Formation, magnetic properties and structures of copper(II) levulinates

The syntheses and characterizations of a series of copper(II) levulinic acid complexes are reported. The structure of [Cu-2(O2C(CH2)(2)COCH3)(4)](n)(-O2C(CH2)(2)COCH3 = lev), 1, and the products of its reaction with pyridine, 2,2'-dipyridine and triphenylphospine have been determined by single crystal X-ray diffraction. The reaction with pyridine leads to [Cu(H2O)(O2CCH2CH2COCH3)(2)(NC5H5)(2)], 2. Reaction with 2,2'-dipyridine leads to [Cu(O2CCH2CH2COCH3)(2)(N2C10H8)], 3. When Cu-2(lev)(4) is reacted with PPh3 the product is [Cu-2(O2CCH2CH2COCH3)(4){(mu-O2CCH2CH2COCH3)(Cu(PPh3)(2)}(2)], 4. Solid-state magnetic susceptibility studies are described for 1 and 4 from 5-300 K, which suggests the system is similar to the known copper(II) acetates. Fitting parameters are -J/k = 410(10) K and g = 2.10(5) for 1 and -2J/k = 425(20) K and g = 2.25(10) for 4. Compounds 1, 2, 3 and 4 have been studied by single crystal X-ray crystallography. (C) 1997 Elsevier Science Ltd.