Synthesis and X-ray structures of tetralithium derivatives of tert-butylcalix[4]arene containing unique Li–O cores based on a square-pyramidal geometry

Synthesis and Structural Analysis of the Polymetallated Alkali Calixarenes [M4(p‐tert‐butylcalix[4]arene‐4H)(thf)x]2⋅n THF (M=Li, K; n=6 or 1; x=4 or 5) and [Li2(p‐tert‐butylcalix[4]arene‐2H)(H2O)(μ‐H2O)(thf)]⋅3 THF

“…Whereas 1 is a dimeric structure, p-tert-butylcalix [4] 4 ], in the presence of LiOH and HMPA (hexamethylphosphoramide). [9] In this case, all four oxygen atoms of the calixarene are lithiated by one lithium ion each, forming a Li 4 O 4 square antiprism. An OH À group bridges the four lithium atoms, which lie in one plane; this structural motive is known in the literature.…”

“…However, not only the ligand is different, but the complete structure of the lithiated calixarene has changed, contrary to what is stated for a compound identical to 1 described very recently by Floriani et al [15] Instead of the fused heterocubane structure of 1, the structure of [ 4 ] can be described as two edgesharing square pyramids, oriented one pointing upwards, the other downwards (Scheme 1). [9] 4 ], bonded endo to the calixarene, are three-coordinate, as the solvent and HMPA ligand are too large to enter the upper rim cavity of the calixarene. This leads to a distortion in the ligand, as one carbon atom of a benzyl ring features a rather short LiÀC distance, indicating weak interactions.…”

“…In the same solvent, but in absence of LiOH, the dimer [(L 1 ) 2 Li 8 (hmpa) 4 ] is observed. [9] At first sight, the eight THF molecules in 1 have been formally replaced by four HMPA molecules. However, not only the ligand is different, but the complete structure of the lithiated calixarene has changed, contrary to what is stated for a compound identical to 1 described very recently by Floriani et al [15] Instead of the fused heterocubane structure of 1, the structure of [ 4 ] can be described as two edgesharing square pyramids, oriented one pointing upwards, the other downwards (Scheme 1).…”

P−H-Functionalized Phosphanyl Alcohols: RHPCH2CHMeOH and 2-PHR-1-OH-cyclo-C6H10 (R = Ph, 2,4,6-Me3C6H2, 2,4,6-iPr3C6H2) and Molecular Structures of (CR,CR,PR/CS,CS,PS)-2-PH(2,4,6-iPr3C6H2)-1-OH-cyclo-C6H10 and its Dilithio Salt [Li2(THF)0.5{(CR,CR/CS,CS)-2-P(2,4,6-iPr3C6H2)-1-O-cyclo-C6H10}]4

“…Although Li 8 clusters are known, [9] the topology of the Li 8 core in 6a is very unusual. While lithium clusters have been observed in electron-deficient alkyl or aryllithium compounds, [10] polyhedral arrangements of lithium phosphanides have been observed only recently.…”

Use of some calixarenes as cleaning agents for low radioactive contaminated waters

“…[2][3][4][5][6]. Some derivatives of calixarenes were thus used to produce new materials (solid supports and membranes), with the purpose of complexation and selective extraction of metallic ions from surface waters by the effluents resulting from mining industry [7][8][9][10].…”