title: Synthesis, structure, and magnetism of a polyoxometalate with coordinatively unsaturated d-electron-transition metal centers.
abstract: A series of tetrabutylammonium salts of transition-metal substituted Wells-Dawson polyoxometalates has been synthesized by phase-transfer techniques and characterized by infrared spectroscopy, elemental analysis, and variable-temperature magnetic measurements. X-ray-quality crystals were obtained with a diffusion method using different organic solvents. The X-ray crystal structure of [(n-C(4)H(9))(4)N](11)H(5)[Cu(4)(P(2)W(15)O(56))(2)] (1) (monoclinic, P2(1)/n, Z = 2, a = 19.7269(6) A, b = 17.6602(5) A, c = 44.2525(11) A, beta = 91.182(2) degrees ; R(1) = 8.35% based on 31 282 independent reflections) reveals the presence of two unusual coordinatively unsaturated Cu(II) centers. In the absence of cocatalysts, 1 does not catalyze the aerobic oxidation of organic substrates in organic solvents.
authors.affiliation: Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Luo
authors.forename: Paul
authors.initials: P
authors.lastname: Kögerler
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill