Chiroptical studies of bicyclic α-diketones

Połoński, Tadeusz; Dauter, Zbigniew

doi:10.1039/p19860001781

Cited by 11 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The curve calculated with Δε/ε = 2 × 10 -3 fits quite well to the experimental data, particularly at the slightly larger angles where the signal-to- noise ratio is optimized between scattered light and technical noise. This value for Δε/ε is in accord with literature values − for camphorquinone in ethanol and with that measured by conventional techniques to be ∼5 × 10 -3 . The figure also demonstrates the large changes that can be seen in the CD signal with relatively small variations in the value of Δε/ε.…”

Section: Resultssupporting

confidence: 92%

Circular Dichroism Spectroscopy Using Coherent Laser-Induced Thermal Gratings

et al. 1997

View full text Add to dashboard Cite

A new pulsed four-wave mixing technique for the detection and real-time measurement of circular dichroism (CD) in liquid samples is demonstrated. The technique is based on the formation and detection of transient thermal gratings formed by the interference of two laser beams whose polarizations are controlled and modulated using a photoelastic modulator. Through an internal heterodyne process, coherent thermal gratings interfere to greatly enhance a weak circular dichroism signal. By measuring the ratio of the difference of scattered laser light from two different polarizations, ΔS, to the average amount of scattered light, S ave, one can determine the value of Δε/ε for the compound under investigation. Samples of chiral camphorquinone are used to demonstrate the technique in the ultraviolet region of the spectrum. These studies of camphorquinone, which has a value of Δε/ε ≈ 10-3 at 266 nm, produce values of ΔS/S ave which are orders of magnitude larger than Δε/ε and which approach 2 (the mathematical limit for ΔS/S ave). Possible extensions of the technique for measuring CD in very small sample volumes and monitoring time-dependence are discussed.

show abstract

Section: Resultssupporting

confidence: 92%

Circular Dichroism Spectroscopy Using Coherent Laser-Induced Thermal Gratings

et al. 1997

View full text Add to dashboard Cite

show abstract

“…Conversely, the Cotton effect observed by Polonski et al [12] at 0.340 mm is much weaker than the peak at the same wavelength obtained by Perekalina et al [9]. This discrepancy leads to the conclusion that this band could be attributed to the transition in the benzoyl moiety [12,25], whereas Chaudhuri and El-Sayed [8] expected that the peak is caused by the second n À p Ã transition resulting from the intramolecular interaction of the two carbonyl groups of the benzoyl units in the benzil molecule.…”

Section: Discussioncontrasting

confidence: 54%

Theory, Measurement, and Origin of Optical Activity in Benzil Crystal

Řı́ha

Vyšín

Lapšanská

2005

Molecular Crystals and Liquid Crystals

View full text Add to dashboard Cite

The three coupled oscillator model and its application to the explanation of opticalrotatory dispersion and circular dichroism of benzil crystal is discussed. The previously measured experimental data are approximated by the theoretical set of formulas provided by this model. The twelve-term formula, which was computed using our computer program, is derived from the interpretation of the opticalrotatory dispersion of benzil. Similarly, the circular-dichroism data are analyzed. Both the previously published experimental data and the latest measurements are used for this reason. The obtained results are compared and discussed with respect to the origin of the optical activity occurring in benzil crystal.

show abstract

“…As expected, lower average molecular weight values are found for the polymerizations involving the DMAEM comonomer, due to transfer and/or termination reactions given by the tertiary amine group during the process, [14] however the polydispersity values appear appreciably low for a polymerization carried out under radical conditions. By contrast with the homopolymer poly(MCQ) (e max = 30.5 at 468 nm), displaying in CHCl 3 solution a significantly lower light absorptivity in the spectral region connected to the n-p* electronic transition of the a-diketone moiety, as compared to PCQ (e max = 38.3 at 467 nm) and CQ (e max = 39 at 483 nm in cyclohexane), [13] poly(MCQco-BM) and poly(MCQ-co-DMAEM-co-BM) exhibited UV absorptions closely related to PCQ (Tab. 1).…”

Section: Samplementioning

confidence: 93%

“…[11] Ester 5 was submitted to oxidation with selenium dioxide to the a-diketone (-)-10-acetoxycamphorquinone (6), which was finally treated with aqueous acid to give (-)-10-hydroxycamphorquinone 7. [13] This latter was used to obtain both the monomer (-)-10-methacryloyloxycamphorquinone (MCQ) and the model compound (-)-10-pivaloyloxycamphorqui-none (PCQ), by reaction, respectively, with methacryloyl or pivaloyl chloride (see Experimental). The model compound 2-(dimethylamino)ethyl pivalate (DMAEP) (Chart 1) was also obtained by reaction of pivaloyl chloride with 2-(N,N-dimethylamino)ethanol as described in the Experimental section.…”

Section: Synthesis Of Photoinitiating Systemsmentioning

confidence: 99%

Synthesis and photoinitiation activity of radical polymeric photoinitiators bearing side-chain camphorquinone moieties

Angiolini¹,

Caretti

Salatelli

2000

Macromol. Chem. Phys.

View full text Add to dashboard Cite

Novel polymethacrylic photoinitiators bearing in the side chain the photosensitive camphorquinone moiety, suitable to the radical polymerization and crosslinking of multifunctional (meth)acrylic monomers under irradiation with visible light, have been synthesized starting from the corresponding methacrylic monomer. The monomer has also been copolymerized with a methacrylic comonomer bearing a pendant tertiary amine group acting as coinitiator, in order to check the effect on the photoinitiation activity of a close vicinity between camphorquinone and amine moieties disposed along the polymer chain. Low molecular weight compounds resembling the repeating units of the polymeric derivatives have also been prepared as reference models with the aim of establishing the influence of the macromolecular chain on the photoinitiating activity. The activity of the above mentioned low‐ and high molecular weight photoinitiating systems, variously combined, has been checked by microwave dielectrometry in the photocuring at room temperature of a mixture of mono‐ and difunctional acrylic monomers by irradiation at a wavelength above 400 nm. The resulting kinetic parameters have been related to the structural features of the systems investigated.

show abstract

Chiroptical studies of bicyclic α-diketones

Cited by 11 publications

References 6 publications

Circular Dichroism Spectroscopy Using Coherent Laser-Induced Thermal Gratings

Circular Dichroism Spectroscopy Using Coherent Laser-Induced Thermal Gratings

Theory, Measurement, and Origin of Optical Activity in Benzil Crystal

Synthesis and photoinitiation activity of radical polymeric photoinitiators bearing side-chain camphorquinone moieties

Contact Info

Product

Resources

About