Synthesis, characterization and reactions of [RhCl(CO){(PPh2P(CH2CH2O)mCH2CH2Ph2P,P′)}]n (m = 3, 4, 5 n = 1, 2 …) metallacrown crown ethers

Publication date: Available online 4 September 2018Source: Journal of Organometallic ChemistryAuthor(s): Dale C. Smith, Ethan Cagle, Gary M. GrayAbstractThe reactions of [RhCl(cod)]2 and Ph2P(CH2CH2O)nCH2CH2PPh2P (n = 3, 4, 5) under a CO atmosphere yield [RhCl(CO){(Ph2P(CH2CH2O)n CH2CH2Ph2-P,P′)}]m monocarbonyl metallacrown ethers. These complexes are mixtures of cyclic n-mers and monomers with trans coordination geometries at the rhodium. The monocarbonyl rhodium metallacrown ethers reversibly react with CO at atmospheric pressure to form [RhCl(CO)2{(Ph2P(CH2CH2O)nCH2CH2Ph2-P,P′)}]m dicarbonyl metallacrown ethers. These complexes are only stable under a CO atmosphere as demonstrated by 31P{1H} NMR spectroscopy. Upon prolonged exposure to the atmosphere, all the monocarbonyl metallacrown ethers lose CO and undergo phosphine ligand oxidation to form [RhCl(H2O){Ph2P(O)(CH2CH2O)nCH2CH2P(O)Ph2-O,O′}] metallacrown ethers. These are the first examples of metallacrown ethers in which the transition metal is coordinated via phosphine oxide donors.Graphical abstract

Source: Journal of Organometallic Chemistry - September 6, 2018 Category: Chemistry Source Type: research