Search results for "PHOTOCHEMISTRY"

Deep-Red-Emitting Electrochemical Cells Based on Heteroleptic Bis-chelated Ruthenium(II) Complexes

2009

Two ruthenium(II)-based complexes were prepared that show intense deep-red light emission at room temperature. Solid-state electroluminescent devices were prepared using one of the ruthenium complexes as the only active component. These devices emit deep-red light at low voltages and exhibit extraordinary stabilities, demonstrating their potential for low-cost deep-red light sources.

Aggregation and Photodimerization of Areno-Condensed Annulenes

2001

Luminescent PhotoCORMs: Enabling/Disabling CO Delivery upon Blue Light Irradiation.

2020

The new luminescent carbonyl compounds [Mn(Oxa-H)(CO)3Br] (1) and [Mn(Oxa-NMe2)(CO)3Br] (2) were synthesized and fully characterized. Complexes 1 and 2 showed CO release under blue light (λ453). Spectroscopic techniques and TD-DFT and SOC-TD-DFT calculations indicated that 1 and 2 release the Oxa-H and Oxa-NMe2 coligands in addition to the carbonyl ligands, increasing the luminescence during photoinduction.

Supramolecular stabilization of the phosphite-based polyoxomolybdate [Mo6(PO3)(HPO3)3O18]9−

2007

Abstract A novel phosphite-based hetero-polyoxomolybdate, [Mo 6 (PO 3 )(HPO 3 ) 3 O 18 ] 9− , has been isolated and structurally characterized. The most striking feature of this polyanion is the presence of peripheral phosphite groups linked to the MoO 6 octahedra. In the solid state, this cluster shows strong hydrogen bonding interactions that apparently play a key role in its stabilization and isolation from solution.

Copper(II) complexes of quinoline polyazamacrocyclic scorpiand-type ligands: X-ray, equilibrium and kinetic studies

2012

The formation of Cu(II) complexes with two isomeric quinoline-containing scorpiand-type ligands has been studied. The ligands have a tetraazapyridinophane core appended with an ethylamino tail including 2-quinoline (L1) or 4-quinoline (L2) functionalities. Potentiometric studies indicate the formation of stable CuL(2+) species with both ligands, the L1 complex being 3-4 log units more stable than the L2 complex. The crystal structure of [Cu(L1)](ClO(4))(2)·H(2)O shows that the coordination geometry around the Cu(2+) ions is distorted octahedral with significant axial elongation; the four Cu-N distances in the equatorial plane vary from 1.976 to 2.183 Å, while the axial distances are of 2.27…

A Bis(tridentate)cobalt Polypyridine Complex as Mediator in Dye‐Sensitized Solar Cells

2015

Dye-sensitized solar cells equipped with cationic and neutral RuII-based sensitizers [Ru(ddpd){tpy(COOH)3}]2+ [12+; ddpd = N,N′-dimethyl-N,N′-di(pyridin-2-yl)pyridin-2,6-diamine, tpy(COOH)3 = 2,2″6′,2″-terpyridine-4,4′,4″-tricarboxylic acid] and [Ru(ddpd){tpy(COOH)(COO)2}] (2) with and without the coadsorbent chenodeoxycholic acid were constructed with I3–/I– or the CoIII/II-based redox mediators [Co(bpy)3]3+/2+ (33+/2+; bpy = 2,2′-bipyridine) and [Co(ddpd)2]3+/2+ (43+/2+) in the presence of LiClO4 and 4-tert-butylpyridine. The best photovoltaic performance was achieved by using the 43+/2+ shuttle and the neutral sensitizer 2 without coadsorbent. The higher short-circuit photocurrent densit…

Heteropolyacid‐Based Materials as Heterogeneous Photocatalysts

2013

Heteropolyacids (HPAs) that are often used as heteropolyanions are cheap and stable compounds that have been extensively used as acid and oxidation catalysts as a result of their strong Brønsted acidity and ability to undergo multielectron-transfer reactions. HPAs, which are very soluble in water and polar solvents, have been also used as homogeneous photocatalysts for the oxidation of organic substrates in the presence of oxygen, but their use in heterogeneous systems is by far desirable. Dispersing HPAs onto solid supports with high surface area is useful to increase their specific surface area and hence (photo)catalytic activity. Moreover, owing to the high energy gap between the HOMO an…

A heteroleptic bis(tridentate)ruthenium(II) polypyridine complex with improved photophysical properties and integrated functionalizability.

2010

The synthesis and photophysical properties of a ruthenium(II) complex bearing an electron-accepting 2,2';6',2''-terpyridine ligand and an electron-donating N,N'-dimethyl-N,N'-dipyridin-2-ylpyridine-2,6-diamine (ddpd) ligand are presented. The heteroleptic complex is easily prepared isomerically pure and features intense low-energy metal-to-ligand charge-transfer (MLCT) absorption bands and intense room temperature (3)MLCT emission with a long (3)MLCT lifetime. The favorable photophysical properties are due to the strong ligand field imposed by the ddpd ligand.

Dithiametacyclophane mit Dreifachbindungen

1994

Dithiametacyclophanes with Triple Bonds Schemes 1 and 2 show the syntheses of dithia[8]metacyclo-phanes 4a-d and tetrathia[m.n]metacyclophanes 9, 10 by cyclization reactions applying the cesium effect. All these cyclophanes contain C—C triple bonds which influence the molecular dynamics; especially the halogen substituents in 4b-d obstruct the topomerization.

Effect of Peripheral Substitution and Extended Conjugation on the Redox Potentials of Nickel Porphycenes

1996

Eight different nickel porphycenes bearing substituents on the pyrrole β and/or ethylenic carbon positions of the macrocycle were investigated as to their redox properties in benzonitrile containin...