Dicarbonyl chelates from 1-cymantrenylalkylamides with the dendrite structure: formation, photochromism, and kinetics of dark reaction with carbon monoxide

Synthesis and Photochemical Study of Thiazolidine Derivatives of Cymantrene and the Corresponding Dicarbonyl Chelates

“…Kinetic studies showed that the half‐conversion time for the reverse dark reaction is about 8 h in the case of chelates 5–7 and 48 h for the transformation 4 to 3 . The kinetics of the dark thermal transformation of chelates to the corresponding tricarbonyl compounds is described by the;1 st order equation with a R value no less than 0.998, which is in accordance with previously described kinetic studies,, that is the ligand exchange in compounds 4–7 occurs via the S N1 mechanism with the cycle opening at the Mn−N or Mn−S bond being the limiting stage.…”

Spectroscopic Studies of Photochemical Transformations of Cymantrenylquinazolinone Derivatives

“…IR monitoring of the irradiation of compounds 1 and 2 in benzene by a Hg lamp with λ = 365 nm showed that two MCO stretches of tricarbonyl complexes at 2019 and 1938 cm –1 disappear and two new bands of approximately equal intensities at 1931 and 1861 cm –1 appear in the ν(MCO) region of the IR spectra and the –NC=O band undergoes a low‐frequency shift of 54 cm –1 . The positions and intensity ratios are typical of the asymmetric and symmetric modes of MCO stretches in dicarbonyl complexes in which, according to our previous data,, , the manganese atom is coordinated to the –NC=O group; the low‐frequency shift of the ν(C=O) band also confirms the O ‐coordination. Thus, after photochemically induced CO loss, O ‐coordinated chelate complexes are formed (Figure , Scheme , Table ).…”

“…Earlier we found that the photolysis of cymantrenylalkylamides of carboxylic acids results in the formation of thermodynamically stable dicarbonyl chelates due to the coordination of the carbonyl fragment –NC=O to the Mn atom. The spectral properties of the chelates and starting tricarbonyl compounds are substantially different, which is the basis for the creation of photochromic systems based on these compounds . The combination of the photochromic properties of cymantrene derivatives and the fluorescence ability of quinazolinones gives reason to expect that the introduction of a cymantrenyl fragment into quinazolin‐4‐one derivatives would provide new systems with photochromic and luminescence properties.…”

Synthesis and Spectroscopic Studies of the Photochromism of Bifunctional Derivatives of Cymantrene in Solution and without Solvent

“…Silica gel 60 (Merck) was used for column chromatography. The starting materials 1‐cymantrenylethylamine ( 17 ), cymantrenylmethylamine ( 18 ), 3,5‐didecyloxybenzoyl chloride ( 13 ), 3,5‐bis(3,5‐didecyloxybenzyloxy)benzoyl chloride ( 15 ), N ‐(cymantrenylmethyl)‐3,5‐didecyloxybenzamide ( 9 ), and N ‐[(1‐cymantrenyl)ethyl]‐3,5‐didecyloxybenzamide ( 10 ) were prepared according to the procedures described recently . Other chemicals were obtained commercially and used without further purification.…”

“…The solid‐phase exchange of CO for triphenylphosphine occurs upon the photolysis of a silica gel supported mixture of cymantrene and PPh 3 . Recently, we found that cymantenylamides with branched substituents have low melting points and are able to form transparent thin layers between KBr windows; the irradiation of these thin layers results in photoinduced intermolecular ligand exchange …”