Feasibility Study of E-Commerce
General Features of Oxidative Additions
Oxidative addition reactions usually involve a coordinatively unsaturated 16-electron metal complex or five-coordinate 18-electron species, and take the general from:
[pic]
If the A and B ligands in the product are considered to be formally –1, then the metal center has increased its oxidation state by +2, and this is the origin of the name oxidative addition.
Oxidative reaction can occur when a metal complex behaves as both a Lewis acid and a Lewis base*.
Oxidative is facile if
❖ MyLx complex is coordinatively unsaturated. Examples: square planar 16VE complexes of d8 and d10 metals: RhI, IrI, Ni0, Pd0, PtII, and Pt0.
❖ The metal has an energetically accessible oxidation state My+2. Ni0 [pic]NiII PtII [pic] PtIV are facile but NiII [pic] NiIV .
Scheme 1:
In order for oxidative reaction to occur, vacant coordtination sites must be available. A six-coordinated complex is not a good candidate unless it losses ligands during the course of the reactions making available a site for interaction. A further requirement is that suitable orbitals must be available for bond formation. An 18-electron complex such as [Fe(CO)4]2- has only four ligands but addition of A[pic]B would require the use of antibonding orbitals, which of course is not energetically favorable.
Besides H2 many substrates undergo oxidative additions: HCl, Cl2 and other halogens and interhalogens, RCOOH, HsiR3, alkyl, aryl, vinyl, and benzylhalides, acyls RC(O)Cl and O2. Substrates with A [pic]B usually add to the metal with retention of an
A[pic]B single bond. For example, aldehydes, ketones, alkenes and alkynes, particularay with electron withdrawing substituents, can undergo reactions which amount to an oxidative addition to the metal:
[pic]
Of course the readiness of the metal center to react with potentially oxidative substrates depends on the nature
Oxidative addition reactions usually involve a coordinatively unsaturated 16-electron metal complex or five-coordinate 18-electron species, and take the general from:
[pic]
If the A and B ligands in the product are considered to be formally –1, then the metal center has increased its oxidation state by +2, and this is the origin of the name oxidative addition.
Oxidative reaction can occur when a metal complex behaves as both a Lewis acid and a Lewis base*.
Oxidative is facile if
❖ MyLx complex is coordinatively unsaturated. Examples: square planar 16VE complexes of d8 and d10 metals: RhI, IrI, Ni0, Pd0, PtII, and Pt0.
❖ The metal has an energetically accessible oxidation state My+2. Ni0 [pic]NiII PtII [pic] PtIV are facile but NiII [pic] NiIV .
Scheme 1:
In order for oxidative reaction to occur, vacant coordtination sites must be available. A six-coordinated complex is not a good candidate unless it losses ligands during the course of the reactions making available a site for interaction. A further requirement is that suitable orbitals must be available for bond formation. An 18-electron complex such as [Fe(CO)4]2- has only four ligands but addition of A[pic]B would require the use of antibonding orbitals, which of course is not energetically favorable.
Besides H2 many substrates undergo oxidative additions: HCl, Cl2 and other halogens and interhalogens, RCOOH, HsiR3, alkyl, aryl, vinyl, and benzylhalides, acyls RC(O)Cl and O2. Substrates with A [pic]B usually add to the metal with retention of an
A[pic]B single bond. For example, aldehydes, ketones, alkenes and alkynes, particularay with electron withdrawing substituents, can undergo reactions which amount to an oxidative addition to the metal:
[pic]
Of course the readiness of the metal center to react with potentially oxidative substrates depends on the nature