This sciencemag paper authored by Nicole M Camasso and Melanie S Sanford was presented by Ashik Biswas, Arun Kumar, Anubhav Rajpoot.

1. Design, synthesis, and carbon-heteroatom coupling
reactions of organometallic nickel(IV) complexes
Nicole M. Camasso, and Melanie S. Sanford
Science
Volume 347(6227):1218-1220
March 13, 2015
Presented by-
Anubhav Rajpoot
Arun Kumar
Ashik Biswas
Instructor-
Dr. Swadhin Mandal
Associate professor
IISER Kolkata

2. Biologically
important
Nature’s
antioxidant
Paramagnetic
C C M+ +
M
CC
C C + M
Introduction to coupling reactions
C X M
M
XC
C X M++ +
C-C Bonds between complex
fragments
Carbon-Heteroatom bonds
Between complex fragments

3. Biologically
important
Nature’s
antioxidant
Coupling Reaction: Traditional Catalytic Cycle
Oxidative Addition:
 M(0)  M(ii)
 Addition of Organic halide
to the M
Transmetalation:
Transfer of alkyl/aryl group
from one metal to another
 High activation energy
 Rate determining step
 Two electron transfer
process
Reductive Elimination:
 Final Product
 Regeneration of the
catalyst
 M(ii)  M(0)

4. Objective
Metal atom having variable Ox. State ie. loose/gain electron relatively easily
Can accelerate many chemical reaction as catalyst
Tune the coordination environment around metal
Can be used in coupling reactions.

5. Concept of Nickel(IV) Complexes
Pd & Ni share same group
so, they should have
similar analogy.
Can Ni(IV) be
prepared & equally
useful?
Pd(IV) has mediated
many important C-X
coupling reactions.

6. Why Ni instead of Pd?
Fig:Price of the elements (in $/kg) Vs. their annual production (in kg/yr
(Chem. Rev. 2016, 116, 3594−3657)
More sustainable and economical
Favourable intrinsic properties
Lower
atomic
radius
More
Number
of
oxidation
states.Less
electronegativity

7. Does Ni(IV) complex accessible?
Cyclic voltammogram of (bpy)Ni(II)(CH2CMe2-o-C6H4)
study of Ni(ii) complex:
two oxidative waves at –0.61 V and
+0.27 V versus Fc/Fc+ (Fc, ferrocene).
NiIII/NiIV NiII/NiIII

8. Reaction Scheme
(3)
-[Ni]
-[Ni]
VERY TRANSIENT.
NO NMR.
At RT or -400 C
Ni(IV) complex is stable
due to presence of
strong EWG.
Which oxidant to
use ?

9. Tridentate instead of bidentate ligand
-[NiII]
>Immediate colour chan
from dark red to yellow.
>much stable than
bidentate ligand Ni
complex.
92% yield isolated by recrystallzation
Solid state, Octahedral geometry
How to stabilise Ni(iv) complex

10. 1.2 equiv NMe4OAc
X
(78%)
Complicated mixtures
of products
Which Ni precursor to use for
Nucleophiles like OPh and SPh?
Works only with Acetate!
Precursor which gives neutral intermediate
Why?
Due to positive charge on Ni(IV) Intermediate!
Reactivity of NiIV complex

11. The Ni(IV) intermediate does not have
any charge on it
Lesser side product.
Good selectivity.
Ni precursor with Tp ligand.(Tp=Trispyrazolylborate)

12. Application of Ni(IV) complex as catalyst
-N2
Adventitious water
-Ni(II)
>Pharmaceuticals
>Chemical industries.
Dimethyl indole (is used as photorefractive material ) can be
prepared by using nickel(IV) complex through alkyl azide formation

13. Conclusion
 A series of Organometallic Niiv complexes are designed,
synthesized .
 Niiv complexes undergo highly selective carbon(sp3)-oxygen,
carbon(sp3)-nitrogen, and carbon(sp3)-sulfur coupling reactions with
exogenous nucleophiles.
 Observed reactivity has the potential for direct applications in the
development of nickel-catalyzed carbon-heteroatom coupling
reactions.

14. Reference………
(1.) Yoshinori Aihara and Naoto Chatani, J. Am. Chem. Soc. 2014, 136, 898−901
(2.) Sarah Z. Tasker1*, Eric A. Standley1* & Timothy F. Jamison1,N AT U R E, V O L 5 0 9 ,2 0 1 4
(3.) Xile Hu*, Chem. Sci., 2011, 2, 1867
(4.) RSC Catalysis Series No. 21,New Trends in Cross-Coupling: Theory and Applications
(5.)Shao M, Chang Q, Dodelet J, Chenitz R, Chem. Rev. 2016, 116, 3594−3657
(6.)Wikipedia