Synthesis and structural characterization of lanthanum and cerium substituted cyclopentadienyl borohydride complexes

Terbocenium: completing a heavy lanthanide metallocenium cation family with an alternative anion abstraction strategy

“…The analytical data obtained for 3-Tb are consistent with homologous complexes; 5, 14,16,18,20 the data for 2-Ln are similar to [Ln(Cp ttt )2(BH4)] (Ln = La, 16 Dy 20 ), and the characterisation data for 3-Y has been reported previously. 5a In common with the synthesis of [La(BH4)3(THF)4] from LaI3, 16 microanalysis and single crystal XRD data indicated that 1-Ln contained iodide impurities (<15%), but these could not be detected in 2-Ln. The paramagnetism of 3-Tb precluded assignment of its 1 H and 13 C{ 1 H} NMR spectra, as previously reported for 3-Gd.…”

Enantiomerically Pure Constrained Geometry Complexes of the Rare‐Earth Metals Featuring a Dianionic N‐Donor Functionalised Pentadienyl Ligand: Synthesis and Characterisation

“…The analysis of the paramagnetic 8‐Nd was limited to 1 H and 11 B{ 1 H} NMR spectroscopy, for which the number of resonances observed in the NMR spectra is consistent with the solid‐state molecular structure. Compared to the diamagnetic 8‐La , the signal in the 11 B{ 1 H} NMR spectrum is significantly broadened and shifted downfield to δ =149 ppm, in line with previous studies on paramagnetic lanthanide BH 4 compounds [17b, 22] …”

“…They are also in good agreement with other Nd‐BH 4 complexes reported in literature [17b, 21] . The M−B bond distances of both compounds lie in the range of literature‐reported compounds featuring bridging BH 4 groups, [17g, 18, 19a, 22] but are longer than in species with terminal BH 4 ligands [17b‐e, 21, 23] …”

“…This can be traced to either partial loss of coordinated solvents or the high air‐ and moisture‐sensitivity. Similar observations for other organometallic rare‐earth metal complexes have previously been described in the literature [6b, 14, 22, 26a, 34] . Furthermore, we provided some explanations in the experimental section below where necessary.…”

Rare Earth Starting Materials and Methodologies for Synthetic Chemistry

“… 19 Furthermore, BH 4 – is effectively a masked hydride which can readily decompose into H – and “BH 3 ”, 19 or can be removed with hydride-abstracting agents. 436 − 439 It is noteworthy that borohydride compounds have more covalent character compared to halides; for this reason, Ln(BH 4 ) 2 and RE(BH 4 ) 3 have a relatively higher solubility than their halide counterparts. 19 Crucially, the formation of higher aggregates and “ate” complexes are less likely when these materials are employed in salt elimination reactions instead of REX 3 , thus making them excellent candidates for obtaining discrete molecular entities.…”