Synthesis and Physico-Chemical Studies of a New Noncentrosymmetric Bis[N-(2-hydroxyethyl)piperazine-1,4-diium] Tetrakis(hydrogen oxalate) Trihydrate: [C6H16N2O]2(HC2O4)4·3H2O

Abstract

The new noncentrosymmetric oxalate with the general formula [C6H16N2O]2(HC2O4)4·3H2O, has been synthesized and single crystals were grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction study on grown crystal reveals that they belong to triclinic system with space group P1. The unit cell dimensions are: a = 5.688(2) A, b = 8.315(2) A, c = 16.634(3) A, α = 96.63(2)°, β = 99.81(3)°, γ = 110.01(2)° with V = 715.4(3) A3 and Z = 1. The structure has been solved using a direct method and refined to a reliability R factor of 0.052. The structure is built up from anionic chains parallel to the a-axis. These chains are interconnected by the organic cations and water molecules via hydrogen bonds so as to build a three dimensional arrangement. FT-IR spectrum confirms the presence of the functional groups in the synthesized material. The 13C CP-MAS NMR spectrum is in agreement with the X-ray structure. UV–Vis spectrum indicates that the crystal is transparent in UV and visible region with a lower cutoff wavelength of 212 nm. The DSC curve indicates that the crystal is thermally stable up to 330 K. The molecular structure of bis(N-(2-hydroxyethyl)piperazine-1,4-diium) Tetrakis(hydrogen oxalate) Trihydrate is formed by N-(2-hydroxyethyl)piperazine-1,4-diium cations, oxalate anions and water molecules held together by means of N–H⋯O, C–H⋯O, O–H⋯OW and OW–H⋯OW(O) hydrogen bonds to form three-dimensional network.