On the chemistry of pyrrole pigments, XCIV: 1-(Dipyrrinon-9-yl)-3-(dipyrrinon-9-ylidene)-1-propene ? a novelb-vinylogous verdin chromophore

Chen, Q. Q.; Falk, Heinz

doi:10.1007/bf00824302

Cited by 9 publications

(1 citation statement)

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“…At the same time, some spectra and some compounds are extremely rare, in which case modification of an existing spectrum, warts and all, may be the only recourse. Other reasons for data revision are multifold, including correction of obvious errors, which can arise as follows: (i) introduction of typographical mistakes; (ii) use of a hand-tracing process (to create the spectrum for publication) might truncate the spectrum or the wavelength scale [58][59][60]; (iii) the spectrometer employed for data collection may afford spectra that are systematically shifted on the wavelength axis; and (iv) a manuscript may be mishandled by a publisher, outside the control of the authors. Beyond annoying errors, new knowledge may have come forth that leads to a desire for modification of prior spectra.…”

Section: Comments On Spectra Modificationsmentioning

confidence: 99%

Digitization of print-based absorption and fluorescence spectra – extracting clarity from clutter

Taniguchi

Sterling

et al. 2023

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XIV

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Absorption and fluorescence spectra are central to the photosciences. The PhotochemCAD initiative, aimed at assembling digital databases of absorption and fluorescence spectra for use across the photosciences, now comprises >1000 absorption spectra and >500 fluorescence spectra for ~1000 compounds along with companion photophysical parameters (molar absorption coefficient, fluorescence quantum yield) and citations to the originating scientific literature. The spectral databases have chiefly been assembled by digitizing spectra from the vast print literature. The conversion of print spectra to digital form presents several technical challenges: (1) print spectra are plagued by line crossing from overlaid spectra, confusion from discontinuous lines, and interference from grids, tick marks, and the graph baseline; (2) the print spectrum may lack wavelength markers or be annotated with markers at odds with values in the accompanying text; and (3) the digitized spectrum often is composed of data with uneven wavelength (x-axis) intervals. Here, manually assisted digitization -where the user steps through a scanned print spectrum with hand-eye assistance to create the corresponding digital dataset -is compared with automated digitization. A hybrid digitization approach that combines the two processes has been found to be expeditious in many cases. Two spreadsheet-based tools have been developed for application postdigitization: (i) conversion of xy-coordinate data from uneven to uniform x-axis intervals, and (ii) calibration of the digitized spectrum with appropriate wavelength values. The two tools enable more accurate rendition of print spectra into digital form, as required for qualitative comparisons and quantitative calculations, and are available at the PhotochemCAD website http://www.photochemcad.com.

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Section: Comments On Spectra Modificationsmentioning

confidence: 99%