Carbon nanostructure and reactivity of soot particles from non-intrusive methods based on UV-VIS spectroscopy and time-resolved laser-induced incandescence

This study describes the catalytic performance of an iron(III) complex bearing a phthalocyaninato-like ligand in two solvent-borne and two high-solid alkyd binders. Standardized mechanical tests revealed strong activity, which appeared in particular cases at concentrations about one order of magnitude lower than in the case of cobalt(II) 2-ethylhexanoate, widespread used in paint-producing industry. The effect of the iron(III) compound on autoxidation process, responsible for alkyd curing, was quantified by kinetic measurements by time-resolved infrared spectroscopy and compared with several primary driers. Effect of the drier concentration on coloration of transparent coatings was determined by UV–Vis spectroscopy.

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Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Photochemical & Photobiological Sciences ◽

10.1007/s43630-021-00045-7 ◽

2021 ◽

Author(s):

Maximilian Theiß ◽

Merten Grupe ◽

Tilman Lamparter ◽

Maria Andrea Mroginski ◽

Rolf Diller

Keyword(s):

Density Functional ◽

Transient Absorption ◽

Vibrational Analysis ◽

Density Functional Theory Calculations ◽

Chem Phys ◽

Molecular Structures ◽

Ir Absorption ◽

Time Resolved ◽

Time Constants ◽

Vis Spectroscopy

AbstractDeactivation processes of photoexcited (λex = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCBA, PCBB and PCBC, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCBB*, of PCBA* and thermal re-equilibration of PCBA, PCBB and PCBC, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm−1 (CA1) and between 1550 and 1450 cm−1 (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X–H…Y). This allows to characterize chromophore protonation/deprotonation processes, associated with the electronic and structural dynamics, on a molecular level. The PCB photocycle is suggested to be closed via a long living (> 1 ns), PCBC-like (i.e. deprotonated), fluorescent species.

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Synthesis, Biomacromolecular Interactions, Photodynamic NO Releasing and Cellular Imaging of Two [RuCl(qn)(Lbpy)(NO)]X Complexes

Molecules ◽

10.3390/molecules26092545 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2545

Author(s):

Luna Song ◽

Hehe Bai ◽

Chenyang Liu ◽

Wenjun Gong ◽

Ai Wang ◽

...

Keyword(s):

Mass Spectrometry ◽

Confocal Imaging ◽

Epr Spectra ◽

Distorted Octahedral Geometry ◽

Ionization Mass ◽

Time Resolved ◽

Pbr322 Dna ◽

Vis Spectroscopy ◽

No Release ◽

Ft Ir

Two light-activated NO donors [RuCl(qn)(Lbpy)(NO)]X with 8-hydroxyquinoline (qn) and 2,2′-bipyridine derivatives (Lbpy) as co-ligands were synthesized (Lbpy1 = 4,4′-dicarboxyl-2,2′-dipyridine, X = Cl− and Lbpy2 = 4,4′-dimethoxycarbonyl-2,2′-dipyridine, X = NO3−), and characterized using ultraviolet–visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (1H NMR), elemental analysis and electrospray ionization mass spectrometry (ESI-MS) spectra. The [RuCl(qn)(Lbpy2)(NO)]NO3 complex was crystallized and exhibited distorted octahedral geometry, in which the Ru–N(O) bond length was 1.752(6) Å and the Ru–N–O angle was 177.6(6)°. Time-resolved FT-IR and electron paramagnetic resonance (EPR) spectra were used to confirm the photoactivated NO release of the complexes. The binding constant (Kb) of two complexes with human serum albumin (HSA) and DNA were quantitatively evaluated using fluorescence spectroscopy, Ru-Lbpy1 (Kb~106 with HSA and ~104 with DNA) had higher affinity than Ru-Lbpy2. The interactions between the complexes and HSA were investigated using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and EPR spectra. HSA can be used as a carrier to facilitate the release of NO from the complexes upon photoirradiation. The confocal imaging of photo-induced NO release in living cells was successfully observed with a fluorescent NO probe. Moreover, the photocleavage of pBR322 DNA for the complexes and the effect of different Lbpy substituted groups in the complexes on their reactivity were analyzed.

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Mechanistic study of the photofragmentation of the clusters [Os3(CO)10(diene)] (diene=cis-1,3-butadiene, 1,3-cyclohexadiene): direct observation of the open-triangle primary photoproduct with nanosecond time-resolved infrared and UV–Vis spectroscopy

Inorganica Chimica Acta ◽

10.1016/s0020-1693(99)00560-5 ◽

2000 ◽

Vol 300-302 ◽

pp. 597-603 ◽

Cited By ~ 3

Author(s):

Maarten J Bakker ◽

Frank W Vergeer ◽

František Hartl ◽

Omar S Jina ◽

Xue-Zhong Sun ◽

...

