Stefan Trummer

Octanuclear Bis(triple‐helical) Metal(II) Complexes

The reaction of H2L1 and H2L2 with divalent metal ions leads to octanuclear bis(triple-helical) metal(II) complexes of the general composition [Zn8O2L26] (3) and [M8O2L16] (4: M = Cd2+; 5: M = Mn2+). NMR studies of the diamagnetic cadmium complex 4c show six equivalent ligands. Unambiguous characterisation of 5b was achieved by X-ray crystallographic analysis.

Towards New Materials Via Self-Assembly Cage Compounds, Coordination Polymers, Discs, and Screws

Abstract Attempts to directly double-deprotonate malonic esters to the corresponding dianions, then quenching the reaction with oxalyl chloride, led finally to the one-pot synthesis of tetranu-clear chelate complexes, formed by self-assembly. Their structure unequivocally is established by X-ray analyses. Highlight among these species is an overall neutral mixed-valence, tetranuclear iron chelate cluster. The alkali cation captured within the cage compensates for the excess negative charge. On the basis of these results, the predictable nature of coordination chemistry has been applied successfully for the specific generation of the metalla-topomers of the well known organic-based coronates, {2}-cryptates, and {3}-cryptates. Consequently, tetrazolylenoles, originally prepared for totally different purposes, offered an additional property and were used as chelating ligands for the generation of one-, two-, and three-dimensional coordination polymers, characterised by X-ray structure analyses.

Synthese und Koordinationschemie eines neuartigen Bistetrazols: Ein 1D-Metallopolymer durch Selbstorganisation koordinativ ungesättigter Zink(II)-M4onomere [1] / Synthesis and Coordination Chemistry of a New Bistetrazole: A 1D-Metallopolymer via Self-Assembly of Monomeric Zinc(II)-Buildingblocks

The new bistetrazole 13 has been obtained by subsequent formation of the two heterocyclic units. In methanolic solution 13 reacts with zinc(II) acetate to yield the pseudo-meso-1 D-coordination polymer [ZnL2(MeOH)]n (n = ∞) 14. The structure of 14 was established by single crystal X-ray diffraction. The generation of the polymeric chain 14 is understandable, if intermediate formation of coordinatively unsaturated zinc(II) buildingblocks (Δ)-15 and (Λ)-15 is assumed. Alternating linkage of the self-complementary chiral monomers 15, across one cyanofunction each, leads to 14 with zinc being essentially octahedrally coordinated. Compared with polymeric compounds of similar bridging ligands, the Zn ··· N≡C-distance in 14 (225,7 pm) is short.