Manuel Melle-Franco

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

The effect of temperature on the electrical conductivity (σ) and Seebeck coefficient (S) of n-type vapor grown carbon nanofibers (CNFs) and poly(vinylidene fluoride) (PVDF) melt-mixed with 15 wt% of those CNFs is analyzed. At 40 °C, the CNFs show stable n-type character (S=−4.8 µV·K−1) with an σ of ca.165 S·m−1, while the PVDF/CNF composite film sh...

Polypeptides lacking aromatic residues can display in the aggregated state anomalous spectroscopic properties, such as UV absorption and fluorescence emission. Despite the fundamental interest and potential applications of this anomalous luminescence, our understanding of this phenomenon is still poor, and no soluble model system or general design...

Organic cages offer numerous opportunities for creating novel materials suitable for a wide range of applications. Among these, energy-related applications are beginning to attract attention. We report here the synthesis of a [3 + 6] trigonal prismatic cage constituted by three redox-active dibenzotetraazahexacene subunits. Cathodes formulated with...

The electronic behavior of polymerized fullerite structures, ranging from one-dimensional to three-dimensional polymers, was studied using density functional theory with the hybrid Heyd-Scuseria-Ernzerhof functional and a 6-31G(d,p) basis set. The bandgap across these structures decreases with the rise of sp³-carbon content until metallic behavior...

It is well known that molecules confined very close to a surface arrange into molecular layers. Because solid-liquid interfaces are ubiquitous in the chemical, biological and physical sciences, it is crucial to develop methods to easily access molecular layers and exploit their distinct properties by producing molecular layered crystals. Here we re...

Covalent organic frameworks (COFs) are crystalline, ordered networks, that, due to their high surface areas and the opportunity for periodic placement of catalytically active sites, are interesting materials for catalysis. Despite the great interest in the use of COFs for this application, there is currently a lack of fundamental understanding on h...

One of the challenges for the realization of molecular electronics is the design of nanoscale molecular wires displaying long-range charge transport. Graphene nanoribbons are an attractive platform for the development of molecular wires with long-range conductance owing to their unique electrical properties. Despite their potential, the charge tran...

Redox-active covalent organic frameworks (COFs) are promising electrode materials for metal-ion batteries owing to their tunable electrochemical properties, adjustable structure, and resource availability. Herein, we report a series of two-dimensional...

The design and synthesis of strained aromatics provide an additional insight into the relationship between structure and properties. In the last years, several approaches to twist pyrene‐fused azaacenes have been developed that allow to introduce twists of different sizes. Herein, we describe the synthesis of a new set of twisted dibenzotetraazahex...

Superconductivity in the new polymerized C 60 fullerite clathrate doped with simple metals was investigated through density functional theory methods. The phonon dispersion curves were systematically computed for the clathrate structures containing the guest dopants (Li, Na, K, Be, Mg, Ca, Al, Ga, Ge) in one of the two distinct cages, fullerene‐lik...

This review provides a fresh overview of non-canonical amino acids and their applications in the design of peptidomimetics. Non-canonical amino acids appear widely distributed in nature and are known to enhance the stability of specific secondary structures and/or biological function. Contrary to the ubiquitous DNA-encoded amino acids, the structur...

Self-assembled peptide-based hydrogels are archetypical nanostructured materials with a plethora of foreseeable applications in nanomedicine and as biomaterials. N-protected di- and tri-peptides are effective minimalist (molecular) hydrogelators. Independent variation of the capping group, peptide sequence and side chain modifications allows a wide...

Invited for the cover of this issue is the group of Manuel Souto and co‐workers at the University of Aveiro and CICECO‐Aveiro Institute of Materials. The image depicts the direct C−H arylation of dithiophene‐tetrathiafulvalene (DT‐TTF) and the self‐assembly of DT‐TTF‐tetrabenzoic acid studied by using scanning tunnelling microscopy. Read the full t...

Tetrathiafulvalene is among the best known building blocks in molecular electronics due to its outstanding electron‐donating and redox properties. Among its derivatives, dithiophene‐tetrathiafulvalene (DT‐TTF) has attracted considerable interest in organic electronics, owing to its high field‐effect mobility. Herein, we report the direct C−H arylat...

