Stampp, Stephen

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MavMatrix (University of Texas at Arlington)

McNair Scholars Research Journal Volume 7 McNair Research Journal 2003 Article 17 12-1-2003 Supramolecular Nanosynthesis: Calix-Peptide Polymers Stephen Stampp Follow this and additional works at: https://mavmatrix.uta.edu/mcnairscholars Recommended Citation Stampp, Stephen (2003) "Supramolecular Nanosynthesis: Calix-Peptide Polymers," McNair Scholars Research Journal: Vol. 7, Article 17. Available at: https://mavmatrix.uta.edu/mcnairscholars/vol7/iss1/17 This Article is brought to you for free and open access by the Mavs Open Press Open Access Journals at MavMatrix. It has been accepted for inclusion in McNair Scholars Research Journal by an authorized editor of MavMatrix. For more information, please contact vanessa.garrett@uta.edu. SuPRAMOLECULAR NANOSYNTHESIS: CALIX-PEPTIDE POLYMERS Stephen P. Stampp Mentor: Dr. Dmitry Rudkevich, Department of Chemistry and Biochemistry In a technologically advancing world, there is need for the creation of new 'materials'. Today, the plat-forms or frontiers used in designing these materials are frequently based on molecular self-assembly and nanotechnology. This was not so in the past, as these are fairly new con-cepts.1 Some of these frontiers are based on ideas such as: (i) chemical frameworks composed of many iden-tical components arranged to serve as receptors for binding units, (ii) mol-ecules designed to self-assemble into supramolecular structures, and (iii) new materials based on 'smart' assem-blies that can be easily manipulated.2 Designing materials with these specific 28 • McNair Re;earch }01mud characteristics requires a clear under-standing of the dynamics of intra/in-termolecular interactions. Polymers, since their discovery have been key molecules because of their multifunction capabilities.3 Many are the result of nanofabrication and are able to carry and store information.4 At the simplest level of reasoning, a polymer is a chain of monomers ar-ranged in repeated units. The bonds between the monomeric units may be covalent or non-covalent such as hy-drogen bonding, electrostatic attrac-tions, and so forth. Some examples of active biological polymers exist as the storage polymers of deoxyribo-nucleic acid (DNA) and proteins. Also many plastics and building ma-terials are polymeric in nature. We are developing new materials based on the platforms mentioned above, where simple calixarenes are covalently bonded to peptide scaffolds forming monomeric units that self-assemble in solution due to hydrogen bonding. Calixarenes are molecules that have established popularity as building blocks in molecular recogni-tion and gas sensing.5 Calixarenes of-fer cavities for binding various guests and for our new polymers these mol-ecules acts as joints in the chain. The experiments began with the synthesis of hexyl (A) and heptylphenyl (B) urea derivatives. We hypothesized that B would be more soluble in solution (apolar solvents) due to its long hydrocarbon tails. Pre-liminary results only showed a slight increase, and A was chosen to work with because it is somewhat easier to handle. The next steps involved co-valent linking of short oligopeptides chains of lysine amino acids to the lower rim of the calixarene. Success-fol linking of one calixarene with an amino acid chain represents one monomer unit. There is great poten-tial for polymerization forming longer chains through hydrogen bonding of the upper rim urea groups. Commercially available tert-butyl calix[4]arene 1 in the presence of bromopropane and Ba(OH)28H20 and BaO were used to create tri-alky-lated calixarene 2 in 78% yield. Fur-ther alkylation of 2 with BrCH2COCH2CH3 and Na2C03 gave compound 3. Nitration of 3 af-forded compound 4-5, which was fur-ther reduced to 6 using Ra/Ni, H 2 in ethanol. Tetra-amino calixarene, and octyl-isocyanate in chloroform gave 7 in 92% yield. Next, 7 was treated with NaOH in THF-H20 and reacted with BOC-protected lysine, DCC and HOBT in DMF yielding compound 8 (see Figure 1). Simultaneously, in-depth visual images of the polymer were created using Macromodel 7.0 molecular ar-the polymer formation after hydrogen bonding (Figures 2 and 3, respec-tively). The project was quite delicate. Calixarenes are fairly rigid structures, but calix-linked peptides are a new idea and the synthetic procedures were complex. The NMR spectroscopy and computer modeling experiments were key in characterizing the struc-tures . At some point microscopic Figure 2: Peptide-supported calixarenes carry small molecules or function as nanoscale building structures for drug delivery. Overall, we believe our poly-Figure 1: Synthetic scheme for tetraurea-lysine techniques or crystalliza-tion might be employed to mers have tremendous promise and future application in practical use and represent an increase in the body of knowledge about such structures. chitecture software. The locations of all the atoms were entered into the program. Unfavorable energy interac-tions were calculated and minimized via the MMFS and MM2 energy re-duction mechanisms. The program generated many possible conforma-tions for monomeric structures. We also explored proposed structures for References: 'see' points in the molecule. The cavity of the calixarenes may allow the polymer to Figure 3: Peptide-supported supramolecular polymer 1. Zhang, S. Biotech. Adv. 2002, 20, 321-339. 2. Smaglik, P. Nature 2000, 406, 807-808. 3. Zeng, S.; Chen, C-H; Santiago, J. G.; Chen, J.-R.; Zare, R. N.; Trip,]. A.; Svec, F.; Frechet, J. Sensors and Actuators B: Chemi-cal. 2002, 82, 209-212. 4. (a)Xu, H .; Kinsel, G. R.; Zhang, J.; Li, M.; Rudkevich, D. M. Tetrahedron, 2003, 59, 5837-5848. (b) Mammen, M.; Chio, S-K.; Whitesides, G.M. Angew. Chem. Int. Ed 1998, 37, 2755-2794. (c) Wolfe, D. B.; Ashcom, ]. B.; Hwang, J.C.; Schaffer, C. B.; Mazur, E.; Whitesides, G. M. Advanced Materials. 2003, 15, 62-65. 5. (a) Calixarenes 2001; Eds.: Asfari, Z.; Bohmer, V; Harrowfield, J.; Vicens,].; Kluwer Academic Publishers, Dordrecht, 2001. (b) Gutsche, D.C.; Lin, L-G. Tetrahedron. 1986, 42, 1633-1640. Summer 2003 • 29 

Supramolecular Nanosynthesis: Calix-Peptide Polymers

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Supramolecular Nanosynthesis: Calix-Peptide Polymers

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