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A tailored design of asymmetric hole-transporting materials (HTMs) is reported with the synthesis of a family of new HTMs based on the use of the 5H-dithieno[3,2-b:20 ,30 -d]pyran (DTP) moiety endowed with donor p-methoxytriphenylamines. A complete experimental and theoretical characterization of the optoelectronic, electrochemical and thermal properties is presented, showing more marked differences in the latter prompted by the different length of the alkyl chains (ethyl, butyl or hexyl) attached to the DTP core. This chemical design plays an important role in the morphological behavior of the new HTMs, displaying a different ability for the deposition on the top surface of the perovskite layer in perovskite solar cells (PSCs), as evidenced by scanning electron microscopy. The photovoltaic performance of the new DTP-based HTMs is highly affected by this morphological behavior, resulting in a maximum power conversion efficiency (PCE) of 17.39% for the ethyl derivative (DTPA-Et) in planar devices in combination with the state-of-the-art triple cation perovskite [(FAPbI3)0.87(MAPbBr3)0.13]0.92[CsPbI3]0.08. Otherwise, the hexyl derivative (DTPA-Hex) showed a decreased value of PCE of 15.04% due to its higher dispersity in chlorobenzene, resulting in a less uniform and lower quality film. In comparison, the reference cell using spiro-OMeTAD reaches a maximum PCE of 18.06%. This work demonstrates that DTP is a good candidate for the preparation of HTMs with high hole mobilities for exploitation in efficient and stable PSCs., Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub, Descuento UCM

A complete series of experimental and theoretical investigations on the supramolecular polymerization of chiral (1 and 2) and achiral (3) oligo(phenylene ethynylene) tricarboxamides (OPE-TAs) is reported. The performance of seargents-and-soldiers (SaS) and majority rules (MR) experiments has allowed deriving a full set of thermodynamic parameters, including the helix reversal penalty (HRP) and the mismatch penalty (MMP). The results described illustrate the influence exerted by the number of stereogenic centers per monomeric unit and the temperature on the chiral amplification phenomenon. While the HRP decreases upon decreasing the number of chiral side chains, the MMP follows an opposite trend. The experimental trend observed in MR experiments contrasts with that reported for benzenetricarboxamides (BTAs), for which the chiral amplification ability increases by lowering the number of stereogenic centers or increasing the temperature. Theoretical calculations predict that the rotational angle between adjacent monomeric units in the stack (ca. 18°) gradually decreases when decreasing the number of branched chiral side chains and leads to higher MMP values, in good accord with the experimental trend. The reduction of the rotational angle gives rise to less efficient H-bonding interactions between the peripheral amide functional groups and is suggested to provoke a decrease of the HRP as experimentally observed. In BTAs, increasing the number of stereogenic centers per monomeric unit results in a negligible change of the rotation angle between adjacent units (ca. 65°), and, consequently, the steric bulk increases with the number of chiral side chains, leading to higher MMP values. The data presented herein contribute to shed light on the parameters controlling the transfer and amplification of chirality processes in supramolecular polymers, highlighting the enormous influence exerted by the size of the self-assembling unit on the final helical outcome., MINECO, Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub

The synthesis of two series of N-annulated perylene bisimides (PBIs), compounds 1 and 2, is reported, and their selfassembling features are thoroughly investigated by a complete set of spectroscopic measurements and theoretical calculations. The study corroborates the enormous influence that the distance between the PBI core and the peripheral groups exerts on the chiroptical properties and the supramolecular polymerization mechanism. Compounds 1, with the peripheral groups separated from the central PBI core by two methylenes and an ester group, form J-type supramolecular polymers in a cooperative manner but exhibit negligible chiroptical properties. The lack of clear helicity, due to the staircase arrangement of the self-assembling units in the aggregate, justifies these features. In contrast, attaching the peripheral groups directly to the N-annulated PBI core drastically changes the self-assembling properties of compounds 2, which form H-type aggregates following an isodesmic mechanism. These Htype aggregates show a strong aggregation-caused quenching (ACQ) effect that leads to nonemissive aggregates. Chiral (S)-2 and (R)-2 experience an efficient transfer of asymmetry to afford P- and M-type aggregates, respectively, although no amplification of asymmetry is achieved in majority rules or “sergeants-and-soldiers” experiments. A solvent-controlled stereomutation is observed for chiral (S)-2 and (R)-2, which form helical supramolecular polymers of different handedness depending on the solvent (methylcyclohexane or toluene). The stereomutation is accounted for by considering the two possible conformations of the terminal phenyl groups, eclipsed or staggered, which lead to linear or helical self-assemblies, respectively, with different relative stabilities depending on the solvent, MICINN, Generalitat Valenciana, Comunidad de Madrid, MICINN, Generalitat Valenciana, Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub

