ABSTRACT
The synthesis and characterization of a series of neo-pentoxide (OCH2C(CH3)3 or ONep) derivatives of group 3 and the lanthanide (Ln) series' metals were undertaken via an amide/alcohol exchange route. Surprisingly, the products isolated and characterized by single-crystal X-ray diffraction yielded isostructural species for every trivalent cation studied: [Ln(mu-ONep)2(ONep)]4 [Ln=Sc (1), Y (2), La (3), Ce (4), Pr (5), Nd (6), Sm (7), Eu (8), Gd (9), Tb (10), Dy (11), Ho (12), Er (13), Tm (14), Yb (15), Lu (16)]. Compounds 3, 4, 6, and 11 have been previously reported. Within this series of complexes, the Ln metal centers are oriented in a square with each Ln-Ln edge interconnected via two mu-ONep ligands; each metal center also binds one terminal ONep ligand. NMR data of 1-3 indicate that the solid-state structure is retained in solution. FTIR spectroscopy (KBr pellet) revealed the presence of significant Ln---H-C interactions within one set of the bridging ONep ligands in all cases; the stretching frequencies of these C-H bonds appear to increase in magnitude with decrease in metal ion radius. These complexes were used to generate nanoparticles through solution hydrolysis routes, resulting in the formation of lanthanide oxide nanoparticles and rods. The emission properties of these ceramics were preliminarily investigated using UV-vis and PL measurements.
ABSTRACT
This minireview outlines the synthetic efforts, from our research group, to produce nanomaterials for use as imaging agents to study cell signaling pathways. An overview of our approach to the synthesis and biofunctionalization of metal, semiconductor, and ceramic nanomaterials is presented. The probes investigated include coinage metals, Cd-based, Ge(o), naturally occurring fluorescent (NOF) minerals, and Ln-based nanoparticles which were synthesized from novel metal alkoxide, amide, and alkyl precursors. We illustrate the applications of some of these materials as imaging probes to detect signaling pathway components and cellular responses to signals (apoptosis and degranulation) in inflammatory and cancer cells.
