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The International Natural Product Sciences Taskforce: et al., Natural products and their structural analogues have historically made a major contribution to pharmacotherapy, especially for cancer and infectious diseases. Nevertheless, natural products also present challenges for drug discovery, such as technical barriers to screening, isolation, characterization and optimization, which contributed to a decline in their pursuit by the pharmaceutical industry from the 1990s onwards. In recent years, several technological and scientific developments — including improved analytical tools, genome mining and engineering strategies, and microbial culturing advances — are addressing such challenges and opening up new opportunities. Consequently, interest in natural products as drug leads is being revitalized, particularly for tackling antimicrobial resistance. Here, we summarize recent technological developments that are enabling natural product-based drug discovery, highlight selected applications and discuss key opportunities., A.C. and E.I. thank the Ministerio de Ciencia, Innovación y Universidades, Spain (Project AGL2017-89417-R) for support. F.A.M. acknowledges the support by Ministerio de Economia y Competitividad, Spain (project AGL2017-88083-R).

Natural products and their structural analogues have historically made a major contribution to pharmacotherapy, especially for cancer and infectious diseases. Nevertheless, natural products also present challenges for drug discovery, such as technical barriers to screening, isolation, characterization and optimization, which contributed to a decline in their pursuit by the pharmaceutical industry from the 1990s onwards. In recent years, several technological and scientific developments — including improved analytical tools, genome mining and engineering strategies, and microbial culturing advances — are addressing such challenges and opening up new opportunities. Consequently, interest in natural products as drug leads is being revitalized, particularly for tackling antimicrobial resistance. Here, we summarize recent technological developments that are enabling natural product-based drug discovery, highlight selected applications and discuss key opportunities. © 2021, Springer Nature Limited.

The fabrication of metal oxide-based gas sensors with tailored structural design is of particular importance for the early recognition of poisonous/explosive analytes like ammonia, an irritating chemical occurring in a plethora of practical contexts. In this regard, the present work reports on the fabrication and gas sensing application of p-Mn3O4/n-MxOy nanocomposites with MxOy = Fe2O3 or ZnO. The target systems are developed by chemical vapor deposition of Mn3O4 nanosystems on alumina substrates and subsequent functionalization with iron or zinc oxides by sputtering under mild conditions. Material characterization reveals the formation of high purity composites with a controllable dispersion of Fe2O3 or ZnO into Mn3O4, and a close contact between the single constituents. The latter feature, resulting in the formation of p-n junctions and in a tailored modulation of Mn3O4 hole accumulation layer, is of strategic importance in obtaining promising responses to ammonia already at moderate temperatures. Furthermore, Fe2O3 or ZnO functionalization empowers the pristine Mn3O4 with good selectivity toward NH3 against other potential interferents. These results, along with the very favorable detection limits, provide new physical insights for the implementation of gas-sensitive devices with p-n junctions aimed at practical end uses.

Preprint (submitted version) of the article:Molecular Engineering of MnII Diamine Diketonate Precursors for the Vapor Deposition of Manganese Oxide Nanostructuresby:C. Maccato, L. Bigiani, G. Carraro, A. Gasparotto, R. Seraglia, J. Kim, A. Devi, G. Tabacchi, E. Fois, G. Pace, V. Di Noto, D. Barreca, To be cited as:Chem. Eur. J. 2017, 23, 17954-17963DOI: 10.1002/chem.201703423supporting data are available at the links below

The iron(III) beta-diketonate Fe(dpm)3 (dpm = 2,2,6,6-tetramethyl- 3,5-heptanedionate) is investigated as precursor for the thermally- assisted chemical vapor deposition (CVD) of hematite (alpha-Fe2O3) nanostructures. To this aim, the compound gas-phase reactivity is first elucidated by in-situ infrared spectroscopy both under N2 and N2+O2 atmospheres. Subsequently, Fe(dpm)3 is tested in CVDexperiments on various substrates, as a function of the growth temperature, to evaluate the precursor applicability in the preparation of diversified hematite-based materials, potentially addressing various technological end-uses. In this study, relevant results concerning the gas-phase behavior of Fe(dpm)3 and the compositional, structural, morphological, and optical properties of the resulting alpha-Fe2O3 deposits are presented and critically discussed.

