title: Ligand-dependent ultrasonic-assistant self-assemblies and photophysical properties of lanthanide nicotinic/isonicotinic complexes.
abstract: Two structural series, including two isomorphous homodinuclear complexes Ln(2)(H(2)O)(4)(C(6)NO(2)H(4))(6) (Ln = Tb (1) and Er (2)) and four isostructural one-dimensional (1-D) chain-like assemblies [Ln(H(2)O)(4)(C(6)NO(2)H(4))(2)](n) x nCl (Ln = Sm (3), Eu (4), Tb (5), and Dy (6)), have been rationally prepared through a facile ultrasonic synthesis and have been characterized by X-ray diffraction and photophysical measurements. Both complexes, 1 and 2, feature a homodinuclear structure, based on two 8-fold coordination lanthanide atoms bridged by four nicotinic acid ligands. Complexes 3-6 are characterized by a 1-D polycationic chain-like structure, containing eight-coordinated lanthanide ions and bridging isonicotinic acid ligands. The 1-D polycationic chains and the isolated chloride anions are interconnected via hydrogen bonds and pi-pi interactions to form a three-dimensional supramolecular network. The effect of nicotinic/isonicotinic acid ligands on the structures and the photoluminescence properties, as well as the relationship between the photoluminescence properties and the structures, was investigated based on IR, UV-vis absorption spectra, low temperature phosphorescent spectra, excitation, and emission spectra. The fluorescence quantum yields of complexes 1 and 2 were determined to be 44% and 21%, respectively.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, SORST, Japan Science Technology Agency, Osaka 565-0871, Japan.
authors.forename: Wentong
authors.initials: W
authors.lastname: Chen
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
mesh_terms: D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008163:Luminescent Measurements; D008958:Models, Molecular; D015394:Molecular Structure; D009538:Nicotine / Q000031:analogs & derivatives / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D014465:Ultrasonics
chemical_list: D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D009538:Nicotine