X-band EPR measurements were performed at room temperature on layered Cu(Hippurate)(2)center dot 4H(2)O single crystals. Despite the dimeric molecular structure the EPR spectra are characteristic for individual Cucomplexes with square-pyramidal structure and g-factors: g(x) = 2.045, g(y) = 2.085 and g(z) = 2.346. The anticipated zero-field splitting from dimers with S = 1 is averaged out by interdimer exchange coupling within the layers. The dimers in adjacent layers are not exchange coupled as we determined from the two-component EPR spectra. Thus, the Crystal is an ideal 2D magnetic system and shows a strong spin diffusion effect in the EPR line width. The spin diffusion contribution to the line width is described as P . (3 cos(2) circle minus - 1)(2) with P = 3.03 mT which is much higher compared to other 2D copper(II) crystals. The background line width is due to dipolar coupling and non-resolved hyperfine structure. Exchange coupling was determined from the exchange narrowing effect as of about 0.1 cm(-1).
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