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Photocrystallographic, Spectroscopic, and Calorimetric Analysis of Light‐Induced Linkage NO Isomers in [RuNO(NO 2 ) 2 (pyridine) 2 OH]
Author(s) -
Kostin Gennadiy A.,
Borodin Alexander O.,
Mikhailov Artem A.,
Kuratieva Natalia V.,
Kolesov Boris A.,
Pishchur Denis P.,
Woike Theo,
Schaniel Dominik
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500702
Subject(s) - chemistry , linkage isomerism , isomerization , raman spectroscopy , pyridine , infrared spectroscopy , infrared , analytical chemistry (journal) , photoexcitation , spectroscopy , crystallography , irradiation , photodissociation , metastability , photochemistry , excited state , atomic physics , medicinal chemistry , biochemistry , physics , organic chemistry , optics , chromatography , quantum mechanics , nuclear physics , metal , catalysis
Through photocrystallography at T = 80 K, light‐induced linkage isonitrosyl NO isomers (κO‐bound) are detected and refined in the complex fac ‐[RuNO(NO 2 ) 2 Py 2 OH] · H 2 O (Py = pyridine) after irradiation with light in the blue spectral range. The infrared and Raman spectra reveal the downshift of the ν(NO), ν(Ru–NO), and δ(Ru–N–O) vibrations by 120–150 cm –1 upon photoexcitation. Furthermore, the infrared spectrum show a significant downshift of the ν as (NO 2 ) and ν s (NO 2 ) bands by ca. 10 cm –1 but without any isomerization of the NO 2 ligands. Furthermore, the downshifts of the ν(Ru–O–H) and δ(Ru–O–H) vibrational modes show the trans influence of the NO isomer on the OH ligand. The populations of the isonitrosyl isomer determined (66–75 % at λ = 443–445 nm) by all three techniques (X‐ray crystallography, IR and Raman spectroscopy) agree well. Such a high population of the isonitrosyl structure is visible in the photodifference map. The activation parameters E a = 63.9 ± 1 kJ/mol and k 0 = (1.8 ± 0.1) × 10 13 s –1 of the reverse transition were determined by differential scanning calorimetry (DSC). The second metastable state (side‐on κ 2 NO mode) was generated by a two‐step irradiation with blue light followed by irradiation with light in the near‐infrared spectral range (980 nm) and identified through its characteristic NO stretching vibration at $\tilde {\nu}$ = 1592 and 1600 cm –1 .