A Supramolecular Multi-Block Copolymer with a High Propensity for Alternation

• Published in: Journal of the American Chemical Society Vol. 128; no. 43; pp. 13986 - 13987
• Main Authors: Park, Taiho, Zimmerman, Steven C
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.11.2006; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Exact sciences and technology; General and physical chemistry; Physical Sciences; Science & Technology; CHEMISTRY; HYDROGEN-BONDED HETEROCOMPLEX; REVERSIBLE POLYMERS; FIDELITY; GLYCOL; Supramolecular structure; Block copolymer
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja064116s

Alternating, multi-block supramolecular copolymers were created using quadruple hydrogen bonding as the noncovalent binding force. One block consisted of two guanosine butyl urea (UG) units attached at the ends of a triethylene glycol linker or a PEG chain (MW = 2 kD). The other block contained a 2,7-diamido-1,8-naphthyridine (DAN) unit at each end of a short alkane diester linker or a 100 kD poly(butyl methacrylate) macromolecule. The UG unit presents an ADDA hydrogen bonding array that is complementary to the DAAD array of DAN, and these form a very strong complex (K assoc ∼ 5 × 107 M-1), whereas UG and DAN weakly self-associate. These recognition properties allowed a multi-block supramolecular polymer to form which exhibits a high propensity for alternation. The self-assembled polymeric structure was shown to be reversibly formed and it was characterized by a combination of dynamic light scattering (DLS), 1H NMR, size exclusion chromatography (SEC), and viscometry.