4,4'-[[2-[[3-(4-Carboxyphenoxy)-2,2-bis[(4-carboxyphenoxy)methyl]propoxy]methyl]-2-[(4-carboxyphenoxy)methyl]-1,3-propanediyl]bis(oxy)]bis[benzoic acid]

4,4'-[[2-[[3-(4-Carboxyphenoxy)-2,2-bis[(4-carboxyphenoxy)methyl]propoxy]methyl]-2-[(4-carboxyphenoxy)methyl]-1,3-propanediyl]bis(oxy)]bis[benzoic acid],