Keyword(s):

Direct Observation ◽

Mechanistic Study ◽

Time Resolved ◽

Vis Spectroscopy ◽

Open Triangle

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Numerical Study of Temperature and Incandescence Intensity of Nanosecond Pulsed-Laser Heated Soot Particles at High Pressures

Heat Transfer, Part A ◽

10.1115/imece2005-81322 ◽

2005 ◽

Cited By ~ 1

Author(s):

Fengshan Liu ◽

David R. Snelling ◽

Gregory J. Smallwood

Keyword(s):

Soot Particle ◽

High Pressures ◽

Particle Diameter ◽

Aggregate Size ◽

Primary Particle Diameter ◽

Time Resolved ◽

Soot Particles ◽

Nanosecond Pulsed Laser ◽

Primary Particles ◽

Laser Heated

Histories of temperature and incandescence intensity of nanosecond pulsed-laser heated soot particles of polydispersed primary particles and aggregate sizes were calculated using an aggregate-based heat transfer model at pressures from 1 atm up to 50 atm. The local gas temperature, distributions of soot primary particle diameter and aggregate size assumed in the calculations were similar to those found in an atmospheric laminar diffusion flame. Relatively low laser fluences were considered to keep the peak particle temperatures below about 3400 K to ensure negligible soot particle sublimation. The shielding effect on the heat conduction between aggregated soot particles and the surrounding gas was accounted for based on results of direct simulation Monte Carlo calculations. After the laser pulse, the temperature of soot particles with larger primary particles or larger aggregates cools down slower than those with smaller primary particles or smaller aggregates due to smaller surface area-to-volume ratios. The effective temperature of soot particles in the laser probe volume was calculated based on the ratio of thermal radiation intensities of the soot particle ensemble at 400 and 780 nm. Due to the reduced mean free path of molecules with increasing pressure, the heat conduction between soot particles and the surrounding gas shifts from the free-molecular to the transition regime. Consequently, the rate of conduction heat loss from the soot particles increases significantly with pressure. The lifetime of laser-induced incandescence (LII) signal is significantly reduced as the pressure increases. At high pressures, the time resolved soot particle temperature is very sensitive to both the primary particle diameter and the aggregate size distributions, implying the time-resolved LII particle sizing techniques developed at atmospheric pressure lose their effectiveness at high pressures.

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Predicting the heat of vaporization of iron at high temperatures using time-resolved laser-induced incandescence and Bayesian model selection

Journal of Applied Physics ◽

10.1063/1.5016341 ◽

2018 ◽

Vol 123 (9) ◽

pp. 095103 ◽

Cited By ~ 7

Author(s):

Timothy A. Sipkens ◽

Paul J. Hadwin ◽

Samuel J. Grauer ◽

Kyle J. Daun

Keyword(s):

Model Selection ◽

High Temperatures ◽

Bayesian Model ◽

Bayesian Model Selection ◽

Time Resolved ◽

Heat Of Vaporization ◽

Laser Induced Incandescence

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Copper Complexes of Benzoylacetone Bis-Thiosemicarbazones: Metal and Ligand Based Redox Reactivity

Australian Journal of Chemistry ◽

10.1071/ch20210 ◽

2021 ◽

Vol 74 (1) ◽

pp. 34 ◽

Cited By ~ 2

Author(s):

Jessica K. Bilyj ◽

Jeffrey R. Harmer ◽

Paul V. Bernhardt

Keyword(s):

Electron Paramagnetic Resonance ◽

Cyclic Voltammetry ◽

Copper Complexes ◽

Atmospheric Oxygen ◽

The Other ◽

Oxidation Reactions ◽

Paramagnetic Resonance ◽

Time Resolved ◽

Vis Spectroscopy ◽

Electron Paramagnetic

Bis-thiosemicarbazones derived from the β-diketone benzoylacetone (H3banR, R=Me, Et, Ph) are potentially tetradentate N2S2 ligands whose coordination chemistry with copper is reported. In the absence of oxygen and in the presence of base they form anionic CuII complexes of the fully deprotonated ligands [CuII(banR)]–. Upon exposure to atmospheric oxygen they undergo a complex series of reactions leading to two types of products; one a ligand oxidised ketone complex [CuII(banRO)] and the other an unprecedented dimeric di-CuIII complex [(CuIII(banR))2] depending on the R substituent. Time-resolved UV-vis spectroscopy, cyclic voltammetry, spectroelectrochemistry, and electron paramagnetic resonance (EPR) spectroscopy have been used to identify intermediates on the way to stable products formed under both anaerobic and aerobic conditions. It is found that both ligand-centred and Cu-centred oxidation reactions are occurring in parallel leading to this unusually complicated mixture of products.

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