+, Δ‑4Ru) shows...

A variety of planar π-conjugated hydrocarbons such as heptauthrene, Clar’s goblet and, recently synthesized, triangulene have two electrons occupying two degenerate molecular orbitals. The resulting spin of the interacting ground state is often correctly anticipated as S = 1, extending the application of Hund’s rules to these systems, but this is n...

There is a lack of fundamental knowledge on deep eutectic solvents, even for the most extensively studied mixtures, such as the mixture of cholinium chloride and urea, that prevents a judicious choice of components to prepare new solvents. The objective of this work is to study and understand the fundamental interactions between cholinium chloride...

A variety of planar {\pi}-conjugated hydrocarbons such as heptauthrene, Clar's goblet and, recently synthesized, triangulene have two electrons occupying two degenerate molecular orbitals. The resulting spin of the interacting ground state is often correctly anticipated as S = 1, extending the application of Hund's rules to these systems, but this...

div> Controlled nitrogen-doping is a powerful methodology to modify the properties of carbon nanostructures and produce functional materials for electrocatalysis, energy conversion and storage, and sensing, among others. Herein, we report a wall- and hybridisation-selective synthetic methodology to produce double-walled carbon nanotubes with an in...

We report the first Ru(II) coordination compounds that interact with DNA through a canonical minor groove insertion mode and with selectivity for A/T rich sites. This was made possible by integrating a bis‑benzamidine minor groove DNA-binding agent with a ruthenium(II) complex. Importantly, one of the enantiomers (Δ‑[Ru(bpy)₂ b4bpy ]<sup...

Controlled nitrogen‐doping is a powerful methodology to modify the properties of carbon nanostructures and produce functional materials for electrocatalysis, energy conversion and storage, and sensing, among others. Herein, we report a wall‐ and hybridisation‐selective synthetic methodology to produce double‐ walled carbon nanotubes with an inner t...

Controlled nitrogen‐doping is a powerful methodology to modify the properties of carbon nanostructures and produce functional materials for electrocatalysis, energy conversion and storage, and sensing, among others. Herein, we report a wall‐ and hybridisation‐selective synthetic methodology to produce double‐ walled carbon nanotubes with an inner t...

Herein, we describe the synthesis of a hole transporting material based on a partially planarised quart-p-phenylene core incorporating tetraketal and diphenylamine substituents that show optimal energy levels and solubility for perovskite solar cell applications. The triple-cation perovskite devices incorporating such quart-p-phenylene derivatives...

div> Herein, we describe the synthesis of a hole transporting material based on a partially planarised quart-p-phenylene core incorporating tetraketal and diphenylamine substituents that show optimal energy levels and solubility for perovskite solar cell applications. Triple-cation perovskite devices incorporating such quart-p-phenylene derivative...

The synthesis and optical, electrochemical, thermal and electrical characterization of a new and unexpected 1-n-octyloxyperopyrene is reported. The structure of 1-n-octyloxyperopyrene has been unambiguously established by single crystal X-ray diffraction. The solubility of this polycyclic aromatic hydrocarbon, endowed by the alkoxy substituent, all...

div> The synthesis and optical, electrochemical, thermal and electrical characterization of a new and unexpected 1-n-octyloxyperopyrene is reported. The structure of 1-n- octyloxyperopyrene has been unambiguously established by single crystal X-ray diffraction. The solubility of this polycyclic aromatic hydrocarbon, endowed by the alkoxy substitue...

Acenes have received a lot of attention because of their inherent and tunable absorbing, emissive, and charge transporting properties for electronic, photovoltaic, and singlet fission applications, among others. Such properties are directly governed by molecular packing, and therefore, controlling their arrangement in the solid state is of utmost i...