title: Highly stable C(60)/poly(vinylpyrrolidone) charge-transfer complexes afford new predictions for biological applications of underivatized fullerenes.
abstract: The equilibrium constants for complexation of C(60) with poly(vinylpyrrolidone) (PVP) in water have been determined by UV-visible spectroscopy. The magnitude of the equilibrium constants was found to describe the formation of a charge-transfer (CT) saturated 1:1 complex for [PVP] = 2.62-5.25 x 10(-2) M (K = 1331.3 M(-1)), and a contact-pairs complex for [PVP] = 7.0-12.25 x 10(-2) M (K = 20.64 x 10(-2) M(-1)). These results indicate that the binding affinity of C(60) for drug receptors, base pairs in double-stranded DNA, or AT-rich segments of its minor groove to form CT complexes is limited by the strong coordination in the C(60)/PVP-saturated CT complex or envelopment by the polymer ligand in the contact CT complex.
authors.affiliation: "P. Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41-A, 6600 Iasi, Romania. rbsscung@ichpp.tuiasi.ro
authors.forename: C
authors.initials: C
authors.lastname: Ungurenasu
authors.forename: A
authors.initials: A
authors.lastname: Airinei
mesh_terms: D002244:Carbon / Q000737:chemistry*; D037741:Fullerenes; D011205:Povidone / Q000737:chemistry*; D011760:Pyrrolidinones / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014867:Water
chemical_list: D037741:Fullerenes; D011760:Pyrrolidinones; D014867:Water; D002244:Carbon; D011205:Povidone; C038678:N-methylpyrrolidone; C069837:fullerene C60