title: Synthesis, Structure, and Photophysical Properties of Novel Ruthenium(II) Carboxypyridine Type Complexes.
abstract: A series of Ru(II) compounds and salts have been synthesized: [Ru(6-carboxylato-bpy)(2)] (5), [Ru(6-carboxylato-bpy)(tpy)]PF(6) (9), [Ru(tpy)(2)](PF(6))(2) (8), and [Ru(bpy)(2)(Pic)]PF(6) (11), where 6-carboxy-bpy (1) = 6-carboxy-2,2'-bipyridine, tpy (2) = 2,2':6',2"-terpyridine, and Pic = 2-carboxylatopyridine. The compounds have been characterized by NMR, electrospray mass spectrometry (ESI-MS), cyclic voltammetry, absorption and emission spectroscopy (at 100, 140, and 298 K), and single-crystal X-ray diffraction (complex 5). Complex 5 crystallizes in the monoclinic system, space group P2(1)/n, formula RuC(22)H(14)N(4)O(4).C(2)H(5)OH, with a = 11.088(3) Å, b = 11.226(3) Å, c = 35.283(9) Å, beta = 91.41(2) degrees, and Z = 8. A linear dependence on the number of coordinated carboxylato groups and the electrochemical redox potentials was found, ca. 0.4 V lower reduction potential for the oxidation step (Ru(II/III)) per carboxylate group. Also, to the best of our knowledge, these are the first examples (9, 11) of mononuclear Ru(II) complexes containing a carboxypyridine-ruthenium moiety displaying any luminescence emission.
authors.affiliation: Department of Organic Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Norrby
authors.forename: Anna
authors.initials: A
authors.lastname: Börje
authors.forename: Björn
authors.initials: B
authors.lastname: Åkermark
authors.forename: Leif
authors.initials: L
authors.lastname: Hammarström
authors.forename: Jan
authors.initials: J
authors.lastname: Alsins
authors.forename: Kianosh
authors.initials: K
authors.lastname: Lashgari
authors.forename: Rolf
authors.initials: R
authors.lastname: Norrestam
authors.forename: Jerker
authors.initials: J
authors.lastname: Mårtensson
authors.forename: Gunnar
authors.initials: G
authors.lastname: Stenhagen