Catalytic Nitrile-Alkyne Cross-Metathesis

Synthesis and characterization of a trianionic pincer supported Mo-alkylidene anion and alkyne insertion into a Mo(IV)-C bond to form metallocyclopropene(η2-vinyl) complexes

“…The metallocyclopropene proton attached to C27 resonates at 4.82 ppm. Consistent with the unusual metric parameters for C27, it also resonates downfield at 73.1 ppm in the 13 C{ 1 H} NMR spectrum of 10-H. A resonance appears downfield at 252 ppm, typical for alkylidene carbons, and is attributable to C28 of metallocyclopropene. The NMR spectral data of 10-F and 10-CF 3 are similar to 10-H. To confirm their spectral assignments (see Supporting information) a suite of 1D and 2D NMR techniques were performed on a benzene-d 6 solution of 10-F to provide the absolute assignment of all 1 H and 13 C{ 1 H} NMR signals.…”

“…of Mo(NAr)(CHCMe 2 Ph)(OTf) 2 (DME) at À35 C and then slowly warming to 25 C, yields analytically pure crystalline [ t BuOCHO]Mo(NAr)(CHCMe 2 Ph) (5) in 72% yield. 1 H, 13 C{ 1 H} NMR spectroscopy, single crystal X-ray diffraction, and combustion analysis confirm the identity and purity of 5. Crystals suitable for a single crystal X-ray experiment grow from a concentrated solution of 5 in Et 2 O at À35 C. Complex 5 crystallizes in the monoclinic space group P2 1 /c, Fig.…”

“…Close to 120 each, the trigonal plane comprises angles of O1eMo1eO2 ¼ 117.07(5), O1eMo1eN1 ¼ 118.90(6), O2eMo1eN1 ¼ 114.56 (6) . The imido ligand is nearly linear creating an angle of Mo1eN1eC37 ¼ 175.34 (13) , whereas the sp 2 alkylidene bends toward the OCO ligand with an angle of Mo1eC27eC28 ¼ 145.94 (14) . Typical for diphenolate Moalkylidenes bearing an arylimido ligand, the Mo1eC27 bond length is 1.8873(17) Å [34e37] and the Mo]N bond distance is 1.7195(14) Å.…”

Development of a well-defined silica-supported tungstenocarbyne complex as efficient heterogeneous catalyst for alkyne metathesis

“…The system is also resistant to alkyne polymerization, which is problematic for similar homogeneous catalysts. In addition, the surface species 2 reacts with acetonitrile, a reaction which can be considered as the first step of nitrile-alkyne cross-metathesis [28].…”

Catalytic alkyne metathesis and stoichiometric metal–alkylidyne formation from N Mo(OR)3 complexes promoted by Lewis acids

“…Bis(4-methoxyphenyl)acetylene [24,25], VCl 3 (thf) 3 [26], N^Mo(OCMe 3 ) 3 (6) [27], N^Mo(OCMe(CF 3 ) 2 ) 3 (1) [28], and N^Mo(OC(CF 3 ) 3 ) 3 (NCMe) (2) [28], were prepared according to literature procedures. Mesitylene, diphenylacetylene, and chlorotitanium tri-isopropoxide were obtained from Acros.…”