title: The organometallic fac-[(CO)3Mn(H2O)3]+ aquaion: base-hydrolysis and kinetics of H2O-substitution.
abstract: The novel organometallic aqua complex [(CO)(3)Mn(H(2)O)(3)](+) (1(+)) was obtained through hydrolysis of the analogous acetone complex. IR [nu(CO) = 2051, 1944 cm(-)(1)] and (17)O NMR spectroscopy revealed the presence of a fac tricarbonyl unit. Potentiometric titrations established that the trimer [(CO)(3)Mn(3)(OH)(4)](-) was the principal condensation product in the pH range >6 prior to slow formation of the tetramer [[(CO)(3)Mn](OH)](4). Water exchange in 1(+), determined by NMR line broadening as k(ex) = 19 +/- 4 s(-)(1) at 298 K, is four orders faster than with the analogous Re complex. The activation volume DeltaV(++) = -4.5 +/- 0.4 cm(3) mol(-1) is indicative of an associatively activated (I(a)) process.
authors.affiliation: Institute of Inorganic Chemistry, Aachen Technical University, D-52056 Aachen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Prinz
authors.forename: Ulrich
authors.initials: U
authors.lastname: Koelle
authors.forename: Stefan
authors.initials: S
authors.lastname: Ulrich
authors.forename: André E
authors.initials: AE
authors.lastname: Merbach
authors.forename: Oliver
authors.initials: O
authors.lastname: Maas
authors.forename: Kaspar
authors.initials: K
authors.lastname: Hegetschweiler