Intrinsic electronic spectra of cryogenically prepared protoporphyrin IX ions in vacuo – deprotonation-induced Stark shifts

2020 ◽  
Vol 22 (36) ◽  
pp. 20295-20302
Author(s):  
Wyatt Zagorec-Marks ◽  
James E. T. Smith ◽  
Madison M. Foreman ◽  
Sandeep Sharma ◽  
J. Mathias Weber

We present electronic spectra containing the Qx and Qy absorption bands of singly and doubly deprotonated protoporphyrin IX, prepared as mass selected ions in vacuo at cryogenic temperatures, revealing vibronic structure of both bands.

1997 ◽  
Vol 52 (5) ◽  
pp. 457-461 ◽  
Author(s):  
Sn. Bakalova ◽  
A. Georgieva ◽  
P. Nikolov ◽  
E. Stanoeva

Abstract The absorption and luminescence characteristics of a group of newly synthesized methyl esters of 2-alkyl (p-substituted-aryl) -aminomethylene-3,4-dihydro-1(2 H)-naphthalenone-4-carboxylic acids have been investigated. The studied compounds may exist in three tautomeric forms. On the basis of comparison of their electronic spectra to those of similar substances, the observed substituent effect on the position of the UV-VIS absorption bands, the IR spectra and the results of PPP-SCF-CI quantum-chemical calculations it is concluded that the keto tautomer predominates in solution.


1967 ◽  
Vol 20 (11) ◽  
pp. 2315 ◽  
Author(s):  
EJ Wells ◽  
AD Jordan ◽  
DS Alderdice ◽  
IG Ross

The spectrum of OsO4 has been measured in the vapour and in solution. Detailed structure reported in the main absorption bands by Langseth and Qviller was not reproduced. The irregularity of the main intervals between peaks, and their sensitivity to temperature, bespeak a perturbed spectrum which is too diffuse to analyse convincingly. Three fragmentary systems of quite different appearance were observed in all samples and could well be weak forbidden transitions. The spectrum of RuO, vapour is no better resolved. Reproducible features of both spectra are tabulated.


2005 ◽  
Vol 44 (18) ◽  
pp. 6211-6218 ◽  
Author(s):  
Koichiro Mizuoka ◽  
Satoru Tsushima ◽  
Miki Hasegawa ◽  
Toshihiko Hoshi ◽  
Yasuhisa Ikeda

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6037
Author(s):  
Reem M. Alghanmi ◽  
Maram T. Basha ◽  
Saied M. Soliman ◽  
Razan K. Alsaeedi

UV–Vis spectroscopy was used to investigate two new charge transfer (CT) complexes formed between the K+-channel-blocker amifampridine (AMFP) drug and the two π-acceptors 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) in different solvents. The molecular composition of the new CT complexes was estimated using the continuous variations method and found to be 1:1 for both complexes. The formed CT complexes’ electronic spectra data were further employed for calculating the formation constants (KCT), molar extinction coefficients (εCT), and physical parameters at various temperatures, and the results demonstrated the high stability of both complexes. In addition, sensitive spectrophotometric methods for quantifying AMFP in its pure form were proposed and statistically validated. Furthermore, DFT calculations were used to predict the molecular structures of AMFP–DDQ and AMFP–TCNE complexes in CHCl3. TD-DFT calculations were also used to predict the electronic spectra of both complexes. A CT-based transition band (exp. 399 and 417 nm) for the AMFP–TCNE complex was calculated at 411.5 nm (f = 0.105, HOMO-1 → LUMO). The two absorption bands at 459 nm (calc. 426.9 nm, f = 0.054) and 584 nm (calc. 628.1 nm, f = 0.111) of the AMFP–DDQ complex were theoretically assigned to HOMO-1 → LUMO and HOMO → LUMO excitations, respectively.


1973 ◽  
Vol 51 (1) ◽  
pp. 92-98 ◽  
Author(s):  
A. D. Allen ◽  
J. R. Stevens

The complexes [Os(NH3)5X]X2, cis-[Os(NH3)4X2]X, and trans-[Os(NH3)4X2]X (X = Cl, Br, I) have been prepared and their infrared spectra measured between 4000–150 cm−1 Assignments have been made for the observed absorption bands. The electronic spectra of the complexes were measured and compared with those of the analogous ruthenium(III) species.


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