All-cis-1,2,3,4,5,6-cyclohexanehexacarboxylate two-dimensional gadolinium(III) complexes: Synthesis, X-ray crystal structure and magnetic properties

摘要

The first gadolinium(III) complexes with the trideprotonated form of the 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (H(3)clhexl(3-)) of formulae [Gd(H(3)clhex)(H2O)(4)](n)center dot 3nH(2)O (1) and [Gd(H(3)clhex)(H2O)(4)](n)center dot 6nH(2)O (2) have been prepared through the gel technique and their structures determined by single crystal X-ray diffraction. The structure of 1 is made up of 6(3) honey-comb layers which are generated by [Gd(H2O)(4)](3+) cations and H(3)clhex(3-) anions acting as three-fold nodes and three-fold connectors, respectively. The structure of 2 consists of a [4(4), 6(2)] two-dimensional network extended in the ac plane where the H(3)clhex(-3) groups act as four-fold connectors and the [Gd(H2O)(4)](3+) units as four-fold nodes. Compound 1 crystallises in a non-centrosymmetric space group P2(1). Its absolute structure could be determined reliably, indicating the spontaneous resolution of a homochiral crystal and the freezing of one of the conformations of the all-cis H(3)clhex(-3) ligand. Compound 2 crystallises in the P2(1) space group, the presence of an inversion centre making both conformations to occur. 1 and 2 are different solvates of the same system, the latter one synthesised under a higher pH value of the gel than the former. The investigation of the magnetic properties of 1 and 2 in the temperature range 1.9-300 K reveals a Curie law behaviour for the two Compounds.