Structure of p-tert-butylhexahomotrioxacalix[3]arene

Selective Binding of Group IIIA and Lanthanide Metals by Hexahomotrioxacalix[3]arene Macrocycles

“…54.9°)], indicating a greater distortion of the macrocycle. The dihedral angles in complexes 2 − 5 are considerably larger than those for the uncomplexed oxacalix[3]arene macrocycles 1a (38.3°, 38.3°, 34.4°) and 1b (34.6°, 33.5°, 29.6°).…”

Trigonal versus tetragonal or pentagonal coordination of the uranyl ion by hexahomotrioxacalix[3]arenes: solid state and solution investigations

“…O(6) is closer to uranium and to the mean plane than O(4), which may indicate some kind of interaction with the cation, and, accordingly, the O(1)Á Á ÁO(5) distance and O(1)-U-O(5) angle are larger than their counterparts involving O(3) and O(5). As in compounds 8 and 9, the calixarene cavity is deeper than in the uncomplexed compound 2, with dihedral angles between the aromatic rings and the mean plane O 3 in the range 46.9(1)-59.7(1) [mean value 37(2) in 219 ]. The triethylammonium cation is included in this cavity and forms as usual a hydrogen bond with the oxo atom O(8) (Table4).Compound 4, [HNPr 3 ][UO 2(2 -3H)] .…”

Effect of p-tert-Butyl Group Substitution on the Quantum Tunneling Rate in Quadruple Proton Rearrangement of Calix[4]arene

“…Recognizing the difference of the potential barrier as originating from this difference in R (O····O), the fact that the elongation of R (O····O) resulted in the increase of the potential barrier against the present quadruple deuteron rearrangements suggests that pathway (a) plays a primary role for deuteron rearrangement in BC4A·T- d . If this is the case, pathway (b) would become effective in systems with longer hydrogen bonds, for example, oxacalixarene in which phenol rings are connected by −CH 2 –O–CH 2 – and R (O····O) is about 3 Å. , …”