Our research work mainly focuses on functionalization and characterization of two types of fascinating nanoscale carbon allotropes, namely single-walled carbon nanotubes (SWNTs) and Buckminster [60] fullerene.

Exhibiting many unprecedented electrical, physical, and mechanical properties, SWNTs have promised many application prospects in future materials science and technology. However, the solubility and compatibility problems have considerably limited the applicability of pristine SWNT. Chemical functionalization on the other hand can dramatically change their properties and behavior, therefore, providing a realistic approach towards extensive, practical uses of SWNTs. Our group is primarily concentrating on: 1) development of efficient, cost-effective functionalization methodologies for SWNTs, and 2) synthesis of various functional oligomer/polymer modified SWNTs composite materials as well as their potential applications in many respects.

C60 fullerene, having a unique 3-dimensional conjugated molecular structure, has displayed appealing photophysical properties and extraordinary electronic characteristics. As an excellent electron acceptor, it has been widely used in numerous artificial photosynthesis systems and organic photovoltaic devices. Our research efforts are directed towards the synthesis of conjugated oligomer bridged C60 and pi-extended tetrathiafulvalene (TTF) polyads. Photophysical characterization regarding charge and energy transfer will be probed by transient absorption spectroscopic techniques. Apart from the in-depth survey on structure-property relationship, one major goal is to achieve long lived and highly efficient photoinduced charge transfer (C-T) species.

Recent publications

1. Y. Zhao, G. Chen, K. Mulla, I. Mahmud, S. Liang, P. Dongare, D. W. Thompson, L. N. Dawe, S. Bouzan"Tetrathiafulvalene Vinylogues as Versatile Building Blocks for New Organic Materials", Pure Appl. Chem., 2012, accepted.
2. K. Mulla, P. Dongare, D. W. Thompson, Y. Zhao "Click Synthesized Dianthryl-TTFV: An Efficient Fluorescent Turn-On Probe for Transition Metal Ions", Org. Biomol. Chem., 2012, accepted, DOI:10.1039/C2OB06828A.
3. S. Liang, G. Chen, J. Peddle, Y. Zhao "Reversible dispersion and releasing of single-walled carbon nanotubes by a stimuli-responsive TTFV-phenylacetylene polymer", Chem. Commun., 2012, in press, DOI:10.1039/C2CC17935K.
4. Y. Pourghaz, P. Dongare, D. W. Thompson, Y. Zhao " Click Functionalized Poly(p-phenylene ethynylene)s as Highly Selective and Sensitive Fluorescence Turn-On Chemosensors for Zn2+ and Cd2+ Ions", Chem. Commun., 2011, 47, 11014-11016.
5. G. Venkataramana, P. Dongare, L. N. Dawe, D. W. Thompson, Y. Zhao, G. J. Bodwell " 1,8-Pyrenylene−Ethynylene Macrocycles", Org. Lett., 2011, 13, 2240–2243.
6. G. Chen, I. Mahmud, L. N. Dawe, D. Lee, Y. Zhao " Synthesis and Properties of Conjugated Oligoyne Centered pi-Extended Tetrathiafulvalene Analogues and Related Macromolecular Systems", J. Org. Chem., 2011, 76, 2701-2715.
7. K. Mulla, P. Dongare, N. Zhou, G. Chen, D. W. Thompson, Y. Zhao " Highly Sensitive Detection of Saccharides under Physiological Conditions with Click Synthesized Boronic Acid-Oligomer Fluorophores", Org. Biomol. Chem., 2011, 9, 1332-1336.
(Top ten most accessed articles in January, 2011, OBC)
8. N. Zhou, L. Wang, D. W. Thompson, Y. Zhao " OPE/OPV H-mers: Synthesis, Electronic properties, and Spectroscopic Responses to Binding with Transition Metal Ions", Tetrahedron, 2011, 67, 125-143.
9. G. Chen, S. Bouzan, Y. Zhao " Synthesis and Properties of TTFV-hinged Molecular Tweezers", Tetrahedron Lett., 2010, 51, 6552-6556.
10. M. Shao, P. Dongare, L. N. Dawe, D. W. Thompson, Y. Zhao " Biscrown-Annulated TTFAQ-Dianthracene Hybrid: Synthesis, Structure, and Metal Ion Sensing", Org. Lett., 2010, 12, 3050-3053.
