Synthesis, spectroscopic and electrochemical studies of a series of transition metal complexes with amino- or bis(bromomethyl)-substituted dppz-ligands: Building blocks for fullerene-based donor–bridge–acceptor dyads

Kleineweischede, Andreas; Mattay, Jochen

doi:10.1016/j.jorganchem.2005.12.008

Cited by 18 publications

(8 citation statements)

References 47 publications

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“…The resultant red solution was filtered over celite and the solvent removed in vacuo to give the corresponding amine as a reddishcoloured solid. Dipyrido[3,2-a:2′,3′-c]phenazine-11-amine (L 1 ) 30 Isolated as a red powder (0.573 g, 90%). 1 General procedure for the synthesis of the chloroacetamide derivatives…”

Section: General Procedures For the Reduction Of Nitro Compoundsmentioning

confidence: 99%

Water-soluble, luminescent iridium(iii)–ytterbium(iii) complexes using dipyrido[3,2-a:2′,3′-c]phenazine derivatives as bridging units

et al. 2012

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Amino-substituted dipyrido[3,2-a:2',3'-c]phenazine (L(1)) and dimethyl-dipyrido[3,2-a:2',3'-c]phenazine (L(2)) have been investigated as: (i) chromophores in cyclen-based ligands for lanthanide(III) ions; (II) ancillary co-ligands in cyclometalated iridium(III) complexes; (III) bridging, linker units in covalently linked, water-soluble bimetallic lanthanide(III) iridium(III) hybrid complexes. The dipyrido[3,2-a:2',3'-c]phenazine (dppz) derivatives can act as sensitising chromophores (λ(ex) 400 nm) for Yb(III), resulting in characteristic near-IR emission at 950-1050 nm. The incorporation of dppz-type ligands into cyclometalated Ir(III) complexes of the general type [Ir(epqc)(2)(L(n))](PF(6)) (where epqc = ethylphenylquinoline carboxylate) gave luminescent species with solvent-sensitive emission properties. Steady state and time-resolved luminescence measurements on the water-soluble d-f hybrid species showed that Yb(III) can be sensitised using visible light.

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Section: General Procedures For the Reduction Of Nitro Compoundsmentioning

confidence: 99%

Water-soluble, luminescent iridium(iii)–ytterbium(iii) complexes using dipyrido[3,2-a:2′,3′-c]phenazine derivatives as bridging units

et al. 2012

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“…This may be achieved by chelation to various metals − which alters the b 1 (phen) MO. Substitution at the dppz ligand has mostly involved lowering the energy of the b 1 (phz) state through appending electron-withdrawing groups to the E ring. ,− In addition, in one study the energy of the b 1 (phen) state was modified through substitution at the A and C rings . Recent studies have used dppz as an acceptor motif, connected to sulfur-based donors. ,,− Jia et al demonstrated a tetrathiafulvalene (TTF)–dppz donor–acceptor (D–A) couple with a change in dipole moment of 16 D .…”

Section: Introductionmentioning

confidence: 99%

“…Substitution at the dppz ligand has mostly involved lowering the energy of the b 1 (phz) state through appending electron-withdrawing groups to the E ring. ,− In addition, in one study the energy of the b 1 (phen) state was modified through substitution at the A and C rings . Recent studies have used dppz as an acceptor motif, connected to sulfur-based donors. ,,− Jia et al demonstrated a tetrathiafulvalene (TTF)–dppz donor–acceptor (D–A) couple with a change in dipole moment of 16 D . Goze et al then demonstrated the same ligand as a series of ruthenium complexes: [Ru(bpy) 2 (dppz-TTF)] 2+ , [Ru(bpy)(dppz-TTF) 2 ] 2+ , and [Ru(dppz-TTF) 3 ] 2+ .…”

Section: Introductionmentioning

confidence: 99%

Intraligand Charge-Transfer Excited States in Re(I) Complexes with Donor-Substituted Dipyridophenazine Ligands