Nanocomposite Fe2O3-Co3O4 photoanodes for photoelectrochemical H2O splitting were prepared by a plasma-assisted route. Specifically, Fe2O3 nanostructures were grown by plasma enhanced-chemical vapor deposition, followed by cobalt sputtering for different process durations. The systems were annealed in air after, or both prior and after, sputtering of Co, to analyze the treatment influence on functional performances. The interplay between processing conditions and chemico-physical features was investigated by a multi-technique characterization. Photocurrent density measurements in sunlight-assisted H2O splitting revealed a performance improvement upon Co3O4 loading. A cathodic shift of the onset potential was also observed, highlighting Co3O4 activity as catalyst for the oxygen evolution reaction.

We report on the design of nanosystems based on functionalized α-Fe2O3 nanostructures supported on fluorine-doped tin oxide (FTO) substrates. The target materials were developed by means of hybrid vapor phase approaches, combining plasma assisted-chemical vapor deposition (PA-CVD) for the production of iron(III) oxide systems and the subsequent radio frequency (RF)-sputtering or atomic layer deposition (ALD) for the functionalization with Au nanoparticles or TiO2 overlayers, respectively. The interplay between material characteristics and the adopted processing parameters was investigated by complementary analytical techniques, encompassing X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), and energy dispersive X-ray spectroscopy (EDXS). The obtained results highlight the possibility of fabricating Au/α-Fe2O3 nanocomposites, with a controlled dispersion and distribution of metal particles, and TiO2/α-Fe2O3 heterostructures, characterized by an intimate coupling between the constituent oxides.

Nanostructured Fe2O3 thin films were grown by plasma enhanced-chemical vapor deposition (PE-CVD) from Ar/O2 plasmas for photoelectrochemical (PEC) water splitting applications. Iron oxide coatings were deposited on fluorine-doped tin oxide (FTO) substrates at 300°C under optimized conditions, and subsequently annealed ex situ in air at 650°C. Structural and compositional analyses confirmed the formation of pure alpha-Fe2O3 (hematite), free from other crystalline iron oxide phases. Controlled variations of the deposition time enabled tuning of the thickness and nano-aggregate sizes in the resulting deposits and, correspondingly, their current-voltage characteristics. A maximum photocurrent density close to 1mA/cm2 was achieved at 1.23 V versus the reversible hydrogen electrode (RHE), without the need of any oxygen evolution catalyst or over/underlayer. The present findings revealed the key role played by the engineering of Fe2O3-based nanomaterials, resulting ultimately in a lowered carrier diffusion length, and in an optimal diffusion of tin from FTO into thinner layers. These features offer an amenable opportunity for harvesting radiant energy to trigger water photoelectrolysis and produce clean hydrogen in a carbon-neutral fashion.

An iron(III) beta-diketonate complex, Fe(dpm)(3) (Hdpm = 2,2,6,6-tetramethyl-3,5-heptanedione), has been investigated as a potential precursor for plasma enhanced chemical vapor deposition (PECVD) of iron(III) oxide nanomaterials. Thanks to the combined experimental-theoretical approach, spectroscopic properties, spin state, thermal behavior and fragmentation pathways of Fe(dpm)(3) have been carefully analysed, obtaining an excellent agreement between simulation and experiment. Preliminary PECVD tests evidenced the possibility of obtaining pure and homogeneous Fe2O3 deposits with controlled nano-organization at temperatures as low as 100 degrees C, even on flexible plastic substrates. The present results open up intriguing perspectives for the exploitation of Fe(dpm)(3) as an efficient molecular source for the preparation of nanostructured iron(III) oxides to be used in energetics and gas sensing applications.