Change in the Electronic Structure of the Cobalt(II) Ion in a One-Dimensional Polymer with Flexible Linkers Induced by a Structural Phase Transition.

A new 1D-coordination polymer [Co(Piv)(NH(CH)NH)] (, Piv is MeCCO anion) was obtained, the mononuclear fragments {Co(OCR)} within which are linked by μ-bridged molecules of hexamethylenediamine (NH(CH)NH). For this compound, two different monoclinic 2/ (α-) and 2/ (β-) phases were found at room temperature by single-crystal X-ray diffraction analysis, with a similar structure of chains and their packages in unit cells. The low-temperature phase (γ-) of crystal at 150 K corresponds to the triclinic space group -1.

Field-Induced Slow Magnetic Relaxation in Co Cyclopropane-1,1-dicarboxylates.

New Co substituted malonate field-induced molecular magnets {[RbCo(cpdc)(HO)]∙6HO} () and [CsCo(cpdc)(HO)] () (where cpdc stands for cyclopropane-1,1-dicarboxylic acid dianions) were synthesized. Both compounds contain mononuclear bischelate fragments {Co(cpdc)(HO)} where the quasi-octahedral cobalt environment (CoO) is complemented by water molecules in apical positions. The alkali metal atoms play the role of connectors between the bischelate fragments to form 3D and 2D polymeric structures for and , respectively.