Solvation Data for the Redox Interaction Between Nano Cobalt Sulfate (NCS) and Fuchsin Acid (FA) Using Doped Nano Composite+ Multicarbon Nanotubes Glassy Carbon Electrode at Different Temperatures

Preparation of nano tantalum pentoxide and nano cobalt sulfate were prepared by ball milling using Retsch MM2000 apparatus with three stainless steel balls having diameter 12 mm.Preparation of new working electrode was done by adding nano tantalum petoxide to multicarbonnatubes and carbon with specic ratioand nish nano paste put at the tip of glassy carbon electrode and used for use. The redox reaction of nano cobalt sulfate were studied in 0.1M KBr alone at two temperatures 292.15K and 297.15 using cyclic voltammetry.Different solvation and kinetic parameters were calculated at the used two temperatures and their data were discussed.Interaction parameters of the nano cobalt sulfate with Fucgsin acid dye was done to study the complexationcharcheterbeteen the two cyclic voltammetrically and the resulted data are discussed.Different thermodynamic data were evaluated for the interaction of nanocobal sulfate NCS with Fuchsin Acid, FA like stability constants, Gibbs free energies of complexation, enthalpies and entropies were evaluated and their values were discussed


Introduction
Progress in the study of magnetic nanoparticles have been made because of their properties and potential uses [1].The potential applications of magnetic nanoparticles as cobalt sulfate in eld of data storage,medical diagnosis and cataltytic magnetic and electrical properties have been achieved [2][3][4].Cobalt sulfate rcieved more attention in last years due to its catalytic,electrical and medicinal applications.Cobalt sulfate is one of the most ferromagnetic materials due to its three metastable phases with different crystallographic structures [5,6].
Cobalt sulfate is used electroplating and electrochemical industries [5].It added to nickel plating to improve the smthness, brightness, hardness and ductitlity of the deposited materials.It used as drier for lithographic inks,varishes, paints and in storage batteries.Cobalt sulfate was used to improve hematocrit, hemoglobin and erythrocyte levels in human patients with refraetoryanemia,including sicklecell disease, thalassemia, chronic renal disease [6] 2. Experimental

Materials and Solvents
The chemicals used in the present study were pure cobalt sulfate salt (CoSO 4 ) from Merck Company, fuchsin acid (FA) from Oxford Laboratory, pure potassium bromide salt (KBr) from Adwic Company and bidestilled water prepared with conductivity of 3.2 µS cm −1 .
Also, the chemicals used for preparation of doped nano glassy carbon electrodewere pure tantaliumpento-oxide salt (Ta 2 O 5 ) from BDH Middle East FZ LLC, Graphite powder from Adwic Egypt and carbon nano-tube fromEgyptian Petroleum Research Institute.

Cyclic voltammetricanalysis (CV)
The cyclic voltammetric studies were done by using DY2000 multichannel potentiometer, delivered from USA. It was connected to a cell of three electrodes, silver/silver chloride put in saturated KBr solution used as reference electrode, doped nano compositeglassy carbon electrode (DGC) as working electrode and platinum wire as auxiliary electrode. The doped nano composite glassy carbon electrode (DGC) surface was polished to mirror state using 1-0,03 micro alumina powder and washed with absolute alcohol and doubly-distilled water till removing any adhering alumina particles. Area of electrode was (5.72x10 −2 ) cm 2 . The system was applied from (0.4 to -1.5)V potential window and different scan rates (0.1, 0.05, 0.02, 0.01)V/sec at two different temperatures (292.15 and 297.15)K. Passing puri ed N 2 was done before each experiment to insure inert atmosphere and diffusion experiment. Finally, the data was analyzed using origin software.

Molecular Docking
The Molecular Operating Environment (MOE) was used as molecular modeling to rationalize the observed anticancer activity of fuchsin acid (FA) with the crystal structure of human Myosin 9b RhoGAP domain at 2.2 Angstrom (5C5S).
The molecular modeling and computational calculations were carried out by using DS Biovia material studio 2017, software material studio 07.0, Gaussian 09 and Docking Server software.

