Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• negligible. Thus, the absorption band at 423 nm provides information of the total amount of paramagnetic cis species and the band at 406 nm comprises the total amount of diamagnetic trans and uncoordinated cis isomer. Combined with the information from NMR the cis/trans ratios were determined. Disulfide 1g

Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

• Henrik Hupatz,
• Marius Gaedke,
• Hendrik V. Schröder,
• Julia Beerhues,
• Arto Valkonen,
• Fabian Klautzsch,
• Sebastian Müller,
• Felix Witte,
• Kari Rissanen,
• Biprajit Sarkar and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2020, 16, 2576–2588, doi:10.3762/bjoc.16.209

• properties of the rotaxane NDIRot were investigated by UV–vis–NIR spectroelectrochemistry in a CH2Cl2/CH3CN 1:1 mixture and compared to NDIC8 and NDIC7 (Figure 4 and Table S3 in Supporting Information File 1). In the neutral state, the rotaxane displays the typical absorption pattern of an N,N’-disubstituted

• contrast, no charge-transfer band is present, neither for NDIRot nor for NDIC8, ruling out the formation of similar charge-transfer complexes in NDIC8 or in the corresponding rotaxane. After one-electron reduction (NDI → NDI•−), a complex absorption band pattern emerges in the visible region of all three

• further reduction, a new absorption pattern emerges for NDIC7, in accordance to a second electrochemical reduction (NDI•− → NDI2−) (Figure 4a, blue curve). However, only small shifts and intensity changes are observed for NDIC8 and the rotaxane NDIRot when going to a more negative potential (−1.2 V

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• TBTQ-(OG)6 C60 in toluene/DMSO. TBTQ-(OG)6 absorbs at 297 nm and C60 exhibits two absorption peaks at 298 nm and 333 nm. When C60 was mixed with TBTQ-(OG)6 in a 1:1 molar ratio, the absorption of C60 at 298 nm was slightly shifted to 302 nm. Similarly, the absorption of C70 at 298 nm was shifted to

• 301 nm after mixing the fullerenes with TBTQ-(OG)6 in the same molar ratio (Figure 3b). In aqueous solution, TBTQ-(OG)6 showed an absorption at 292 nm and, as expected, practically no absorption was observed for C60 and C70 due to their poor solubility (Figure 4a and Figure 4b). However, 1:1 molar

• mixture of TBTQ-(OG)6 and C60 in water exhibited an increased absorption at 292 nm and generated a new absorption band at 354 nm (Figure 4a). This observation is attributed to the increased solubility of C60 in water due to formation of the host–guest complex with TBTQ-(OG)6. A similar absorption behavior

Dawn of a new era in industrial photochemistry: the scale-up of micro- and mesostructured photoreactors

• Emine Kayahan,
• Mathias Jacobs,
• Leen Braeken,
• Leen C.J. Thomassen,
• Simon Kuhn,
• Tom van Gerven and
• M. Enis Leblebici

Beilstein J. Org. Chem. 2020, 16, 2484–2504, doi:10.3762/bjoc.16.202

• match the absorption spectrum of the photoactive molecule. In addition, the distance between the light source and the reactor should be taken into account while positioning the lamp. The irradiance pattern changes depending on the distance from the light source. At a long distance between the light

• calculation of the local volumetric rate of photon (or energy) absorption (LVRPA or LVREA) is the main aspect of the modeling of photoreactors. LVRPA represents the amount of photons absorbed per unit time and per unit reactor volume at different locations in the reactor. Then, the reaction rate at a given

• location can be related to the light field by using the quantum yield (Equation 9), where r is the reaction rate (mol⋅m−3⋅s−1), ϕ is the quantum yield (mol⋅mol⋅photons−1), and LVRPA is local volumetric rate of photon absorption (mol⋅photon⋅m−3⋅s−1). In order to obtain the average reaction rate, both the

Recent developments in enantioselective photocatalysis

• Callum Prentice,
• James Morrisson,
• Andrew D. Smith and
• Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

• enantioselectivities (7 examples, up to 97:3 er) (Scheme 28a) [81]. A lower energy wavelength irradiation was able to be used, which limited the amount of background reaction as the absorption spectra of photocatalyst and substrate were more clearly resolved. The first intermolecular process using these catalysts was

Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

• Zhishu Zeng,
• Jun Xie,
• Guangyan Luo,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194

• in the case of an excess of OA, the port interactions and inclusion interactions of OA andQ[8] can exist simultaneously. To further determine the host–guest ratio of the inclusion complex formed by Q[8] and OA, their interaction was investigated using UV–visible absorption spectroscopy via a molar

• ratio method and Job's method. Figure 3A shows the UV–visible absorption spectra of the interaction between Q[8] and OA. It can be seen that the UV absorption of OA at 275 nm and 316 nm decreased significantly as the concentration of Q[8] was increased. When n(Q[8])/n(OA) = 1, there was a clear

• transition of the absorbance of the system. Upon further addition of Q[8], the absorption value of the system tended to be constant, indicating the formation of a 1:1 complex with a binding constant K = 1.299 × 107 L·mol−1. The result of the Job’s plot also confirmed the combination of Q[8] and OA in a 1:1

Formation of an exceptionally stable ketene during phototransformations of bicyclo[2.2.2]oct-5-en-2-ones having mixed chromophores

• Asitanga Ghosh

Beilstein J. Org. Chem. 2020, 16, 2297–2303, doi:10.3762/bjoc.16.190

• less congested one has been observed. The ketenes were exceptionally stable both in air and solution. Its stability studies in acetonitrile through time-dependent UV absorption spectra revealed that it remained almost unchanged at least for a couple of weeks. Keywords: α,β- and β,γ-enones; bridgehead

• systems show an absorption band at about 210–250 nm characteristic for (π,π*) transition and at around 280–300 nm characteristic for (n,π*) transition. However, enone D shows enhanced intensity of an (n,π*) absorption band near 300 nm (log ε ≈ 3.5), along with an additional weak (n,π*) absorption band

• -dependent absorption spectra [13]. Also no external sensitizer was needed for these transformations. So an efficient intersystem crossing (ISC) may be involved in such systems to reach to the triplet state. A further fascinating aspect is that the two competitive pathways viz. 1,2-AS and photoindiuced 1,5

Styryl-based new organic chromophores bearing free amino and azomethine groups: synthesis, photophysical, NLO, and thermal properties

• Anka Utama Putra,
• Deniz Çakmaz,
• Nurgül Seferoğlu,
• Alberto Barsella and
• Zeynel Seferoğlu

Beilstein J. Org. Chem. 2020, 16, 2282–2296, doi:10.3762/bjoc.16.189

• with different polarities and showed absorption in the visible region and green-red emission with low quantum yields. The absorption and the emission maxima were shifted bathocromically by increasing the solvent’s polarity. However, there was no correlation with the polarity parameters of the solvents

• comprising of electron-donating and accepting groups in a donor–π–acceptor (D–π–A) system. The dyes exhibit strong absorption and emission properties in solution and in the solid state [1][2][3]. One important feature of these molecules is an exceptional polarizability which is a crucial criterion for NLO

• , Figures S41 and S42 in Supporting Information File 1). Absorption and emission properties To assess the effect of the solvent on the absorption and emission spectra of 3–7 and 8–12 (c = 10 μM for absorption, and c = 1 μM for emission), various solvents with different polarity were employed at room

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• ) in the conventional approach was higher compared to the ball billing approach (Figure 2A). The yield of both, solution-based and ball mill conjugations was monitored by measuring the absorption of the conjugates (λmax = 508–511 nm) and the relative amount of conjugated PBA-BODIPY (1) was calculated

• compared to Dex. Therefore, mechanochemical reactions were carried out using a glucose units/1 molar ratio of 120:1 and 600:1. The conjugations yield was determined by measuring the absorption of the conjugates (λmax = 508–511 nm, Figure 2B and Supporting Information File 1, Figures S3 and S4), and

• -BODIPY-dextran conjugate Dex-1b were studied in water. The UV–vis spectra of Dex-1b reported in Figure 3A shows the same absorption pattern of the PBA-BODIPY (1, see Supporting Information File 1) [26]. The main absorption band corresponding to the transition S0 → S1, is observed at λabs = 508 nm. The

