Chromium (V) is also found in organic matter for example humus. These trimeric species are usually known as “basic chromium carboxylates”. Alfred Werner as early as 1908, synthesized the chromium metal triangular complex, Cr 3O(RCO 2) 6(H 2O) 3+ and its derivatives were used theoretically for molecular magnetic interactions. The carboxylates, oxides and hydroxyl moieties usually bridged with metal centres via the presence of water in the reaction system. In different manufacturing industries, patented commercial products containing Cr(III) are used. In catalytic and materials applications, Cr(III) carboxylates are utilized commercially. Ĭr(III) carboxylates show a ridiculous structural diversity like simple dimers as well as high nuclearity clusters. Above a certain pH level, the carboxylic acid groups usually dissociate, which makes them very reactive. Sargassum sp., a brown seaweed which was decorated with electron donor groups carboxylates studied for the biosorption of Cr(VI) to reduce less toxic Cr(III) under acidic condition at pH 2.

The Chromium species predominantly occurs in the environment at the trivalent and hexavalent state. Especially in acid solution, the +4 oxidation state disproportionates easily to chromium (III) and chromium (VI). The oxidation state of +4 is the most stable at high pH. Pourbaix diagram (pH plotted against EB) shows the existence of predominant or stable species of +3 state, ( The electronic configuration of the element chromium in the ground state is 3d 54s 1, whereas the most prevalent states +3 and +6, it is 3d 34s 0 and 3d˚4s˚, respectively.

For chromium metal, thermodynamically, +3 and +2 are the most stable states, while in the environment, +3 and +6 oxidation states are the most common ones. The particular oxidation state of a metal is reliant on many factors comprising pH, redox potentials and kinetics. The toxic heavy metal chromium subsists in aqueous waste streams has the oxidation states of −2 to +6. Major contributors to the metal binding affinities, with promising possibilitiesįor the design of metal-ligand complexes and sensing of the metal ions. The findings of this study identify efficient electronic factors as TheĬalculated binding energies (ΔE) and interactions energies S E ij (2) favor the formation of 3+ complexes. Of NBO analysis confirmed the greater charge transfer for the observed trends in the metal binding. Stabilization energies derived using the second order perturbation theory, E ij (2), Using the time - dependent DFT (TD-DFT) at the level ofĬAM-B3LYP/6-311++G(d,p), the vertical excitation energies were obtained. Good harmony with the experimental and theoretical calculated frequencies. Monomers of tris 0 and 3+ complexes, illustrate Vibrational frequency analysis, for the homoleptic TheĬoordination strength of Cr(VI) with the acetate ligand was predominantly the strongest compare d to the other oxidation states. States and spin states in gas phase were examined. The structures and binding energies of chromium met al - carboxylate complexes at various oxidation decorated with carboxylate (acetate) at the wB97XD/6-311++ G(d,p) level of theory. Interactions of transition metal chromium ion with different oxidation statesĪnd spin states with the Sar gassum sp. In this study, a systematicĭensity functional theory (DFT) calculations were performed to study the Hexavalent chromium is reduced to trivalent chromium in an aqueous solution. Study of various oxidation states of chromium with Sargassum sp.

Chromium charge of six