3.1.Transmission electron microscopy (TEM)
Transmission electron microscope was used to discover the internal structure and size of nanotantalumpentoxide, multi nano carbon nano tube paste of the used electrode and nano Nano cobalt sulphate salt, Fig. 1.
It was found that nanocobalt sulfate is in the form of distorted hexagonal forms in size range from 19 nm to 27 nm.Nano tantalum pentoxide is in the form of irregular spheres with size in the range between 60-72 nm.  Fig. 3.
The appearance of reduction wave at -0.5 V and oxidation at 0.4 may due to oxygen wave in supporting electrolyte which dispears ion adding cobalt solution.
Where, i p is the current in Ampere, A is the surface area of working electrode in cm 2 , D is the diffusion coe cient in cm 2 /Sec, ν is the scan rate in volts/Sec and C is the Bi 3+ concentration, ΔE P is the peak potential difference, k s is the standard heterogeneous electron transfer rate constant in cm/sec, α is charge transfer coe cient and n a is the numbers of electron transfer in the rate determining step, E pc/2 is the half wave potential for cathodic peak, Γ is the surface coverage in mol.cm −2 and the quantity of charge consumed during the reduction or adsorption of the adsorbed layer Q can be used to calculate the surface coverage.
The calculated solvation and kinetic parameters are Ep a (anodic peak potential),Ep c (cathodic peak potential), Ip a (anodic peak current), Ip c (cathodic peak current), ΔE P (peak potential difference), D a ( anodic diffusion coe cient), D c (cathodic diffusion coe cient), k s ( electron transfer rate constant ), Г a (anodic surface coverage), Г c (cathodic surface coverage), Q a (anodic quantity of electricity) and Q c (cathodic quantity of electricity) are tabulatedin Table.1 (a,b).
On reduction wave was observed in the window range used from 0.4V to -1.4V at the experimental two used temperatures which are 292.15 and 297.15K.The oxidation proceed through two waves as shom in Figs. 1 and 2.We noticed that same trend was followed at the two temperatures with more de ned waves at the higher temperature, We obsereve the following from Table 1a and 1b: 1-Epc and Epa are increased at higher temperature than that at lower one.
2-Ipa and IPc are bigger at 297.15K than that at 292.15K.
3-Da and Dc are increase by at high temperature than that at lower one.

5-Γa and
Γc are decreased at temperature 297.15K than that at 292.25K due to the migration of products away from the surface of electrode by more increase of temperature.  Fig. 4.Then the solvation and kinetic parameters at the different scan rates can be calculated, Table.2(a,b).
The appearance of maxima in Fig. 4 are maily due adsorption,catalysis and electro catalysis of the adsorbed species to the nano electrode surface.This maxima appeared only by the use of multicarbon nano tube electrode due to the great adsorption at the working electrode for the ionic species by using multi polymer nano electrode.The competition between adsorption and dehydration also explain the voltammetricbehavior.In order to observe the catalytic mechanism, minimum coverage is necessary as shown for Γ a andΓ c in Tables   2a and 2b. The relation between cathodic and anodic peak current against the square root of scan rate was applied using RandlessSevicek equation [24][25][26][27][28] Table.3 (a,b).
Fuchsin acid increase the maxima appeared for Co +2 ions in 0.1M KBr solution. in the reduction window due to the increase in the dehydration and catalysis of the adsorbed ions.This prove that the use of Fuchsin acid increase the adsorbed ions and the ionization of the used aqueous solutions.

Effect of different scan rates
Effect of different scan rates on the interaction between NCS and FA was studied at different scan rates (0. 1, 0.05, 0.02 and 0.01) (V/sec), Fig. 7.Then the solvation and kinetic parameters at the different scan rates can be calculated, Table.4(a,b).
Also, the relation between cathodic and anodic peak current I p against the square root of scan rate in 0.1M KBr were shown in Fig. 8.  (9) Where E˚M is the formal peak potential of metal at nally adding in the absence of FA, E˚C is the formal peak potential of metal complex after each addition of FA, R is a gas constant (8.314 J.mol −1 .degree −1 ), T is the absolute temperature, j is the coordination number of the stoichiometric complex and C x is the concentration of FA in the solution. E pa and E pc are anodic peak potential and cathodic peak potential, respectively and the Gibbs free energy of interaction ΔG for NCS with FA were calculated from stability constant (β MX ).
The relation between Gibbs free energy against stability constant of Bi(No 3 ) 3 complexes with CFZ were shown in Fig. 9.
By using Van't Hoff equation (10) The calculated values of β MX , ΔG, ΔH, and ΔS for the formed complex were collected in Table.5.

Molecular docking
A molecular modeling study using the Molecular Operating Environment (MOE) was performed to rationalize the observed anticancer activity of FA. The binding modes between FA and active sites of the crystal structure of human Myosin 9b RhoGAP domain at 2.2 angstrom (5C5S) was predicted using MOE, Fig. 10. The docking study of the inhibitor was performed with rmsd value (2.086 A˚) and binding free energies of (-5.8502 kcal.mol −1 ). Docking of FA with (5C5S) active sites revealed the presence of H-donor interactions between N atoms in FA and Asp288, Asn 279 amino acids residue as shown in Fig .11 andalso, the interaction between O atoms in FA and Arg 212, Ala 205 amino acids residue. The molecular surface structure of FA with (5C5S) receptor was shown in Fig .12.   The relation between peak current Ip (Ip C -Ip a ) against the square root of different scan rates at (a) 292.15K (b) 297.15K.    The relation between Gibbs free energy and Stability constant for the formed Complex at (a) 292.15K (b) 297.15K.

Figure 10
The binding mode of FA with (5C5S) receptor Page 16/16 Figure 11 The interaction between FA and (5C5S) receptor The molecular surface structure of FA with (5C5S) receptor