Cobalt Bis(dicarbollides)(1-) Covalently Attached to the Calix[4]arene Platform: The First Combination of Organic Bowl-Shaped Matrices and Inorganic Metallaborane Cluster Anions

Various calix[4]arene and resorc[4]arene ionic compounds substituted by cobalt bis(dicarbollide) anions (1) have been prepared for the first time. From tBu‐calix[4]arene (A) the complete series of mono‐, di‐, tri‐ and tetrasubstituted derivatives bearing one to four cluster anions on the lower rim (3–6) have been obtained in the form of their alkali‐metal salts by O‐alkylation with the 1‐dioxane derivative [8‐O(CH2CH2)2O(+)‐1,2‐C2B9H10)‐(1',2'‐C2B9H11)‐3,3'‐Co] (2), all of which are syn or cone isomers. In contrast, disubstitution of the dipropyl ether of tBu‐calix[4]arene (B) led to a mixture of the cone and 1,3‐alternate conformers 7a and 7b, respectively. Starting from tetrapropoxy‐calix[4]arene functionalised at the upper rim by carboxylic acid groups in distal positions (C) and an amino‐bridged derivative [8,8'‐μ‐H2N