Tuning the Electrochemical and Photophysical Properties of Osmium-Based Photoredox Catalysts

Synlett ◽  
2022 ◽  
Author(s):  
Eva Bednářová ◽  
Logan R. Beck ◽  
Tomislav Rovis ◽  
Samantha L. Goldschmid ◽  
Katherine Xie ◽  
...  
Keyword(s):  
Ground State ◽  
Emission Spectroscopy ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Low Energy ◽  
Redox Potentials ◽  
Nir Light ◽  
Osmium Complexes ◽  
Absorption And Emission Spectroscopy

AbstractThe use of low-energy deep-red (DR) and near-infrared (NIR) light to excite chromophores enables catalysis to ensue across barriers such as materials and tissues. Herein, we report the detailed photophysical characterization of a library of OsII polypyridyl photosensitizers that absorb low-energy light. By tuning ligand scaffold and electron density, we access a range of synthetically useful excited state energies and redox potentials.1 Introduction1.1 Scope1.2 Measuring Ground-State Redox Potentials1.3 Measuring Photophysical Properties1.4 Synthesis of Osmium Complexes2 Properties of Osmium Complexes2.1 Redox Potentials of Os(L)2-Type Complexes2.2 Redox Potentials of Os(L)3-Type Complexes2.3 UV/Vis Absorption and Emission Spectroscopy3 Conclusions

Scanning Time-domain Optical Mammography: Detection and Characterization of Breast Tumors In Vivo

2005 ◽  
Vol 4 (5) ◽  
pp. 483-496 ◽  
Author(s):  
Herbert Rinneberg ◽  
Dirk Grosenick ◽  
K. Thomas Moesta ◽  
Jörg Mucke ◽  
Bernd Gebauer ◽  
...  
Keyword(s):  
Time Domain ◽  
Near Infrared ◽  
Strong Light ◽  
New Techniques ◽  
Optical Mammography ◽  
Scanning Time ◽  
Nir Light ◽  
Tissue Scattering

Optical mammography is one of several new techniques for breast cancer detection and characterization presently under development for clinical use that provide information other than morphologic, in particular on the biochemical and metabolic state of normal and diseased tissue. In breast tissue, scattering of red to near infrared (NIR) light dominates absorption and NIR light may penetrate several centimeters through the breast. Optical mammography avoids the use of ionizing radiation and offers the power of diffuse optical spectroscopy. However, because of strong light scattering, spatial resolution of optical mammography is generally low. The paper reviews the results of a clinical study on scanning time-domain optical mammography comprising 154 patients carrying a total of 102 carcinomas validated by histology. Ninety two of these tumors were detected in optical mammograms retrospectively and for 87 of the detected tumors optical properties and tissue parameters were derived. In addition developments on instrumentation and data analysis are covered and possible improvements of optical mammography are briefly discussed.

Syntheses, electrochemistry and photophysical properties of a series ofmeso-pyridylpentafluorophenylporphyrins

2010 ◽  
Vol 14 (11) ◽  
pp. 975-984 ◽  
Author(s):  
Emmanuel Z. Moreira ◽  
Alba D.Q. Ferreira ◽  
Cláudio Roberto Neri ◽  
Sumitra Mukhopadhyay ◽  
Sérgio Dovidauskas ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Photophysical Properties ◽  
Synthesis And Characterization ◽  
Redox Potentials ◽  
Trans Isomers ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cis And Trans Isomers ◽  
Cis And Trans

This work presents the synthesis and characterization of a series of substituted pyridylpentafluroporphyrins, including the separation of the cis- and trans-isomers, the latter being characterized by X-ray crystallography. The spectroscopic and electrochemical properties of the series are dependent on the number of electron withdrawing pentafluorophenyl substituent, but they do not depend on the symmetry of the molecule. Ongoing from the monosubstituted to the more substituted pentafluorophenyl porphyrin H2(MPyTFPP) derivative, the Soret bands are slightly red-shifted and their quantum fluorescence yields range from 0.035 to 0.046, consistent with the value of 0.045 for the fully substituted 5,10,15,20-tetrapentafluorophenylporphyrin (dichloromethane solutions). The redox potentials of the reductive processes of monoanion and dianion formation are also sensitive to the number of pentafluoro substituents, shifting 180 mV to more positive values for the P0/P-1process ongoing from the monopentafluoro to the tris-pentafluorophenyl substituted derivative.

scholarly journals Characterization of near-infrared low energy ultra-short laser pulses for portable applications of laser induced breakdown spectroscopy

