RESUMO
The significant variety in the crystal structures of rare-earth carboxylate complexes is due to both the large coordination numbers of the rare-earth cations and the ability of the carboxylate anions to form several types of bridges between rare-earth metal atoms. Therefore, these complexes are represented by mono-, di- and polynuclear complexes, and by coordination polymers. The interaction of LnCl3(thf)x (Ln = Eu or Y; thf is tetrahydrofuran) with sodium or diethylammonium diphenylacetate in methanol followed by recrystallization from a DME/THF/hexane solvent mixture (DME is 1,2-dimethoxyethane) leads to crystals of the non-isomorphic dinuclear complexes tetrakis(µ-2,2-diphenylacetato)-κ(4)O:O';κ(3)O,O':O';κ(3)O:O,O'-bis[(1,2-dimethoxyethane-κ(2)O,O')(2,2-diphenylacetato-κ(2)O,O')europium(III)], [Eu(C14H11O2)6(C4H10O2)2], (I), and tetrakis(µ-2,2-diphenylacetato)-κ(4)O:O';κ(3)O,O':O';κ(3)O:O,O'-bis[(1,2-dimethoxyethane-κ(2)O,O')(2,2-diphenylacetato-κ(2)O,O')yttrium(III)], [Y(C14H11O2)6(C4H10O2)2], (II), possessing monoclinic (P21/c) symmetry. The [Ln(Ph2CHCOO)3(dme)]2 molecule (Ln = Eu or Y) lies on an inversion centre and exhibits three different coordination modes of the diphenylacetate ligands, namely bidentate κ(2)O,O'-terminal, bidentate µ2-κ(1)O:κ(1)O'-bridging and tridentate µ2-κ(1)O:κ(2)O,O'-semibridging. The terminal and bridging ligands in (I) are disordered over two positions, with an occupancy ratio of 0.806â (2):0.194â (2). The interaction of EuCl3(thf)2 with Na[Ph3CCOO] in methanol followed by crystallization from hot methanol produces crystals of tetrakis(methanol-κO)tris(2,2,2-triphenylacetato)-κ(4)O:O';κO-europium(III) methanol disolvate, [Eu(C19H15O2)3(CH3OH)4]·2CH3OH, (III)·2MeOH, with triclinic (P-1) symmetry. The molecule of (III) contains two O,O'-bidentate and one O-monodentate terminal triphenylacetate ligand. (III)·2MeOH possesses one intramolecular and four intermolecular hydrogen bonds, forming a [(III)·2MeOH]2 dimer with two bridging methanol molecules.
