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The aim of my Ph.D. was to widen the chemistry of heterometallic Rh carbonyl clusters and synthesise and characterize new atomically-precise nanoclusters. Along with this, we evaluated the cytotoxicity of some heterometallic clusters through preliminary biological tests against different cell lines, in order to investigate their possible use in biology. Finally, we started testing homometallic Rh clusters in catalytic processes to compare their performances in low-temperature steam reforming reactions with more conventional Rh-based catalysts. More specifically, over these years we focused our attention on the study of four systems, Rh-Bi, Rh-Ge, Rh-Sb and Rh-Au obtaining several new compounds, which we characterized through single crystal X-ray diffractometry, IR spectroscopy, ESI-MS spectrometry and, in some cases, 31P{1H} NMR. As for the biological part, during my period at the Ecole Polytechnique Fédérale de Lausanne (EPFL), we tested some of our new Rh clusters against three cell lines, namely A2780, A2780cisR and HEK-293, in order to evaluate our species as potential cytotoxic agents. The Rh-Ge clusters achieved the best results. Finally, in collaboration with another research group of our same Department, we tested some Rh clusters as active phases in catalysts for the methane steam reforming at low temperature, obtaining similar results with those achieved by using a conventional Rh-based catalyst.

The reaction of the [Rh-7(CO)(16)](3-) cluster anion with Ge2+ salts, in different stoichiometric ratios and under different atmospheres, leads to the formation of new heterometallic Rh-Ge clusters, representing the first known examples of Rh carbonyl compounds containing interstitial germanium atoms. More specifically, under N-2 the reaction progressively affords the new [Rh13Ge(CO)(25)](3-) and [Rh14Ge2(CO)(30)](2-) clusters in good yields, with the Ge atoms located in cubic and square-anti-prismatic cavities, respectively. However, under a CO atmosphere, the [Rh13Ge(CO)(25)](3-) derivative undergoes a significant structural and chemical rearrangement giving the new compound, [Rh12Ge(CO)(27)](4-), where Ge is hosted in an icosahedral metal cage. All species have been characterized by IR spectroscopy and ESI mass spectrometry, and their structures have been elucidated by single-crystal X-ray diffraction. Additionally, preliminary biological tests on the [Rh13Ge(CO)(25)](3-) and [Rh14Ge2(CO)(30)](2-) clusters show that they are cytotoxic to various cell lines.

The reaction of [Rh7(CO)16]3- with BiCl3 under N2 and at room temperature results in the formation of the new heterometallic [Bi@Rh12(CO)27]3- cluster in high yields. Further controlled addition of BiCl3 leads first to the formation of the dimeric [(Bi@Rh12(CO)26)2Bi]5- and the closo-[Bi@Rh14(CO)27Bi2]3- species in low yields, and finally, to the [Bi@Rh17(CO)33Bi2]4- cluster. All clusters were spectroscopically characterized by IR and electrospray ionization mass spectrometry, and their molecular structures were fully determined by X-ray diffraction studies. Notably, they represent the first examples of Bi atoms interstitially lodged in metallic cages that, in this specific case, are all based on an icosahedral geometry. Moreover, [Bi@Rh14(CO)27Bi2]3- forms an exceptional network of infinite zigzag chains in the solid state, thanks to intermolecular Bi-Bi distances.

Aim of the study was to evaluate the influence of living in highly polluted areas in Malta and in Sicily on reported allergic respiratory diseases in children. Malta has a very high population density while the petrochemical industry located close to Gela is one of the main sources of industrial air pollution in Sicily. In the context of RESPIRA Project, we evaluated 2,047 schoolchildren (972 M), aged 10-15 yrs, selected from 12 junior high schools of Southern Sicily (n=1,189 evaluated subjects) and 6 of Malta (n=858). Children′s parents fulfilled an ISAAC respiratory questionnaire. Rhinitis in the last 12 months was reported by 6.6% in Italy and 7.9% in Malta (p=.05); wheeze in the last 12 months (W12m) by 7.4% in Italy and 12.7% in Malta (p, N/A

