Reaction of trimethylaluminum with calixarenes. I. Synthesis and structure of [Calix[8]arene methyl ether] [AlMe3]6·2 toluene and of [p-tert-butylcalix[8]arene methyl ether] [AlMe3]6·4 benzene

Reaction of the methyl ether of calix8]arene with AlMe₃ yields calix8]arene methyl ether] AlMe₃]₆·2 toluene,1, while that ofp-tert-butylcalix8]arene gives p-tert-butylcalix8]arene methyl ether] AlMe₃]₆·4 benzene,2. Both compounds1 and2 fail to react with alkali metal salts, MX. In1, the absence of a butylpara-substituent affords greater flexibility than is the case for thetert-butyl compound2. Thus, all six of the AlMe₃ groups are located on the outside of the macrocyclic ring (in projection) in1, but two AlMe₃ units are found on the inside in2. Colorless, air-sensitive crystals of1 belong to the triclinic space group witha=13.690(8),b=14.317(4),c=14.738(6) Å, =76.11(3), =62.36(4), =82.41(4)^o, andD _c =1.06 g cm^–3 forZ=1. Refinement led toR=0.101 for 1154 observed reflections.2 crystallizes in with =12.400(6),b=16.229(8),c=19.251(5) Å, =96.17(3), =107.25(3), =101.54(3)^o, andD _c =1.01 g cm^–3 forZ=1. Refinement of2 gaveR=0.128 for 4351 observed reflections. The macrocyclic array in both1 and2 lies about a crystallographic center of inversion. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82049 (48 pages).