Author(s)

Pierre R. Ndong¹, Martin Signé¹, Patrice T. Kenfack^2*, Yves A. Mbiangué³, Gouet Bebga^4*, Emmanuel Wenger⁵

¹Department of Inorganic Chemistry, Faculty of Science, University of Yaounde I, Yaounde, Cameroon.
²Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon.
³Department of Chemistry, Higher Teachers’ Training College, University of Maroua, Maroua, Cameroon.
⁴Department of Chemistry, Higher Teacher Training College, University of Yaounde I, Yaounde, Cameroon.
⁵CRM², Université de Lorraine, CNRS, Nancy, France.

A novel organic-inorganic chromium(III) hybrid salt, triethylammonium trans-diaquabis(oxalato-κ²O¹,O²)chromate(III), (C₆H₁₆N)[Cr(C₂O₄)₂(H₂O)₂] (1), has been synthesized in aqueous solution and characterized by elemental and thermal analyses, FTIR and UV-Vis spectroscopies, and by single crystal X-ray structure determination. Compound 1 crystallizes in the orthorhombic system, Pbcn space group with the unit cell parameters a = 11.1776(10), b = 7.6105(10), c = 17.5654(2) Å, α = β = γ = 90°, V = 1494.24(3) Å3, Z = 4 and Z’ = 1/2. The structure of 1 consists of [Cr(C₂O₄)₂(H₂O)₂]⁻ mononuclear anions and triethylammonium [(C₂H₅)₃NH]⁺ cations. In the anionic unit, the CrIII ion is six coordinated, in a distorted octahedral geometry, by four equatorial O atoms of two oxalate anions acting as chelating ligands and two O atoms from trans-coordinated water molecules occupying the apical positions with longer metal-oxygen distances. In the solid, O-H … O and N-H … O intra and inter molecular hydrogen bonding interactions connect the components into a 3D network. The triethylammonium cations are disordered among two possible orientations with occupancies rates around 50% for C4, N1, C1a, C1b, C4ⁱⁱ, N1ⁱⁱ, C1aⁱⁱ, C1bⁱⁱ (ii = −x + 1, y, − z + 1/2). The IR spectrum of 1 is consistent with the presence of the various molecular building constituents. The UV-Vis spectrum shows two absorption bands around 564 and 416 nm which are compatible with an anionic chromium (III) complex in an octahedral environment. Thermal studies carried out in air between 25°C and 700°C confirm the anhydrous character of 1 and show that it is stable up to 210°C.

Hybrid Salt, Chromium(III) Oxalate Complex, Triethylammonium, Static Disorder, Spectroscopy, Crystal Structure, Thermal Study

Ndong, P. , Signé, M. , Kenfack, P. , Mbiangué, Y. , Bebga, G. and Wenger, E. (2020) A Novel Chromium(III) Hybrid Salt, Triethylammonium Trans-Diaquabis(Oxalato-κ²O¹,O²) Chromate(III), (C₆H₁₆N)[Cr(C₂O₄)₂(H₂O) ₂]: Synthesis, Spectroscopic Studies, Thermal Behavior and Crystal Structure. Open Journal of Inorganic Chemistry, 10, 39-51. doi: 10.4236/ojic.2020.104005.