LAUSR

tetrazole substituted calix[4]arenes Rene Z.H. Phe,[a] Brian W. Skelton,[b] Massimiliano Massi*[a] and Mark I. Ogden,*[a] [a] School of Molecular and Life Sciences and Curtin Institute for Functional Molecules and Interfaces, Curtin University, Kent Street, Bentley 6102 WA, Australia. [b] School of Molecular Sciences, M310, University of Western Australia, Crawley 6009 WA, Australia. *E-mail: [email protected]; [email protected] https://staffportal.curtin.edu.au/staff/profile/view/M.Massi/ https://staffportal.curtin.edu.au/staff/profile/view/M.Ogden/ Abstract 5,11,17,23-Tetra-tert-butyl-25,27-dihydroxy-26,28-bis(tetrazole-5-ylmethoxy)calix[4]arene has been reported to form remarkable Ln19 and Ln12 elongated clusters, upon addition of aqueous ammonium carboxylates. The impact of the para substituent on lanthanoid cluster formation has been studied by synthesising two new bis-tetrazole calixarenes, with p-H, and p-allyl substituents. Solution phase dynamic light scattering measurements of the reaction mixtures indicated that clusters are not formed with the p-H and p-allyl derivatives, in contrast with the behaviour of the t-butyl analogue. Lanthanoid complexes of the p-H and pallyl calixarenes were characterised by single crystal X-ray diffraction, and were found to form mononuclear complexes, linked to form a one-dimensional coordination polymer for the pallyl system. All of the complexes were isolated as ammonium salts, with ammonium cation included in the calixarene cavity in most cases. It is concluded that the nature of the para substituent has a profound impact on the lanthanoid cluster formation process, and derivatives with more subtle structural changes will be required to determine if additional lanthanoid “bottlebrush” clusters can be isolated.