Rare Earth Starting Materials and Methodologies for Synthetic Chemistry

Abstract

The number of rare earth (RE) starting materials used in synthesis is staggering, ranging from simple binary metal-halide salts to borohydrides and “designer reagents” such as alkyl and organoaluminate complexes. This review collates the most important starting materials used in RE synthetic chemistry, including essential information on their preparations and uses in modern synthetic methodologies. The review is divided by starting material category and supporting ligands ( i.e. , metals as synthetic precursors, halides, borohydrides, nitrogen donors, oxygen donors, triflates, and organometallic reagents), and in each section relevant synthetic methodologies and applications are discussed.

Expanding Bismuth Trihalide Coordination Chemistry with Trimethyltriazacyclohexane and Trimethyltriazacyclononane

“…When considering the two centroids and iodides, the Bi (1) center in the cation of 3 adopts a geometry reminiscent of a (C 5 R 5 ) 2 MX 2 bent metallocene (R = H, alkyl; X = halide or pseudohalide). The 135.6° Cnt–Bi (1)–Cnt angle is similar to analogous angles in (C 5 R 5 ) 2 MX 2 bent metallocenes. − In the anion, Bi (2) has a trigonal bipyramidal coordination by this metric, with the Me 3 tach centroid occupying an axial position opposite one iodide with a 174.2° Cnt–Bi (2)–I (4) angle. The Cnt–Bi (2)–equatorial iodide angles are 94.8°, 95.8°, and 97.8°.…”

Flexible Coordination of the Bis(amino-oxazoline) Ligand in Rare-Earth Metal Complexes: Synthesis, Structure, and Their Reactivity and Polymerization Performance

“…Single crystals suitable for X-ray single-crystal analysis were generated from a saturated mixture solution (benzene:hexane 1:1 (v/v)) at −30 °C. 1 H NMR (500 MHz, C 6 D 6 , 25 °C): δ 7.94 (d, J = 8.2 Hz, 2H), 7.28 (d, J = 7.6 Hz, 2H), 7.08 (t, J = 7.6 Hz, 3H), 7.04 (d, J = 7.8 Hz, 2H), 7.01−6.95 (m, 2H), 6.90 (t, J = 7.4 Hz, 2H), 6.57 (d, J = 8.7 Hz, 2H), 6.42 (t, J = 7.5 Hz, 2H), 3.46 (dd, J = 8.0, 2.0 Hz, 2H), 3.42 (s, 2H), 3.38 (s, 4H), 1.28 (d, J = 1.9 Hz, 6H), 1.23 (s, 6H), 1.18 (s, 4H), 0.17 (d, J = 1.9 Hz, 9H), −0.52 (d, J = 10.9 Hz, 1H), −0.70 (d, J = 11.2 Hz, 1H). 13 Synthesis of Complex 3.…”

“…Less characteristic peaks were observed in the 13 C NMR spectrum probably due to accidental equivalence of the anilide fragments. 1 ] (63.69 mg, 0.151 mmol) was added to a solution of 1 (100 mg, 0.151 mmol) in toluene (10 mL) at room temperature and stirred for 1.5 h. The mixture was filtered and collected the solid, giving complex 10 as an orange powder in 44% yield (59 mg, 0.066 mmol). Complex 10: 1 H NMR (500 MHz, o-C 6 D 4 Cl 2 , 25 °C): δ 7.82 (t, J = 5.9 Hz, 12H), 7.69 (d, J = 8.3 Hz, 2H), 7.37−7.28 (m, 5H), 7.24 (d, J = 11.3 Hz, 6H), 7.11 (d, J = 7.4 Hz, 3H), 6.97 (d, J = 4.4 Hz, 4H), 6.79 (d, J = 8.8 Hz, 2H), 6.61 (s, 2H), 3.79 (d, J = 10.0 Hz, 4H), 1.22 (s, 9H), 0.80 (s, 3H).…”

Carbon bridged biphenolate ligands in rare earth chemistry

“…Alkoxide and aryloxide ligands have attracted significant attention over the last two decades, especially as bulky ligands for low coordination number lanthanoid complexes. [1][2][3][4] This attention has also led to a focus on methylene bridged biphenolate ligands, which have the propensity to act as dianionic, chelating ligands. These ligands can provide a more stereochemically rigid framework for the metal centre, offering the potential to affect stereospecific transformations, alongside reduced likelihood of redistribution reactions.…”