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[Na5(THF)10Ce(mnt)4]:  A Honeycomb Network Polymer That Yields Homoleptic Cerium(III) Tetrakis(Dithiolene) Complexes in Donor Solvents

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journal contribution
posted on 11.12.2006, 00:00 by Eric M. Weis, Charles L. Barnes, Paul B. Duval
The first example of a lanthanide tetrakis(dithiolene) complex, [Na5(THF)10Ce(mnt)4] (1) (mnt = 1,2-maleonitrile-1,2-dithiolate), has been synthesized and characterized by X-ray crystallography and spectroscopic methods. In the solid state, 1 exists as a 2-D corrugated honeycomb network polymer in which the monomeric units comprising the trigonal nodes are knitted together by interlocking dative Na−N bonds extended from nitrile groups of bifunctional mnt ligands coordinated through the sulfur atoms to adjacent cerium centers. Individual honeycomb sheets are separated by 14.8 Å. Compound 1 dissolves in donor solvents such as THF and acetonitrile to give soluble [Ce(mnt)4]5- units that exhibit spectroscopic features (i.e., NMR, luminescence, UV−vis) that are consistent with the 4f1 Ce(III) ion. In the first examination of the redox chemistry of a lanthanide dithiolene complex, cyclic voltammetry measurements conducted on 1 reveal a single irreversible oxidation wave that is likely attributable to ligand-centered oxidation.