RESPIRA Study showed living in Malta (urban), Gela (industrial) is a risk for respiratory symptoms compared to rural south Sicily. Aim: To chemically analyze outdoor PM2.5 in these locations. Method: FAI pumps at 10l/min and Teflon(Whatman) filters collected PM2.5 for 48 hours, Malta(n=54), Gela(n=42) and rural areas (n=42), including schools and homes. The ionic component of ICP-MS extraction was measured at CNR Rome. Aeroqual IQM60 measured PM2.5 levels in Malta. PM2.5 in Sicily was calculated from filter weights. Results: Outdoor PM2.5 Malta(n=53) Mean41.1 µg/m3, Median29.7, Q1-13.9, Q3-57.7, p, N/A

Pollutants in particulate matter (PM) are associated with respiratory disorders. Data on indoor concentration of elemental chemical pollutants in highly polluted areas is scanty. In the context of RESPIRA Project, we evaluated both outdoor and indoor concentrations of air pollutants in the Mediterranean area. Gravimetric samples of PM with aerodynamic diameter, N/A

The RESPIRA study (EU-funded Italia-Malta) was performed in the District of Gela (Southern Sicily) and Malta in 2012/3 in 10-15 years children (n=2,047) by questionnaires and clinical exam of cases and controls. Aims: To assess sensitivity to common allergens in these southern Mediterranean islands. Cases (n=137, M=84) reported wheeze and/or use of asthma medications in the last 12 months, while controls (n=159, M=70) answered negatively to both and rhinitis in the last 12 months. A positive SPT (>=3mm) for at least one allergen tested was found in 80/137 cases and 51/159 controls (p=0.0001). House Dust Mite (cases 62/137, controls 28/159, p=0.001), Parietaria (22/137, 10/159, p=0.008), Alternaria (19/137, 9/159, p=0.018), and Blattella (12/137, 5/159, p=0.046) were more frequently positive in cases than in controls. Olive (25/137, 19/159, p=0.142), cat (17/137, 11/159, P=0.116), and dog (9/137, 5/159, p=0.182) did not show a significant difference . Grass pollen sensitization was slightly higher in controls (10/137, 13/159). There was a significant difference by gender in a 2x4 chi2 comparing positive subjects amongst cases and controls. HDM: Males (cases 41/84 Controls 15/70), females (cases 21/53, controls 13/89) p=0.011; Olive: in Males (cases 19/84, controls 10/70) Females (cases 6/53, controls 9/89) p=0.007; Cat: Males (cases.12/84, controls 6/70) Females (cases.5/53 and 5/89) p=0.019; Dog: Males (cases 7/84 and 2/70) and Females (Cases 2 /53 and 4/89) p=0.017. SPT sensitivity to common Mediterranean aero-allergens in asthma patients vs controls was significantly higher in 10-15 year old Males when compared to females., N/A

The reaction of the [Rh-7(CO)(16)](3-) cluster anion with Ge2+ salts, in different stoichiometric ratios and under different atmospheres, leads to the formation of new heterometallic Rh-Ge clusters, representing the first known examples of Rh carbonyl compounds containing interstitial germanium atoms. More specifically, under N-2 the reaction progressively affords the new [Rh13Ge(CO)(25)](3-) and [Rh14Ge2(CO)(30)](2-) clusters in good yields, with the Ge atoms located in cubic and square-anti-prismatic cavities, respectively. However, under a CO atmosphere, the [Rh13Ge(CO)(25)](3-) derivative undergoes a significant structural and chemical rearrangement giving the new compound, [Rh12Ge(CO)(27)](4-), where Ge is hosted in an icosahedral metal cage. All species have been characterized by IR spectroscopy and ESI mass spectrometry, and their structures have been elucidated by single-crystal X-ray diffraction. Additionally, preliminary biological tests on the [Rh13Ge(CO)(25)](3-) and [Rh14Ge2(CO)(30)](2-) clusters show that they are cytotoxic to various cell lines.

