Syntheses, Structures and Magnetic Properties of Layered Metal( II ) Mandelates

A series of Mn II , Fe II , Co II , Ni II and Cu II layered mandelates has been synthesised in the form of crystalline powders by a hydrothermal route. The five compounds are isostructural with the copper analogue, also obtained in a single crystal form, except that the latter shows a strong Jahn−Teller distortion of the coordination spheres around the Cu II centres. The complexes crystallise in the monoclinic centrosymmetric space group P 2 1 / a and their structures consist of layers of six‐coordinate metal( II ) ions interconnected through carboxylato bridges in a diamond‐like network. The magnetic data indicate very small antiferromagnetic in‐plane couplings for 1 , 2 , 3 and 5 , with J / k B = −0.122 K for 1 . The Ni II compound 4 exhibits ferromagnetic coupling within the layers ( J / k B = +1.213 K) and ferromagnetic 3D ordering can be observed at T C = 2.7 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)