2007 ◽  
Vol 15 (21) ◽  
pp. 14044 ◽  
Author(s):  
Alexander W. Schill ◽  
David A. Heaps ◽  
Dimitra N. Stratis-Cullum ◽  
Bradley R. Arnold ◽  
Paul M. Pellegrino
Keyword(s):  
Near Infrared ◽  
Laser Pulses ◽  
Low Energy ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Short Laser Pulses

scholarly journals Characterization of material around the centaur (2060) Chiron from a visible and near-infrared stellar occultation in 2011

2019 ◽  
Vol 491 (3) ◽  
pp. 3643-3654
Author(s):  
A A Sickafoose ◽  
A S Bosh ◽  
J P Emery ◽  
M J Person ◽  
C A Zuluaga ◽  
...  
Keyword(s):  
Near Infrared ◽  
Detailed Examination ◽  
Optical Data ◽  
Infrared Telescope ◽  
Nir Light ◽  
Spherical Diameter ◽  
Telescope Facility ◽  
Nasa Infrared Telescope Facility ◽  
Scattering Material

ABSTRACT The centaur (2060) Chiron exhibits outgassing behaviour and possibly hosts a ring system. On 2011 November 29, Chiron occulted a fairly bright star (R ∼ 15 mag) as observed from the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and the 2-m Faulkes Telescope North (FTN) at Haleakala. Data were taken as visible wavelength images and simultaneous, low-resolution, near-infrared (NIR) spectra. Here, we present a detailed examination of the light-curve features in the optical data and an analysis of the NIR spectra. We place a lower limit on the spherical diameter of Chiron's nucleus of 160.2 ± 1.3 km. Sharp, narrow dips were observed between 280 and 360 km from the centre (depending on event geometry). For a central chord and assumed ring plane, the separated features are 298.5–302 and 308–310.5 km from the nucleus, with normal optical depth ∼0.5–0.9, and a gap of 9.1 ± 1.3 km. These features are similar in equivalent depth to Chariklo's inner ring. The absence of absorbing/scattering material near the nucleus suggests that these sharp dips are more likely to be planar rings than a shell of material. The region of relatively increased transmission is within the 1:2 spin-orbit resonance, consistent with the proposed clearing pattern for a non-axisymmetric nucleus. Characteristics of possible azimuthally incomplete features are presented, which could be transient, as well as a possible shell from ∼900–1500 km: future observations are needed for confirmation. There are no significant features in the NIR light curves, nor any correlation between optical features and NIR spectral slope.

scholarly journals Rational Design and Synthesis of Large Stokes Shift 2,6-Sulphur-Disubstituted BODIPYs for Cell Imaging

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 19
Author(s):  
Abigail E. Reese ◽  
Charles Lochenie ◽  
Ailsa Geddis ◽  
Luana A. Machado ◽  
Marcos C. de Souza ◽  
...  
Keyword(s):  
Immune Cells ◽  
Emission Spectroscopy ◽  
Rational Design ◽  
Cell Imaging ◽  
Photophysical Properties ◽  
Stokes Shift ◽  
Design And Synthesis ◽  
Confocal Fluorescence ◽  
Absorption And Emission Spectroscopy ◽  
Stokes Shifts

Five new disubstituted 2,6-thioaryl-BODIPY dyes were synthesized via selective aromatic electrophilic substitution from commercially available thiophenols. The analysis of the photophysical properties via absorption and emission spectroscopy showed unusually large Stokes shifts for BODIPY fluorophores (70–100 nm), which makes them suitable probes for bioimaging. Selected compounds were evaluated for labelling primary immune cells as well as different cancer cell lines using confocal fluorescence microscopy.

scholarly journals Corroles and Hexaphyrins: Synthesis and Application in Cancer Photodynamic Therapy

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3450
Author(s):  
Susana M. M. Lopes ◽  
Marta Pineiro ◽  
Teresa M. V. D. Pinho e Melo
Keyword(s):  
Photodynamic Therapy ◽  
Potential Application ◽  
Energy Region ◽  
Near Infrared ◽  
Photophysical Properties ◽  
Low Energy ◽  
Full Potential ◽  
Biological Applications ◽  
Recent Developments ◽  
Unique Capability

Corroles and hexaphyrins are porphyrinoids with great potential for diverse applications. Like porphyrins, many of their applications are based on their unique capability to interact with light, i.e., based on their photophysical properties. Corroles have intense absorptions in the low-energy region of the uv-vis, while hexaphyrins have the capability to absorb light in the near-infrared (NIR) region, presenting photophysical features which are complementary to those of porphyrins. Despite the increasing interest in corroles and hexaphyrins in recent years, the full potential of both classes of compounds, regarding biological applications, has been hampered by their challenging synthesis. Herein, recent developments in the synthesis of corroles and hexaphyrins are reviewed, highlighting their potential application in photodynamic therapy.

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