Formation of two diverse classes of poly(amino-alkoxide) chelates and their mononuclear and polynuclear lanthanide(III) complexes.

Factors that influence aggregation of lanthanide(III) (Ln(III)) ions to form polynuclear complexes were studied utilizing 1-aziridineethanol as a versatile source of macrocyclic and acyclic chelates. The facile ring-opening cyclo-oligomerization of 1-aziridineethanol leads to the formation of a series of polyaza cyclic oligomers (series A). In the presence of ethylenediamine, a competing N-alkylation reaction occurs to produce a new class of acyclic ligands (series B).

Asbestos: old foe in 21st century developing countries.

While use of asbestos materials in developed nations has been decreasing because of the harmful health effects of asbestos dust mining, processing and use of the ancient material in developing countries is increasing. The regulatory mechanism for use, handling and disposal of asbestos and associated waste in developing countries are weak and information on asbestos-related diseases is scanty but emerging. We identify lack of epidemiological data on asbestos health effects as a major gap to be bridged in the promotion of occupational and environmental health in developing countries.

Comparative Study of the Luminescence Properties of the Europium(III) Complexes of the Squarate, Phenylsquarate, and (Diphenylamino)squarate Ligands.

Reaction of EuCl(3).6H(2)O with 3-phenyl-4-hydroxycyclobut-3-ene-1,2-dione (phenylsquarate) in methanol produces the polymeric complex {Eu(&mgr;-C(6)H(5)C(4)O(3))(2)(C(6)H(5)C(4)O(3))(2)(CH(3)OH)(2)(H(2)O)(2).(CH(3)OH)}(n)() (1) which crystallizes in the space group P2(1)/n with a = 13.

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(OCH(3))(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(OCH(3))(4))Nd(sal)(3)}](n)() [4(Ln = Nd)]: monoclinic; space group, C2/c (15), a = 20.884(2) Å, b = 12.

Intense Photosensitized Emission from Stoichiometric Compounds Featuring Mn(2+) in Seven- and Eightfold Coordination Environments.

Synthetic, structural and luminescence studies of stoichiometric crown ether compounds of Mn(2+) in well-defined coordination environments were undertaken in an effort to understand the origin of emitting crystal defects found in cubic F23 [(K18C6)(4)MnBr(4)][TlBr(4)](2) crystals (Fender, N. S.; et al.