title: Donor-acceptor biomorphs from the ionic self-assembly of porphyrins.
abstract: Microscale four-leaf clover-shaped structures are formed by self-assembly of anionic and cationic porphyrins. Depending on the metal complexed in the porphyrin macrocycle (Zn or Sn), the porphyrin cores are either electron donors or electron acceptors. All four combinations of these two metals in cationic tetra(N-ethanol-4-pyridinium)porphyrin and anionic tetra(sulfonatophenyl)porphyrin result in related cloverlike structures with similar crystalline packing indicated by X-ray diffraction patterns. The clover morphology transforms as the ionic strength and temperature of the self-assembly reaction are increased, but the structures maintain 4-fold symmetry. The ability to alter the electronic and photophysical properties of these solids (e.g., by altering the metals in the porphyrins) and to vary cooperative interactions between the porphyrin subunits raises the possibility of producing binary solids with tunable functionality. For example, we show that the clovers derived from anionic Zn porphyrins (electron donors) and cationic Sn porphyrins (electron acceptors) are photoconductors, but when the metals are reversed in the two porphyrins, the resulting clovers are insulators.
authors.affiliation: Advanced Materials Laboratory and Center for Integrated Nano Technologies, Sandia National Laboratories, Albuquerque, New Mexico 87185-1349, USA.
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Martin
authors.forename: Zhongchun
authors.initials: Z
authors.lastname: Wang
authors.forename: Tito
authors.initials: T
authors.lastname: Busani
authors.forename: Robert M
authors.initials: RM
authors.lastname: Garcia
authors.forename: Zhu
authors.initials: Z
authors.lastname: Chen
authors.forename: Yingbing
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yujiang
authors.initials: Y
authors.lastname: Song
authors.forename: John L
authors.initials: JL
authors.lastname: Jacobsen
authors.forename: Tony T
authors.initials: TT
authors.lastname: Vu
authors.forename: Neil E
authors.initials: NE
authors.lastname: Schore
authors.forename: Brian S
authors.initials: BS
authors.lastname: Swartzentruber
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Medforth
authors.forename: John A
authors.initials: JA
authors.lastname: Shelnutt
mesh_terms: D004581:Electronics; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D055620:Optical Phenomena; D011166:Porphyrins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014001:Tin / Q000737:chemistry; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry
chemical_list: D011166:Porphyrins; D014001:Tin; D015032:Zinc