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Search for "solvent polarity" in Full Text gives 90 result(s) in Beilstein Journal of Organic Chemistry.

A new synthetic protocol for coumarin amino acid

  • Xinyi Xu,
  • Xiaosong Hu and
  • Jiangyun Wang

Beilstein J. Org. Chem. 2013, 9, 254–259, doi:10.3762/bjoc.9.30

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  • coumarin amino acid 1a (Figure 1) is sensitive to both pH and solvent polarity, which makes it a good probe to investigate protein functionalities and biological processes related to them. The following examples are several applications of it. Shan and co-workers used compound 1a to form a FRET pair with
  • cannot be achieved by using GFP labeling technique since GFP is relatively insensitive to the pH and the solvent polarity of the solution. Many more examples of the usage of 1a have also been reported [5][6][7][8]. Due to the high importance of 1a, there has been a great need for a highly efficient and
  • different sensitivities to pH and solvent polarity, and can serve as new fluorescent probes in a variety of applications. Results and Discussion Scheme 1 gives an outline of the new protocol used to synthesize compound 1. First, the coumarin ring with a 4-chloromethyl group (compound 3) was formed through
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Published 06 Feb 2013

Asymmetric desymmetrization of meso-diols by C2-symmetric chiral 4-pyrrolidinopyridines

  • Hartmut Schedel,
  • Keizo Kan,
  • Yoshihiro Ueda,
  • Kenji Mishiro,
  • Keisuke Yoshida,
  • Takumi Furuta and
  • Takeo Kawabata

Beilstein J. Org. Chem. 2012, 8, 1778–1787, doi:10.3762/bjoc.8.203

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  • isobutyric anhydride in the presence of catalyst 12b (Table 2, entries 1–5). A clear relationship between the enantioselectivity and the solvent polarity was observed: The lower the polarity of the solvent, the higher the enantioselectivity. This suggests that the hydrogen-bonding interaction between the
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Published 17 Oct 2012

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

  • Gareth L. Nealon,
  • Romain Greget,
  • Cristina Dominguez,
  • Zsuzsanna T. Nagy,
  • Daniel Guillon,
  • Jean-Louis Gallani and
  • Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

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  • , squarelike and stripelike arrangements as a function of both the length of the tethering group and the solvent polarity (Figure 26). These results bode well for the use of these discotic materials in NP self-organisation, and it appears only a matter of time before LC phases are observed for discrete hybrids
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Published 08 Mar 2012

The interplay of configuration and conformation in helical perylenequinones: Insights from chirality induction in liquid crystals and calculations

  • Elisa Frezza,
  • Silvia Pieraccini,
  • Stefania Mazzini,
  • Alberta Ferrarini and
  • Gian Piero Spada

Beilstein J. Org. Chem. 2012, 8, 155–163, doi:10.3762/bjoc.8.16

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  • moment than those of cercosporin (1), therefore 2 should be more sensitive to solvent polarity (acetone has a dielectric constant of about 20 at room temperature). HTP predictions by the SC method Within the SC approach, the HTP of a chiral dopant in a nematic solvent is proportional to the so-called
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Published 24 Jan 2012

Fluorescent hexaaryl- and hexa-heteroaryl[3]radialenes: Synthesis, structures, and properties

  • Antonio Avellaneda,
  • Courtney A. Hollis,
  • Xin He and
  • Christopher J. Sumby

Beilstein J. Org. Chem. 2012, 8, 71–80, doi:10.3762/bjoc.8.7

Graphical Abstract
  • (~0.04 mM) indicates that 1 – which has 12 methyl substituents arranged above and below the [3]radialene core – aggregates in the more polar acetone solvent (polarity index for dichloromethane 3.1; acetone 5.1). The less hydrophobic [3]radialenes, 2 and 3, do not show the same behaviour. The more
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Published 11 Jan 2012

Valence isomerization of cyclohepta-1,3,5-triene and its heteroelement analogues

  • Helen Jansen,
  • J. Chris Slootweg and
  • Koop Lammertsma

Beilstein J. Org. Chem. 2011, 7, 1713–1721, doi:10.3762/bjoc.7.201

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  • methyl groups in benzene oxide (4) [38][40][51]. Thus, in contrast to the cycloheptatriene–norcaradiene (1–2) pair, the equilibrium constant for oxepine (3) and bicyclic benzene oxide (4) varies widely with solvent polarity and to some extent with temperature and substituents, making it possible to work
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Published 21 Dec 2011

Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene

  • Aurélien Hameau,
  • Sabine Fuchs,
  • Régis Laurent,
  • Jean-Pierre Majoral and
  • Anne-Marie Caminade

Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186

Graphical Abstract
  • or in pyridine, and was ascribed to the solvent polarity, which modifies the interactions between both parts of the molecule [17]. In our case, we may consider that the structure of dendron 10 in solution in dioxane is more expanded than in water, which should bring the hydrophobic moieties (the
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Published 28 Nov 2011

