title: Optimized synthesis of a tert-butyl-phenyl-substituted tetrapyridophenazine ligand and its Ru(II) complexes and determination of dimerization behaviour of the complexes through supramolecular "Fingerhakel".
abstract: The synthesis of tpphz(tbp)2 (tpphz(tbp)2 = 3,16-di(tert-butyl-phenyl)-tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine) has been optimized by using a new synthetic route. The complexes Ru(tbp)2tpphz, Rutpphz(tbp)2, Rutpphz(tbp)2Ru and the reference compound Ru(tbp)2phen (where Ru = (tbbpy)2Ru, tbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine and (tbp)2phen = 3,8-bis(4-tert-butyl-phenyl)-1,10-phenanthroline) have been synthesized and characterized. Crystal structures or structural motifs could be obtained for each intermediate and complex and for the first time a tpphz based uncomplexed ligand could be investigated in the solid state. The mononuclear complexes Ru(tbp)2tpphz and Rutpphz(tbp)2 form π–π stacked dimers in the solid state. The latter exhibits an interesting aggregation in the solid state with three π-interactions. Concentration dependent aggregation of these isomers in solution is observed with the aid of 1H-NMR investigations. Out of those dimerization constants (KD) could be calculated for the complexes Ru(tbp)2tpphz and Rutpphz(tbp)2. The values differ significantly. Photophysical and electrochemical properties of the presented complexes were investigated and compared with reference compounds. The tert-butyl-phenyl-substitution induces a stabilization of the 1MLCT and 3MLCT states localized on the phenanthroline part of the bridging ligand. The 3MLCT localized on the phenazine portion seems to be not or only to a minor extent influenced by these substituents.
authors: Department of Inorganic Chemistry I, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany. sven.rau@uni-ulm.de.
authors: K
authors: K
authors: Ritter
authors: C
authors: C
authors: Pehlken
authors: D
authors: D
authors: Sorsche
authors: S
authors: S
authors: Rau