Exploiting the potential of curcuminoids (CCMoids) as molecular platforms, a new 3.53 nm extended system (pyACCMoid, 2) has been designed in two steps by reacting a CCMoid with amino-terminal groups (NH2-CCMoid, 1, of 1.79 nm length) with polycyclic aromatic hydrocarbon (PAH) aldehydes. CCMoid 2 contains pyrene units at both ends as anchoring groups to optimize its trapping in graphene nano-junctions created by feedback-controlled electro-burning. The measured I-V characteristics show gate-dependent behaviour at room temperature and 10 K, with increased conductance values compared to shorter CCMoids previously reported, and in agreement with DFT calculations. Our results show that the adjusted molecular design improves the conductance, as system 2 separates the conductive backbone from the anchor groups, which tend to adopt a planar configuration upon contact with the graphene electrodes. DFT calculations using Green functions of a set of different molecular conformations of 2 on graphene electrodes show a direct relationship between the units (e.g. pyrene, amide, etc.), in the molecule, through which electrons are injected and the conductance values; where the size of the spacing between the graphene electrodes contributes but is not the dominant factor, and thus, counter-intuitively the smallest spacing gives one of the lowest conductance values.

Increasingly, technological progress in miniaturisation for electronic purposes requires synergy between different disciplines, with the connection between chemists, physicists, biologists, theorists, and engineers, for example, being crucial. This is clearly demonstrated in the multidisciplinary approach of OSS, where experimental physics coexists with a solid application of chemical reactivity, supported by theoretical studies, which together have demonstrated the ability to develop 0D-3D molecular-based systems with promising prospects. From a chemical point of view, this fosters the exploration of new families of molecules that may provide different properties, inspire new synthetic routes, and broaden knowledge (and thus new applications). In relation to this, in FunNanoSurf (Functional Nanomaterials and Surfaces, https://funnanosurf.icmab.es/) we focus on the synthesis of curcuminoid species (CCMoids)[1] and derivatives and explore their different uses, apart from their well-known biological applications. CCMoids are linear molecules containing a conjugated backbone, with a central keto-enol moiety and aromatic groups at both ends of the molecular unit, conferring the final system with an overall symmetry. Thanks to their high chemical versatility, straightforward synthesis, and purification, in recent years, we have demonstrated that these systems are excellent molecular platforms and can be used in areas related to molecular electronics (as nanowires),[2] coordination polymers (as excellent heterodiotopic linkers)[3] and now also in OSS exploration. This work aims to make known precisely these points about CCMoid systems and derivatives: their growing potential for use in the same way as other molecular families. Examples of their synthetic plurality, applications, and their possible expansion on surfaces, mainly for electronic purposes, will be presented. [1] Riba-Lopez, D,. Zaffino, R., Herrera, D., Matheu, R., Silvestri, F., Ferreira da Silva, J., Sanudo, E. C., Mas-Torrent, M., Barrena, E., Pfattner, R., Ruiz, E., Gonzalez-Campo, A., Aliaga-Alcalde, N. iScience, 25(12),105686 (2022). [2] (a) Olavarria-Contreras, I. J., Etcheverry-Berrios, A., Qian, W., Gutierrez-Ceron, C., Campos-Olguin, A., Sanudo, E. C., Dulić, D., Ruiz, E., Aliaga-Alcalde, N., Soler, M., van der Zant, H. S. J.Chem. Sci., 9, 34, 6988-6996 (2018). (b) Etcheverry-Berríos, A., Díaz-Torres, R., Jullian, D., Ponce, I., Vásquez, S. O., Olavarria, I., Perrin, M. L., Frisenda, R., van der Zant, H. S. J., Dulić, D., Aliaga-Alcalde, N., Soler, M. Chem. Eur. J., 22, 12808-12818 (2016). (c) Burzurí, E., Island, J., Díaz-Torres, R., Fursina, A., González-Campo, A., Roubeau, O., Teat, S. J., Aliaga-Alcalde, N., Ruiz, E., van der Zant, H. S. J. ACS Nano, 10 (2), 2521-2527 (2016). [3] (a) Rodríguez-Cid, L., Qian, W., Iribarra-Araya, J., Etcheverry-Berríos, Á., Martínez-Olmos, E., Choquesillo-Lazarte, D., Sañudo, E. C., Roubeau, O., López-Periago, A. M., González-Campo, A., Planas, J. G., Soler, M., Domingo, C., Aliaga-Alcalde,N. Dalton Trans. 50, 7056-7054 (2021). (b) L. Rodríguez-Cid, E. C. Sañudo, A. M. López-Periago, A. González-Campo, N. Aliaga-Alcalde, C. Domingo, Crystal Growth and Design, 20, 6555-6564 (2020).

