Chemistry of the Metal Carbonyls. XII. New Complexes Derived from Cyclopentadienylcobalt Dicarbonyl¹

Cyclopentadienyl Cobalt Complexes as Precatalysts for Electrocatalytic Hydrogen Evolution

“…All reagents were used as received unless otherwise described. 3‐Phenyl‐5‐(2‐pyridyl)pyrazole (Hpzpy–Ph), 3‐ tert ‐butyl‐5‐(2‐pyridyl)pyrazole (Hpzpy– t Bu), CpCoI 2 (CO), [CpCo(bipy)(CH 3 CN)][ClO 4 ] 2 1 , [CpCo(Hpypz–H)(CH 3 CN)][ClO 4 ] 2 2 , [CpCo(azpy)(CH 3 CN)][ClO 4 ] 2 5 , [CpCo(COD)] 6 , and [DMF–H + ][OSO 2 CF 3 ] were prepared as described previously. Tetra‐ n ‐butylammonium perchlorate (Sigma–Aldrich) was recrystallized from ethanol, dried under reduced pressure, and stored in an inert atmosphere glove box.…”

Conversion of Carbon–Fluorine Bonds α to Transition Metal Centers to Carbon–Hydrogen, Carbon–Carbon, and Carbon–Heteroatom Bonds

“…In contrast, the selective reductive activation of saturated fluorocarbons is rather rare; [126] in one case reduction was stopped at the fluoroalkene stage by chemical interception to give a stable enolate. [127] Activation of Carbon-Fluorine Bonds α to Transition Metal Centers Stable transition metal organometallic compounds containing fluoroalkyl ligands have been known since the halcyon days of organotransition metal chemistry, [128][129][130][131][132] and an early report indicated that their C-F bonds were reactive towards acids (and bases). [133] Not surprisingly, the first complexes of transition metals with tetrafluoroethylene ligands were prepared by chemists at DuPont, [134][135] and it was quickly realized that the structure of the M(η 2 -C 2 F 4 ) fragment resembled that of a saturated metallacyclopropane, with extensive rehybridization of the C-F bonds to acquire more p character.…”

“…Building on early reports from pioneers in the field, [128,131,[160][161] we have published accounts of synthetic routes to such compounds from readily available fluoroalkyl iodides, along with detailed structural characterization of the products. [142][143][144][145][146][147][148][149][150][151][152] Our current longterm objectives are to develop methodology for the catalytic conversion of C-F bonds to C-H and C-C bonds and to design and develop catalytic systems that will accomplish metathesis reactions of perfluorinated alkenes.…”

Spatially Resolved Raman and UV‐visible‐NIR Spectroscopy on the Preparation of Supported Catalyst Bodies: Controlling the Formation of H2PMo11CoO405− Inside Al2O3 Pellets During Impregnation

“…Stable transition metal organometallic compounds containing fluoroalkyl ligands have been known since the halcyon days of organotransition metal chemistry,128–132 and an early report indicated that their C–F bonds were reactive towards acids (and bases) 133. Not surprisingly, the first complexes of transition metals with tetrafluoroethylene ligands were prepared by chemists at DuPont,134–135 and it was quickly realized that the structure of the M(η 2 ‐C 2 F 4 ) fragment resembled that of a saturated metallacyclopropane, with extensive rehybridization of the C–F bonds to acquire more p character 135–136.…”

“…We chose to study fluoroalkyl metal systems as models for fluorocarbon activation. Building on early reports from pioneers in the field,128,131,160–161 we have published accounts of synthetic routes to such compounds from readily available fluoroalkyl iodides, along with detailed structural characterization of the products 142–152. Our current long‐term objectives are to develop methodology for the catalytic conversion of C–F bonds to C–H and C–C bonds and to design and develop catalytic systems that will accomplish metathesis reactions of perfluorinated alkenes.…”