In the title hybrid salt, (C5H7N2)[Cr(H2O)2(C2O4)2], the CrIII ion is coordinated in a slightly distorted octa­hedral environment by four O atoms from two oxalate ligands in the equatorial plane and by two water O atoms in the axial sites. The 2-amino­pyridinium cation is disordered over two sets of sites in a 0.800 (7):0.200 (7) ratio. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds connect the components into a three-dimensional network. The crystal studied was an inversion twin with components in a ratio 0.75 (2):0.25 (2).

A new organic-inorganic hybrid salt pipéridinium trans-diaquabis(oxalato)chromate(III) tetrahydrate, (C 5 H 10 NH 2 )[Cr(C 2 O 4 ) 2 (H 2 O) 2 ]•4H 2 O (1), has been synthesized in water and characterized by FTIR and UV-Vis spectroscopies, elemental and thermal analyses and by single-crystal X-ray diffraction. 1 crystallizes in the orthorhombic non-centrosymmetric space group Cmc2 1 with the unit cell parameters a = 7.4329(3), b = 9.9356(5), c = 23.6756(11) Å, α = β = γ = 90˚, V = 1748.45(14) Å 3 and Z = 4. The structure of 1 consists of [Cr(C 2 O 4 ) 2 (H 2 O) 2 ] − mononuclear anions, piperidinium cations and uncoordinated water molecules. The Cr III ion in the complex [Cr(C 2 O 4 ) 2 (H 2 O) 2 ] − is coordinated in a slightly distorted octahedral environment by four O atoms from two chelating oxalate dianions in the equatorial plane, and two O atoms from trans-coordinated water molecules occupying the apical positions. In the crystal, N-H⋯O and O-H⋯O hydrogen bond interactions connect the components into a 3-D framework. The IR spectrum of 1 is consistent with the presence of the various molecular building constituents, namely oxalato and aqua ligands, piperidinium cations and solvent water molecules. The UV-Vis spectrum shows two absorption bands around 564 and 416 nm which are

Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.003 Å; R factor = 0.041; wR factor = 0.111; data-to-parameter ratio = 17.8.The asymmetric unit of the title solvated molecular salt, (C 5

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

The geometric parameters of stationary points on the potential surface energy of the chlorination reaction of nitrobenzene in the presence of Aluminium chloride as catalyst were investigated theoretically by hybrid DFT (Density Functional Theory) calculations in order to determine his general reaction mechanism in gas phase and in solution. The results obtained by DFT have been compared with CCSD(T) method which is the most powerful post-Hartree Fock method in terms of inclusion of dynamic correlation. Although the electrophilic substitution reaction is widely taught in most courses in organic chemistry, the mechanism has been very few studied theoretically. The results obtained in gas phase are consistent with the traditional description of these reactions: the orientation of this substitution in meta position depends on the stability of a reaction intermediate (Wheland said). Without taking in consideration the reactants and products, six stationary points are found on the potential surface energy of this reaction. The reaction has also been studied in the presence of solvent and we’ve noted that the influence of solvent decreases the electrostatic attraction on the Wheland complex, but the general reaction mechanism remains unchanged in solution.