• Di Giuseppe, Andrea
• Zacchini, Stefano
• Bresciani, Giulio
• Marchetti, Fabio
• Funaioli, Tiziana
• Zappelli, Chiara
• Taglieri, Francesco
• Schoch, Silvia
• Crucianelli, Marcello

Abstract

The new diiron(I) complexes [Fe2Cp2(mu-CO){mu-k3C,kN-C(R1)C(R2)C(CN)NMe(R)}], 3 a-o (R=alkyl or 4-C6H4OMe; R1=alkyl, aryl, ferrocenyl (Fc), thiophenyl, CO2Me or SiMe3; R2=H, Me or CO2Me) were synthesized in moderate to high yields from the thermal decarbonylation of the bis-carbonyl precursors 2 a-o, and were structurally characterized by IR and NMR spectroscopy, and single crystal X-ray diffraction in four cases. Electrochemical behavior of one complex was also investigated. Complexes 3 a-o comprise a highly functionalized, multisite amino-(cyano)allylidene ligand, including metal coordination of a tertiary amine group. Selected complexes displayed negligible to moderate catalytic activity in CO2/propylene oxide coupling, working under ambient conditions. Additionally, they were investigated as catalysts for the conversion of benzaldehyde to the corresponding borate ester 6 a, using pinacolborane (HBpin) as the borylating agent. Most complexes achieved good conversions at room temperature with 1 % catalyst loading, and data highlight the significant influence of the multisite ligand substituents on the catalytic performance. Notably, complex 3 m (featuring R=4-methoxyphenyl, R1=Fc, R2=H) displayed the highest activity and effectively catalyzed the hydroboration of various aldehydes and ketones. A plausible mechanistic cycle involves metal coordination of the carbonyl substrate, its activation being possibly facilitated by intramolecular interactions.New diiron(I) complexes have been synthesized via thermal decarbonylation of bis-carbonyl precursors. They have been characterized by means of IR, NMR, and X-rays. These complexes feature functionalized multisite amino-(cyano)allylidene ligands. Some of them showed high catalytic activity for the conversion of various aldehydes and ketones to the corresponding borate esters, using pinacolborane (HBpin) as the borylating agent. image

Topics

• single crystal X-ray diffraction
• single crystal
• activation
• Nuclear Magnetic Resonance spectroscopy
• ketone
• ester
• amine
• aldehyde