Mercaptothiacalixarenes Steer 24 Copper(I) Centers to form a Hollow‐Sphere Structure Featuring Cu₂S₂ Motifs with Exceptionally Short Cu⋅⋅⋅Cu Distances

Abstract

Tetramercaptotetrathiacalix[4]arene (LH4) can be used as a coordination platform to bind four CuI ions at the thiolate and thioether S atoms. Donor ligands such as phosphanes can stabilize the resulting [LCu4] units, which then remain monomeric ([(Ph3PCu)4L]). In the absence of donor ligands, they aggregate, providing a hexamer ([LCu4]6) in high yields, with a hollow‐sphere structure formed by an unprecedented Cu24S48 cage that is surrounded by the organic framework of the calixarene chalices. Preliminary NMR experiments with regard to the host‐guest chemistry in solution showed that the compound represents a polytopic host for acetonitrile and methane.

Binding of a TlCl Entity by a Tetragold Tetramercaptothiacalixarene Metalloligand via Metallophilic Interactions

“…As in the di‐ and trinuclear complexes, discussed above, two of the aryl rings are oriented almost parallel to each other, while the other two are almost orthogonal (85.6°), so that the thiolate groups are pointing toward the interior of the complex. Each of the four gold atoms is coordinated by two thiolate functions, a thioether donor as well as a phosphine ligand, similarly as in case of the Cu ions in the compound [(Ph 3 PCu) 4 (MTC[4])] [7] . However, while in the latter the Cu atoms have a tetrahedral coordination sphere with Cu‐S distances that were all similar, in [(Me 3 PAu) 4 TlCl(MTC[4])] a see‐saw type arrangement is found.…”

“…Recently, we investigated the copper(I) chemistry of H 4 (MTC[4]) and found that [(Ph 3 PCu) 4 (MTC[4])] complexes are rather stable entities and are formed independently of the stoichiometry between ligand and metal precursor [7] . In the absence of phosphine co‐ligands [Cu 4 (MTC[4])] units are formed as well and subsequently stabilize by aggregation to a hexamer with a hollow ball structure [7] …”

Mercaptothiacalixarenes Steer 24 Copper(I) Centers to form a Hollow‐Sphere Structure Featuring Cu2S2 Motifs with Exceptionally Short Cu⋅⋅⋅Cu Distances

“…Symmetry code: (') À1 + z, À1 + x, y; (*) 1Àx, À1 + z, y; (#) 1Àz, 0.5Ày, 1.5Àx; (+) À1 + x, 0.5Ày, 1.5Àz. [19] 93 3 of the 187 3 cavity remain empty. Considering the suggestion that a packing coefficient of around % 55 % is favorable for molecular cavities, [16] it is unlikely that a stable situation can be reached where other molecules permanently reside in the central cavity beside Et 2 NH.…”

“…[14] DFT calculations on [LCu 4 ] 6 reproduced the rather short Cu···Cu distances (deviation of 0.083-0.031 depending on the functional used, see Supporting Information), and a similar value was predicted for an extract of the structure as depicted in Scheme 2 (right hand side), so that the phenomenon is intrinsic to the Cu 2 S 2 core with this ligation. (2), S4-Cu2-S5 88.341 (19), Cu2-S5-Cu3 148.08 (2). [19] Angewandte Chemie…”

Structural Insights into the Host–Guest Complexation between β-Cyclodextrin and Bio-Conjugatable Adamantane Derivatives

“…Among this rich class of cyclic oligosaccharides, α-/β-/γ- CDs are widely studied as hosts for a variety of organic molecular guests because of their suitable size, amphiphilic structures, and good availability. Compared to other synthetic host systems, e.g., crown ethers [ 7 , 8 , 9 ], calixarenes [ 10 , 11 , 12 ], cucurbiturils [ 9 , 13 , 14 ], and pillararenes [ 15 , 16 , 17 ], CDs are less toxic and/or exhibit good water solubility and biocompatibility [ 11 , 18 ]. Their facile covalent modification also renders them highly promising candidates as functional delivery systems [ 19 , 20 , 21 , 22 ].…”