Our work examines the structural-electronic correlation of a new curcuminoid, AlkCCMoid, as a dielectric material on different substrates. For this purpose, we show a homemade sublimation method that allows the direct deposition of molecules on any type of matrix. The electronic properties of AlkCCMoid have been evaluated by measurements on single crystals, microcrystalline powder, and sublimated samples, respectively. GIWAXS studies on surfaces and XRD studies on powder have revealed the existence of polymorphs and the effect that substrates have on curcuminoid organization. We describe the dielectric nature of our system and identify how different polymorphs can affect electronic parameters such as permittivity, all corroborated by DFT calculations.

Triarylphosphines substituted with carboxylic and trifluoromethlyl groups have been prepared by the hydrolysis of trifluoromethyl groups using fuming sulfuric acid and boric acid. The reaction has been studied in a set of homoleptic and heteroleptic trifluoromethylated triarylphosphines and offers a new synthetic procedure for the preparation of carboxylic phosphines with a relatively simple methodology. The degree of carboxylation is modulated by the reaction conditions and is sensitive to the substitution pattern of the starting trifluoromethylated phosphines. A pH-dependent procedure based on the amphiphilic character of these phosphines was developed for their separation and purification. The electronic properties of the synthesized carboxylic-trifluoromethylated phosphines have been analyzed by 31P NMR of the corresponding selenide derivatives. Finally, the structures of two palladium complexes, containing the para and meta carboxylic-trifluoromethylated phosphines are also described, showing different dimeric structures.

The stereoelectronic properties of a series of trifluoromethylated aromatic phosphines have been studied using different approaches. The sigma-donating capability has been evaluated by nuclear magnetic resonance (NMR) spectroscopy of the selenide derivatives and the protonated form of the different trifluoromethylated phosphines. The coupling constants between phosphorous and selenium ((1)J(SeP)) and phosphorous and hydrogen ((1)J(HP)) can be predicted by empirical equations and correlate the basicity of the phosphines with the number and relative position of trifluoromethyl groups. In contrast, the pi-acceptor character of the ligands has been evaluated by measuring the frequency of the CO vibration in the infrared (IR) spectra of the corresponding Vaska type iridium complexes ([IrCl(CO)(PAr3)(2)], PAr3=triarylphosphine). Moreover, the correlation between the electronic properties and the performance of these phosphines as ligands in the rhodium-catalysed hydroformylation of 1-octene has been established. Phosphines with the lowest basicity, that are those with the highest number of trifluoromethyl groups, gave rise to more active catalytic systems.

Trifluoromethylated and sulfonated triarylphosphines are remarkably resistant toward oxidation and very active for the biphasic hydroformylation of polar alkenes.

Nanocrystalline high surface area Mn3O4 powder was obtained at low temperature by a solvent-free route. The precursor was a mixture of manganese (II) acetate, 3,6,9-trioxadecanoic acid (TODA) and ammonium acetate that were intimately mixed by grounding in an agate mortar. Nanocrystalline Mn3O4 was obtained by thermal treatment at 120°C. Powder X-ray diffraction, selected area electron diffraction, high resolution transmission electron microscopy, and Fourier transformed infrared characterization confirmed the formation of the hausmannite phase. The as-prepared mesoporous material has high specific surface area (120m2g−1). The performances of tape casted Mn3O4 nanopowder electrodes were investigated as anode material for lithium ion batteries. High capacity values were achieved at diverse C rates. Capacity fading was found to be dependent on the upper cut off voltage, the presence of a plateau at 2.25V vs. Li+/Li being detrimental for long term cyclability.