Luminescence Probes of DNA-Binding Interactions Involving Copper Complexes

McMillin, David R.; Hudson, Brian P.; Liu, Fang; Sou, Jenny; Berger, Daniel; Meadows, Kelley A.

doi:10.1021/ba-1993-0238.ch011

Cited by 10 publications

(4 citation statements)

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“…This is a well-established approach, e.g., to determine the coordination geometry of Cu-containing dendrimers, metaloproteins, or metastable complexes that cannot be crystallized . This method has also been used to probe the excited-state geometry of various copper(I)–bisphenanthroline complexes in solution. − XAS has been used on copper complexes for almost 30 years because of its high accuracy and sensitivity. ,,, Information on the oxidation state as well as on the coordination number and symmetry of the copper ion can be extracted from the XANES region. XANES spectra for crystalline samples of complexes 1 , 2 , and 3 and a powder sample of complex 2 are depicted in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Photoluminescent Cu(I) complexes − are increasingly employed as functional materials in optoelectronic devices such as organic light-emitting diodes (OLEDs), − light-emitting electrochemical cells, oxygen sensors, anddespite potential toxicity of Cu(I)luminescent markers in biochemistry. , The use of copper has several advantages: Apart from the low price and good availability of various base materials, they have a favorable d 10 -electron configuration, prohibiting many common quenching mechanisms involving empty, metal-centralized d orbitals . Because of this, the photoluminescence quantum yield (PLQY) for Cu complexes can be very high, close to unity. , Most commonly, the copper moieties are directly involved in the luminescence because metal-to-ligand charge transfer (MLCT) emission occurs.…”

Section: Introductionmentioning

confidence: 99%

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Labile or Stable: Can Homoleptic and Heteroleptic PyrPHOS–Copper Complexes Be Processed from Solution?

et al. 2014

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Luminescent Cu(I) complexes are interesting candidates as dopants in organic light-emitting diodes (OLEDs). However, open questions remain regarding the stability of such complexes in solution and therefore their suitability for solution processing. Since the emission behavior of Cu(I) emitters often drastically differs between bulk and thin film samples, it cannot be excluded that changes such as partial decomposition or formation of alternative emitting compounds upon processing are responsible. In this study, we present three particularly interesting candidates of the recently established copper-halide-(diphenylphosphino)pyridine derivatives (PyrPHOS) family that do not show such changes. We compare single crystals, amorphous bulk samples, and neat thin films in order to verify whether the material remains stable upon processing. Solid-state nuclear magnetic resonance (MAS (31)P NMR) was used to investigate the electronic environment of the phosphorus atoms, and X-ray absorption spectroscopy at the Cu K edge provides insight into the local electronic and geometrical environment of the copper(I) metal centers of the samples. Our results suggest that--unlike other copper(I) complexes--the copper-halide-PyrPHOS clusters are significantly more stable upon processing and retain their initial structure upon quick precipitation as well as thin film processing.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Labile or Stable: Can Homoleptic and Heteroleptic PyrPHOS–Copper Complexes Be Processed from Solution?

et al. 2014

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“…One difference was that binding to DNA induced an even greater degree of hypochromism. ,47a With the bcp complex the binding interaction also produced a weak monosignate CD signal in the CT absorption region as well as a CT luminescence signal. ,47a, Concentration-dependent studies established that at least two different types of adducts formed. At DNA-P/Cu < 8 (where DNA-P denotes the number of phosphateor nucleic acidresidues in solution and Cu denotes the number of copper centers), the presence of the bcp complex induced a significant alteration of the CD spectrum in the UV region where the DNA absorbed . However, at DNA-P/Cu >30, the effect on the DNA signal was minor.…”

Section: Cu(bcp)2 +mentioning

confidence: 99%

Photoprocesses of Copper Complexes That Bind to DNA

1998

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“…Complexes or materials containing copper ions often show tremendous extinction when used in dyes. Recently, the search for new luminescent coordination compounds has led to the development of ubiquitous photoluminescent copper(I)complexes. − Their employment as emitters in organic light-emitting diodes (OLEDs), , light-emitting electrochemical cells, oxygen sensors, and even luminescent markers in biochemistry , promises new applications for these materials. Due to the favorable d 10 -electron-configuration found for Cu(I), many common quenching mechanisms involving empty, metal-centered d-orbitals are prohibited .…”

Section: Introductionmentioning

confidence: 99%

How the Quantum Efficiency of a Highly Emissive Binuclear Copper Complex Is Enhanced by Changing the Processing Solvent

et al. 2013

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Polymorphism is often linked to the choice of processing solvents. Packing effects or the preference of one certain conformer as possible causes of this phenomenon are strongly dependent on solvents and especially on their polarity. Even in amorphous solids, the microstructure can be controlled by the choice of solvents. Polymorphs or amorphous solids featuring different packing densities can exhibit different properties in terms of stability or optical effects. The influence of these effects on a binuclear, strongly luminescent copper(I) complex was investigated. Many possible applications for luminescent, amorphous coordination compounds, such as organic light-emitting diodes, sensors, and organic lasers, rely on photophysical properties like quantum efficiency to be repeatable. The effect of processing solvents in this context is often underestimated, but very relevant for utilization in device manufacturing and should therefore be understood more deeply. In this work, theoretical derivations, DFT calculations, X-ray-diffraction, photoluminescence spectroscopy, and the time-dependent single-photon-counting-technique (TDSPC) were used to understand this phenomenon more deeply. The influence of five different solvents on Cu2I2(MePyrPHOS)3 was probed. This resulted in a modulation of the photoluminescence quantum yield ϕ between 0.5 and 0.9 in amorphous solid state. A new polymorph of the material with slightly reduced values for ϕ has been identified. The reduced efficiency could be correlated with a higher porosity and a reduced packing density. Dense packing reduces nonradiative decay by geometrical fixation and thus increases the quantum efficiency. The existence of similar effects on aluminum and iridium compounds has been confirmed by application of different processing solvents on Alq3 and Ir(ppy)3. These results show that a tuning of the efficiency of a emissive metal complexes by choosing a proper processing solvent is possible. If highly efficient materials for practical applications are desired, an evaluation of multiple solvents has to be considered.

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Luminescence Probes of DNA-Binding Interactions Involving Copper Complexes

Cited by 10 publications

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Labile or Stable: Can Homoleptic and Heteroleptic PyrPHOS–Copper Complexes Be Processed from Solution?

Labile or Stable: Can Homoleptic and Heteroleptic PyrPHOS–Copper Complexes Be Processed from Solution?

Photoprocesses of Copper Complexes That Bind to DNA

How the Quantum Efficiency of a Highly Emissive Binuclear Copper Complex Is Enhanced by Changing the Processing Solvent

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