Characteristic solid-state color properties and crystal structures of 2-methyl-3-chlorophenylthio-1,4-naphthalenedione

The novel compounds 2-methyl-3-(2-chlorophenylthio)-1,4-naphthalenedione and 2-methyl-3-(3-chlorophenylthio)-1,4-naphthalenedione were successfully synthesized. Although the color of three types of 2-methyl-3-[2-chloro (or 3-chloro or 4-chloro)phenylthio]-1,4-naphthalenedione in solution are similar, the solid-state color of these compounds could be easily changed according to the position of the chloro group in the phenylthio ring.