CIS- TRANS-ISOMERISM OF BIS-(TRISALKOXY)- HEXAVANADATES - O-7(OH)(6)((OCH2)(3)CCH2OH)(2))-CENTER-DOT-8H(2)O, V)O-V(13)((OCH2)(3)CCH2OH)(2)]-CENTER-DOT-4,5H(2)O AND 2)[V-6(V)O-13((OCH2)(3)CCH2OH)(2)]-CENTER-DOT-H2O/

Polyoxovanadates with distorted Lindquist-structure, in which six of t he twelve mu(2)-oxygen atoms are formally replaced by the oxygen atoms of two coordinated pentaerythritol ligands, can be prepared by a simp le method in an aqueous medium. The ''fully reduced'', six-fold proton ated compound cis-(Na2V6O7)-O-V(OH)(6){(OCH2)(3)CCH2OH}(2)]. 8H(2)O (1 ), the mixed valence species CN3H6)(3)[(VV5O13)-V-IV-O-V{[(OCH2)(3)CCH 2OH}(2)]. 4.5H(2)O (2) containing one localized V-IV centre and the '' fully oxidized'' compound trans-(CN3H6)(2)[(V6O13)-O-V{(OCH2)(3)CCH2 . OH}(2)]. H2O (3) have been synthesized and characterized by UV/VIS-, IR- and EPR-spectroscopy, by magnetic measurements, cyclic voltammetry and by a single-crystal X-ray structure analysis. The organic {(CH2)( 3)CCH2OH}(3+)-groups tend to cap the triangular faces formed by mu(2)- oxygen atoms of the central approximately octahedral {V6O19}-unit. The refore the anions of bis-(trisalkoxy)-hexavanadates can exist in a tra ns-form as well as in an isomeric cis-form referring to a ''basic'' pl ane of four vanadium atoms of the [V-6]-octahedron. The different rela tive positions of the ligands have a significant influence on the redo x potentials of the compounds. For structural details see ''Inhaltsiib ersicht''.