US EPA

1577379 

Journal Article 

SYNTHESIS AND MAGNETIC-SUSCEPTIBILITY OF NEW BIMETALLIC, TETRANUCLEAR AND OCTANUCLEAR COMPLEX-IONS CONTAINING MOLYDENUM(VI) TUNGSTEN(VI) AND CHROMIUM(III) RHODIUM(III) - CRYSTAL-STRUCTURES OF ([MOO4CRCYCLAM]2)(CLO4)2, ([MOO4RHCYCLAM]2)(CLO4)2 AND ([WO4CRCYCLAM]4)(CLO4)4.3H2O 

Glerup, J; Hazell, A; Michelsen, K; Weihe, H 

1994 

Yes 

Acta Chemica Scandinavica
ISSN: 0904-213X
EISSN: 1902-3103 

48 

8 

618-627 

WOS:A1994PE14800002 

The synthesis, spectroscopic and magnetic properties of new
types of bimetallic, tetranuclear and octanuclear complexes containing Mo(VI)/W(VI) and Cr
(III)/Rh(III) are described. The crystal structures of {[MoO4Crcyclam]2}(ClO4)2, {[MoO4Rhcyclam]
2}(ClO4)2 and {[WO4Creyclam]4}(ClO4)4.3H2O, where cyclam = 1.4,8,11-tetraazacyclotetradecane have
been determined from X-ray diffraction data. {[MoO4Crcyclam]2}{(ClO4)2 crystallizes in the
monoclinic space group P2(1)/n with two formula units in a cell of dimensions a = 10.051(1), b =
15.162(2), c = 12.244(1) angstrom, beta = 104.001(8)-degrees. The structure was refined to a
final R-value of 0.064 for 2133 independent intensities. {[MoO4Rhcyclam]2}(ClO4)2, which is
isomorphous with the chromium analogue and has cell dimensions a = 9.858(2), b = 15.269(2),
12.373(2) angstrom, beta = 105.203(9)-degrees, refined to a final R-value of 0.036 for 4070
independent intensities. The cations are centrosymmetric dimers with almost planar eight-membered
(Mo-O-M-O)2 (M = Cr or Rh) rings. Molybdenum is tetrahedrally coordinated to four oxygen atoms.
{[WO4Crcyclam]4}(ClO4)4.3H2O crystallizes in the orthorhombic space group Pbcn with for formula
units in a cell of dimensions a = 9.572(2), b = 24.347(4), c = 16.601(2) angstrom and refined to
a final R-value of 0.054 for 2454 independent intensities. The cation has two-fold symmetry and
is built up about a distorted cube of tungsten and oxygen atoms. The cyclam ligands in all three
complexes have a folded configuration in which alternate amine hydrogen atoms are on opposite
sides of the macrocyctic ring. The magnetic susceptibilities of the chromium complexes reveal
that they are weakly antiferromagnetically coupled. For the bimetallic tetranuclear complexes the
J-values are 0.78 and 2.08 cm-1 for the perchlorate salt and the iodide salt. respectively. For
the octanuclear bimetallic tungsten complex J is 8.41 cm-1.