Zinc(II) Slides on a Ligand Surface: The X-Ray Crystal Structure and Dynamic Behavior in Solution of [Zn(H2L)(tacn)] H4L=p-tert-Butylsulfonylcalix[4]arene (an analogue of p-tert-butylcalix[4]arene in which the bridging methylene groups are replaced by sulfonyl moieties) and tacn=1,4,7-triazacyclononane. This work was supported by a Grant-in Aid for Scientific Research (Nos. 10149102 and 11740366) from the Ministry of Education, Science, Sports and Culture, Japan, as well as by JSPS Research for the Future Program.