Effect of β-bromo substitution on the photophysical properties of meso-phenyl, meso-carbazole, and meso-triphenylamine porphyrins

We present results of an experimental photophysical study of a series of novel brominated and non-brominated porphyrins that contain phenyl, carbazole, or triphenylamine in the meso-position. In addition we have looked at the effects of incorporating a zinc metal into the porphyrin system relative to the free base. Structure-property relationships are established using various absorption and emission techniques including femtosecond pump probe transient absorption and nanosecond laser flash photolysis. With slightly increasing electron donating strength (phenyl < carbazole < triphenylamine) red shifts were observed in all data. The same effect was observed upon the addition of bromine in the beta position. Due to the heavy atom affect of the bromines both the singlet and triplet excited state lifetimes were significantly shorter in the brominated porphyrins. For the T1–Tn absorption data we observe a large absorption in the near infrared region with the brominated carbazole and triphenylamine. The largest effect of the addition of zinc was in the ground state absorption and emission where a blue shift in the data was observed. Some effects were also observed in the kinetic decays with zinc as the metal compared to the free base porphyrins.

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Structure Property Characterization of Nonlinear Optical Materials

MRS Proceedings ◽

10.1557/proc-846-dd3.4 ◽

2004 ◽

Vol 846 ◽

Author(s):

Joy E. Rogers ◽

Jonathan E. Slagle ◽

Daniel G. McLean ◽

Benjamin C. Hall ◽

Thomas M. Cooper ◽

...

Keyword(s):

Nonlinear Optical ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Photophysical Properties ◽

Excited State Absorption ◽

Laser Flash ◽

Nanosecond Laser ◽

Structure Property ◽

Absorption Properties ◽

Structure Property Relationships

ABSTRACTThis research is comprised of understanding the linear photophysical properties of various dyes to better understand the more complicated nonlinear optical properties. Determining structure property relationships of a series of structurally closely related chromophores is the key in understanding the drivers for the various photophysical properties. In this paper we survey the effect of physically changing the Pt poly-yne structure on the S0-S1 and T1-Tn absorption properties for each of the chromophores. A series of structurally modified platinum poly-ynes have been studied using experimental methods including UV/Vis absorption and nanosecond laser flash photolysis. We found that with extension of the ligand length both the ground and triplet excited state absorption shift to lower energies. Comparing the absorption properties of the ligands and butadiynes with the platinum containing versions reveal that the S1 and Tn exciton is localized on one portion of the ligand with extension and not conjugated through the whole molecule. Changing the phosphine R group results in little effect to the absorption properties except when the R group is conjugated in the case of phenyl. However, changing the R group results in varied materials properties.

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Synthesis and Characterization of Novel Platinum Acetylide Oligomers

MRS Proceedings ◽

10.1557/proc-771-l4.21 ◽

2003 ◽

Vol 771 ◽

Author(s):

Thomas M. Cooper ◽

Benjamin C. Hall ◽

Daniel G. McLean ◽

Joy E. Rogers ◽

Aaron R. Burke ◽

...

Keyword(s):

Absorption Spectra ◽

Ground State ◽

Near Infrared ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Laser Flash ◽

Structure Property ◽

Ground State Absorption ◽

Excitation Spectra ◽

C Nmr

AbstractAs part of an effort to develop a spectroscopic structure-property relationship in platinum acetylide oligomers, we have prepared a series of bidentate Pt(PBu3)2L2 compounds. The ligand was the series o-syd-C6H4-CΞC-(C6H4-CΞC)n-H, n = 0,1,2. The terminal oligomer unit consisted of a sydnone group ortho to the acetylene carbon. The compounds were characterized by various methods, including 13C-NMR, ground state absorption, fluorescence, phosphorescence and laser flash photolysis. The acetylenic 13C-NMR resonances showed sydnone influences that decreased with increasing number of monomer units. The ground state absorption spectra were slightly red shifted from those of the baseline oligomers not having a sydnone group. The low temperature emission and excitation spectra showed complex dependence on excitation and emission wavelengths, suggesting the chromphores resided in a distribution of solvent environments and conformations. Finally, broad triplet state absorption spectra were observed, with absorption throughout the visible and near infrared regions.

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Photochemistry of Free-Base Porphyrin Linked to Methyl Viologen

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19920026 ◽

1992 ◽

Vol 57 (1) ◽

pp. 26-32 ◽

Cited By ~ 2

Author(s):

N. M. Guindy ◽

F. M. Elzawawy ◽

D. Y. Sabry

Keyword(s):

Methyl Viologen ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Phenyl Group ◽

Laser Flash ◽

Porphyrin Ring ◽

Free Base ◽

Intramolecular Quenching ◽

Quenching Efficiency ◽

Triton X

The photochemistry of free-base meso-tetraphenylporphyrin linked to methyl viologen via an alkoxy chain (n = 3) at the ortho, meta or para-position of one meso-phenyl group, in Triton X-100 micellar aqueous solutions is reported. The appended viologen does not quench the porphyrin fluorescence nor its triplet excited state due to the different solubilization of both parts of the molecule in the medium where the porphyrin ring resides in the hydrophobic phase and the alkoxy linker protrudes into the rather diffuse outer phase of detergent oxyethylene units, while the viologen moiety penetrates into the aqueous layer. However, laser flash photolysis measurements show that in the presence of nicotinamide dinucleotide, NADH, the porphyrin ring is reduced to phlorin due to the penetration of NADH into the organic phase. For porphyrin-tetraviologen in which a viologen molecule is linked to each of the porphyrin meso-position via alkoxy chain, fluorescence quenching could be achieved. The values of the quenching efficiency are high (94% in acetonitrile) compared to intramolecular quenching and are dependent upon the solvent viscosity.

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Study of the aqueous photochemistry of 4-fluorophenol, 4-bromophenol and 4-iodophenol by steady state and nanosecond laser flash photolysis

Journal of the Chemical Society Perkin Transactions 2 ◽

10.1039/a705287a ◽

1998 ◽

pp. 365-370 ◽

Cited By ~ 24

Author(s):

Anne-Pascale Durand ◽

Robert G. Brown ◽

David Worrall ◽

Francis Wilkinson

Keyword(s):

Steady State ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Laser Flash ◽

Nanosecond Laser ◽

Nanosecond Laser Flash Photolysis

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Onium salts improve the kinetics of photopolymerization of acrylate activated with visible light

RSC Advances ◽

10.1039/d0ra03818k ◽

2020 ◽

Vol 10 (42) ◽

pp. 24817-24829 ◽

Cited By ~ 1

Author(s):

Janina Kabatc ◽

Katarzyna Iwińska ◽

Alicja Balcerak ◽

Dominika Kwiatkowska ◽

Agnieszka Skotnicka ◽

...

Keyword(s):

Steady State ◽

Visible Light ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Laser Flash ◽

Nanosecond Laser ◽

Chemical Mechanisms ◽

Onium Salts ◽

Nanosecond Laser Flash Photolysis ◽

Kinetics Of

The chemical mechanisms were investigated by steady state photolysis and nanosecond laser flash photolysis experiments. A mechanism for initiating polymerization using both onium salts is proposed here.

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