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In this work, the Eu(III) and Sm(III) coordination polymers {[Eu(2-stp)2(H2O)6]·2(4,4′-bipy)·4(H2O)}, denoted as (1), and {[Sm(2-stp)2(H2O)2]·2(4,4′-bipy)·5(H2O)}n, denoted as (2), (2-stp = 2-sulfoterephthalate and 4,4′-bipy = 4,4′-bipyridine) were synthesized. Different concentrations of these complexes were combined with the polymer matrix of poly(methylmethacrylate) (PMMA) via the electrospinning technology to form a series of Eu@PMMA and Sm@PMMA nanofibers. The morphology, structure, luminescence and magnetic properties of the synthesized materials were investigated by a variety of techniques. The results indicated that the photostability and thermal stability of the composite nanofibers were greatly improved because the PMMA provided a solid environment for the complexes. Moreover, as the incorporation of complexes into PMMA increased, the luminescence intensities were significantly enriched and the emission color coordinates changed with the concentration of the complexes in the PMMA substrate. Color tunability was achieved with the luminescence changing from reddish orange in the bulk state to near-white light in nanofiber stage. [ABSTRACT FROM AUTHOR]

Two new tetranuclear [Ni 4 (L1) 4 (MeOH) 4 ] (1) and [Ni 4 (L2) 4 (EtOH)(MeOH)(H 2 O) 2 ]·H 2 O (2) complexes have been synthesized by solvothermal method. We here report the spectroscopic, structural, photoluminescence and magnetic properties of both complexes. Complex 1 and 2 exhibit a cubane-like Ni 4 O 4 structure. All Ni(II) center has a slightly distorted octahedral geometry. The optical properties of 1 and 2 have been analyzed by photoluminescence spectra obtained in the visible region. Variable-temperature (2–300 K) magnetic studies have been analyzed by using the Heisenberg Hamiltonian model with 2J exchange pathways. The best–fit parameters in analysis of the magnetic data are found as J 1 = −2.38 cm−1, J 2 = +5.43 cm−1, g = 2.2, N α = 0.08 for 1 , J 1 = −2.34 cm−1, J 2 = +4.90 cm−1, g = 2.2 and N α = 0.11 for 2. These results are shown dominant ferromagnetic interactions between Ni(II) centers. Finally, the strong luminescence emission of both complexes makes them potentially useful photoactive material in developing optical and electronic materials. New tetranuclear cubane-like Ni(II) complex has been synthesized and characterized by elemental analyses, UV and IR spectroscopy, single crystal X-ray diffraction and photoluminescence and magnetism study. Image 1 • Two new cubane-like Nickel (II) complex has been synthesized. • Two Nickel (II) complexes have been characterized by structural, spectroscopic, photoluminescence and magnetic properties. • Photoluminescence work showed that it can be used as a green light-emitting diode in developing optical and electronic materials. • Complex 1 and 2 shows ferromagnetic spin-exchange interaction. [ABSTRACT FROM AUTHOR]