title: Lanthanide derivatives comprising arylhydrazones of β-diketones: cooperative E/Z isomerization and catalytic activity in nitroaldol reaction.
abstract: Two complexes [KLa(HL(1))2{(CH3)2NCHO}2(H2O)3] (1) and [Sm(H2O)9](E-H2L(2))3·2H2O (2) were synthesized by the reaction of lanthanum(III) and samarium(III) nitrates with potassium 3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonate (KH2L(1)) and potassium (E,Z)-5-chloro-3-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)hydrazinyl)-2-hydroxybenzenesulfonate (KH2L(2)), respectively. Both complexes were fully characterized by elemental analysis, IR, (1)H and (13)C NMR spectroscopy, ESI-MS and single-crystal X-ray diffraction. Cooperative E,Z→E isomerization of KH2L(2), induced by resonance assisted hydrogen bonding and ionic interactions, occurs upon the interaction with Sm(III). Catalytic activities of KH2L(1,2) and their lanthanide derivatives were evaluated in the Henry reaction of nitroethane with a variety of aromatic and aliphatic aldehydes. Good yields (up to 91%) and diastereoselectivities (syn/anti 3 : 1) were observed in the reactions catalyzed by 1 in water.
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal. kamran_chem@yahoo.com kamran_chem@mail.ru fatima.guedes@tecnico.ulisboa.pt pombeiro@tecnico.ulisboa.pt.
authors.forename: Kamran T
authors.initials: KT
authors.lastname: Mahmudov
authors.forename: M Fátima C
authors.initials: MF
authors.lastname: Guedes da Silva
authors.forename: Manas
authors.initials: M
authors.lastname: Sutradhar
authors.forename: Maximilian N
authors.initials: MN
authors.lastname: Kopylovich
authors.forename: Fatali E
authors.initials: FE
authors.lastname: Huseynov
authors.forename: Nazim T
authors.initials: NT
authors.lastname: Shamilov
authors.forename: Anna A
authors.initials: AA
authors.lastname: Voronina
authors.forename: Tatyana M
authors.initials: TM
authors.lastname: Buslaeva
authors.forename: Armando J L
authors.initials: AJ
authors.lastname: Pombeiro