Physical Chemistry Properties of Fe 3 O 4 @ Cyclodextrin @ ( 12 , 12 ) SWCNTs as a Catalyst

Fe3O4 is used in the water gas shift reaction as a catalyst in the “Haber process”. In this work, the physical and chemical properties of Fe3O4 @ α-Cyclodextrin @ (12, 12) SWCNTs has been investigated. Our calculations have been done in point of chemical phenomenon and electronic properties. The Magnetic behavior, Electron densities and electrical properties such as NMR Shielding, potential energies densities, energy density, ellipticity for electron densities, ELF, LOL, index of eta and finally ECP for Fe3O4 @ -Cyclodextrin@ (12, 12) SWCNTs have been calculated and simulated in our system. Our Calculation indicate that the Fe3O4 @ -Cyclodextrin@ (12, 12) SWCNTs are suitable surfaces for Fe3O4 such silica surfaces.


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. Fe 3 O 4 is one of the most important electrical conductors within conductivities considerably higher comparison to Fe 2 O 3 3,4 and this is imputed for exchange electron between two parts of the Fe (II) and Fe (III) centers [1][2][3] .Fe 3 O 4 family are ferromagnetic with remarkable curie temperature (858 K) and this ferromagnetism properties of Fe 3 O 4 appears because the spin electron of the Fe(II) and Fe(III) ions are coupled together in the octahedral structures and the spin of the Fe(III) ion are coupled (anti-parallel to the former [1][2][3][4] ) in a tetrahedral structure.Fe 3 O 4 is used in the water gas shift reaction as a catalyst in the "Haber process" Magnetite (Fe 3 O 4 ) is structured in the inverse-cubic-spinel-crystal 4 .Each of cubic-spinel-cell contains "8" inter-penetrating oxygens within the tetrahedral sites 4,5 and has been occupied through "1/3" of the Fe atoms, such as diamond structures.The other iron atoms are placed at the octahedral situations with closest atoms arranged as string in six various directions [5][6][7] .
In the noncovalent interaction of two parts of Fe3O4 and Cyclo-dextrin, the density functional methods such as B3LYP are not suitable for describing the van-der-Waals forces in medium 55 ranges interaction.So, the QM/MM such as ONIOM method with three classes of (1): high, (2): medium, and (3): low calculations, has been used in this studies between two parts of Fe3O4 and Cyclodextrin.
The ab-initio of DFT methods are used for the model of systems through definition of ONIOM [53][54][55][56] layers and the various semi-empirical 55 methods such as pm6 within pseudo=lanl2 57  and the Pm3MM 58 for the second and third layers, respectively 59 .
The most general of density-functionaltheory are inexpressive to exhibit the correlation 56 and exchange 57 energies for medium-range of nonbonded systems correctly.In addition, some of the recent works have exhibited the inexactitude of the medium-ranges exchange energies lead to the large principled error in prognostication of the molecular properties [51][52][53] .
Electronic structure calculations and geometry optimization have been performed using the m06-DFT.This Functional theories are based on an repetition solution of the Kohn & Sham equation 53,54 of DFT theory in the plane-wave sets including a projector-augmented-wave-pseudo potential [50][51][52][53][54] .The PBE 55 (Burke, Ernzerh &Perdew), XC (exchange/correlation) of the GGA (generalizedgradient-approximation) are also has applied.The calculation of the lattice-constant 57 and the atomic coordinate is made by the minimized the systems for the total energies.
The charges transfer 56 of electrostatics potentials derived 57 charges were also estimated using MKS(Merz-Kollman-Singh) and Chelp or chelpG 56,57 .The charges calculation method based on electrostatic-potentials fitting or MESP are not well befit for remedy of the bigger system.0.24 0.12 0.12 0.0 By these conditions, changes of the inner-most atomic-charge would not topped toward a remarkable changes of the MESP [50][51][52][53][54][55][56] for the molecules, which means that the precise value for the inner-most atomic-charge is not well specified out-side molecules .The agent atomic charge for a molecule might be calculated as the intermediate value over a few molecular conformations [50][51][52][53][54] .
In an overview of the effect of the basis sets and the "Hamiltonian" on the charges distributions would be found in the references [56][57][58] .The charges densities profile in this kind studies have been extracted from the ûrst principle calculations via an intermediate processing as explained in the references 53,54 .The interaction energies of these non-bonded interactions were calculated according to the equation as follows for all items: Where the " " are the stability energies.
Both electron densities of Laplacian and gradient, values of orbital-wave-functions, spinelectron densities, total potential of electrostatics (ESP), electrostatic potential from atomic charges of nucleus, ELF (localization-function for electron ), LOL (locator & orbital-localized), detailed by correlation hole, as well as the correlation & exchange densities, Becke & Tsirelson, correlation-factor, and the expectation of ionization energies (local) using the Multifunctional [55][56][57] have also been applied in these kind studies.The contour lines maps were also drawn using the Multi-wfn software [55][56][57] .The contour lines corresponding to the VdW surfaces including of electron densities are defined by Bader and has been drawn in this study [55][56][57] .That is clearly useful for analyzing of distributions for the electrostatics potentials on VdW surfaces.Those contour 55 lines have also been drawn in the gradient-lines 55 and vector-fields-maps 56 by the equal option [55][56][57] .The relief 62 maps were applied for presenting the height values at the points.Shaded-surface 61 maps with and without a projection 56 is used in our representation 56 of height values at various situation [60][61][62] .