Predicting the UV–vis spectra of oxazine dyes

  • Scott Fleming,
  • Andrew Mills and
  • Tell Tuttle

Beilstein J. Org. Chem. 2011, 7, 432–441, doi:10.3762/bjoc.7.56

Graphical Abstract
  • been observed and the mechanism(s) explored in previous studies by various authors [9][10][11]. Most of these investigations have involved measuring experimentally the spectroscopic features of oxazine dyes, upon varying the solvent polarity. However, some attempt has been made to rationalize these
  • observations by a computational study of the solvatochromism of the oxazine dye Nile red [12]. In the investigation, TD-DFT was applied in order to try and explore the contributing factors in the solvatochromism observed with Nile red, upon gradually increasing the solvent polarity from benzene to acetonitrile
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Published 15 Apr 2011

Formation of macrocyclic lactones in the Paternò–Büchi dimerization reaction

  • Junya Arimura,
  • Tsutomu Mizuta,
  • Yoshikazu Hiraga and
  • Manabu Abe

Beilstein J. Org. Chem. 2011, 7, 265–269, doi:10.3762/bjoc.7.35

Graphical Abstract
  • detected by 1H NMR (500 MHz). To investigate the medium effect on the formation of 2a, the photochemical reaction of 1a was performed in several solvents (entries 4–6). The yield of 2a decreased with increasing solvent polarity; 16% in toluene (entry 4) and 10% in CH3CN (entry 6). Temperature had no effect
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Published 28 Feb 2011

Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor

  • Kumaresh Ghosh and
  • Debasis Kar

Beilstein J. Org. Chem. 2011, 7, 254–264, doi:10.3762/bjoc.7.34

Graphical Abstract
  • in emission in CHCl3 containing 0.1% CH3CN (Supporting Information File 1). These observations thus intimate that solvent polarity is an important aspect for monitoring the sensing behavior of benzimidazolium-based receptors. In our opinion, CH3CN in the present case participates in H-bonding with
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Published 25 Feb 2011

Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission

  • Ritesh Nandy and
  • Sethuraman Sankararaman

Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112

Graphical Abstract
  • absorption and fluorescence emission properties of these molecules have been studied in solvents of different polarity. For a given derivative, solvent polarity had minimal effect on the absorption maxima. However, for a given solvent the absorption maxima red shifted with increasing conjugation of the
  • substituent. The fluorescence emission of these derivatives was very sensitive to solvent polarity. In the presence of strongly electron withdrawing (–CN) and strongly electron donating (–NMe2) substituents large Stokes shifts (up to 130 nm, 7828 cm−1) were observed in DMSO. In the presence of carbonyl
  • whose fluorescence emission is sensitive to environment and solvent polarity are of significant interest due to their versatile applications in chemistry, biology and environmental science [1][2][3][4]. Considerable effort has been expended into shifting the fluorescence emission of organic molecules
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Published 18 Oct 2010

Synthesis of the fluorescent amino acid rac-(7-hydroxycoumarin-4-yl)ethylglycine

  • Manfred Braun and
  • Torsten Dittrich

Beilstein J. Org. Chem. 2010, 6, No. 69, doi:10.3762/bjoc.6.69

Graphical Abstract
  • ), which not only displays a relatively large Stokes shift but also a fluorescence that is sensitive to both pH and solvent polarity [10][11]. Although a straightforward, short approach to the L-amino acid 1 has been reported [10], its isolation and purification was found to be difficult and tedious
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Published 24 Jun 2010

Molecular recognition of organic ammonium ions in solution using synthetic receptors

  • Andreas Späth and
  • Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

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Published 06 Apr 2010

Recognition properties of receptors consisting of imidazole and indole recognition units towards carbohydrates

  • Monika Mazik and
  • André Hartmann

Beilstein J. Org. Chem. 2010, 6, No. 9, doi:10.3762/bjoc.6.9

Graphical Abstract
  • the limitations of the NMR method, see ref. [55]). After the addition of 5% DMSO-d6 the binding constants for 4•6a were determined to be 35000 (K11) and 1000 M−1 (K12). Thus, the affinity of 4 significantly decreases as solvent polarity increases (the addition of dimethyl sulfoxide also caused the
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Published 02 Feb 2010

Quinoline based receptor in fluorometric discrimination of carboxylic acids

  • Kumaresh Ghosh,
  • Suman Adhikari,
  • Asoke P. Chattopadhyay and
  • Purnendu Roy Chowdhury

Beilstein J. Org. Chem. 2008, 4, No. 52, doi:10.3762/bjoc.4.52

Graphical Abstract
  • behaviors of the receptors 1 and 2 were noticed in solvents of different polarities. In the ground state the absorption peak at 289 nm for quinoline of 1 and at 290 nm for naphthalene of 2 in CHCl3 are considerably affected in intensities as well as positions (red shift; ~18 nm) as the solvent polarity is
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Published 17 Dec 2008
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