1. International Conference and Exhibition on Biopolymers and Bioplastics
10th - 12th August 2015, San Francisco, USA
Production of Biodegradable Polymers using Group IV Complexes of Salicyl-benzotrizole and benzoxazole Ligands
Sreenath Pappuru
Research Scholar
Department of Chemistry
Indian Institute of Technology Madras, India

2. Contents Introduction
Construction of group IV metal complexes containing Salicyl-benzotrizole
and benzoxazole scaffold
Homo polymerization of rac-LA
Copolymerization of L-LA with -CL
DFT studies
Summary

3. Introduction Surgery Bone replacement Degradable materials Medical
Green sutures
Packaging

4. Catalyst Development Ligand precursors used in this study
Synthetic routes for complexes 1−12
S. Pappuru, E. R. Chokkapu, D. Chakraborty, V. Ramkumar, Dalton Trans. 2013, 42, 16412–16427.

5. Single Crystal X-ray Structures

6. Single Crystal X-ray Structures
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

7. Single Crystal X-ray Structures
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

8. Single Crystal X-ray Structures
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

9. Homo-Polymerization of rac-lactide
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

10. 1H NMR spectrum (500 MHz, CDCl3) of the poly(rac-LA) obtained from a reaction of rac–LA with 2 in 20:1 ratio at 140 oC.

11. MALDI-TOF spectrum of the poly(rac-LA) obtained from a reaction between rac–LA and 4 in 20:1 ratio at 140 oC.

12. Microstructural Analysis of PLA
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Cat 1
Cat 3
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Cat 2
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Cat 4
Cat 5
Cat 6
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Homonuclear decoupled 1H NMR (500 MHz, CDCl 3 ) spectrum of the methine region of PLA obtained using group IV complexes.

13. Thermal analysis
DSC traces (heating rate: 10 °C/min, 2nd scan) of homopolymers of rac-LA with complexes 2-6 at 200 : 1 monomer initiator ratio
DSC traces (heating rate: 10 °C/min, 2nd scan) of homopolymers of rac-LA with complex 6 at various monomer initiator ratios.

14. co-polymerization of L-LA with -CL
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

15. 1H NMR spectra of co-polymers
Cat 1
Cat 2
Cat 3
Cat 6
1H NMR spectra (500 MHz, CDCl3) of the copolymer showing the - and α-methylene ranges in the copolymers produced by the reaction of L-LA and -CL using catalysts a) 6, b) 3, c) 2 and d) 1

16. 13C NMR spectra of co-polymers
Cat 1
Cat 2
Cat 3
Cat 6
Carbonyl range of 13C NMR spectra (125 MHz, CDCl3) of copolymers produced by the reaction of L-LA and -CL using catalysts
a) 6, b) 3, c) 2 and d) 1

17. 13C NMR spectra of co-polymers
13C NMR spectra (500 MHz, CDCl3) of Poly L-LA and PCL (a, d) and random poly(LA-co-CL) copolymers (b, c) prepared using 4 and 6 respectively, representing the linkages between LA and CL units along the copolymer chain

18. Thermal analysis
Tg values are lower than the physiological temperature of 37.4 oC, indicating that they can be used for the pharmaceutical and biomedical applicatons.
DSC traces (heating rate: 10 °C/min, 2 nd scan) of copolymers by complex 4 and 6 from Table.

19. DFT Calculations The M06-2X functional was used.
Calculated free energy profiles (kcal mol-1) of the initiation step in the ROP of LA mediated by Ti (1) and Zr (2) complexes.
Pappuru, S.; Chakraborty, D.; Chand, D. K.; Unpublished results.

20. DFT Calculations
Optimized structures of Zr complex (2) involved in the initiation step of the ROP of LA.

21. Summary
Ligands
Catalysts
Polymer Synthesis
High reactive
complex

22. Our Campus

23. Thank You