NHCP Ligands for Catalysis

Luminescent Di- and Tetranuclear Gold Complexes of Bis(diphenylphosphinyl)-Functionalized Dipyrido-Annulated N-Heterocyclic Carbene

“…Suitable crystals for X-ray analysis were obtained by slow evaporation of the solution of 1 in THF/hexane. 1 Synthesis of 1(H)PF 6 . The solution of 1(H)I (100 mg, 0.129 mmol) and KPF 6 (47.4 mg, 0.258 mmol) in CH 2 Cl 2 (20 mL) was stirred at room temperature for 24 h. After the reaction solution was concentrated to 2−3 mL under reduced pressure, hexane (10 mL) was added to precipitate the yellow solid 1(H)PF 6 that was collected by filtration.…”

“…Yield: 85.7% (87.8 mg, 0.111 mmol). 1 Synthesis of Complex 2. To a solution of 1(H)PF 6 (20.0 mg, 0.025 mmol) in CH 2 Cl 2 (10 mL) was added [AuCl(SMe 2 )] (14.8 mg, 0.051 mmol), and the resulting solution was stirred at room temperature for 1 h. After being concentrated to 2−3 mL under reduced pressure, hexane (15 mL) was added to precipitate the yellow solid complex 2 that was collected by filtration.…”

“…Suitable crystals for X-ray analysis were obtained by slow diffusion of diethyl ether into the solution of 2 in dimethylformamide. 1 Synthesis of Complex 3. The approximately saturate solution of [AuCl(SMe 2 )] (74.8 mg, 0.254 mmol) in CH 2 Cl 2 (6 mL) was slowly added dropwise to a solution of free carbene 1 (150.0 mg, 0.231 mmol) in hexane (80 mL), and the instantly formed yellow precipitate was collected by filtration.…”

“…Multidentate ligands − containing both N-heterocyclic carbene (NHC) and phosphine moieties can offer combined, complementary electronic properties and coordination geometries to transition metal centers to enhance the desired physical and chemical properties. − Since the first isolation of P-functionalized imidazolium iodide by Herrmann et al in 1996, a growing number of designs of this hybrid class of ligands have been used for synthesizing multinuclear complexes of group 11 metal cations for potential photoluminescent properties. The different geometric designs of the ligand resulted in various degrees of intra- or intermolecular d 10 –d 10 metal interactions, which have been shown to influence their photophysical properties. , …”

A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts

“…Our interest in phosphine­(V) oxides reduction originates from our desire to explore bulky N -phosphinomethyl-functionalized N -heterocyclic carbene ligands (NHCPs) , as potential ligands for new olefin metathesis catalyst (Scheme ). Progress has been severely hampered due to difficulties accessing azolium salt 5 , with the problematic reduction of 4 being achievable only with a large excess of trichlorosilane (27.0 equiv) in anhydrous degassed chlorobenzene at elevated temperature over 2 days .…”