A Novel Chromium(III) Hybrid Salt, Triethylammonium Trans-Diaquabis(Oxalato-κ 2 O 1 ,O 2 ) Chromate(III), (C 6 H 16 N)[Cr(C 2 O 4 ) 2 (H 2 O) 2 ]: Synthesis, Spectroscopic Studies, Thermal Behavior and Crystal Structure

A novel organic-inorganic chromium(III) hybrid salt, triethylammonium trans-diaquabis(oxalato-κ 2 O 1 ,O 2)chromate(III), (C 6 H 16 N)[Cr(C 2 O 4) 2 (H 2 O) 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) Å 3 , Z = 4 and Z' = 1/2. The structure of 1 consists of [Cr(C 2 O 4) 2 (H 2 O) 2 ] − mononuclear anions and triethylammonium [(C 2 H 5) 3 NH] + cations. In the anionic unit, the Cr III 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, C4 ii , N1 ii , C1a ii , C1b ii (ii = −x + 1, y, −z + 1/2). The IR spectrum of 1 is P. R. Ndonget al.DOI: 10.4236/ojic.2020.10400540 Open Journal of Inorganic Chemistryconsistent 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 octahe-dral environment. Thermal studies carried out in air between 25 ̊C and 700 ̊C confirm the anhydrous character of 1and show that it is stable up to 210 ̊C.