title: Hydrolysis of 8-quinolyl phosphate monoester: kinetic and theoretical studies of the effect of lanthanide ions.
abstract: 8-Quinolyl phosphate (8QP) in the presence of the trivalent lanthanide ions (Ln = La, Sm, Eu, Tb, and Er) forms a [Ln x 8QP]+ complex where the lanthanide ion catalyzes hydrolysis of 8QP. In reactions with Tb3+ or Er3+, there is evidence of limited intervention by a second lanthanide ion. Rate constants are increased by more than 10(7)-fold, and kinetic data and B3LYP/ECP calculations indicate that the effects are largely driven by leaving group and metaphosphate ion stabilization. The lanthanides favor a single-step D(N)A(N) mechanism with a dissociative transition state, with limited nucleophilic assistance, consistent with the low hydroxide ion dependence and the small kinetic effect of Ln3+ radii.
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil.
authors.forename: Bruno S
authors.initials: BS
authors.lastname: Souza
authors.forename: Tiago A S
authors.initials: TA
authors.lastname: Brandão
authors.forename: Elisa S
authors.initials: ES
authors.lastname: Orth
authors.forename: Ana C
authors.initials: AC
authors.lastname: Roma
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Longo
authors.forename: Clifford A
authors.initials: CA
authors.lastname: Bunton
authors.forename: Faruk
authors.initials: F
authors.lastname: Nome
mesh_terms: D002384:Catalysis; D006868:Hydrolysis; D006912:Hydroxyquinolines / Q000138:chemical synthesis / Q000737:chemistry; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D010755:Organophosphates / Q000737:chemistry*; D011199:Potentiometry; D011804:Quinolines / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D017186:Titrimetry
chemical_list: C517653:8-quinolyl phosphate; D006912:Hydroxyquinolines; D028581:Lanthanoid Series Elements; D010755:Organophosphates; D011804:Quinolines