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

Kelbysheva, E. S.; Telegina, Lyudmila N.; Rodionov, А. N.; Стрелкова, Т. В.; Ezernitskaya, M. G.; Lokshin, B. V.; Loim, N. M.

doi:10.1002/ejic.201600343

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…This loss would be very obvious. For example, in case one CO ligand of 3 is replaced by pentane, the IR bands of pure cymantrene (2031 and 1950 cm −1 ) change substantially to 1965 and 1899 cm −1 …”

Section: Resultsmentioning

confidence: 99%

Adsorption of Metallocenes on Silica

Cluff

Blümel

2016

Chemistry A European J

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The adsorption of the metallocenes ferrocene, doubly deuterated ferrocene, cymantrene and nickelocene, as well as molybdenum hexacarbonyl, proceeds in the absence of a solvent. Large single pieces of silica gel were placed in contact with the solid metallocenes and the adsorption process was visualized on a macroscopic scale and the maximal loadings were determined. H, H, and C solid-state NMR studies confirmed fast isotropic reorientation of the surface-adsorbed metallocene molecules within the pores of the silica. All prevalent anisotropic solid-state interactions were averaged out. The solid diamagnetic and paramagnetic materials were amenable to measurements with a standard solution NMR instrument. All metallocenes adsorbed in a monolayer. In the case of ferrocene and cymantrene, different C MAS signals were obtained for the cyclopentadienyl ring carbon nuclei and assigned to one ring interacting with the surface and one ring pointing away from it. The relative adsorption strengths of ferrocene on different silica supports, nanotubes, and activated carbon were determined by a novel straightforward method recording the desorption temperature. The reversibility of adsorption has been demonstrated by competition experiments using ferrocene, doubly deuterated ferrocene, and cymantrene. Adsorbed nickelocene could be reduced to small Ni aggregates on the surface and the catalytic activity of the resulting material for the cyclotrimerization of phenylacetylene was proven.

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Section: Resultsmentioning

confidence: 99%

Adsorption of Metallocenes on Silica

Cluff

Blümel

2016

Chemistry A European J

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“…Removal of an electron from the molecule is thought to facilitate the metabolic transformation of the prodrug to its active quinone methide form. − Given the fact that there are significant spectroscopic limitations in following the metabolic pathways of ferrocifens, there is interest in tagging tamoxifens with an organometallic moiety that has strong, structurally informative spectroscopic properties. One of the most attractive units for bioimaging is the metal–carbonyl group, owing to its intense infrared CO absorptions that occur in a spectral region (1800–2200 cm –1 ) which is generally nearly transparent in biological systems. − …”

Section: Introductionmentioning

confidence: 99%

Oxidation of Cymantrene-Tagged Tamoxifen Analogues: Effect of Diphenyl Functionalization on the Redox Mechanism

Pudasaini

Park

et al. 2020

Organometallics

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The oxidations of 1,1′-di-p-anisolyl-2-cymantrenylbutene (3b) and 1,1′-di-p-hydroxyphenyl-2-cymantrenylbutene (3c) were investigated by electrochemical and spectroscopic experiments and by density functional theory (DFT) calculations. Both compounds undergo a reversible one-electron oxidation followed closely by a partially chemically reversible second oxidation (E 1/2 values vs ferrocene: 0.60 and 0.74 V for 3b; 0.63 and 0.78 V for 3c). In comparison to the nonphenyl-functionalized parent, 1,1′diphenyl-2-cymantrenylbutene (3a), 3b,c have lower and more closely spaced oxidation potentials and more rapid follow-up reactions of their dications, 3b 2+ and 3c 2+ . Shifts in the calculated charge distributions of the neutral compounds and their singly and doubly oxidized products corroborated trends in the measured shifts of Mn−CO ν CO frequencies in assigning the redox sites primarily to the diarylbutene fragment. Upon removal of electrons, the lost charge density is partially compensated by the polarizable cymantrenyl tag. The half-lives of the dications 3b 2+ and 3c 2+ are about 10 s at room temperature in dichloromethane/0.05 M [NBu 4 ][B(C 6 F 5 ) 4 ]. Their follow-up reactions are initiated by loss of a proton either from a hydroxyl group or from the CH 2 group of the diarylbutene unit, giving rise to two products having quinone methide structures. Although the initial oxidation sites of cymantrene-tagged diarylbutenes are primarily ligand based and those of ferrocene-tagged diarylbutenes are metalbased, the ultimate oxidation products of their p-OH-or p-OMe-functionalized derivatives are very similar.

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“…Photolysis of cymantrenes (cyclopentadienylmanganese tricarbonyl) attracts attention in view of application in catalysis, as a method for controlled dosing of CO for therapeutic goals and creation of photochromic systems. , …”

Section: Introductionmentioning

confidence: 99%

“…(Scheme ). , An increase in a number of functional donor fragments in a substituent expands the possibility for the formation of various chelates and linkage isomerization during irradiation or thermal reactions.…”

Section: Introductionmentioning

confidence: 99%

Thioureido Cymantrene Derivatives: Synthesis and Photochromic Properties

et al. 2019

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Photolysis of thioureido derivatives of cymantrene in solution and solvent-free affords stable six-membered dicarbonyl chelates due to coordination of sulfur of the CS group to manganese. The process is accompanied by a color change and the appearance of new bands at 400 and 500 nm in the UV–vis spectra. In the presence of carbon monoxide, these chelates enter the reverse thermal reaction to give the parent tricarbonyl complexes thus forming photochromic systems. In the air, dicarbonyl chelates are oxidized to form stable dicarbonyl Mn-based radicals, which were isolated, and their structure was proved by electron paramagnetic resonance spectra and density functional theory calculations. The irradiation of these dark violet radicals, in turn, also results in formation of stable photochromic systems. Dicarbonyl olefin chelates were synthesized; upon photolysis of these compounds, stable intramolecular photochromic systems with high quantum yield were obtained. The reverse thermal reaction occurs via dissociative isomerization of the substituent.

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

Cited by 9 publications

References 28 publications

Adsorption of Metallocenes on Silica

Adsorption of Metallocenes on Silica

Oxidation of Cymantrene-Tagged Tamoxifen Analogues: Effect of Diphenyl Functionalization on the Redox Mechanism

Thioureido Cymantrene Derivatives: Synthesis and Photochromic Properties

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