Palladium(II) complexes with 2,4-dichloro-N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives and triphenylphosphine as effective catalysts for oxidation of alcohols in ionic liquid

• Published in: Inorganic chemistry communications Vol. 89; pp. 55 - 59
• Main Author: Gunasekaran, Nanjappan
• Format: Journal Article
• Language: English
• Published: AMSTERDAM Elsevier B.V 01.03.2018; Elsevier
• Subjects: Acylthiourea; Chemistry; Chemistry, Inorganic & Nuclear; H2O2; Ionic liquid; Oxidation of alcohols; Palladium(II); Physical Sciences; Science & Technology; Acylthiourea; Palladium(II); H2O2; Oxidation of alcohols; Ionic liquid; PROPERTY; AEROBIC OXIDATION; COORDINATION; ALDEHYDES; MONODENTATE ACYLTHIOUREA LIGANDS; BENZYL ALCOHOL
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2018.01.008

New four-coordinated distorted square-planar palladium(II) complexes of the type [Pd(PPh3)2(L)]+PF6− (1–4) {where L = 2,4-dichloro-N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives} were prepared from the reactions between [PdCl2(PPh3)2] and 2,4-dichloro-N-(diisobutylcarbamothioyl)benzamide (HL1) or 2,4-dichloro-N-(diethylcarbamothioyl)benzamide (HL2) or 2,4-dichloro-N-(dibutylcarbamothioyl)benzamide (HL3) or 2,4-dichloro-N-(dibenzylcarbamothioyl)benzamide (HL4) in methanol. These complexes have been characterized by elemental analyses, IR, UV/Vis, 1H, 13C and 31P NMR spectroscopy. Besides, without any additive and base, the complexes 1–4 (0.005 mmol) exhibited good catalytic activity with the combination of hydrogen peroxide (3.0 mmol) and 1-butyl-3-methylimidazolium hexafluorophosphate {[bmim][PF6]} (0.1 mL) for the oxidation of primary and secondary alcohols (0.5 mmol) to their corresponding aldehydes and ketones respectively, at 80 °C. New four-coordinated distorted square-planar palladium(II) complexes of the type [Pd(PPh3)2(L)]+PF6− were found to be active catalysts in 1-butyl-3-methylimidazolium hexafluorophosphate medium in the presence of H2O2 for the oxidation of various alcohols at 80 °C. Interestingly, the present catalytic system worked for the oxidation of alcohols without any additive and base. [Display omitted] •Efficient oxidation of alcohols to carbonyl compounds in the presence of H2O2 in 1-butyl-3-methylimidazoliumhexafluorophosphate•Benzylic and allylic alcohols are oxidized efficiently•Square-planar Pd(II) complexes act as effective catalysts for the oxidation of alcohols in ionic liquid.