Outer Sphere And Inner Sphere Electron Transfer
Outer sphere and Inner Sphere Electron TransferThe transfer of electrons between molecular compounds is an extremely important phenomenon.We will discuss here the electron transfer between inorganic complexes.There are two mechanisms by which inorganic complexes transfer electrons.1. Outer sphere mechanismWhen electron transfer occurs between complexes that do not undergo substitution. No newbonds are broken or formed.2. Inner sphere mechanism. Electron transfer occurs between complexes via a bridging ligand.At least one of the complexes needs to be labile to allow the bridge to form. Bonds are brokenand formed.1. Outer sphere mechanism: In this mechanism one reactant is reduced and other isoxidized by involving three stepsThe energy change can be expressed by the following plot
Some examples of outer sphere mechanism areFactors affecting outer sphere mechanismThe effect of solvent ( G0‡)
More is the interaction with solvent, difficult is the electron transfer and therefore the rate of reactionwould be slow.Solvent those interact strongly with complexes (such as by Hydrogen bonding) will reduce the rate ofelectron transferEnergy required for reorganization of bondsGi‡:Metal-ligand bond lengths will change when the oxidation state of the metal changes. The FrankCondon principle states that because nuclei are much more massive than electrons, an electronictransition occurs much faster than the nuclei can respond. Complexes must adjust their M-Lbond lengths before electron transfer.Example: Here Fe(III)-O and Fe(II)-O bond length are different in the reactant, but in thetransition state identical bond length make the electron transfer possibleFig. Transition state for outer sphere electron transfer
Fig. Outer sphere electron transferElectron transfer requires orbital overlap and occurs between orbitals of the samesymmetryIf the electron transition is occurring from eg to eg in Oh fieldlarge change in bond length (M-L) has to occur in sigma type of orbital, therefore the electrontransfer would be Slow. Also the steric hindrance due to ligand is there.
Fig. sigma type symmetry orbital dx2-y2 and dz2If the electron transition is occurring from t2g to t2g in Oh fieldIn Oh field t2g is *: t2g t2g transition small change in bond length. ‘Fast’ electron transferOverlap2nd and 3rd row metals generally undergo fast electron transfer than 1st row due to better overlapof 4d and 5d orbitals.Ligands that have extended -systems e.g. Phen, bipy etc can assist electron transfer.2. Inner sphere electron transfer: It is mediated by a bridging ligandi) Reductant and oxidant share a ligand in the precursor and successor complex.ii) On activation the electron is transferred between the metals.iii) The ligand may transfer between complexes.
Change of Inner sphere mechanism to outer sphere mechanismExample of Inner sphere mechanism:The labile group is needed always in this type of reaction. Here Cl is the labile groupExample of Outer sphere mechanism:If we replace the Cl by NH3 in the reaction then outer sphere mechanism is followedFactors that affect the rate of inner sphere electron transfer reactionsi) Formation of the bridging complex can be the rate limiting step (ka). This will be dependent onhow inert or labile the complexes are. (kET vs ka). It is also possible that dissociation (kd) is therate limiting step.(ii) Electronic configurations. * (‘eg’) orbitals interact strongly with bridging ligand. Orbitalsymmetries of metal * and bridging ligands facilitate electron transfer. Massive acceleration in
rates from outer to inner sphere can be achieved.iii) Bridging ligand. Inner sphere electron transfer is very sensitive to bridging ligand.1) The bridge connects the two metals.2) Transfer can be a two step process from metal to ligand then ligand to metal. Thiscircumvents the simultaneous reorganisation energy of both complexes that is required forouter sphere.
There are two mechanisms by which inorganic complexes transfer electrons. 1. Outer sphere mechanism When electron transfer occurs between complexes that do not undergo substitution. No new bonds are broken or formed. 2. Inner sphere mechanism. Electron transfer
Misalkan terdapat table A dan B, maka hasil inner join dapat diperlihatkan sebagai bidang terasir dalam diagram Venn seperti Gambar 1. Gambar 1. Inner Join b. Outer Join Outer join dibagi ke dalam tiga jenis, yaitu left outer join, right outer join dan full outer join. Left Outer Join Left outer join atau left join mengembalikan semua nilai .
BNL Demonstration Coil Stored Energy 1.7 MJ Currrent 700 Amperes Inductance 7 Henry Maximum Field 25 Tesla Operating Temperature 4.2 Kelvin Overall Ramp Rate 1.2 Amp/sec Number of Inner Pancakes 28 Number of Outer Pancakes 18 Total Number of Pancakes 46 Inner dia of Inner Pancake 102 mm Outer dia of Inner Pancake 194 mm Inner dia of Outer .
Apr 09, 2015 · inner “terrestrial” planets are Mercury, Venus, Earth, and Mars. The outer “Jovian,” planets are Jupiter, Saturn, Uranus and Neptune. Which statement best compares the differences between the inner and outer planets? A. The outer planets are warmer and larger than the inner planets. B. The inner
The inner critic, or the critical inner voice, is the inner-chatterbox that relentlessly attacks a person’s mind, causing shame, guilt, anxiety and stress. What is the inner critical voice? 6 The inner critics are often the psychic representations (inner
3.1 Integrating Sphere Theory 3 3.2 Radiation Exchange within a Spherical Enclosure 3 3.3 The Integrating Sphere Radiance Equation 4 3.4 The Sphere Multiplier 5 3.5 The Average Reflectance 5 3.6 Spatial Integration 5 3.7 Temporal Response of an Integrating Sphere 6 4.0 Integrating Sphere Design 7 4.1 Integrating Sphere Diameter 7
Thrust Ball Bearing with Outer Cover The structure of thrust ball bearing with outer cover is the same as that of single direction thrust ball bearing, but, there is an outer cover on the seat washer (or there are outer covers on the inner and outer diameters of a seat washer). The structure is as Fig.1 and Fig.2. Thrust ball
Between the inner liner and outer shell, we add Prodex insulation and then chemically bond the inner liner and outer shell together. The inner liner and outer shell completely encloses all water tanks, water lines and
Leo Aronson. My hope is that your wonderful capacity for empathy and compassion will help make the world a better place. —E.A. To my family, Deirdre Smith, Christopher Wilson, and Leigh Wilson —T.D.W. To my children, Genevieve and Everett —B.F. To my mentor, colleague, and friend, Dane Archer —R.M.A.
