Polyoxovanadates: High-nuclearity spin clusters with interesting host-guest systems and different electron populations. Synthesis, spin organization, magnetochemistry, and spectroscopic studies

Müller A, Sessoli R, Krickemeyer E, et al. Polyoxovanadates: High-nuclearity spin clusters with interesting host-guest systems and different electron populations. Synthesis, spin organization, magnetochemistry, and spectroscopic studies. INORGANIC CHEMISTRY. 1997;36(23):5239-5250.The compounds Cs-12[(V18O42)-O-IV(H2O)]. 14H(2)O (1a), K-12[(V18O42)-O-IV(H2O)]. 16H(2)O (1b), Rb-12[(V18O42)-O-IV(H2O)]. 19H(2)O (1c), K-9[(H3V18O42)-O-IV(H2O)]. 14H(2)O . 4N(2)H(4) (1d), K-11[(H2V18O42)-O-IV(Cl)]. 13H(2)O . 2N(2)H(4) (2a), K-9[(H4V18O42)-O-IV(Br)]. 14H(2)O . 4N(2)H(4) (2b), K-9[(H4V18O42)-O-IV(I)]. 14H(2)O . 4N(2)H(4) (2c), K-10[(H3V18O42)-O-IV(Br)]. 13H(2)O . 0.5N(2)H(4) (2d), K-9[(H4V18O42)-O-IV(NO2)]. 14 H2O . 4N(2)H(4) (3), Cs-11[(H2V18O42)-O-IV(SH)]. 12H(2)O (4), K-10[(HV16V2O42)-V-IV-O-V(Cl)]. 16H(2)O (5a), Cs-9[(H2V16V2O42)-V-IV-O-V(Br)]. 12H(2)O (5b), K-10[(HV16V2O42)-V-IV-O-V(Br)]. 16H(2)O (5c), Cs-9[(H2V16V2O42)-V-IV-O-V(I)]. 12H(2)O (5d), K-10[(HV16V2O42)-V-IV-O-V(I)]. 16H(2)O (5e), K-10[(HV16V2O42)-V-IV-O-V(HCOO)]. 15H(2)O (6), (NEt4)(5)[(V10V8O42)-V-IV-O-V(I)] (7) and Na-6[H7VIV (16V2O42)-O-V(VO4)]. 21H(2)O (8) have been characterized by elemental analyses, redox titrations, IR and EPR spectroscopy, and magnetic susceptibility measurements, as well as by single crystal X-ray structure analyses. The anions contain-as a common structural feature-an approximately spherical (V18O42) shell, which can act as a unique host system for neutral and anionic guests. Remarkably, the electron population of these clusters can-depending on the specific reaction conditions-be varied in a wide range between 10 and 18 3d electrons without changing the overall structure. The related magnetic properties in connection with the phenomenon of electron-dependent spin organization on a spherical cluster shell have been discussed in detail