Crystal structures of two erbium(III) complexes with 4-amino-benzoic acid and 4-chloro-3-nitro-benzoic acid.

ABSTRACT: The crystal structures of two erbium(III) complexes with 4-amino-benzoic acid (4-ABAH), namely bis-(?2-4-amino-benzoato-?(2) O:O')bis-[bis(4-amino-benzoato-?(2) O,O')di-aqua-erbium(III)] dihydrate, [Er2(C7H6NO2)6(H2O)4]·2H2O, (I), and 4-chloro-3-nitro-benzoic acid (CLNBAH), namely poly[hexa-kis-(?2-4-chloro-3-nitro-benzoato-?(2) O:O')bis-(dimethyl sulfoxide-?O)dierbium(III)], [Er2(C7H3ClNO4)6(C2H6OS)2] n , (II), have been determined. In the structure of solvatomorphic compound (I), the symmetry-related irregular ErO8 coordination polyhedra in the discrete centrosymmetric dinuclear complex comprise two monodentate water mol-ecules and six carboxyl-ate O-atom donors, four from two bidentate carboxyl-ate O,O'-chelate groups and two from the bis-monodentate O:O'-bridging group of the third 4-ABA anion. The Er-O bond-length range is 2.232?(3)-2.478?(3)?Å and the Er?Er separation in the dinuclear complex unit is 4.7527?(4)?Å. One of the coordinating water mol-ecules is involved in an intra-unit O-H?O hydrogen-bonding association with an inversion-related carboxyl-ate O-atom acceptor. In contrast, the anhydrous compound (II) is polymeric, based on centrosymmetric dinuclear repeat units comprising ErO7 coordination polyhedra which involve four O-atom donors from two bidentate O:O'-bridging carboxyl-ate groups, one O-atom donor from the monodentate dimethyl sulfoxide ligand and two O-atom donors from the third bridging CLNBA anion. The latter provides the inter-unit link in the one-dimensional coordination polymer extending along [100]. The Er-O bond-length range in (II) is 2.239?(6)-2.348?(6)?Å and the Er?Er separation within the dinuclear unit is 4.4620?(6)?Å. In the crystal of (I), extensive inter-dimer O-H?O and N-H?O hydrogen-bonding inter-actions involving both the coordinating water mol-ecules and the solvent water mol-ecules, as well as the amine groups of the 4-ABA anions, give an overall three-dimensional network structure. Within this structure are also weak ?-? ring inter-actions between two of the coordinating ligands [ring-centroid separations = 3.676?(3) and 3.711?(2)?Å]. With (II), only weak intra-polymer C-H?O, C-H?Cl and C-H?S inter-actions are present.

SUBMITTER: Smith G 

PROVIDER: S-EPMC4719813 | biostudies-other | 2015 Dec

REPOSITORIES: biostudies-other