1965 年 85 巻 8 号 p. 686-692
From the color reaction of hydroxyfluorans and its halogen derivatives with metal ions, 3′, 4′, 5′, 6′-and 2′, 3′, 6′, 7′-tetrahydroxyfluoran, and 2′-, 4′-halo-and 2′, 4′-dihalo-3′, 6′, 7′-and 3′, 5′, 6′-trihydroxyfluorans were found to undergo sensitive coloration. Examinations were made on the color reaction of 3′, 5′, 6′-trihydroxyfluoran, 3′, 4′, 5′, 6′-tetrahydroxyfluoran, amino acetic acid and iminodiacetic acid complexones of hydroxyfluorans, and their derivatives substituted in 2′-, 4′-, or 2′, 4′-positions with chlorine, bromine, and/or iodine with metal ions (Hg2+, Th3+, Bi3+, Zr4+, In3+, Ce3+, La3+, Cd2+, Zn2+, Cu2+, Co2+, Ni2+, Ba2+, Sr2+, Ca2+, Mg2+). 3′, 4′, 5′, 6′-Tetrahydroxyfluoran, hydroxyfluoran complexones, and bromo and chloro derivatives of 3′, 5′, 6′-trihydroxyfluoran were found to form colored complex in high sensitivity, and the tone of color was deep, especially in the case of 2′, 4′-disubstituted 3′, 5′, 6′-trihydroxyfluoran, and change of color in the chelate titration was also very sensitive. Coloration of iodine-substituted 3′, 5′, 6′-trihydroxyfluoran with a metal ion was hypsochromic and color change was also indistinct. Good indicator quality was found in Bi3+, Hg2+, Th3+, Cd2+, Co2+, Zn2+, Cu2+, Ni2+, La3+, Pb2+, and rare earth metal ions.