ИСТИНА

Ligands containing phenanthroline moiety are known to have interesting coordination and photochemical properties which are used in catalysis and analytical chemistry. Macrocycles comprising 4,7-diamino-1,10-phenanthroline were synthesized in this work. The Buchwald-Hartwig reaction was used. 4,7-dibromo-1,10-phenanthroline was chosen as a starting material. The main problem is the coordination of palladium by phenanthroline which prevents the amination reaction and leads the yield to decrease. Catalytic systems Pd(dba)2/BINAP and Pd(dba)2/JosiPhos were studied. The highest yields (17-35%) were obtained when Pd(dba)2/JosiPhos were used. The influence of base on the yield was investigated. Sodium tret-butylate appears to decompose the primary 4,7-dibromo-1,10-phenantroline under conditions of the reaction. Using of cesium carbonate as more gentle reagent allows to increase yield of the product. It should be noted that 4 equivalents of Cs2CO3 is enough for synthesis of the oxygen-containing macrocycles, but 10 equivalents of the base are required for synthesis of nitrogen-containing ones. The 2,9-disubstituted 4,7-dibromo-1,10-phenanthroline tends to give higher yield of macrocyclization. This fact is caused by the more restricted ability of 2,9-dimethylphenanthroline to coordinate palladium.