14774-77-7Relevant articles and documents
Synthesis of Ether-Functionalized and Sterically Demanding Molybdenum Alkylidyne Complexes
àrias, òscar,Ehrhorn, Henrike,H?rdter, Johanna,Jones, Peter G.,Tamm, Matthias
, p. 4784 - 4800 (2018)
The synthesis of ether-functionalized molybdenum benzylidyne complexes [ArC-Mo{OC(CF3)2Me}3] (6, Ar = para-methoxyphenyl; 7, Ar = 2,4,6-trimethoxyphenyl) and of the sterically demanding benzylidyne complex [{2,4,6-(i-Pr)3C6H2}C-Mo{OC(CF3)2Me}3] are presented, together with their spectroscopic characterization, molecular structures, and catalytic activity in alkyne metathesis. Complexes 6 and 7 feature intermolecular contacts between the para-methoxy group and the molybdenum center that give rise to 1D-polymeric structures in the solid state. The preparation of other functionalized alkylidyne complexes, [ArC-Mo{OC(CF3)2Me}3] (Ar = 2-(i-PrO)C6H4, 8-MeO-Naph, 2,6-(i-Pr)2C6H3), was also attempted, but only the acyl precursors [ArC(=O)Mo(CO)5]- could be isolated. The synthesis of the molybdenum acyl complexes was challenging, and appropriate alternative protocols were developed.
Generation of Phosphonium Sites on Sulfated Zirconium Oxide: Relationship to Br?nsted Acid Strength of Surface -OH Sites
Rodriguez, Jessica,Culver, Damien B.,Conley, Matthew P.
supporting information, p. 1484 - 1488 (2019/01/25)
The reaction of (tBu)2ArP (1a-h), where the para position of the Ar group contains electron-donating or electron-withdrawing groups, with sulfated zirconium oxide partially dehydroxylated at 300 °C (SZO300) forms [(tBu)2ArPH][SZO300] (2a-h). The equilibrium binding constants of 1a-h to SZO300 are related to the pKa of [(tBu)2ArPH]; R3P that form less acidic phosphoniums (high pKa values) bind stronger to SZO300 than R3P that form more acidic phosphoniums (low pKa values). These studies show that Br?nsted acid sites on the surface of SZO300 are not superacidic.
Nickel-Catalyzed Cross-Coupling of Organolithium Reagents with (Hetero)Aryl Electrophiles
Heijnen, Dorus,Gualtierotti, Jean-Baptiste,Hornillos, Valentín,Feringa, Ben L.
supporting information, p. 3991 - 3995 (2016/03/16)
Nickel-catalyzed selective cross-coupling of aromatic electrophiles (bromides, chlorides, fluorides and methyl ethers) with organolithium reagents is presented. The use of a commercially available nickel N-heterocyclic carbene (NHC) complex allows the reaction with a variety of (hetero)aryllithium compounds, including those prepared via metal-halogen exchange or direct metallation, whereas a commercially available electron-rich nickel-bisphosphine complex smoothly converts alkyllithium species into the corresponding coupled product. These reactions proceed rapidly (1 h) under mild conditions (room temperature) while avoiding the undesired formation of reduced or homocoupled products. Nickel-catalyzed cross-coupling of aromatic electrophiles with organolithium reagents is presented. The use of a commercially available nickel N-heterocyclic carbene complex allows reaction with a variety of (hetero)aryllithium compounds, whereas a commercially available electron-rich nickel bisphosphine complex smoothly converts alkyllithium species into the corresponding coupled product.
