Helically twisted chiral cyanine dyes: Influence of chromophore length on observed and calculated rotatory strengths

Eggers, Lutz; Kolster, Klaus; Buß, Volker

doi:10.1002/(sici)1520-636x(1997)9:3<243::aid-chir7>3.3.co;2-e

Cited by 2 publications

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“…Cyanines are a class of organic dyes discovered in 1856 by Williams that are used today in numerous applications over wide areas of chemistry and technology. One of the earliest and most important uses of the cyanines was as photosensitizers for silver halide photography. − Cyanines are also used as saturable absorbers for lasers. ,− Chiral examples of these dyes have been used to test helicity rules for optical rotation. , Paired with borates, reactive electron donors, cyanines are used to photoinitiate acrylate polymerization . Cyanine borates have also been used as probes of lipid bilayer membranes − where their spectroscopic perturbation reports on the microenvironment.…”

Section: Introductionmentioning

confidence: 99%

Cyanine Borate Penetrated Ion Pair Structures in Solution and the Solid State: Induced Circular Dichroism

1998

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An induced circular dichroism (CD) spectrum is observed for 1,1‘,3,3,3‘,3‘-hexamethyl-9-phenyl-indocarbocyanine, 1,1‘-diethyl-2,2‘-cyanine, 1,1‘-di-(3,5-di-tert-butyl)benzyl-2,2‘-cyanine, or 1,1‘-di-(4-tert-butyl)benzyl-2,2‘-cyanine when penetrated into a chiral cavity of either spirobi[(2-methyl)borataxanthene] or spirobi[(3-methyl)borataxanthene]. Within the ion pair, the cyanine dye exists in two (or more) interconverting conformations of unequal energy. Solid-state structural evidence suggests that a nitrogen-forward mode for penetration by the cyanine dominates the solution behavior. A critical feature for the observation of induced circular dichroism is that the dye is twisted in the ground state. The free energy difference between the diastereomers with right- and left-handed twist in the chiral cavity of the borate is less than 1 kcal/mol, but this is sufficient to induce the CD spectrum. The magnitude of the observed CD spectrum is dependent on the structure of both the cyanine and borate.

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Section: Introductionmentioning

confidence: 99%

Cyanine Borate Penetrated Ion Pair Structures in Solution and the Solid State: Induced Circular Dichroism

1998

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“…Therefore, we were interested to see whether the use of chiral head groups affected the supramolecular assembly in a similar way. The absence of CD signals from methanolic solutions of the dyes indicates that the chirality of head groups has, at best, a negligible effect on the conformation of the monomeric (non‐aggregated) chromophores . In contrast, the aggregated mesomer ( 1 c ) shows negative and positive Cotton effects at λ =577 and 605 nm, respectively (Figure , red line).…”

Section: Resultsmentioning

confidence: 99%

Stereochemistry‐Controlled Supramolecular Architectures of New Tetrahydroxy‐Functionalised Amphiphilic Carbocyanine Dyes

Schade

Singh

Wycisk

et al. 2020

Chemistry A European J

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The syntheses of novel amphiphilic5 ,5',6,6'-tetrachlorobenzimidacarbocyanine( TBC) dye derivatives with aminopropanediol head groups, whicho nly differ in stereochemistry (chiral enantiomers, meso form and conformer), are reported. For the achiral meso form, an ew synthetic route towards asymmetric cyanine dyes was established. All compounds form Ja ggregates in water,t he opticalp roperties of which were characterised by means of spectroscopic methods. The supramolecular structure of the aggregates is investigated by means of cryo-transmissione lectron micros-copy,c ryo-electron tomographya nd AFM, revealing extended sheet-like aggregates for chiral enantiomers andn anotubesf or the mesomer,r espectively,w hereast he conformer formsp redominately needle-like crystals. The experiments demonstrate that the aggregation behaviour of compounds can be controlled solelyb yh ead group stereochemistry, whichi nt he case of enantiomerse nables the formation of extended hydrogen-bond chains by the hydroxyl functionalities. In case of the achiral meso form, however,s uch chains turnedo ut to be sterically excluded.

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Helically twisted chiral cyanine dyes: Influence of chromophore length on observed and calculated rotatory strengths

Cited by 2 publications

References 0 publications

Cyanine Borate Penetrated Ion Pair Structures in Solution and the Solid State: Induced Circular Dichroism

Cyanine Borate Penetrated Ion Pair Structures in Solution and the Solid State: Induced Circular Dichroism

Stereochemistry‐Controlled Supramolecular Architectures of New Tetrahydroxy‐Functionalised Amphiphilic Carbocyanine Dyes

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