The reaction of 1,2-bis(halomercurio)tetrafluorobenzene (halide = chloride (3) or bromide (4)) with the corresponding indium(I) halide in THF results in spontaneous ring closure and formation of the tetrakis(THF) adducts of 9,10-dichloro-9,10-dihydro-9,10-diindaoctafluoroanthracene (5) and 9,10-dibromo-9,10-dihydro-9,10-diindaoctafluoroanthracene (6), respectively. Diindacycle 6 can also be prepared by reaction of indium(I) bromide with trimeric perfluoro-o-phenylenemercury in refluxing toluene, followed by treatment with THF. Upon addition of pyridine, the ligated THF molecules of 6 are readily displaced and 9,10-dibromo-9,10-dihydro-9,10-diindaoctafluoroanthracene tetrakis(pyridine) (7) is obtained. Compounds 5-7 have been characterized by1H,13C, and19F NMR spectroscopy, MSCI, and elemental analysis, and their molecular structure has been determined by single-crystal X-ray analysis. All compounds crystallize in monoclinic space groups. Two modifications of compound 6 have been analyzed. 5: space group P21/c with a = 9.686(1) , b = 11.071(1) , c = 15.725(2) , = 105.55(1), V = 1624.5(3) 3, and Z = 2. 6: space group P21/c with a = 9.636(1) , b = 11.129(1) , c = 16.029(2) , = 104.40(1), V = 1664.9(3) 3, and Z = 2; space group P21/n with a = 10.258(1) , b = 13.926(1) , c = 11.892(2) , = 97.86(1), V = 1682.8(2) 3, Z = 2. 7: space group P21/c with a = 17.632-(2) , b = 15.010(1) , c = 14.562(1) , = 101.72(1), V = 3773.6(6) 3, and Z = 4. The perfluorination of the phenylene rings in 5-7 has a consequent effect on the Lewis acidity of the indium centers which is reflected by the relatively short O-In and N-In dative bond distances.
