Cobalt Bis(dicarbollides)(1–) Covalently Attached to the Calix[4]arene Platform: The First Combination of Organic Bowl‐Shaped Matrices and Inorganic Metallaborane Cluster Anions

tert‐Butyl‐calix[4]arenes Substituted at the Narrow Rim with Cobalt Bis(dicarbollide)(1–) and CMPO Groups – New and Efficient Extractants for Lanthanides and Actinides

“…[20] Most probably a low solubility of the sodium salt of 3c in the reaction mixture played some role. However, these facts stimulated the synthesis of 4c*, which was (nearly) the only product formed when Cs 2 CO 3 was employed as a base (isolated in 48 % yield by crystallization from hot aqueous ethanol followed by chromatography).…”

“…[20] CMPO functions are usually attached to the narrow rim in three steps (O-alkylation with N-(ω-bromoalkyl)phthalimide or ω-bromonitrile, deprotection of the amino group or reduction of the nitrile, and acylation of the amino groups with the active ester 9). [9,10] Among several possibilities we chose to introduce the precursor to the amino function in the first step, [22] mostly by alkylation with an ω-bromonitrile.…”

“…1,3-Dinitriles 3, easily available as syn isomers for n = 2 and 4-7 (for n = 3, see below), were treated with two equivalents of 10 [20][21][22][23] in toluene/DME at room temperature in the presence of NaH as base for the deprotonation. In the case of 3a the formation of the almost pure cone isomer was indicated by the NMR spectrum of the crude product, and 4a was isolated in 76 % yield.…”

“…[20] However, no further ligating groups were present in these molecules, and such species were therefore not efficient enough for the extraction of trivalent radionuclides and only mimicked the extraction behaviour of the parent ion 1 or its halogenated analogues. Without addition of synergists, these species were able to extract only Cs + .…”

Advanced Extraction Methods for Actinide/Lanthanide Separations

“…Moreover, the nitrogen donor should be a better ligand for the metal as opposed to sulfur, particularly since the metal-ligand bond will be smaller and the distortion away from the idealized tricapped trigonal prismatic geometry should not be as pronounced. systems wherein the addition of the synergistist CCD greatly facilitates the extraction event, [70][71][72][73][74][75][76][77] presumably due to the fact that the resulting metal complex is more soluble in the organic media with large cations. The extraction experiment with CCD and 21 will be run in the future and should produce an active extractant…”