Background: Few studies have examined the impact of urban greenspace exposure on lung function in children-adolescents, and the available evidence is still inconsistent. The aim of the current study was to verify the hypothesis that the effects of greenspace exposure vary with differing levels of lung function of children-adolescents. Methods: Between November 2005 and May 2006, 2150 children-adolescents (age-range: 10-15 years) living in the city of Palermo were enrolled in a cross-sectional survey. Parents were interviewed through a modified version of the Italian Studies on Respiratory Disorders in Children and the Environment (SIDRIA) questionnaire. All children-adolescents performed spirometry and were tested for allergic sensitization. Exposures to greenspace and grey space at the home addresses were measured using the CORINE land-cover classes. Parametric quantile regression models were applied for assessing the association between greenspace exposure and spirometry parameters, accounting for possible confounders and effect modifiers. A p-value lower than 0.05 was considered statistically significant. Results: From the 1st to the 21st percentile, children-adolescents living within greenspace had higher FEV1 than those living within grey space. In particular, the estimated effects were: 1st (? = 0.238 L, p = 0.01), 5th (? = 0.140 L, p = 0.01), 10th (? = 0.097 L, p = 0.015), and 15th (? = 0.073 L, p = 0.025). Similarly, from the 1st to the 29th percentile, children-adolescents living within greenspace had higher FVC than those living within grey space. In particular, the estimated effects were: 1st (? = 0.367 L, p = 0.0003), 5th (? = 0.215 L, p = 0.0003), 10th (? = 0.150 L, p = 0.0004), and 15th (? = 0.112 L, p = 0.001). No significant associations were found for FEV1/FVC, FEF25-75 and FEF25-75/FVC. Conclusion: Quantile regression techniques may provide new insights into the evaluation of the association between greenspace exposure and lung function in children-adolescents, showing substantially heterogeneous effects from lower to higher quantiles of spirometry parameters. These results may help implementing policies for planning sustainable housing and surrounding greenspaces.

Chemical research in synthesizing metal nanoparticles has been a major topic in the last two decades, as nanoparticles can be of great interest in many fields such as biology, catalysis, and nanotechnology. However, as their chemical and physical properties are size-dependent, the reliable preparation of nanoparticles at a molecular level is highly desirable. Despite the remarkable advances in recent years in the preparation of thiolate- or p-MBA or PA-protected gold and silver nanoclusters (p-MBA = p-mercaptobenzoic acid; PA = phenylalkynyl), as well as the large palladium clusters protected by carbonyl and phosphine ligands that initially dominated the field, the synthesis of monodispersed and atomically precise nanoparticles still represents a great challenge for chemists.Carbonyl cluster compounds of high nuclearity have become more and more part of a niche chemistry, probably owing to their handling issues and expensive synthesis. However, even in large size, they are known at a molecular level and therefore can play a relevant role in understanding the structures of nanoparticles in general. For instance the icosahedral pattern, proper of large gold nanoparticles, is also found in some Au-Fe carbonyl cluster compounds.Rh clusters in general can also be employed as precursors in homo- and heterogeneous catalysis, and the possibility of doping them with other elements at the molecular level is an important additional feature. The fact that they can be obtained as large crystalline species, with dimensions of about 2 nm, allows one to place them not only in the nanometric regime, but also in the ultrafine-metal-nanoparticle category, which lately has been attracting growing attention. In fact, such small nanoparticles possess an even higher density of active catalytic sites than their larger (up to 100 nm) equivalents, hence enhancing atom efficiency and reducing the cost of precious-metal catalysts. Finally, the clusters' well-defined morphology could, in principle, contribute to expand the studies on the shape effects of nanocatalysts.In this Account, we want to provide the scientific community with some insights on the preparation of rhodium-containing carbonyl compounds of increasing nuclearity. Among them, we present the synthesis and molecular structures of two new heterometallic nanoclusters, namely, [Rh23Ge3(CO)(41)](5-) and [Rh16Au6(CO)(36)](6-), which have been obtained by reacting a rhodium-cluster precursor with Ge(II) and Au(III) salts. The growth of such clusters is induced by redox mechanisms, which allow going from mononuclear complexes up to clusters with over 20 metal atoms, thus entering the nanosized regime.

