Alexander Rohde

Crystal structures of Gd2(Cl3CCOO)6(bipy)2(H2O)2 · 4 bipy, Pr(Cl3CCOO)3(bipy)2, Nd(Cl3CCOO)3(bipy)2 and Er(Cl3CCOO)3(bipy)2(H2O)

Abstract Single crystals of Gd2(Cl3CCOO)6(bipy)2 × (H2O)2 · 4 bipy, Pr(Cl3CCOO)3(bipy)2, Nd(Cl3CCOO)3 × (bipy)2 and Er(Cl3CCOO)3(bipy)2(H2O) have been obtained by reaction of the corresponding trichloroacetate salts with 2,2′-bipyridyl (bipy) in a water/ethanol (1:1) solution. Gd2(Cl3CCOO)6(bipy)2(H2O)2 · 4 bipy crystallizes in the monoclinic space group P21/c (no. 14, Z = 4, a = 1642.40(9) pm, b = 1227.36(10) pm, c = 2303.48(14) pm, β = 107.043(7)°). The Gd3+ ions are bridged to dimers by carboxylate groups and are surrounded by six oxygen and two nitrogen atoms. One 2,2′-bipyridyl molecule is coordinated to Gd3+, the two other ones are non-coordinated. The monomeric compounds Ln(Cl3CCOO)3(bipy)2 (Ln = Pr, Nd) are isotypic with each other and crystallize in the triclinic space group P-1 (no. 2, Z = 2, Pr: a = 989.83(8) pm, b = 1032.22(8) pm, c = 1791.56(13) pm, α = 99.312(9)°, β = 102.036(9)°, γ = 99.166(9)°; Nd: a = 990.09(7) pm, b = 1030.74(8) pm, c = 1788.70(13) pm, α = 99.393(9)°, β = 102.064(8)°, γ = 99.242(9)°). The Ln3+ atom is surrounded by six oxygen and four nitrogen atoms. A chelating coordination by the carboxylate groups is observed. There are two 2,2′-bipyridyl molecules coordinated to Ln3+. The compound Er(Cl3CCOO)3(bipy)2(H2O) crystallizes in the triclinic space group P-1 (no. 2, Z = 2, a = 1060.65(9) pm, b = 1273.35(11) pm, c = 1402.49(11) pm, α = 105.484(10)°, β = 104.504(9)°, γ = 93.712(10)°). The Er3+ ion is coordinated by four oxygen and four nitrogen atoms. There are two 2,2′-bipyridyl molecules attached to Er3+.

Synthesis, Crystal Structure and Magnetic Behaviour of Dimeric and Polymeric Gadolinium Trifluoroacetate Complexes

The gadolinium(III) trifluoroacetates ((CH3)2NH2)[Gd(CF3COO)4] (1), ((CH3)3NH)[Gd(CF3 COO)4(H2O)] (2), Gd(CF3COO)3(H2O)3 (3) as well as Gd2(CF3COO)6(H2O)2(phen)3 · C2H5OH (4) (phen = 1,10-phenanthroline) were synthesized and structurally characterized by X-ray crystallography. These compounds crystallize in the space group P1̅ (No. 2, Z = 2) (1, 2 and 4) and P 21/c (No. 14, Z = 4) (3), respectively, with the following lattice constants 1: a = 884.9(2), b = 1024.9(2), c = 1173.1(2) pm, α = 105.77(2), β = 99.51(2), γ = 107.93(2)°; 2: a = 965.1(1), b = 1028.6(1), c = 1271.3(2) pm, α = 111.83(2), β = 111.33(2), γ = 90.44(2)°; 3: a = 919.6(2), b = 1890.6(4), c = 978.7(2) pm, β = 113.94(2)°; 4: a = 1286.7(8), b = 1639.3(8), c = 1712.2(9) pm, α = 62.57(6), β = 84.13(5), γ = 68.28(5)°. The compounds consist of Gd3+ ions which are bridged by carboxylate groups either to chains (1 and 2) or to dimers (3 and 4). In addition to the Gd3+ dimers, compound (4) also contains monomeric Gd3+ units. The magnetic behaviour of 2 and 3 was investigated in a temperature range of 1.77 to 300 K. The magnetic data for these compounds indicate weak antiferromagnetic interactions