A family of hexakis-substituted [60]fullerene adducts endowed with the well-known tridentate 2,6- bis(pyrazol-1-yl)pyridine (bpp) ligand for spin-crossover (SCO) systems has been designed and synthesized. It has been experimentally and theoretically demonstrated that these molecular scaffolds are able to form polynuclear SCO complexes in solution. UV-vis and fluorescence spectroscopy studies have allowed monitoring of the formation of up to six Fe(II)–bpp SCO complexes. In addition, DFT calculations have been performed to model the different complexation environments and simulate their electronic properties. The complexes retain SCO properties in the solid state exhibiting both thermaland photoinduced spin transitions, as confirmed by temperature-dependent magnetic susceptibility and Raman spectroscopy measurements. The synthesis of these complexes demonstrates that [60]fullerene hexakis-adducts are excellent and versatile platforms to develop polynuclear SCO systems in which a fullerene core is surrounded by a SCO molecular shell., Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads. By exploiting the intrinsic redox nature of the MIL-100(Fe) material, it is possible to achieve a prolonged activity against Escherichia coli and Listeria innocua due to a triggered two-step carvacrol release from films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction between MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge-transfer process between the metallic MOF counterpart and carvacrol upon certain chemical stimuli. During this process, the preferred carvacrol binding site was monitored by infrared, Mössbauer, and electron paramagnetic resonance spectroscopies, and the results are supported by theoretical calculations.

Electrically conductive metal-organic frameworks (MOFs) have emerged in the past few years as promising materials towards applications in (opto)electronics, electrocatalysis and energy storage, among others. One of the most common strategies for the design of conductive MOFs is based on the use of electroactive organic ligands and their partial oxidation/reduction to increase the number of charge carriers. Although perylene salts were reported as the first molecular conductors, they have been scarcely explored as building blocks for the construction of conductive MOFs. Herein we report the electrical conductivity enhancement of a microporous perylene-based MOF upon partial ligand oxidation by using two-probe single-crystal devices. The origin of the conductivity enhancement is rationalised by means of spectroscopic studies and quantum-chemical calculations, supporting a through-space hopping transport along the herringbone perylene packing. This study opens the way for the design of conductive MOFs based on perylene building blocks.

CRUE-CSIC (Acuerdos Transformativos 2021), The synthesis of two series of N-annulated perylene bisimides (PBIs), compounds 1 and 2, is reported, and their selfassembling features are thoroughly investigated by a complete set of spectroscopic measurements and theoretical calculations. The study corroborates the enormous influence that the distance between the PBI core and the peripheral groups exerts on the chiroptical properties and the supramolecular polymerization mechanism. Compounds 1, with the peripheral groups separated from the central PBI core by two methylenes and an ester group, form J-type supramolecular polymers in a cooperative manner but exhibit negligible chiroptical properties. The lack of clear helicity, due to the staircase arrangement of the self-assembling units in the aggregate, justifies these features. In contrast, attaching the peripheral groups directly to the N-annulated PBI core drastically changes the self-assembling properties of compounds 2, which form H-type aggregates following an isodesmic mechanism. These Htype aggregates show a strong aggregation-caused quenching (ACQ) effect that leads to nonemissive aggregates. Chiral (S)-2 and (R)-2 experience an efficient transfer of asymmetry to afford P- and M-type aggregates, respectively, although no amplification of asymmetry is achieved in majority rules or “sergeants-and-soldiers” experiments. A solvent-controlled stereomutation is observed for chiral (S)-2 and (R)-2, which form helical supramolecular polymers of different handedness depending on the solvent (methylcyclohexane or toluene). The stereomutation is accounted for by considering the two possible conformations of the terminal phenyl groups, eclipsed or staggered, which lead to linear or helical self-assemblies, respectively, with different relative stabilities depending on the solvent., Ministerio de Ciencia, Innovación y Universidades (España), Unidad de Excelencia María de Maeztu, Comunidad de Madrid, Generalitat Valenciana, Depto. de Química Orgánica, Fac. de Ciencias Químicas, TRUE, pub

Two redox and magnetically active perchlorotriphenylmethyl (• PTM) radical units have been connected as end-capping groups to a bis(phenylene)diyne chain through vinylene linkers. Negative and positive charged species have been generated, and the influence of the bridge on their stabilization is discussed. Partial reduction of the electron-withdrawing • PTM radicals results in a class-II mixed-valence system with the negative charge located on the terminal PTM units, proving the efficiency of the conjugated chain for the electron transport between the two terminal sites. Counterintuitively, the oxidation process does not occur along the electron-rich bridge but on the vinylene units. The • PTM radicals play a key role in the stabilization of the cationic species, promoting the generation of quinoidal ring segments.

We demonstrate a simple and effective host–guest strategy for preparing ultra-small lead bromide perovskite QDs through the use of nano-sized MOFs that function as nucleating and host sites.