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• thermoelectric properties in addition to the onigiri-type core-shell assemblies have been reported for sumanene and its derivatives. More interestingly, its application in the absorption of small molecules such as NH3, CO2, CO, and H2 using density functional theory (DFT) calculations has also been revealed [25

• experimentally that compound 68 has a deeper bowl architecture and also a higher bowl inversion energy as compared to the sumanene (2), measured by NMR studies. In this report, these workers further revealed the electronic state of 68 by means of electrochemical and UV-absorption measurements. Recently, they

• reaction yielded 92 (Scheme 21). As can be seen from the literature, pyrene-based compounds remain among the highest beautiful and fascinating classes of molecules because of their extremely characteristic (“fingerprint”) optical absorption as well as emission behavior. Keeping in mind the uniqueness of

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• molecules in water. The absorption maxima and corresponding molar extinction coefficients (ε) are given in Table S1 (Supporting Information File 1). Heating of the aqueous solution of 4 up to 90 °C did not yield any significant changes in its UV–vis spectrum, suggesting that the chromophores are not

• absence of ICD bands within the naphthalene diimide absorption range (350–420 nm) suggested that the NDI transition dipole moment associated with the higher energy transition (NDI longer axis) was not well-oriented in respect to the DNA chiral axis [14]. At variance to ds-DNA, the addition of compound 4

• ICD band characteristic for NDI intercalation [26][27]. At pH 5 the 4/ds-RNA complex changes in the CD spectrum (Figure 3b) were somewhat different in respect to those observed at pH 7 (Figure 3a), but again showing no ICD bands in the naphthalene diimide absorption range characteristic for

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• a positive impact on the biological absorption and distribution. Moreover, C–H/C–F substitution strongly decreases the basicity of neighboring amines (and lowers the pKa by a similar increment) due to the σ-inductive effect of F. This results in i) a higher oral bioavailability [19], ii) a potential

• absorption of radiation by another molecular entity called a photosensitizer. In mechanistic photochemistry, the term is limited to cases in which the photosensitizer is not consumed in the reaction” [89]. One can appreciate the close connection of this definition to that of photocatalysis, defined by the

• photosensitizers is acetone. Frequently, it is used as a solvent or in high concentration where its optical density allows light absorption at approximately 300 nm, even though λmax is about 270 nm [132]. Benzil, 9-fluorenone and 9,10-phenanthrenequinone are also well-established visible light triplet PSCats that

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• colourless and non-fluorescent core-unsubstituted NDI with a new charge transfer band with an absorption maximum in the visible spectral range and a high fluorescence quantum yield (up to 58%) [23][25]. Further, the 2-amino substituent offers the possibility to connect various amino acid side chains, thus

• stability of similar NDI compounds is greater in weakly acidic buffer solution over a longer period of time [24]. Compounds 3a,b, and 5 revealed absorption maxima of 518–540 nm with molar extinction coefficients of nearly 10000 M−1 cm−1 (Figure 2). Further, 3a,b, and 5 show strong fluorescence at 573–602 nm

• ][41][42]. Values for Ks and n given in Table 3 all have satisfactory correlation coefficients (>0.999). Thermal melting curves for DNA, RNA, and their complexes with the studied compounds (Table 2) were determined as previously described [39][61] by following the absorption change at 260 nm as a

Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

• Dandan Li,
• Enjuro Harunari,
• Tao Zhou,
• Naoya Oku and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

• . UV and IR absorption spectra were recorded on a Shimadzu UV-1800 and a Perkin Elmer Spectrum 100 spectrophotometer, respectively. NMR spectra were obtained on a Bruker AVANCE 500 spectrometer, referencing to the residual solvent peaks at δH 7.26 and δC 77.0 for CDCl3. HRESIMS–TOF spectra were

• DMSO. The respiration of live cells was quantified by the measurement of the absorption at 540 nm by a microplate reader. The experiment was run in a triplicate, and the rates of the cell-growth inhibition at each concentration were plotted on a single logarithmic chart to deduce the GI50 values of the

Synthesis and highly efficient light-induced rearrangements of diphenylmethylene(2-benzo[b]thienyl)fulgides and fulgimides

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Valerii V. Tkachev,
• Andrey N. Utenyshev,
• Olga Yu. Karlutova,
• Alexander D. Dubonosov,
• Vladimir A. Bren,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2020, 16, 1820–1829, doi:10.3762/bjoc.16.149

