organic

1. • Main Group Organometallic Chemistry

2. Bertrand and coworkers Science 2007, 316, 439-441

3. Power, Nature, 2010, 463, 171-177

4. Ethylene activation
Power and co-workers Science 2009, 325, 1668–1670.

5. Inspiration from the Interstellar Space
Silicon(II):
Silicon monoxide(SiO)
Silicon monosulfide(SiS)
Silicon(I):
Silicon cyanide (SiCN)
Silicon isocyanide(SiNC)
Magnesium (I):
Magnesium cyanide (MgCN)
Magnesium isocyanide(MgNC)

6. N
N
Mg Mg
N
N
Jones et al Science 2007, 318,
1754–1757
(steric protection)

7. Low-valent Organomain Group Chemistry
Schleyer, Robinson and coworkers
Science 2008, 321, 1069-1071
Mandal and Roesky Chem.
Commun. 2010, 46, 6016–6041
(Highlighted on front cover)

8. Reversing Chemical Property: Nucleophilic Boron!
Elements Electronic config.
B [He]2s22p1
Al [Ne]3s23p1
Ga [Ar]3d104s24p1
In [Kr]4d105s25p1
Tl [Xe]4f145d106s26p1
Group 13 elements Lewis Acceptor
Inert Pair Effect
B(I) compounds with an active pair of electrons :
RB:(I) ---(Borylene)----
Dimerization of BH3
(Nobel Prizes in Chemistry
1976 W Lipscomb and
1979 HC Brown)
Angry Pair Effect!

9. First Borylene by X-Ray
Bertrand et al Science 2011, 333, 610-612.

10. Metal-Free Nitrogen Activation!
Braunscheweig et al Science 359, 896–900 (2018)

11. Metal Free Activation to Catalysis: NHC
Catalysis

12. 12
Global CO2 emission in last 20 years
IEA, Annual change in global energy-related CO2 emissions, IEA, Paris

13. 13
IEA, Annual change in global energy-related CO2 emissions, IEA, Paris
Global Energy Balance (2015)

14. 14
CO2 emissions by sector, World 1990-2017
IEA, Annual change in global energy-related CO2 emissions, IEA, Paris

15. 15
CCS and CCU

16. 16
Carbon Capture and Recycling (CCR)

17. Only 7-10 % CO2 is chemically converted
 Thermodynamic stability of CO2
 Metal based catalysts are required to activate CO2
 Harsh Condition
 Expensive and toxic
 Energy intensive Process
How to avoid?
Metal free catalyst 17
Current status and major challenges

18. 18

19. Activation of CO2 without metals: Learning from nature
How CO2 is captured during photosynthetic process?
19
CO2 Activation

20. 20
Learning from Nature
Nucleophilic activation!!

21. Catalyst Design : Learning from Transition Metals
21
Nucleop
hilicity
Redox
activity
Lewis
Acidit
y

22. 22
Crabtree et al. Chem. Commun. 2001, 2274–
2275.
The metal attached
at the ‘wrong’
carbon, C-5 not C-2.
‘Wrong way’ bound NHC: Abnormal NHC
Bertrand et al.
Science, 2009, 326, 556-559.
First isolated
aNHC
“Normal carbenes rapidly became a key tool for organometallic chemistry and organic synthesis once they were available as
stable free ligands some 20 years ago. Given the unique impact of abnormal carbenes on the reactivity of transition
metals, the accessibility of free abnormal carbenes may become another cornerstone in this field, and it will be
exciting to witness developments in these directions.”
Martin Albrecht, Science, 2009, 326, 532-533.

23. 23
Entry Catalyst (mol %) Time (h) TON of 4
1 0.10 6 380
2 0.01 8 3500
3 0.005 12 6000
aNHC in Reduction of CO2 to MeOH
Mandal et al. Angew. Chem. Int. Ed., 2016, 55, 15147 –15151.

24. G. A. Olah,
Angew. Chem., Int. Ed., 2013, 52,
104 – 107.
Prakash and Olah JACS 2016, 138, 778-
781
(homogeneous CO2 capture from air
under drastic conditions)
‘Coming from fuel and returning to fuel’
David W. Keith,
Science, 2009, 325, 1654-1655.
24
Fuel from Air

25. Patent Application No.
PCT/IB2017/056698
Mandal et al. Chem. Sci., 2019, 10, 1879-1884
25
Metal free CO2 reduction from air
3
2

26. New Catalytic Reactions with CO2
26
Cantat et al. ACS Catal. 2015, 5, 3983-3987
Unknown
Known
Unknown
Unknown
 Poor solubility
 Low basicity
 Extended hydrogen bonding
Primary Amide
functionalization?
Unknown

27. 27
27
Formylation of amides using CO2
Mandal et al. ACS Catal., 2018, 8, 11999−12003

28. Uncommon oxidation state: +I
From Carbene to Low-Valent Phosphorous Compound
Phosphinidene
Carbene: H2C:
No catalytic application is
reported!!
28
Selected Examples
Mandal et al. Chem. Eur. J, 2021, 27, 11656-11662.

29. Mesoionic N-Heterocyclic Olefin
(mNHO)
Hansmann et al. Angew. Chem. Int.
Ed., 2020, 59, 5782–5787
Mesoionic N-Heterocyclic
Phosphinidene
(mNHP)
Unknown
Mesoionic N-Heterocyclic Imine
(mNHI)
Extending Scope of aNHC Based CCU
Mandal et al. Angew. Chem. Int. Ed.,
2022, in pree

30. The First mNHI: Synthesis and CO2 activation
30
Stable at room temp under argon atmosphere.
Crystallised from n-hexane at 25℃.
Crystallised from CD3CN under CO2 atmosphere.
Mandal et al. Unpublished results

31. 31
Methylenation of amides: Homo and Hetero Coupling by CO2
Mandal et al. Angew Chem 2022 in press

32. Metal free catalysts for CO2 reduction
Chem. Sci., 2020, 11, 10571-10593
32

33. 33
Frustrated Lewis Pairs (FLPs)
Stephan et al. Science, 2006, 314, 1124-1126.

34. 34
FLPs for small molecule activation

35. 35
Stephan, Erker et al. Angew. Chem., Int. Ed., 2009, 48, 6643-
6646.
FLP for CO2 activation

36. 36
Interaction of CO2 with metals
How to mimic metals for CO2 activation!!