One-pot synthesis, structure, and unusual luminescence of novel one-dimensional lanthanide(III) tetramethoxyborates

Detailed studies of formation, structure, and luminescence characteristics of novel ionically linked sinusoidal chains of [{Na}{(sal)(3)Ln(B(OCH3)(4))Ln(sal)(3)}](n) [Ln = Nd, Sm, Tb-Lu, Y (4); Ln = Eu (5); Ln = Gd (6)] was undertaken to assess the versatility of tetramethoxyborate anions as consistent general synthons for one-dimensional materials. Crystal data for [{Na}{(sal)(3)Nd(B(OCH3)(4))Nd(sal)(3)}](n) [4(Ln = Nd)]: monoclinic; space group, C2/c (15), a = 20.884(2) Angstrom, b = 12.454(1) Angstrom, c = 37.663(5) Angstrom, beta = 102.09(2)degrees, Z = 8; [{Na}{(sal)(3)Eu(B(O CH3)(4))Eu(sal)(3)}], (5): monoclinic; space group, C2/c (15), a = 20.846(2) Angstrom, b = 12.460(1) Angstrom, c = 37.365(4) Angstrom, beta = 102.17(1)degrees, Z = 8. Europium luminescence from [{Na}{(sal)(3)Ln(1-x)Eu(x)(B(OCH3)(4))Ln(1-x)Eu(x)(sal)(3)}](n) [Ln = Eu (5); Gd (7-11), Y (12), Dy (13-18), Dy/Gd (19)] reveals the presence of defect Eu3+ sites, possibly resulting from swapping regular Eu3+ and Na+ positions. Strong Eu3+-Eu3+ electronic interactions result in multidimensional energy migration and a dynamic excitation energy-transport regime. Efficient thermally activated regular Eu3+-to-defect Eu3+ back-energy transfer dominates at 297 K.