• transformation is thermally and photochemically irreversible. Although the appearance of 3Z and 4-(3-methoxybenzo[b]thiophen-2-yl)-9-phenyl-4,4a-dihydronaphtho[2,3-c]furan-1,3-dione (9I) shown in Scheme 4 was not directly registered in the absorption spectra (Figure 3), their existence was evidenced by the data

• bathochromic shift of the 441 nm band accompanied by a typical redistribution of intensity of absorption bands (see Table 1) is detected. At longer irradiation times, the rearrangement processes are reflected by the spectral curves depicted in Figure 3. Crystal packing of the product of the photoinduced

• absorption spectra were recorded on a Varian Cary 100 spectrophotometer. The irradiation of acetonitrile solutions in quartz cells (l = 10 mm, V = 2.mL) with a high pressure Hg lamp (250 W) was performed on a Newport 66941 equipment supplied with a set of interferential light filters. The intensity of light

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• photochemical reactions due to the inherent lack of scalability issues as a consequence of the Beer–Lambert law of absorption. Consequently, continuous-flow chemistry represents one of the few ways in which pharmaceutically relevant quantities of compounds can be synthesized through photoinduced transformations

• to close the catalytic cycle. Direct metalation and visible-light absorption by a single catalyst: Ru and Rh-catalyzed photoinduced transformations The dual catalytic systems, combining visible-light photocatalysis and C–H activation generally require the use of two distinct metal catalysts, one able

• directed ortho-metalation should exhibit visible-light absorption property and thus, under visible-light irradiation, the overall catalytic cycle could benefit from the photocatalytic activation. Following the initial hypothesis, the direct functionalization of phenylpyridine substrates turned out to be

Et₃N/DMSO-supported one-pot synthesis of highly fluorescent β-carboline-linked benzothiophenones via sulfur insertion and estimation of the photophysical properties

• Dharmender Singh,
• Vipin Kumar and
• Virender Singh

Beilstein J. Org. Chem. 2020, 16, 1740–1753, doi:10.3762/bjoc.16.146

• measurement of UV–vis absorption and fluorescence emission of the samples, stock solutions of 1.0 mM concentration were prepared using analytical grade CHCl3 as the solvent, and diluted to the final concentration of 4.0 μM. Next, we carefully measured the photophysical properties at room temperature including

• absorption, excitation, emission, Stokes shift, fluorescence quantum efficiency, molar extinction coefficient, and brightness. The photophysical data of the β-carboline C1 or C3-tethered benzothiophenone derivatives are summarized in Table 2, and their graphical data are depicted in Figure 3 and Figure 4

Clickable azide-functionalized bromoarylaldehydes – synthesis and photophysical characterization

• Dominik Göbel,
• Marius Friedrich,
• Enno Lork and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2020, 16, 1683–1692, doi:10.3762/bjoc.16.139

• triazole 45 in 83% yield. Photophysical properties Finally, we examined the photophysical properties of both the azides and the triazoles. UV–vis absorption measurements of para-bromobenzaldehyde 3 and ortho-bromobenzaldehyde 4 as well as the corresponding triazoles 33–40 were conducted in chloroform

• . Intense absorption bands below 270 nm were observed, which could be attributed to typical π–π* transitions derived from the single-benzene core. In addition, unstructured absorption bands above 290 nm were observed, while ortho-derivatives exhibited more broadened bands than the para-derivatives (see

• fluorescence. This may be owing to the azide moiety, either as a functional group or as part of the triazole heterocycle. Similar observations were already made for luminescent materials [74][75]. Fluorene derivatives were subjected to photophysical measurements as well. UV–vis absorption spectra of

Synthesis of new dihydroberberine and tetrahydroberberine analogues and evaluation of their antiproliferative activity on NCI-H1975 cells

• Giacomo Mari,
• Lucia De Crescentini,
• Serena Benedetti,
• Francesco Palma,
• Stefania Santeusanio and
• Fabio Mantellini

