Isostructural neo-Pentoxide Derivatives of Group 3 and the Lanthanide Series Metals for the Production of Ln₂O₃ Nanoparticles

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.

Structurally Characterized Erbium Alkoxides for Use as an Amphoteric Dopant in PErZT Ceramic Thin Film and Nanoparticles

“…Using the more sterically demanding Onep ligand reduced the nuclearity and prevented the formation of an oxo ligand as noted for the smaller OiPr derivative Er 5 (µ 5 -O)(µ 3 -OiPr) 4 (µ-OiPr) 4 (OiPr) 5 . [10,11] The resultant species, identified as [Er(µ-Onep) 2 (Onep)] 4 (1), is consistent with the other Ln-and Group 3 neopentoxide species (Figure 1) [31] wherein, each of the four trigonal bipyramidal (TBP) Er metal centers possess two µ-Onep and one Onep ligand. Attempts to isolate this compound using the Lewis basic solvents thf (2) did not lead to X-ray quality crystals; however, from py the tetramer observed in 1 was reduced to a trinuclear species surprisingly forming an oxo species, [Er(µ 3 -O)(µ-Onep) 6 (Onep) 4 (py) 3 ] (3).…”

“…The source of the oxo species is not known as of yet and typically not observed for the Onep derivatives, unless esterification mechanisms from side reactions with carboxylic acids occur but may be due to adventitious water in the solvent. [30][31][32] Increasing the steric bulk to the OtBu groups, led to crystallization of the trinuclear 4 which had additional HOtBu bound to it, as shown in Figure 2. Previously, we isolated a Ce/OtBu tetramer [30] that did not possess any Lewis basic solvents (i.e., thf, py, or HOtBu) however, the Er corollary could not be isolated without bound solvents as noted for the pyridine adduct, Er 3 (µ 3 -O)(µ-OtBu) 4 -(OtBu) 3 (py) 3 (7).…”

“…[31] . General X-ray Crystal Structure Information: [44] Crystals were mounted onto a glass fiber from a pool of Fluorolube and immediately placed in a cold N 2 vapor stream, with a Bruker AXS diffractometer equipped with a SMART 1000 CCD detector using graphite-monochromatized Mo-K α radiation (λ = 0.7107 Å).…”

The Search for Hydrogen Stores on a Large Scale; A Straightforward and Automated Open Database Analysis as a First Sweep for Candidate Materials

“…Some organic compounds that are notable in terms of gravimetric and volumetric capacities are highlighted in Figure 3. Again, it is important to check for outliers where the values might not represent true information (e.g., "C6 H132 O12 Sc4 O", where the carbon atom count should be 60, rather than 6; structural formula: [Sc(OCH2C(CH3))3]4) [25]. Inevitably, crystallised hydrocarbons like propane and butane possess high gravimetric and volumetric hydrogen capacities [26].…”

Synthesis and characterization of 4,4′-methylenebis (2,6-di-tert-butylphenol) derivatives of a series of metal alkoxides and alkyls

“…In many instances, the nuclearity of the M(OR) x precursor has been shown to play a role in determining the various properties of the final ceramic [1][2][3][4][5][6][7][8][9][10][11][12][13]; therefore, it is of interest to garner control over the structure of these precursors. Unfortunately, due to the large cation size and small charge of the ligands, M(OR) x often suffer from clustering and oligomerization with bridging alkoxide (m-OR) ligands filling open coordination sites.…”