Tenacic Acids: A New Class of Tenacious Binders to Metal Oxide Surfaces

The backbone of 2-hydroxyisophthalic acid was identified as a potential metal oxide anchor because of the perfect alignment of all three of its donor groups for binding to inorganic surfaces. It can therefore be used in the design of organic linkers for metal oxide based hybrid materials. Optimized and scalable methods for the synthesis of 2-hydroxyisophthalic acid (1) and its 5-substituted derivatives: 5-bromo- (2), 5-sulfooxy- (3), 5-hydroxy- (4), and 5-PEG600 (5) are presented. Dynamic light scattering (DLS) demonstrated that compound 2 inhibits Fe(OH)3 precipitation when FeIII aqueous solutions are titrated with NaOH, while similar titrations in the presence of the structurally-related isophthalic and salicylic acids, both missing the third donor group, show turbidity at pHs as low as 2.3 and 3.5, respectively. The adduct synthesized from 4.5 nm γ-Fe2 O3 nanoparticles and 5 is water-, alcohol- and CH2 Cl2 -soluble, and forms stable aqueous colloids in the pH range of 4.4-8.7. Moreover, at a pH close to neutral these colloids survive at 100 °C, demonstrating the high practicality of 2-hydroxyisophthalic acid for nanoparticulate inorganic/organic hybrid material design.

Synthesis and luminescence properties of lanthanide complexes with a new tripodal ligand featuring N-thenylsalicylamide arms

To explore the relationship between the structure of the ligands and the luminescent properties of the lanthanide complexes, luminescent lanthanide complexes of a new tripodal ligand, featuring N-thenylsalicylamide arms, were synthesized and characterized by elemental analysis, IR and TGA measurements. Photophysical properties of the complexes were studied by means of UV - visible absorption and steady-state luminescence spectroscopy. The results of UV - vis spectra indicate that metal binding does not disturb the electronic structure of the ligand. Excited-state luminescence lifetimes and quantum yields of the complexes were determined. The photoluminescence analysis suggested that there is an efficient ligand - Ln(III) energy transfer for the Tb(III) complex, and the ligand is an efficient 'antenna' for Tb(III). From a more general perspective, the results demonstrated the potential application of the lanthanide complex as luminescent materials in material chemistry.