Beilstein J. Org. Chem. 2020, 16, 1606–1616, doi:10.3762/bjoc.16.133

• an intestinal absorption rate 5-fold higher than that of BER [26][27][28]. Currently, DHBER is a drug candidate for the treatment of type 2 diabetes [29][30], can reduce the atherosclerotic plaque size [31], has therapeutic potential for myotonic dystrophy type I due to its central nervous system

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• nanoparticles) or by introducing impurities into the crystal lattice, otherwise known as doping [44][84][85][86]. Semiconductor doping adds additional filled or vacant quantum states to the band structure that lie within the band gap, reducing the Eg and typically resulting in a bathochromic shift in absorption

• . Synthetic TiO2 commonly has oxygen atom vacancy defects, especially at its surface, resulting in Ti3+ ions that produce quantum states close to the conduction band minimum. These states lower the Eg, enabling visible light absorption and producing reactive centres on the catalyst surface, which has been

• via physisorption. However, functionalised molecules and ions can strongly bind through chemisorption by covalent bonds, hydrogen bonding, or electrostatic attraction and have been shown to influence the photophysical properties of TiO2, generally causing a bathochromic shift of the absorption

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• (5.2 mg) with sufficient purity for structure characterization. The molecular formula of 1 was determined to be C10H9NO2 based on a sodium adduct molecular ion peak at m/z 198.0525 observed by a HRESITOFMS measurement (calcd 198.0526). The broad IR absorption band around 3100 cm−1 and an intense peak

Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

• Kazuyuki Sato,
• Akira Kawasaki,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2020, 16, 1411–1417, doi:10.3762/bjoc.16.117

• ][38], their optical properties feature a large Stokes shift and high molar absorption coefficients (ε) that are similar to the corresponding boron diketonates. The synthesis and properties of BKIs have been reported recently and they are easily accessible either from the corresponding 1,3-diketones 1

• 8 and their conversion to BKIs (yields refer to isolated yields; aboron complexation of 8a to 9a was not attempted). Attempted selective fluorination of BKI 6b. Ring-opening reaction of 4-fluoroisoxazoles 3 and their conversion into F-BKIs 9 (yields refer to isolated yields). UV–vis absorption and

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors

• Abimelek Cortes-Pacheco,
• María Adelina Jiménez-Arellanes,
• Francisco José Palacios-Can,
• José Antonio Valcarcel-Gamiño,
• Rodrigo Said Razo-Hernández,
• María del Carmen Juárez-Vázquez,
• Adolfo López-Torres and
• Oscar Abelardo Ramírez-Marroquín

Beilstein J. Org. Chem. 2020, 16, 1277–1287, doi:10.3762/bjoc.16.108

• compounds was opposed to that observed with the TPA topical model. This may be a consequence of the lower lipophilicity of 3 (clogP = 0.58) and 4 (clogP = 1.39) compared to 5 (clogP = 1.80) and 6 (clogP = 1.85), influencing the better dissolution of 3 and 4 in an aqueous medium prior to its absorption

Anthelmintic drug discovery: target identification, screening methods and the role of open science

• Frederick A. Partridge,
• Ruth Forman,
• Carole J. R. Bataille,
• Graham M. Wynne,
• Marina Nick,
• Angela J. Russell,
• Kathryn J. Else and
• David B. Sattelle

Beilstein J. Org. Chem. 2020, 16, 1203–1224, doi:10.3762/bjoc.16.105

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• concentrations in toluene were 1.0 × 10−5 and 1.0 × 10−3 M for the absorption and photoluminescence (PL) measurements, respectively, and the absorption and PL spectra are shown in Figure 4. The photophysical data obtained from these measurements are summarized in Table 1. The methoxy-substituted fluorinated

• ·cm−1) (Figure 4B). Both 2a and 2b exhibit weak absorption at around 400 nm (ε: ≈170 M−1·cm−1). As shown in Figure 4C–E, on the other hand, the bisbenzil derivatives 3a–c show an absorption band at 290 nm (ε: 29600–51200 M−1·cm−1) as the major signal, together with a quite weak absorption band at 402

• –405 nm (ε: 180–260 M−1·cm−1). To gain more information about the slight difference between the absorption behaviors of the benzil and bisbenzil derivatives, DFT and time-dependent DFT (TD-DFT) calculations at the CAM-B3LYP/6-31+G(d) level of theory were performed for fluorinated benzil 2a and