A series of pentadecanuclear lanthanide-hydroxo complexes possessing a common core of the formula [Ln15(μ3OH)20 (μ5-X)]24+(1, Ln = Eu, X = Cl-; 2, Ln = Nd, X = Cl-; 3, Ln = Gd, X = Cl-; 4, Ln = Pr, X = Br-; 5, Ln = Eu, X = Br-) were prepared by L-tyrosine-controlled hydrolysis of corresponding lanthanide perchlorates in the presence of added Cl- or Br-. The cationic cluster core comprises five vertex-sharing cubane-like [Ln4(μ3-OH)4]8+ units centered on the halide template. In the case of templating I-, dodecanuclear complexes were isolated instead. The core component, [Ln12(μ3-OH)16 (I)2]18+ (6, Ln = Dy; 7, Ln = Er), consists of four vertex-sharing cubane-like [Ln4(μ3-OH)4]8+ units and exists as a square-shaped cyclic structure with one I- located on each side of the square plane. An analogous hydrolytic reaction involving Er(NO3)3, L-tyrosine, and NaOH affords the known hexanuclear complex [Er6(μ6-O)(μ3-OH)8 (NO3)6(H2O)12] (NO3)2 whose core component is a face-capped octahedral [Er6(μ6-O)(μ3- OH)8]8+ cluster with an interstitial μ6-oxo group (Wang, R.; Carducci, M. D.; Zheng, Z. Inorg. Chem. 2000, 39, 1836-1837.). The efficient self-assembly of halide-encapsulating multicubane complexes (1-7) and the inability to produce an analogous nitrate-containing complex demonstrate the superior templating roles played by the halide ion(s). Further credence for the halide template effects was provided by the isolation of the cationic pentadecanuclear complex 3 as the sole product when tyrosine-supported hydrolysis of Gd(NO3)3 was carried out in the presence of competitive Gl-Cl-. Magnetic moments of complexes 1-7 measured at room temperature by using Evans' method are in excellent agreement with those calculated by the Van Vleck equation, assuming magnetically noninteractive lanthanide ions.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry