SYNTHESES, X-RAY STRUCTURES, COMPLEXATION, AND THERMAL-STABILITY STUDIES OF BIS(5-CARBOMETHOXY-1,3-PHENYLENE)-(3-CHI+2)-CROWN-CHI COMPOUNDS

Bis(5-carbomethoxy-1,3-phenylene)-(3x + 2)-crown-x compounds [x = 6 (3a), x = 8 (3b), and x = 10 (3c)] have been synthesized in one step by reaction of methyl 3,5-dihydroxybenzoate oxybenzoate (1) and the corresponding oligo(ethylene glycol) dichlorides (2a, 2b, and 2c) in the presence of NaH or KH in N,N-dimethylformamide (DMF). The smaller monoester, 5-carbomethoxy-1,3-phenylene-16-crown-5 (4c), was also isolated along with 3c. The X-ray crystal structures of these macrocycles (3b, 3c, and 4c) have been determined. Macrocycle 3b crystallizes in the triclinic space group P-1 with unit cell parameters of a = 8.632(2) Angstrom, b = 10.006(2) Angstrom, c = 11.527(2) Angstrom, alpha = 78.30(3)degrees, beta = 71.98(3)degrees, gamma = 65.00(3)degrees. Macrocycle 3c crystallizes in the triclinic space group P-1 with unit cell parameters of a = 8.911(2) Angstrom, b = 9.497(2) Angstrom, c = 10.140(2) Angstrom, alpha = 93.66(2)degrees, beta = 94.03(1)degrees, gamma = 105.95(1)degrees. Macrocycle 4c crystallizes in the triclinic space group with unit cell parameters of a = 8.748(2) Angstrom, b = 9.163(2) Angstrom, c = 12.025(3) Angstrom, alpha = 74.90(2)degrees, beta = 86.81(2)degrees, gamma = 61.73(2)degrees. The thermal stabilities of these macrocycles and the complexation abilities of the bis(m-phenylene)-32-crown-10 derivatives with methyl viologen bis(hexafluorophosphate) (8) have been examined by H-1 NMR spectroscopy.