Uranyl complexes of p-t-butylcalix[8]arene as H-bond acceptors-subtle effects of the donors

Leaving a mixture of excess N,N,N ',N '-tetramethyl-1,4-butanediamine (Me(4)BDA) with p-t-butylcalix[8]arene (L) and [(UO2)(dmso)(5)](ClO4)(2) in a 1:2 ratio in acetonitrile solution to stand for an extended period resulted in the deposition of a mixture of three different crystalline materials. Single crystal X-ray structural studies were carried out to determine that the three materials were the solvated uncomplexed macrocycle L.1.5MeCN, and two uranyl complexes. These were formulated as (Me(4)BDAH(2))(2+)[(HO)(UO2)(2)(L-5H)](2-)center dot 9MeCN center dot H2O and (Me(4)BDAH(2))(2+)[HO(UO2)(2){L-5H)](2-)center dot(Me(3)BDAH)(+)[H2O(UO2)(2)(L-5H)](-)center dot Me(4)BDA center dot 14MeCN center dot H2O center dot CH3OH respectively. In contrast to analogous systems based on 1,2-ethanediamine and 1,3-propanediamine derivatives, extension of the chain length separating the N-centres to (CH2)(4) in the present systems has resulted in the formation of polymeric chains where the calixuranate anions are linked by H-bond acceptance from diammonium units. These links are still not completely direct and pass in part through solvent bridges. Direct double interactions do occur in the inverse situation where the calixarene acts as an H-bond donor to neutral 1,4-butanediamine species but lead only to dimerisation.

Automated summary

Mixing excess N,N,N',N'-tetramethyl-1,4-butanediamine (Me(4)BDA) with p-t-butylcalix[8]arene (L) and [(UO2)(dmso)(5)](ClO4)(2) in a 1:2 ratio in acetonitrile solution resulted in the deposition of three different crystalline materials, including two uranyl complexes. Single crystal X-ray structural studies revealed the structures and chemical compositions of these materials.