11. M. Shao, Y. Zhao "TTFAQ-Cored D/A Ensembles: Synthesis, Electronic Properties, and Redox Responses to Transition Metal Ions", Tetrahedron Lett., 2010, 51, 2892-2895.
12. M. Shao, Y. Zhao "Phenylboronic Acid Functionalized TTFAQ: Modular Synthesis and Electrochemical Recognition for Saccharides", Tetrahedron Lett., 2010, 51, 2508-2511.
13. N. Zhou, Y. Zhao "Conjugated Oligoyne Bridged [60]Fullerene Molecular Dumbbells: Synthesis, Thermal and Morphological Properties", J. Org. Chem., 2010, 75, 1498-1516.
14. G. Chen, I. Mahmud, L. Dawe, Y. Zhao "Acetylenic Phenyldithiafulvene: A Versatile Synthon for TTFV-Based Macromolecules", Org. Lett., 2010, 12, 704-707.
15. M. Shao, Y. Zhao "Synthesis and Properties of Thiophene-Functionalized pi-Extended Tetrathiafulvalenes", Tetrahedron Lett., 2009, 50, 6897-6900.
16. G. Chen, L. Dawe, L. Wang, Y. Zhao "Planar Acetylene-Expanded TTFAQ Analogues", Org. Lett., 2009, 11, 2736-2739.
17. I. Mahmud, N. Zhou, L. Wang, Y. Zhao "Triazole-Linked Dendro[60]fullerenes: Modular Synthesis via a 'Click' Reaction and Acidity-Dependent Self-Assembly on the Surface", Tetrahedron, 2008, 64, 11420-11432.
18. N. Zhou, L. Wang, D. W. Thompson, Y. Zhao "H-Shaped OPE/OPV Oligomers: A New Member of 2D Conjugated Fluorophore Cores", Org. Lett., 2008, 10, 3001-3004.
19. R. R. Tykwinski, M. Gholami, S. Eisler, Y. Zhao, F. Melin, L. Echegoyen, "Expanded radialenes: Modular synthesis and properties of cross-conjugated enyne macrocycles", Pure Appl. Chem., 2008, 80, 623-639.
20. G. Chen, L. Wang, D. W. Thompson, Y. Zhao, "Highly pi-Extended TTF Analogues with a Conjugated Macrocyclic Enyne Core", Org. Lett., 2008, 10, 657-660.
21. A. Spantulescu, T. Luu, Y. Zhao, R. McDonald, R. R. Tykwinski, "Synthesis and Characterization of Cyclic Alkyl Tetraynes", Org. Lett., 2008, 10, 609-612.
22. M. Shao, G. Chen, Y. Zhao, "Synthesis and Electronic Properties of a Conjugated TTFAQ Trimer and Donor-Acceptor Ensembles of TTFAQ and Anthraquinone", SYNLETT, 2008, 371-376.
23. G. Chen, M. Shao, L. Wang, Y. Zhao, "Donor-Acceptor Effects on Anthraquinoid-Type pi-Extended Tetrathiafulvalenes through 2,6-Diethynyl Bridges", Asian Chem. Lett., 2007, 11, 185-196. (Invited article to a special issue on tetrathiafulvalene and acetylene chemistry)
24. N. Zhou, L. Wang, M. Tobin, D.W. Thompson, Y. Zhao, "Studies on Dumbbell-Shaped Bisfullerene and Conjugated Oligomer Hybrids", in Fullerene Research Advances, Novapublishers, 2007 (publish date: 2007-4th quarter, ISBN: 1-60021-824-5)
25. Y. Zhao, N. Zhou, A.D. Slepkov, S.C. Ciulei, R. McDonald, F.A. Hegmann, R.R. Tykwinski, "Donor/Acceptor Effects on Linear and Nonlinear Optical Properties of Geminal-Diethynylethenes (g-DEEs)", Helv. Chim. Acta 2007, 90, 909-927.
26. N. Zhou, L. Wang, D. W. Thompson, Y. Zhao, "Synthesis, electronic and photophysical properties of cruciform OPE/OPV hybrid oligomer bridged bisfullerene triads", Tetrahedron Lett. 2007, 48, 3563-3567.
27. N. Rice, K. Soper, N. Zhou, E. Mershrod, Y. Zhao, "Dispersing As-Prepared Single-Walled Carbon Nanotube Powders with Linear Conjugated Polymers", Chem. Commun. 2006, 4937-4939.