et al. 2014

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The donor-acceptor ligands 11-(4-diphenylaminophenyl)dipyrido[3,2-a:2',3'-c]phenazine (dppz-PhNPh2) and 11-(4-dimethylaminophenyl)dipyrido[3,2-a:2',3'-c]phenazine (dppz-PhNMe2), and their rhenium complexes, [Re(CO)3X] (X = Cl(-), py, 4-dimethylaminopyridine (dmap)), are reported. Crystal structures of the two ligands were obtained. The optical properties of the ligands and complexes are dominated by intraligand charge transfer (ILCT) transitions from the amine to the dppz moieties with λabs = 463 nm (ε = 13 100 M(-1) cm(-1)) for dppz-PhNMe2 and with λabs = 457 nm (ε = 16 900 M(-1) cm(-1)) for dppz-PhNPh2. This assignment is supported by CAM-B3LYP TD-DFT calculations. These ligands are strongly emissive in organic solvents and, consistent with the ILCT character, show strong solvatochromic behavior. Lippert-Mataga plots of the data are linear and yield Δμ values of 22 D for dppz-PhNPh2 and 20 D for dppz-PhNMe2. The rhenium(I) complexes are less emissive, and it is possible to measure resonance Raman spectra. These data show relative band intensities that are virtually unchanged from λexc = 351 to 532 nm, consistent with a single dominant transition in the visible region. Resonance Raman excitation profiles are solvent sensitive; these data are modeled using wavepacket theory yielding reorganization energies ranging from 1800 cm(-1) in toluene to 6900 cm(-1) in CH3CN. The excited state electronic absorption and infrared spectroscopy reveal the presence of dark excited states with nanosecond to microsecond lifetimes that are sensitive to the ancillary ligand on the rhenium. These dark states were assigned as phenazine-based (3)ILCT states by time-resolved infrared spectroscopy. Time-resolved infrared spectroscopy shows transient features in which Δν(CO) is approximately -7 cm(-1), consistent with a ligand-centered excited state. Evidence for two such states is seen in mid-infrared transient spectra.

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“…As with DCBTz, DCQ, and DNQ building blocks can be used to introduce solubilizing alkyl groups as well as acceptor character to a material, in the case of the quinoxalines, at the 2,3-positions. Although several derivatives of DCQ and DNQincluding DNQ-containing porphyrins, bisphenazines, azaacenes, and dipyrido[3,2- a :2′,3′- c ]phenazine ligandshave been reported, to our knowledge, DCQ and DNQ have not been functionalized in the 5- and 8-positions. In the present study, 2,3-diethyl-substituted DCQ and DNQ cores were used in most cases to enhance the solubility and to eliminate the possibility of side products arising from coupling of bromoarenes to C–H groups at the 2,3-positions (although as shown by experiments with unsubstituted DNQ, vide infra, these side reactions do not appear to be a significant issue).…”

Section: Resultsmentioning

confidence: 99%

C–H-Activated Direct Arylation of Strong Benzothiadiazole and Quinoxaline-Based Electron Acceptors

et al. 2015

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Electron acceptors are important components of π-conjugated materials, but the strong electron-withdrawing properties of the required synthetic intermediates often make them poor substrates in synthetic schemes designed around conventional organometallic cross-coupling. Here, strong benzodiimine-based acceptors, including 5,6-difluoro[2,1,3]benzothiadiazole, 5,6-dicyano[2,1,3]benzothiadiazole, 5,6-dicyanobenzo[d][1,2,3]triazole, 6,7-dicyanoquinoxaline, and 6,7-dinitroquinoxaline, are shown to undergo facile palladium-catalyzed C-H direct arylation with a variety of bromoarenes in moderate to high yields. The electrochemical characteristics of di-2-thienyl derivatives synthesized using this methodology are compared and suggest that, in an electron-transfer sense, 5,6-dicyano[2,1,3]benzothiadiazole is a comparably strong acceptor to benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazole. The synthetic results suggest that high electron-withdrawing ability, which has traditionally limited reaction yields and structural variety in organic electronic materials, may be advantageous when employing C-H activated direct arylation in certain circumstances.

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Synthesis, spectroscopic and electrochemical studies of a series of transition metal complexes with amino- or bis(bromomethyl)-substituted dppz-ligands: Building blocks for fullerene-based donor–bridge–acceptor dyads

Cited by 18 publications

References 47 publications

Water-soluble, luminescent iridium(iii)–ytterbium(iii) complexes using dipyrido[3,2-a:2′,3′-c]phenazine derivatives as bridging units

Water-soluble, luminescent iridium(iii)–ytterbium(iii) complexes using dipyrido[3,2-a:2′,3′-c]phenazine derivatives as bridging units

Intraligand Charge-Transfer Excited States in Re(I) Complexes with Donor-Substituted Dipyridophenazine Ligands

C–H-Activated Direct Arylation of Strong Benzothiadiazole and Quinoxaline-Based Electron Acceptors

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