title: Heterometallic Homo- and Heteroleptic Porphyrinate Dimers with a Rhodium-Thallium Bond.
abstract: The synthesis and spectroscopic characterization of four heterometallic porphyrinate dimers containing rhodium-thallium metal-metal bonds are reported. The investigated compounds are represented by the formula (Porph)Rh-Tl(Porph'), where Porph and Porph' are OEP and/or TPP. UV/visible spectroscopy of the title complexes confirms the presence of a strong pi-pi interaction between the macrocycles in each derivative. With (1)H and (13)C NMR data, we were able to distinguish two major NMR regions: the endo, between the metal-metal bonded macrocycles, and the exo, outside the macrocycles, which are characteristic features of porphyrinic dimers. (205)Tl NMR for the title complexes was performed, and the chemical shifts of the thallium nucleus are presented. For the four complexes, the magnitudes of spin-spin coupling constants between thallium and rhodium nuclei have been measured for the first time. Finally, reactions with selected substrates were studied in order to investigate the reactivity as well as the polarity of the metal-metal bond.
authors.affiliation: Department of Chemistry, Laboratory of Bioinorganic Coordination Chemistry, School of Sciences, University of Crete, P.O. Box 1470, 714 09 Heraklion, Crete, Greece, and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Daphnomili
authors.forename: W. Robert
authors.initials: WR
authors.lastname: Scheidt
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Zajicek
authors.forename: Athanassios G.
authors.initials: AG
authors.lastname: Coutsolelos