Synthesis and Crystal Structure of a Novel Inorganic-Organic Hybrid Diphosphate, [C9H11NH3]2[Co(H2P2O7)2(H2O)2]

Ahmed SELMI, Samah AKRICHE, Mohamed RZAIGUI
2006 Analytical Sciences X-ray Structure Analysis Online  
The synthesis of inorganic-organic hybrid phosphates template by transition metal continues to be a focus area in chemistry and material science because their great potential applications in diverse areas, such as magnetism, luminescence, ceramic and supersonic. 1-3 In these compounds, the transition metal seems to play a key role in the richness of the structural chemistry. Here, we report on the synthesis of a new Co(II) complex with formula [2-C2H5-6-CH3C6H4NH3]2[Co(H2P2O7)2(H2O)2] (Fig. 1)
more » ... Good qualities of crystals with well-developed morphology were obtained at ambient temperature according to the following scheme: 4(2-C2H5-6-CH3-C6H3NH2) + CoCl2 + 2 H4P2O7 + 2 H2O → [2-C2H5-6-CH3-C6H3NH3]2[Co(H2P2O7)2(H2O)2] + 2[2-C2H5-6-CH3-C6H3NH3]Cl Then, 0.5 cm 3 (3.75 mmol) of 2-ethyl-6-methylaniline (d = 0.96) was added drop by drop to a mixture of H4P2O7 (3.75 mmol) and CoCl2 (1.88 mmol) in 15 cm 3 of water. The H4P2O7 was obtained by passing a sodium salt solution, Na4P2O7, on Amberlite IR 120 ion-exchange resin. A single crystal of dimensions 0.28 × 0.25 × 0.20 mm 3 with pink color was selected for an X-ray diffraction study. The crystal structure was solved by direct methods and refined by the full-matrix least-squares based on F for all data using teXsan software. Some data-collection parameters and results of the structure determination are given in Table 1 . All non-hydrogen atoms were refined anisotropically. The hydrogen atom positions were located by difference Fourier maps and were not refined. The final atomic coordinates of the non-hydrogen atoms of the structure and their Beq are reported in Table 2 . The crystal structure can be described by inorganic layers parallel to the ab plane and built up from the [Co(H2P2O7)2(H2O)2] 2complex anions, between which the organic molecules are located (Fig. 2) . The Co atom is six-fold coordinated, since the anionic complex contains two diphosphoric anions, H2P2O7 2-, coordinated to the Co II metal in the equatorial plane with Co-O distances ranging from 2.063(2) to 2.075(2)Å and two water molecules at axial positions with a Co-OW distance of 2.144(3)Å. An ORTEP view of the [Co(H2P2O7)2(H2O)2] 2complex is depicted in Fig. 3 . The Co atoms located on the (000) inversion center exhibit a slightly distorted octahedral coordination, since the distortion x135 ANALYTICAL SCIENCES 2006, VOL. 22 X-ray Structure Analysis Online A hybrid compound, [C9H11NH3]2[Co(H2P2O7)2(H2O)2], was prepared. It crystallizes in the triclinic P1 unit cell with a = 7.400(6), b = 7.627(3), c = 13.655(5)Å, α = 87.79(6), β = 74.65(6), γ = 73.92(8)˚, V = 713.6(8)Å 3 and Z = 1. The crystal structure can be described by anionic layers where the monomeric entities, [Co(H2P2O7)2(H2O)2] 2-, are located in the ab plane. Between these layers, the organic cations are displayed by establishing strong H-bonds to successfully participate to the cohesion of a three-dimensional network.
doi:10.2116/analscix.22.x135 fatcat:ju52vuk55vacphwzisgp32yrd4