Cigarette smoke is the main source of indoor chemical and toxic elements. Cadmium (Cd), Thallium (Tl), Lead (Pb) and Antimony (Sb) are important contributors to smoke-related health risks. Data on the association between Rare Earth Elements (REE) Cerium (Ce) and Lanthanum (La) and domestic smoking are scanty. To evaluate the relationship between cigarette smoke, indoor levels of PM2.5 and heavy metals, 73 children were investigated by parental questionnaire and skin prick tests. The houses of residence of 41 "cases" and 32 "controls" (children with and without respiratory symptoms, respectively) were evaluated by 48-hours PM2.5 indoor/outdoor monitoring. PM2.5 mass concentration was determined by gravimetry; the extracted and mineralized fractions of elements (As, Cd, Ce, La, Mn, Pb, Sb, Sr, Tl) were evaluated by ICP-MS. PM2.5 and Ce, La, Cd, and Tl indoor concentrations were higher in smoker dwellings. When corrected for confounding factors, PM2.5, Ce, La, Cd, and Tl were associated with more likely presence of respiratory symptoms in adolescents. We found that: i) indoor smoking is associated with increased levels of PM2.5, Ce, La, Cd, and Tl and ii) the latter with increased presence of respiratory symptoms in children

Syngas and Hydrogen productions from methane are industrially carried out at high temperatures (900 &deg, C). Nevertheless, low-temperature steam reforming can be an alternative for small-scale plants. In these conditions, the process can also be coupled with systems that increase the overall efficiency such as hydrogen purification with membranes, microreactors or enhanced reforming with CO2 capture. However, at low temperature, in order to get conversion values close to the equilibrium ones, very active catalysts are needed. For this purpose, the Rh4(CO)12 cluster was synthetized and deposited over Ce0.5Zr0.5O2 and ZrO2 supports, prepared by microemulsion, and tested in low-temperature steam methane reforming reactions under different conditions. The catalysts were active at 750 &deg, C at low Rh loadings (0.05%) and outperformed an analogous Rh-impregnated catalyst. At higher Rh concentrations (0.6%), the Rh cluster deposited on Ce0.5Zr0.5 oxide reached conversions close to the equilibrium values and good stability over long reaction time, demonstrating that active phases derived from Rh carbonyl clusters can be used to catalyze steam reforming reactions. Conversely, the same catalyst suffered from a fast deactivation at 500 &deg, C, likely related to the oxidation of the Rh phase due to the oxygen-mobility properties of Ce. Indeed, at 500 &deg, C the Rh-based ZrO2-supported catalyst was able to provide stable results with higher conversions. The effects of different pretreatments were also investigated: at 500 &deg, C, the catalysts subjected to thermal treatment, both under N2 and H2, proved to be more active than those without the H2 treatment. In general, this work highlights the possibility of using Rh carbonyl-cluster-derived supported catalysts in methane reforming reactions and, at low temperature, it showed deactivation phenomena related to the presence of reducible supports.

In this review, the authors describe the role of gold in the chemistry of transition metal carbonyl clusters, a field that has been very active over the past fifty years. Both homo- and heteroleptic Au-containing species of metal carbonyl clusters, fully characterized by X-ray analysis, are discussed across three categories: those which are surface decorated by Au(I) fragments, cluster units connected by naked Au(I) atoms, and Au core–shell species with metallic gold structures embedded in the cluster frameworks.

In this microreview, the authors summarize the reactions of [Pt3n(CO)6n]2-(n = 1-10) Chini clusters aimed at their functionalization, modification and transformation. The results are organized on the basis of the fact that the final products do or do not retain the structure of the parent Chini clusters. The first category comprises the redox reactions of homoleptic Chini clusters, CO/phosphine substitution affording heteroleptic Chini-type clusters and the formation of Lewis acid-base adducts by capping the external Pt3-triangular faces with Lewis acids. The second category consists of globular molecular platinum nanoclusters (platinum browns) obtained by thermal decomposition of Chini clusters, as well as surface decorated platinum carbonyl clusters, composed of a low valent Pt-CO core decorated by cationic metal fragments. The relevance of such species to molecular cluster chemistry and metal nanoclusters is outlined.