POLYOXOVANADATES - HIGH-NUCLEARITY SPIN CLUSTERS WITH INTERESTING HOST-GUEST SYSTEMS AND DIFFERENT ELECTRON POPULATIONS - SYNTHESIS, SPIN ORGANIZATION, MAGNETOCHEMISTRY, AND SPECTROSCOPIC STUDIES

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 ti trations, IR and EPR spectroscopy, and magnetic susceptibility measure ments, as well as by single crystal X-ray structure analyses. The anio ns contain-as a common structural feature-an approximately spherical ( V18O42) shell, which can act as a unique host system for neutral and a nionic guests. Remarkably, the electron population of these clusters c an-depending on the specific reaction conditions-be varied in a wide r ange between 10 and 18 3d electrons without changing the overall struc ture. The related magnetic properties in connection with the phenomeno n of electron-dependent spin organization on a spherical cluster shell have been discussed in detail.