title: Synthesis and structure of dimeric anthracene-9-carboxylato bridged dinuclear erbium(III) complex, [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)].
abstract: We study the influence of the bulky aromatic rings, e.g. anthracence-9-carboxylic acid (9-ACA) with a large conjugated pi-system on the structure and spectroscopic properties of [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)] complex where 9-AC=anthracence-9-carboxylato and DMF=N,N'-dimethylformamide. The complex has been prepared from the erbium chloride and 9-ACA in the mixture of H(2)O:DMF solution (4:1, v/v) followed by pH adjustment to 6. The complex is crystallized in a monoclinic system with space group P2(1)/n. The two Er(III) ions are double bridged by the deprotonated carboxyl groups of two 9-AC anions (O1 and O1A), forming an eight-coordination number. The chelating bidentate (O,O), chelating-bridging tridentate (O,O,O') and monodentate of 9-AC anions are observed in the dinuclear [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)] complex. The Er-Er distance is 4.015A in the dimeric unit. Intramolecular O-Hcdots, three dots, centeredO and C-Hcdots, three dots, centeredO hydrogen bonds as well as numerous of intermolecular C-Hcdots, three dots, centeredpi interactions between the anthracene rings by edge-to-face interactions linked the dinuclear dimeric units into two-dimensional supramolecular network in a propeller-arrangement. Electronic absorption spectra of the Er(III) complex and its salt were measured. The emission spectrum of the complex is composed of a broad band due to the emission of intraligand pi*-->pi transition from the 9-AC anions and a shoulder peak originating from the 4f-4f emission transition of the Er(III) ions. The complex has a high thermal stability which can be attributed to the effectively increase the rigidity of the 9-AC anions.
authors.affiliation: University of Pancasila, Srengseng Sawah, Jagakarsa, Jakarta, Indonesia. eny2kus@yahoo.com
authors.forename: Eny
authors.initials: E
authors.lastname: Kusrini
authors.forename: Rohana
authors.initials: R
authors.lastname: Adnan
authors.forename: Muhammad I
authors.initials: MI
authors.lastname: Saleh
authors.forename: Lim-Kong
authors.initials: LK
authors.lastname: Yan
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun
mesh_terms: D000873:Anthracenes / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D004871:Erbium / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure
chemical_list: D000873:Anthracenes; D002264:Carboxylic Acids; D004871:Erbium; C034020:anthracene