Porphyrins. 43. Triplet sublevel emission of platinum tetrabenzoporphyrin by spectrothermal principal component decomposition

Aartsma, Thijs J.; Gouterman, Martin; Jochum, Clemens; Kwiram, Alvin L.; Pepich, Barry V.; Williams, Loren Dean

doi:10.1021/ja00387a021

Cited by 48 publications

(32 citation statements)

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“…PCA-SM can only hope to achieve accurate decomposition of the mixture spectra when nonlinear spectral changes in the spectra of the individual components are negligible relative to changes in the component composition. Applications of PCA-SM to spectrothermal matrices have led to resolutions of (a) the phosphorescence spectrum of platinum tetrabenzoporphyrin into two distinct spectra from different triplet sublevels 15 and (b) the luminescence of benzophenone in solution to phosphorescence and thermally populated delayed fluorescence spectra. 16 PCA-SM attempts to resolve spectrothermal matrices of mixtures of conformer absorption 17 and fluorescence 18 spectra measured in solution have failed.…”

Section: Introductionmentioning

confidence: 99%

UV Spectrum of the High Energy Conformer of 1,3-Butadiene in the Gas Phase

2001

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Principal component analysis and singular value decomposition (PCA and SVD) with self-modeling (SM) based on the van't Hoff equation constraint, were applied to 1,3-butadiene UV spectra measured in the 5.0-93.0°C range. The shape of the resolved UV spectrum of the high-energy conformer of 1,3-butadiene is sensitive to broadening of the spectra of the individual conformers with increasing T. A simulated spectral set, in which temperature broadening was purposely included, was used to develop a procedure that allows precise recovery of the pure component spectra. A set of Gaussians is derived that, on convolution with the spectrum for each corresponding T, creates a uniformly broadened spectral set. Exact recovery of the "s-cis spectrum" from the simulated spectral set is accomplished. Treatments of the experimental spectra using this method yields a minor conformer 1,3-butadiene spectrum that is only slightly red-shifted relative to the s-trans-1,3-butadiene spectrum and is consistent with the s-gauche structure. Application of PCA-SM to the onsets of the simulated spectral set showed that temperature broadening does not significantly alter the conformer enthalpy difference derived from the best-fit van't Hoff plot (compare 3.00000 kcal/mol assumed with 2.99992 kcal/mol recovered). The experimental onset spectra give ∆H°) 2.926 kcal/mol, in excellent agreement with previously reported values.

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Section: Introductionmentioning

confidence: 99%

UV Spectrum of the High Energy Conformer of 1,3-Butadiene in the Gas Phase

2001

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“…This will be illustrated by comparing results from experiments performed at constant ionic strength with those performed at variable ionic strength in which the buffer concentration was held constant. In addition, a novel method using principal component analysis (104)(105)(106)(107)(108)(109)(110)(111)(112), developed by the author and Harry E. Bell, to determine the number of absorbing species in solution and the absorptivity and solution concentration of each will be introduced.…”

Section: Contributions Of ~Is Studymentioning

confidence: 99%

“…If the second isosbestic point has a clear ending concentration this spectrum can be used directly as its spectral line shape. Otherwise, a most plausible line shape is chosen among those possible within the wedgeshaped region in the space of eigenvalue coefficients (108,111). The v-P-V absorptivity is determined such that it crosses the P-V absorptivity curve at the second isosbestic wavelength point.…”

Section: )mentioning

confidence: 99%

“…where the number of equilibrium equations was not specified, to allow the possibility of the presence of the porphyrin dimer, or some other unforeseen equilibrium. We developed a method using principal component analysis (104)(105)(106)(107)(108)(109)(110)(111)(112) to analyze these data. In the following section we present a table summarizing the published values for porphyrin/viologen association constants followed by a detailed review of seven publications (44,47,48,52,53,55,57) which study tetraphenylporphyrin/viologen complexation.…”

Section: Concentration Of Phosphate (Mil)mentioning

confidence: 99%

“…The first step was to determine the number of unique absorbing species in the data set which, after eliminating certain spectra due to monochrometer slip error, In this first part of the process we were interested in the eigenvalues, shown in Figure 47, which can be related to the number of principal components (104)(105)(106)(107)(108)(109)(110)(111)(112). We have explained our spectrophotometric titration data by two equilibrium equations (2 and 3 in Table XI) which means that we assume three prinCipal components (absorbing species).…”

Section: Determination Of Association Constantsmentioning

confidence: 99%

See 2 more Smart Citations

The Effect of Two Viologens on the Solution Speciation of Tetrakis([rho]-carboxyphenyl)porphine

Clarke¹

2000

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Tetrabenzoporphyrins: Metal Incorporation and Exchange Kinetics, Ligational Equilibria and Pulse Radiolysis Studies

Cromer

Hambright

Grodkowski

et al. 1997

J. Porphyrins Phthalocyanines

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The solution chemistry of tetrabenzoporphyrin ( TBP ) and several of its metal derivatives were compared with that of the corresponding octaethylporphyrins. Kinetic studies were done on zinc and cadmium ion incorporation and the exchange reactions of cadmium porphyrins with zinc. Formation constants of Cd (II), Cu (II), VO (IV), Ni (II), Zn (II) and Mg (II) porphyrins with pyridine were determined for both compounds. The spectra of the radical cations of Ni (II), Mg (II) and H 2- TBP were obtained, as well as that of the radical anion of Mg (II)- TBP . Aside from the new Ni (I)- TBP , no long-lived intermediates, as noted with other porphyrins, were observed upon reduction of the tetrabenzoporphyrins. The low basicity and rigidity of the tetrabenzoporphyrin nucleus may explain many of its relative reactivity properties.

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Porphyrins. 43. Triplet sublevel emission of platinum tetrabenzoporphyrin by spectrothermal principal component decomposition

Cited by 48 publications

References 0 publications

UV Spectrum of the High Energy Conformer of 1,3-Butadiene in the Gas Phase

UV Spectrum of the High Energy Conformer of 1,3-Butadiene in the Gas Phase

The Effect of Two Viologens on the Solution Speciation of Tetrakis([rho]-carboxyphenyl)porphine

Tetrabenzoporphyrins: Metal Incorporation and Exchange Kinetics, Ligational Equilibria and Pulse Radiolysis Studies

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