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This work describes a complete laboratory experiment that involves the synthesis of a ruthenium complex [Ru(p-cym)(NHC)Cl[subscript 2]] (NHC = N-heterocyclic carbene) and its use as a catalyst for the coupling of hydrosilanes and alcohols. The hydrogen gas produced in the reaction is measured using an inverted buret to trap the gas which allows student to monitor the evolution of the reaction. The complete experience constitutes an opportunity to focus on experimental skills and fundamental concepts in organometallic chemistry and catalysis.

The catalytic performance of a series of mono‐ and bimetallic Ir(I) and Rh(I) complexes bearing the (COC) bis‐triazolylidene ligand, coordinated in a bridging or chelating fashion, was evaluated in the cyclization of 4‐pentynoic acid. The chelated mononuclear cationic complex [Ir(cod)(COC)]PF6 (cod=1,5‐cyclooctadiene; COC=biscarbene ether) displayed the highest reaction rate for 4‐pentynoic acid to form γ‐methyl‐ene‐γ‐butyrolactone (5‐methylenedihydrofuran‐2(3H)‐one). Density Functional Theory calculations were carried out to rationalize the reaction mechanism which proceeds in three steps, namely coordination of the alkyne to the active catalyst followed by intramolecular cyclization and final reductive elimination. Its catalytic performance was further assessed against different substituted 4‐pentynoic acid derivatives. [ABSTRACT FROM AUTHOR]

The deprotonation of a corannulene-based bisazolium salt allowed the preparation of a corannulene-based NHC di-AuI complex. The prepared di-AuI-complex was tested in the recognition of fullerene-C60, demonstrating good binding affinity in toluene solution, and producing a host-guest complex with 3:1 stoichiometry, as evidenced by a combination of NMR spectroscopy and ITC titrations. The experimental results are fully supported by DFT calculations. The binding of C60 with the di-AuI complex in toluene solution is enthalpically and entropically favoured. Remarkably, the entropic term is the dominant parameter in the binding process. The good complementarity that exists between the concave shape of the corannulene-di-gold complex and the convex surface of the fullerene, together with the presence of tBu groups and the AuCl fragment are key factors for the measured high affinity between host and guest. The obtained results indicate that fullerene may be acting as a template for the formation of a self-assembled aggregate involving up to three molecules of the di-AuI complex. [ABSTRACT FROM AUTHOR]

The deprotonation of a corannulene-based bisazolium salt allowed the preparation of a corannulene-based NHC di-AuI complex. The prepared di-AuI-complex was tested in the recognition of fullerene-C60, demonstrating good binding affinity in toluene solution, and producing a host-guest complex with 3:1 stoichiometry, as evidenced by a combination of NMR spectroscopy and ITC titrations. The experimental results are fully supported by DFT calculations. The binding of C60 with the di-AuI complex in toluene solution is enthalpically and entropically favoured. Remarkably, the entropic term is the dominant parameter in the binding process. The good complementarity that exists between the concave shape of the corannulene-di-gold complex and the convex surface of the fullerene, together with the presence of tBu groups and the AuCl fragment are key factors for the measured high affinity between host and guest. The obtained results indicate that fullerene may be acting as a template for the formation of a self-assembled aggregate involving up to three molecules of the di-AuI complex. [ABSTRACT FROM AUTHOR]

A seriesof novel tris-azolium salt precursors based on 1,3,5-triphenylbenzenehave been prepared. These salts exhibit fluorescence emission in the320–420 nm region. The coordination of these salts to [MCl(COD)]2(M = Rh, Ir) was carried out in the presence of KHMDS andallowed the formation of the corresponding tris-NHC complexes of Rhand Ir in high yield. The electronic properties of the new complexeswere analyzed by means of cyclic voltammetry and IR spectroscopy ofthe related carbonylated species. The catalytic activity of the trirhodiumcomplex toward the addition of arylboronic acids to cyclohexen-2-onehas been evaluated and compared to the activity shown by a relatedmonometallic complex. [ABSTRACT FROM AUTHOR]