2D monoelemental materials, particularly germanene and silicene (the single layer of germanium and silicon), which are the base materials for modern electronic devices demonstrated tremendous attraction for their 2D layer structure along with the tuneable electronics and optical band gap. The major shortcoming of synthesized thermodynamically very...

A one-step procedure is reported for the synthesis of a crystalline magnetic covalent organic framework (COF) composite. While pre-functionalization of the solid substrate with a building block prior to COF growth is typically required to obtain a crystalline COF composite, our approach uses a sub-stoichiometric amount of the diamino building block...

Neutron capture therapy (NCT) is a form of radiotherapy that exploits the potential of some specific isotopes to capture thermal neutrons and subsequently yield high linear energy transfer (LET) particles, suitable for cancer treatment. Recently, relevant technological improvements have been made in terms of accelerators as suitable neutron sources...

Density functional theory calculations with the hybrid Heyd-Scuseria-Ernzerhof (HSE) functional were used to study the electronic structure of polymerized fullerites, ranging from one-dimensional to three-dimensional polymerized structures. We found that the bandgap across these structures decreases with the rise of the number of sp3 carbons until...

Superconductivity in the new polymerized C60 fullerite clathrate doped with simple metals was investigated through density functional theory methods. The phonon dispersion curves were systematically computed for the clathrate structures containing the guest dopants (Li, Na, K, Be, Mg, Ca, Al, Ga, Ge) in one of the two distinct cages, fullerene-like...

Several dimerization products of fullerene C60 are presented and thoroughly characterized with a quantum chemical DFT model augmented by dispersion. We reanalyze and expand significantly the number of known dimers from 12 to 41. Many of the novel bonding schemes were found by analyzing more than 2 nanoseconds of high energy molecular dynamics semie...

Considerable improvements in the electrocatalytic activity of 2D metal phosphorous trichalcogenides (M2P2X6) have been achieved for water electrolysis, mostly with MII2[P2X6]⁴⁻ as catalysts for hydrogen evolution reaction (HER). Herein, MIMIIIP2S6 (MI = Cu, Ag; MIII = Sc, V, Cr, In) are synthesized and tested for the first time as electrocatalysts...

Organic cages have gained increasing attention in recent years as molecular hosts and porous materials. Among these, barrel‐shaped cages or molecular nanobarrels are promising systems to encapsulate large hosts as they possess windows of the same size as their internal cavity. However, these systems have received little attention and remain practic...

Tetrathiafulvalene is among the most well-known building block in molecular electronics due to its outstanding electron-donating and redox properties. Among its derivatives, dithiophene-tetrathiafulvalene (DT-TTF) received a lot of interest for organic electronics due to its high charge mobility. Herein we report the direct C-H arylation of DT-TTF...

Organic cages have gained increasing attention in recent years as molecular hosts and porous materials. Among these, barrel‐shaped cages or molecular nanobarrels are promising systems to encapsulate large hosts as they possess windows of the same size as their internal cavity. However, these systems have received little attention and remain practic...

The thermoelectric properties, at temperatures from 30 °C to 100 °C, of melt-processed poly(ether ether ketone) (PEEK) composites prepared with 10 wt. % of carbon nanofibers (CNFs) are discussed in this work. At 30 °C, the PEEK/CNF composites show an electrical conductivity (σ) of ~27 S m−1 and a Seebeck coefficient (S) of −3.4 μV K−1, which means...

The synthesis of crystalline one-dimensional polymers provides a fundamental understanding about the structure-property relationship in polymeric materials and allows the preparation of materials with enhanced thermal, mechanical, and conducting properties. However, the synthesis of crystalline one-dimensional polymers remains a challenge because p...

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 length of the longest pyrene‐pyrazinoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach—with a 60 linearly‐fused ring backbone (14.9 nm) and a 324‐...

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...

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 analogues is mostly limited by lack of appropriate monomers and methods. Herein, we descri...

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...

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.

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...

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) 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 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. A thorough analysis is presented of the spin‐state energetics of Clar Goblet and bowtie nanographenes by a battery of...

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...

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...

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...

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...

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)...

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

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...

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