Cobalt bis(dicarbollides)(1-) covalently attached to the calyx[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…