Presentation of Post Doctoral Research

Dr. Parantap Sarkar

Postdoctoral Experience1. IISER Kolkata, India (Oct 2012 – Jan 2013, 4 months)

2. Ewha Womans University, South Korea (March 2013 – Feb 2014, 1 year)

3. WPI-AIMR, Tohoku University, Japan (Apr 2014 – Jan 2017, 2 years 10 months)

1. IISER Kolkata, India

Work on progress

synthesis that was finished by me in 4 monthsYield of the steps were not optimized

due to lack of time

2. Ewha Womans University, South Korea

Project A. Synthesis of NHC-fullerene adduct

Project B. Synthesis of NHC-bis Carbene

2. Ewha Womans University, South Korea

Flexible nanohoops

Rigid nanohoops

3. WPI-AIMR Tohoku University, Japan

Project A & B: Introduction

Project A Project B

3. WPI-AIMR Tohoku University, Japan Project A

Unbridged (flexible at r.t. in solution)

Angew. Chem. 2015, 54, 12800-12804

3. WPI-AIMR Tohoku University, Japan Project A

Angew. Chem. 2015, 54, 12800-12804

3. WPI-AIMR Tohoku University, Japan Project A

Angew. Chem. 2015, 54, 12800-12804

3. WPI-AIMR Tohoku University, Japan Project A

Angew. Chem. 2015, 54, 12800-12804

3. WPI-AIMR Tohoku University, Japan Project A

Conclusion of Project A

1. the first belt-shaped cyclonaphthylenes were synthesized, and their structures were revealed by crystallographic and spectroscopic analyses.

2. The rigidity of the nanohoop structures is reinforced by methylene bridges, which gives rise to the atropisomerism of cyclonaphthylene in solutionand correlated rotation.

3. WPI-AIMR Tohoku University, Japan Project B

Chem. Lett. 2015, 44, 1582-1583

3. WPI-AIMR Tohoku University, Japan Project B

Chem. Lett. 2015, 44, 1582-1583

3. WPI-AIMR Tohoku University, Japan Project B

Chem. Lett. 2015, 44, 1582-1583

Slow arylene rotation

3. WPI-AIMR Tohoku University, Japan Project B

Chem. Lett. 2015, 44, 1582-1583

3. WPI-AIMR Tohoku University, Japan Project B

Chem. Lett. 2015, 44, 1582-1583

3. WPI-AIMR Tohoku University, Japan Project B

Conclusion of Project B

1. Synthesis of a new member in cyclo-arylene chemistry with very high numbers of π-degenerated system.

2. Investigation on the rotational behavior of the arylene units in the hybrid nanohoop that revealed both free arylene rotation and correlated rotation.

3. Considering the synchronous broadening of the 1H-NMR resonances, we believe, that the correlated rotation of anthanthrenylene-phenylene is occurring competitively with the single phenylene rotation in solution.

3. WPI-AIMR Tohoku University, Japan Project C

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P M

U-[8]CaNAP

[8]CPhen3,9

Introduction

ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

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ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

Crystal Structure

Condition to obtain Single crystal:

Slow diffusion of pentane into o-DCB

solution of [8]CPhen3,9

3-3’ linkage9-9’ linkage

Dihedral angles :4-3-3’-4 linkage => 141°, 149°, 166°, 166°8a-9-9’-8a’ linkage => –142°, –142°, –143°, –143°

ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

Separation of [8]CPhen3,9 enantiomers and CD Spectra

Analytical HPLC ChromatogramColumn: Cosmosil Cholester (250+250+250) mm x 4.6 ϕEluent: 30% MeOH in CHCl3

CD spectra of isolated enantiomers in toluene at 25 °C.

(by Prep. HPLC) Gray bars show the rotatory

velocity calculated by the DFT method at the B3LYP/6-31G(d,p)

level of theory for the (E,R,E,R,E,R,E,R)-structure.

ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

VT-NMR study

ACS Cent. Sci. 2016, 2(10), 740-747

3. WPI-AIMR Tohoku University, Japan Project C

Conclusion of Project C

1. Cyclophenanthrenylene nanohoop with heterogeneous biaryl linkage has been synthesised.

2. Due to presence of R/S-linkage the nanohoop deviates from coplanar belt-shape and unique cyclostereoisomerism has been emerged.

3. The nanohoop follows two-stage isomerization pathways, E/Z- and R/S-isomerization respectively, where the later is restricted at ambient temperature resulting isolable stereoisomers with intrinsic axial chirality at biaryl linkages.