619326-07-7Relevant articles and documents
A rigid molecular scaffold affixing a (polypyridine)ruthenium(II)- and a nickel(II)-containing complex: Spectroscopic evidence for a weakly coupled bichromophoric system
Pellegrin, Yann,Berg, Katja E.,Blondin, Genevieve,Anxolabehere-Mallart, Elodie,Leibl, Winfried,Aukauloo, Ally
, p. 1900 - 1910 (2003)
The synthesis of DppztBuSalH2 (7), a rigid conjugated ditopic ligand containing a Dppz (dipyrido[3,2-a:2′,3′-c]phenazine) skeleton and a salophen-type chelate, is reported. The complexes DppztBuSalNi (10), [Ru(bpy)2(DppztBuSalH2)]2+ (11), and [Ru(bpy)2(DppztBuSalNi)]2+ (12) have been prepared and characterised using common spectroscopic methods. Electrochemical, UV/Vis spectroelectrochemical and EPR studies were conducted on compounds 7, 10, 11, and 12. The singly reduced radical forms of 7 and 10 can be generated electrochemically, with the lone electron located on the low-lying phenazine π*-molecular orbital. Complexes 11 and 12 show several reduction waves and electronic and EPR data obtained for the electrogenerated singly reduced species show them to be closely related to the radical species 7.- and 10.-, respectively. The presence of nickel(II) in compound 12 renders the addition of the second electron on the phenazine group reversible. Both 11 and 12 show common features on the cathodic side of their cyclic voltammograms, with reversible one-electron ruthenium-centred oxidation. An additional low-potential reversible oxidation wave is observed for 12, and this is ascribed to oxidation of the nickel(II) ion. The combined spectroscopic data best describe the ruthenium-containing complexes as weakly coupled bichromophoric systems. Photophysical studies attest to the formation of a charge-separated state for 11, whereas a strong quenching is detected for 12. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Synthesis of amino- and bis(bromomethyl)-substitued bi- and tetradentate N-heteroaromatic ligands: Building blocks for pyrazino-functionalized fullerene dyads
Kleineweischede, Andreas,Mattay, Jochen
, p. 947 - 957 (2007/10/03)
In this paper we describe the synthesis of amino- and bis(bromomethyl)- substituted derivatives of phenanthrofine (phen), pyrazino[2,3-f]-phenanthroline (pphen), dipyrido[3,2-a:2′,3′-c]phenazine (dppz), pyrazino[2,3-i]dipyrido[3,2-a:2′,3′-c]phenazine, 2,3-bis(2-pyridyl)pyrazine (dpp), 2,3-bis(2-pyridyl)quinoxaline (dpq) and 7,8-bis(2-pyridyl)pyrazino[2,3-g]quinoxaline. These substituted bi- and tetradentate N-heteroaromatic ligands are potential synthons for the preparation of the fullerene ligands 4-9. The diketones, 1,10-phenanthroline-5,6-dione 11a (phendione), 2,2-pyridyl 11b and 1,4-dibromo-2,3-butanedione 33 were used as starting materials. Phendione was converted into the phendiamine 13 by a two-step synthesis via the dioxime of the diketone 11a. Amino-substituted dppz and dpq derivatives were obtained by the reduction of the corresponding nitro compounds that were obtained by the Schiff base condensation of the diketones 11a and 11b and the appropriate o-phenylenediamine derivatives. An alternative synthetic route to the diamines 20a and 20b by detosylation of the diamino-substituted dppz and dpq ligands is also presented. Synthesis of the bis(bromomethyl)-substituted pphen, dpp, dppz and dpq derivatives was performed by the photochemical addition of bromine. Alternatively, synthesis of the bis(bromomethyl)-substituted pphen, pdppz and pdpq is also possible by the condensation of 1,4-dibromo-2,3-butanedione 33 and phendiamine or the diamino-substituted dppz and dpq derivatives. The latter two compounds can be also prepared by the condensation of diketones 11a and 11b with 6,7-diamino-2,3-bis(bromomethyl)-quinoxaline. Although the synthesis of some dppz and dpq ligands is already published, we herein present improved or alternative synthetic strategies leading to higher yields and/ or higher purity of these N-heteroaromatic ligands. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
