title: pH dependent molecular self-assembly of octaphosphonate porphyrin of nanoscale dimensions: nanosphere and nanorod aggregates.
abstract: Self-assembled nanostructures of zwitterionic octaphosphanatoporphyrin 1, of either nanoparticles or nanorods, depending on small changes in the pH, is demonstrated based on the J-aggregates. Porphyrin 1 self-assembled into nanosphere aggregates with a diameter of about 70-80 nm in the pH range 5-7, and nanorod aggregates were observed at pH 8.5. Hydrogen bonding, π-π stacking and hydrophilic interactions play important roles in the formation of this nanostructure morphology. Nanostructures were characterized by UV/Vis absorbance, fluorescence, atomic force microscopy (AFM) and transmission electron microscopy (TEM). This interesting pH dependent self-assembly phenomenon could provide a basis for development of novel biomaterials.
authors.affiliation: School of Chemistry, Monash University, Wellington road, Clayton Victoria 3800, Australia; E-Mails: kalyankar.mb@rediffmail.com (M.B.K.); cecilia.lalander@monash.edu (C.H.L.); steven.langford@monash.edu (S.J.L.); ruth.oliver@monash.edu (R.F.O.).
authors.forename: Sheshanath V
authors.initials: SV
authors.lastname: Bhosale
authors.forename: Mohan B
authors.initials: MB
authors.lastname: Kalyankar
authors.forename: Santosh V
authors.initials: SV
authors.lastname: Nalage
authors.forename: Cecilia H
authors.initials: CH
authors.lastname: Lalander
authors.forename: Sidhanath V
authors.initials: SV
authors.lastname: Bhosale
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Langford
authors.forename: Ruth F
authors.initials: RF
authors.lastname: Oliver
mesh_terms: D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D054118:Nanospheres / Q000737:chemistry* / Q000648:ultrastructure; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D063065:Organophosphonates / Q000737:chemistry*; D010316:Particle Size; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D063065:Organophosphonates; D011166:Porphyrins