Direct oxidation of europium metal with acetic acid: Anhydrous europium(III) acetate, Eu(OAc)(3), its sesqui-hydrate, Eu(OAc)(3)(H2O)(1.5), and the 'hydrogendiacetate', [Eu(H(OAc)(2))(3)](H2O)

摘要

Anhydrous europium(III) acetate, Eu(OAc)(3) (1), its sesquihydrate Eu(OAc)(3)(H2O)(1.5) = [Eu-2(OAc)(6)(H2O)](H2O)(2) (2) and the "hydrogendiacetate" [Eu(H(OAc)(2))(3)](H2O) = [Eu-2(OAc)(6)(HOAc)(2)(H2O)(2)](HOAc)(4) (3) were obtained as colourless single crystals by direct oxidation of europium metal with acetic acid in glass ampoules at 130 degrees C. The coordination polymer Eu(OAc)(3) (1) crystallizes in the monoclinic space group C2/c (no. 15) with a = 1126.0(3), b = 2900.5(6), c = 799.1(2) pm, beta = 132.03(2)degrees, V = 1938.6(8) 10(6).pm(3), Z = 4, R-1 = 0.0374 [I > 2 sigma]. The crystals of Eu(OAc)(3)(H2O)(1.5) (2) are monoclinic, space group Cc (no. 9) with a = 1608.7(2), b = 1665.6(2), c = 839.1(1) pm, beta = 115.75(9)degrees, V = 2025.2(4) 10(6).pm(3), Z = 4, R-1 = 0.0424 [I > 2 sigma]. [Eu(H(OAc)(2))(3)](H2O) (3) crystallizes in the monoclinic space group P2(1)/c (no. 14) with lattice parameters of a = 1157.7(1), b = 2131.6(3), c = 901.3(1) pm, beta = 110.36(1)degrees, V = 2085.6(4) 10(6).pm(3), Z = 4, R-1 = 0.0331 [I > 2 sigma]. The linear chain structure of I is modified by the addition of one coordinating water molecule in 2 to a corrugated chain whose packing leaves room for crystal water. In 3 the same dimers are observed as in [Eu-2(OAc)(6)(HOAc)(2)(H2O)(2)] (4) itself which had previously been synthesized from an ammonium acetate melt. With a higher acetic acid pressure, four molecules of acetic acid per dimer are included in the structure in 3.