Gas-Phase Ion Spectroscopy of Congo Red Dianions and
Their Complexes with Betaine
Version 2 2018-03-20, 18:49
Version 1 2018-03-20, 18:49
Posted on 2018-03-20 - 18:49
Congo
Red (CR) is an azo dye that is negatively charged in aqueous
solutions. Here we report on the intrinsic electronic properties of
CR dianions from mass spectroscopy experiments on bare dianions and
their complexes with betaine (B). As betaine is a zwitterion, it possesses
a large dipole moment and is a good reporter on the sensitivity of
CR to microenvironmental changes. Photoexcitation of CR2– in the visible region resulted in several fragment ions after absorption
of at least three photons, with major fragmentation routes due to
breakage of one or both C–NN bonds, one azo linkage, and/or
the bonds to sulfite. Their yields as a function of excitation wavelength
reveal a broad absorption in the visible region with the lowest-energy
band located at ∼500 nm. Features are observed with a spacing
of ∼1500 cm–1. One photon was sufficient
to dissociate CR2–·B, and its action spectrum
was almost identical to those of CR2– in accordance
with previous findings that a symmetric ion is essentially unaffected
by changes in its microenvironment. Electron detachment occurs in
the UV with threshold energy of 3.6 ± 0.1 eV for CR2– and 3.81 ± 0.06 eV for CR2–·B. Attempts
to measure fluorescence from photoexcited CR2– were
unsuccessful.
CITE THIS COLLECTION
DataCite
3 Biotech
3D Printing in Medicine
3D Research
3D-Printed Materials and Systems
4OR
AAPG Bulletin
AAPS Open
AAPS PharmSciTech
Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg
ABI Technik (German)
Academic Medicine
Academic Pediatrics
Academic Psychiatry
Academic Questions
Academy of Management Discoveries
Academy of Management Journal
Academy of Management Learning and Education
Academy of Management Perspectives
Academy of Management Proceedings
Academy of Management Review
Kjær, Christina; Lisy, James M.; Nielsen, Steen Brøndsted (2018). Gas-Phase Ion Spectroscopy of Congo Red Dianions and
Their Complexes with Betaine. ACS Publications. Collection. https://doi.org/10.1021/acs.jpca.8b00904
or
Select your citation style and then place your mouse over the citation text to select it.
SHARE
Usage metrics
Read the peer-reviewed publication
AUTHORS (3)
CK
Christina Kjær
JL
James M. Lisy
SN
Steen Brøndsted Nielsen