Monte-Carlo Approaches
The section of ab-initio methods are given by computation that is yielded from principals of theory phenomenon, without inclusion of the experiment information 63,64 .The important usual types of ab-initio optimization are called HF, while the primary approximations are called: central-field or CFA.An important method that eschews making the HF problems is popular as the name Quantum-Monte-Carlo * .Also in contrast to the molecular  Estimations of those primary configurations are then produced by this consecutive random displacement which works through variation of QMC * , Green's functions and diffusion approaches.Those methods work via wave-functions and have evaluated the numerical integrals.Although those optimization might be much more time consuming, these are seems the most precise and suitable ways which are known up to now.An ab-initio calculation gives high quality results and then might yields increasingly high quanty results.
There are 3 levels for accomplishing of any QM/MM optimization in the "Hyper-Chem version 8.0" packages.Firstly sets up the structures of the molecules with an appropriate starting geometry or coordinates.For the second step it should be chosen suitable optimization including its associatedchoices * .For the 3 rd step it should be selected a kind of optimization with the related options.The MC simulation detects a so-called important phasespace * region that is of the lowest energies.Because of fault of the force fields, these lower energies basin usually (in most cases) does not equal to the normal states, so the rank of native structures produced by the force fields themselves is low-order.By this work, differences in the force-fields are investigated with comparison the energies optimization using force fields among the Amber, MM+, and OPLS of charmm.In addition, we investigated the polar solvents and the temperature effect (from 260K to 400K) for the stability of single wall of CNTs bonded to CGA or CFA by the various solvent.The QM or quantum mechanics This work basically accomplished on the magnetic properties of Fe 3 O 4 in the non-bonding systems of Cyclo-dextrin ( and Fe 3 O 4 .The nonbonding interactions are exhibited in figs1-3.As it is cleared in tables 1-10, the electrical 55 property can be yielded from changing in a non-bonding interaction.Potential energy, electron density, ELF, energy density 55 , Ellipticity, LOL, eta indexes and ECP of Fe 3 O 4 @Cyclodextrin (@ (12, 12) SWCNTs were calculated of each simulations (Table1-10) [55][56][57][58][59] .

CONCLUSION
Fe 3 O 4 is Ferro-magnetic including a curie * temperature of the 858+0.5K and these Ferro-magnetism arises for "Fe 3 O 4 " because the spin of electrons for the FeIII and FeII in the octahedral location are in a coupled situations together and those spins of the Fe(III) ions in the tetrahedral locations are also coupled together but are in antiparallel * situations to the previous one.Fe 3 O 4 is used in the water gas shift reaction as a catalyst in the "Haber process".It has been emphasized this study have great potentials for developing the novel multi-functional catalysts with high selectivity and reactivity.The other amazing developments are using the (12,12) single wall Nano tube carbon over the magnetic nano-particles that causes useful removal of transition metals based catalyst in drug chemistry.These approaches should find relevant industrials applications in food additive, biopharmaceutical, fragrance and others.