@misc{novak_tang_2009, title={Devices containing chiroptical switching materials and methods of making and using the same}, volume={7,485,740}, number={2009 Feb. 3}, author={Novak, B. M. and Tang, H. Z.}, year={2009} }
 @article{tang_garland_novak_he_polavarapu_sun_sheiko_2007, title={Helical polyguanidines prepared by helix-sense-selective polymerizations of achiral carbodiimides using enantiopure binaphthol-based titanium catalysts}, volume={40}, ISSN={["1520-5835"]}, DOI={10.1021/ma0618777}, abstractNote={The polymerization of N-(n-hexyl)-N‘-phenylcarbodiimide was studied using a number of homochiral catalysts based on binaphthol derivatives. All polymers showed optical activity due to the formation of a predominant screw sense controlled by the chirality of the catalyst. The helicity and chirality of these materials were studied by VCD, ECD, and polarimetry. Structures calculated using density functional theory were used to compare with their simulated VCD and experimental VCD, thus allowing the absolute screw sense to be determined. AFM imaging showed epitaxial ordering of these rigid chains on graphite surfaces and single chains measuring nearly 3 mm were observed in spin-cast samples on silicon.}, number={10}, journal={MACROMOLECULES}, author={Tang, Hong-Zhi and Garland, Eva R. and Novak, Bruce M. and He, Jiangtao and Polavarapu, Prasad L. and Sun, Frank Chen and Sheiko, Sergei S.}, year={2007}, month={May}, pages={3575–3580} }
 @article{barto_frank_bedworth_taylor_anderson_ermer_jen_luo_ma_tang_et al._2006, title={Bonding and molecular environment effects on near-infrared optical absorption behavior in nonlinear optical monoazo chromophore-polymer materials}, volume={39}, DOI={10.1021/mo060033k}, number={22}, journal={Macromolecules}, author={Barto, R. R. and Frank, C. W. and Bedworth, P. V. and Taylor, R. E. and Anderson, W. W. and Ermer, S. and Jen, A. K. Y. and Luo, J. D. and Ma, H. and Tang, H. Z. and et al.}, year={2006}, pages={7566–7577} }
 @article{tang_novak_he_polavarapu_2005, title={A thermal and solvocontrollable cylindrical nanoshutter based on a single screw-sense helical polyguanidine}, volume={44}, ISSN={["1521-3773"]}, DOI={10.1002/anie.200501977}, abstractNote={Helix-sense-selective polymerization of an achiral carbodiimide using a chiral titanium catalyst yields the regioregular, stereoregular poly[N-(1-anthryl)-N′-n-octadecylguanidine] (poly-1). A reversible thermo- and solvent-driven switching phenomena is exhibited by poly-1 (see scheme) in electronic circular dichroism and optical rotation studies. Furthermore, the helicity of poly-1 is assigned and the mechanism of this switching process is elucidated. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z501977_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.}, number={44}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Tang, HZ and Novak, BM and He, JT and Polavarapu, PL}, year={2005}, pages={7298–7301} }
 @article{tang_boyle_novak_2005, title={Chiroptical switching polyguanidine synthesized by helix-sense-selective polymerization using [(R)-3,3 '-dibromo-2,2 '-binaphthoxy](di-tert-butoxy)titanium(IV) catalyst}, volume={127}, ISSN={["1520-5126"]}, DOI={10.1021/ja0453533}, abstractNote={A series of chiral binaphthyl titanium alkoxide complexes were synthesized. Among them, chiral titanium complex [(R)-3,3'-dibromo-2,2'-binaphthoxy](di-tert-butoxy)titanium(IV) (R-3) exists as a crystallographic C2 dimer in the solid state but a monomer in solution at room temperature. Application of R-3 in the helix-sense-selective polymerization of achiral carbodiimide, N-(1-anthryl)-N'-octadecylcarbodiimide (1), yielded a well-defined regioregular, stereoregular poly[N-(1-anthryl)-N'-octadecylguanidine] (poly-1b) with a relatively narrow polymer dispersity index of 2.7. Full racemization of poly-1b at +80 degrees C in toluene requires more than 100 h. Interestingly, poly-1b was found to undergo fast reversible chiroptical switching at +38.5 degrees C in toluene. Furthermore, at room temperature, poly-1b shows a positively signed Cotton effect in toluene, but negative ones in THF and chloroform, respectively. The chiroptical switching takes place around the toluene content of 90% (vol) in the mixed toluene/THF solvents. This is the first example of chiroptical switching phenomenon occurring in a helical polymer possessing no chiral moieties in the polymer chains. We believe this reversible chiroptical switching phenomenon occurs by reorientation of anthracene rings relative to the chain director.}, number={7}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Tang, HZ and Boyle, PD and Novak, BM}, year={2005}, month={Feb}, pages={2136–2142} }
 @article{tang_lu_tian_capracotta_novak_2004, title={Stable helical polyguanidines: Poly{N-(1-anthryl)-N '-[(R)- and/or (S)-3,7-dimethyloctyl]guanidines}}, volume={126}, ISSN={["1520-5126"]}, DOI={10.1021/ja049937g}, abstractNote={Using chiral catalysts of (R)- and/or (S)-BINOL-Ti, the asymmetrical polymerization of achiral monomer, N-(1-anthryl)-N'-n-octadecylcarbodiimide, yielded soluble nonregioregular polyguanidines of Poly-R1 and Poly-S1. A racemization process occurred when the toluene solution of Poly-R1 was annealed at elevated temperatures (70-80 degrees C). Kinetic studies reveal this to be a slow process with an activation energy of ca. 36 kcal/mol. On the other hand, using titanium(IV) trifluoroethoxide catalyst, the polymerization of N-(1-anthryl)-N'-[(R)- and/or (S)-3,7-dimethyloctyl]carbodiimides afforded highly regioregular polyguanidines of Poly-R2 and Poly-S2. These polymers adopt stable helices in various solvents and elevated temperatures, whose kinetically controlled conformations and thermodynamically controlled conformations are essentially the same.}, number={12}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Tang, HZ and Lu, YJ and Tian, GL and Capracotta, MD and Novak, BM}, year={2004}, month={Mar}, pages={3722–3723} }