Synthesis and characterization of a proton-transfer complex of 1,2,4,5-benzenetetracarboxylic acid with 1, 10-phenanthroline

Abstract

A proton-transfer complex of 1,2,4,5-benzenetetracarboxylic acid (H4BTC) with 1,10-phenanthroline (phen), [(H2BTC)2−·2(Hphen)+·(H4BTC)] was synthesized and characterized by IR, UV-Vis spectra and luminescence. The structure was determined by X-ray single crystal diffraction. It crystallizes in the triclinic system, space group P-1 with a=7.3767(15), b=10.704(2), c=12.890(3) A, α=102.96(3), β=105.71(3), γ=99.68(3)o, V=926.0(3) A3, Dc=1.558 g/cm3, Z=2, μ(Mo-Kα)=0.121 mm−1 and F(000)=448. The final R=0.0401 and wR=0.0862 for 2983 observe reflections with [1>2σ(1)]. It is composed of discrete H4BTC molecules, H2BTC2− anions and, [Hphen]+ cations. The extensive hydrogen-bonding associations formed between the H4BTC molecules and H2BTC2− anions result in the formation of a two-dimensional layer, to which the [Hphen]+ cations are attached through the hydrogen bonds formed between the carboxyl groups of H4BTC and the NH groups of [Hphen]+. Under the excitation of UV light, it emits an intense blue luminescence.