Cytosinium Isophthalate: Crystal Structure Redetermination and Room Temperature Phosphorescence

The title compound cytosinium isophthalate(C-H2IA)self-assembly of cytosine(C)and isophthalic acid(H2IA)in aqueous media has been synthesized and the crystal structure with a reasonable protonation state is redetermined.Single-crystal X-ray diffraction analysis reveals that each asymmetric unit contains one protoned cytosine molecule and one deprotoned isophthalic acid.The proton transferred from carboxylic acid to the pyrimidine ring is disordered across an inversion center with occupancy of 0.5 and the proton located to one of the carboxylate group lies on an inversion center shared by two crystallographically equivalent oxygen atoms.In addition,the cytosine molecules are connected by complementary hydrogen bonds to form a one-dimensional tape structure.The neighboring isophthalic acids are connected via hydrogen bonds between carboxyl groups to form a one-dimensional lattice like tape.Furthermore,the adjacent organic base tapes and organic acid tapes are stacked one with another throughπ-πstacking interactions to form a three-dimensional supramolecular structure.Interestingly,C-H2IA displays a green phosphorescence in solid state at room temperature with the lifetime of 0.7 s determined by time resolved studies,indicating that supramolecular C-H2IA is a potential pure organic phosphorescent luminogens.