AUTHOR=Ayi Ayi A. , Kinnibrugh Tiffany L. , Clearfield Abraham 

TITLE=Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates

JOURNAL=Frontiers in Chemistry

VOLUME=2

YEAR=2014

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2014.00094

DOI=10.3389/fchem.2014.00094

ISSN=2296-2646

ABSTRACT=<p>Using <italic>N</italic>-(phosphonomethyl) iminodiacetic acid (H<sub>4</sub>PMIDA), as a complexing agent, two new complexes, (NH<sub>4</sub>)La(PMIDA)(H<sub>2</sub>O)•H<sub>2</sub>O, <bold>1</bold> and (NH<sub>4</sub>)Yb(PMIDA), <bold>2</bold> have been synthesized hydrothermally. In both compounds, the metal ions are trapped by a three five-membered chelate rings by the chelating PMIDA anions giving a tricapped trigonal prismatic LaO<sub>8</sub>N and monocapped trigonal prismatic YbO<sub>6</sub>N geometries for <bold>1</bold> and <bold>2</bold>, respectively. The structure of <bold>1</bold> consists of La(PMIDA)(H<sub>2</sub>O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a chain along the <italic>c</italic>-axis. The chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures. The structure of <bold>2</bold> consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4- and 6-membered apertures in the <italic>bc</italic>-plane. Under excitation of 330 nm, compound <bold>2</bold> shows a broad emission band at λ<sub>max</sub> = 460 nm. This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence.</p>