28. G. Chen, Y. Zhao, "Synthesis and Electronic Properties of Alkyne-TTFAQ Based Molecular Wires", Tetrahedron Lett. 2006, 47, 5069-5073.
29. Y. Shirai, A. J. Osgood, Y. Zhao, Y. Yao, L. Saudan, H. Yang, Y.-H. Chiu, L. B. Alemany, T. Sasaki, J.-F. Morin, J. M. Guerrero, K. F. Kelly, J. M. Tour, " Surface-Rolling Molecules", J. Am. Chem. Soc., 2006, 128, 4854-4864.
30. Y. Shirai, A.J. Osgood, Y. Zhao, K.F. Kelly, J.M. Tour, "Directional Control in Thermally Driven Single-Molelcule Nanocars", Nano Lett., 2005, 11, 2330-2334.
31. N. Zhou, E. Mershrod, Y. Zhao, "Preparation of Fullerene-Polyyne Nanospheres via Thermally-Induced Solid-State Polymerizations", J. Am. Chem. Soc., 2005, 127, 14154-14155.
32. J. Cho, Y. Zhao, R. R. Tykwinski, "Synthesis and Characterization of Cross-Conjugated Oligo(phenylene enynylene)s", Arkivoc, 2005, iv, 142-150.
33. Y. Zhao, Y. Shirai, A. D. Slepkov, L. Cheng, L. B. Alemany, T. Sasaki, F.A. Hegmann, J. M. Tour, “ Synthesis, Spectroscopic and Nonlinear Optical Properties of Multiple [60]Fullerene-Oligo( p -Phenylene Ethynylene) Hybrids ”, Chem. Eur. J., 2005, 11, 3643-3658.
34. Y. Zhao, A.D. Slepkov, O.A. Clement, R. McDonald, F.A. Hegmann, R.R. Tykwinski, “Synthesis, Structures, and Nonlinear Optical Properties of Cross-Conjugated Perphenylated iso-Polydiacetylenes”, Chem. Eur. J., 2005, 11, 321-329.
35. Y. Shirai, Y. Zhao, L. Cheng, J.M. Tour, “Facile Synthesis of Multifullerene-OPE Hybrids via in situ Ethynylation”, Org. Lett. 2004, 13, 2129-2132.
36. A.D. Slepkov, F.A. Hegmann, K. Kamada, Y. Zhao, R.R. Tykwinski, “Optical Properties of Cross-Conjugated iso-Polydiacetylene Oligomers as Measured by UV-Vis Spectroscopy and Optical Kerr Effect”, J. Opt. A, Pure Appl. Opt. 2002, 4, S207-S211.
37. R.R. Tykwinski, Y. Zhao, “Cross-Conjugated Oligo(enyne)s”, Synlett 2002, (12), 1939-1953 (invited account).
38. Y. Zhao, R. McDonald, R.R. Tykwinski, “Study of Cross-Conjugated iso-Polytriacetylenes and Related Oligoenynes”, J. Org. Chem. 2002, 67, 2805-2812.
39. A.D. Slepkov, F.A. Hegmann, Y. Zhao, R.R. Tykwinski, K. Kamada, “Ultrafast Optical Kerr Effect Measurement of Third-Order Nonlinearities in Cross-Conjugated iso-Polydiacetylene Oligomers”, J. Chem. Phys. 2002, 116, 3834-3840.
40. Y. Zhao, K. Campbell, R.R. Tykwinski, “Iterative Synthesis and Characterization of Cross-Conjugated iso-Polydiacetylenes”, J. Org. Chem. 2002, 67, 336-344.
41. Y. Zhao, S.C. Ciulei, R.R. Tykwinski, “The Effect of π-Acceptor and π-Donor Substitution in Cross-Conjugated Enynes”, Tetrahedron Lett. 2001, 42, 7721-7723.
42. Y. Zhao, R. McDonald, R.R. Tykwinski, “Synthesis and Characterization of Cross-Conjugated Polyenynes”, Chem. Commun. 2000, 77-78.
43. Y. Zhao, R.R. Tykwinski, “Iterative Synthesis and Properties of Cross-Conjugated iso-Polydiacetylene Oligomers”, J. Am. Chem. Soc. 1999, 121, 458-459.