The reactivity of [Rh7(CO)16]3– with SbCl3 has been deeply investigated with the aim of finding a new approach to prepare atomically precise metalloid clusters. In particular, by varying the stoichiometric ratios, the reaction atmosphere (carbon monoxide or nitrogen), the solvent, and by working at room temperature and low pressure, we were able to prepare two large carbonyl clusters of nanometer size, namely, [Rh20Sb3(CO)36]3– and [Rh21Sb2(CO)38]5–. A third large species composed of 28 metal atoms was isolated, but its exact formulation in terms of metal stoichiometry could not be incontrovertibly confirmed. We also adopted an alternative approach to synthesize nanoclusters, by decomposing the already known [Rh12Sb(CO)27]3– species with PPh3, willing to generate unsaturated fragments that could condense to larger species. This strategy resulted in the formation of the lower-nuclearity [Rh10Sb(CO)21PPh3]3– heteroleptic cluster instead. All three new compounds were characterized by IR spectroscopy, and their molecular structures were fully established by single-crystal X-ray diffraction studies. These showed a distinct propensity for such clusters to adopt an icosahedral-based geometry. Their characterization was completed by ESI-MS and NMR studies. The electronic properties of the high-yield [Rh21Sb2(CO)38]5– cluster were studied through cyclic voltammetry and in situ infrared spectroelectrochemistry, and the obtained results indicate a multivalent nature.

Nanoclusters

Reactivity

Stoichiometry

10.1021/acs.inorgchem.9b03135

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Interstitial Bismuth Atoms in Icosahedral Rhodium Cages: Syntheses, Characterizations, and Molecular Structures of the [Bi@Rh₁₂(CO)₂₇]^3–, [(Bi@Rh₁₂(CO)₂₆)₂Bi]^5–, [Bi@Rh₁₄(CO)₂₇Bi₂]^3–, and [Bi@Rh₁₇(CO)₃₃Bi₂]^4– Carbonyl Clusters

Inorganic Chemistry (2017)

Cristina Femoni Guido Bussoli Iacopo Ciabatti Marco Ermini Mohammad Hayatifar

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.

Bismuth

10.1021/acs.inorgchem.7b00409

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Citations (22)

From Mononuclear Complexes to Molecular Nanoparticles: The Buildup of Atomically Precise Heterometallic Rhodium Carbonyl Nanoclusters

Accounts of Chemical Research (2018)

Cristina Femoni Maria Carmela Iapalucci Silvia Ruggieri Stefano Zacchini

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.

Nanoclusters

10.1021/acs.accounts.8b00354

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Citations (29)

X-Ray Excited Optical Luminescence from Lanthanide Ions in Double Phosphate and Double Silicate Crystalline Hosts

Vince Xiaoxuan Guo Marco Bettinelli Fabio Piccinelli Silvia Ruggieri Zhiqiang Wang

Using tunable X-rays from a synchrotron light source, we have observed the X-ray Excited Optical Luminescence (XEOL) from rare earth doped whitlockite phosphate: Ca9La(PO4)7 and Ca9Lu(PO4)7, doped with 1 mol% Ce3+, and silicate garnets: Ca3Sc2Si3O12, doped with 0.5 mol% Pr3+, 1 mol% Eu3+ and 1 mol% Tb3+. Excitation at photon energies across the M5,4-edge of the dopants reveals additional information not normally obtainable with conventional UV/visible or an X-ray line source (Al Kα). It is found that despite the low concentration, photoluminescence yields excited with photon energy at the M5,4-edge of the rare-earth dopant can affect the overall energy transfer to the optical channel positively and negatively. The implication of these observations is discussed. The application of XEOL in the investigation of X-ray scintillators is illustrated.

10.2139/ssrn.4600165

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CCDC 1530618: Experimental Crystal Structure Determination

The Cambridge Structural Database (2017)

Cristina Femoni Guido Bussoli Iacopo Ciabatti Marco Ermini Mohammad Hayatifar

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

10.5517/ccdc.csd.cc1ncqsj

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CCDC 1960490: Experimental Crystal Structure Determination

The Cambridge Structural Database (2020)

Cristina Femoni Tiziana Funaioli Maria Carmela Iapalucci Silvia Ruggieri Stefano Zacchini

10.5517/ccdc.csd.cc23t1mm

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