title: Porphyrins linked directly to the 5,5' positions of 2,2'-bipyridine: a new supramolecular building block and switch.
abstract: The synthesis and coordination chemistry of two porphyrin dimers linked either at the 5,5' or the 4,4' positions of 2,2'-bipyridine are described. These compounds, which may serve a molecular tectons for the constructions of a variety of supramolecular arrays of diverse function, reveal that the ground- and excited-state electronic communication between the chromophores is only moderately affected by the complexation state of the bipyridyl moiety. The nature of the metal ion chelated by the bipyridine only slightly perturbs the ground-state spectra, and differences observed in the excited state are largely ascribed to the heavy atom effect. This work also shows that conformational changes in structural subunits, in this case induced by bipyridyl complexation of various metal ions, do not necessarily require reorganization of supramolecular systems.
authors.affiliation: Department of Chemistry and Biochemistry, Hunter College and Graduate Center of the City University of New York, 695 Park Avenue, New York, New York 10021, USA.
authors.forename: Kai Fan
authors.initials: KF
authors.lastname: Cheng
authors.forename: Charles Michael
authors.initials: CM
authors.lastname: Drain
authors.forename: Klaus
authors.initials: K
authors.lastname: Grohmann
mesh_terms: D015082:2,2'-Dipyridyl / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D008665:Metalloporphyrins; D015082:2,2'-Dipyridyl; D015032:Zinc