Structure and linear spectroscopic properties of near IR polymethine dyes

Webster, Scott; Padilha, Lázaro A.; Hu, Honghua; Przhonska, Olga V.; Hagan, David J.; Stryland, Eric W. Van; Bondar, Mykhailo V.; Davydenko, Iryna; Slominsky, Yuriy L.; Kachkovski, A.D.

doi:10.1016/j.jlumin.2008.06.002

Cited by 43 publications

(59 citation statements)

References 23 publications

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“…Hence, in the symmetrical dye 9, HOMOs (as donor orbitals) of both pyridinium residues are conjugated with the PC as well as with each other, as presented in Figure 3 b. As shown earlier, [21] their interaction leads to the splitting of donor orbitals, resulting in two new MOs which, in the first approximation, could be presented by the symmetrical and unsymmetrical linear combination of the HOMOs of each of the two terminal groups f(D 1 ) and f(D 2 ), as given in Equations (4) and (5), that is, the corresponding two levels could be interpreted as two split donor ones, as the chain is considered to be a common external conjugated substituent for each donor D.…”

Section: Dye Hetmentioning

confidence: 55%

“…[21] In contrast to the HOMO of the terminal pyridinium residue, the previous occupied orbital, HOMOÀ1 (see Figure 3 a) has its node at a carbon atom connected with the chain, hence it cannot conjugate with the rest of the molecule and remains as a "pure" local MO. As a result, two local orbitals of both terminal groups produce two degenerate occupied MOs in the symmetrical pyrido trimethine cyanine 9 (Figure 3 b).…”

Section: Dye Hetmentioning

confidence: 98%

“…Two approaches for the generation of HOMOs in symmetrical trimethine cyanines: As established earlier, [21] terminal groups with their own highly localized orbitals can make the main contributions to the highly occupied MOs of cyanine dyes with comparatively short PCs. Taking into account that the positive charge in the cationic polymethine dye is localized practically in the external PC, symmetrical dyes 1 or 3 can be presented as the following system: D-p(+)-D or D-A-D, in which the acceptor A is a PC, and D is a donor residue.…”

Section: Dye Hetmentioning

confidence: 99%

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Studies of 2‐Azaazulenium Derivatives: Unsymmetrical Trimethine Cyanine Dyes Bearing a 2‐Azaazulenium Moiety as One of the Terminal Groups

Bricks

Ryabitskii

Kachkovskii

2010

Chemistry A European J

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We report here the synthesis of a series of symmetrical and unsymmetrical trimethine cyanine dyes derived from 2-azaazulene, combined spectral and quantum-chemical investigations of their molecular geometry and electron structure, as well as the nature of the lowest electron transitions. Based on the analysis of both calculations and experimental data obtained from absorption and (13)C NMR spectra, it was concluded that the 2-azaazulene residue can be treated as a weakly basic terminal group; its donor properties are provided with the participation of the HOMO-1, in contrast to the typical Brooker's terminal residues with their donor HOMOs. The new classification of the terminal groups of cyanine dyes, and hence the classification of types of unsymmetrical cyanines, is proposed. It is shown that the nature of the higher electron transitions (delocalized or local) in the cyanine dyes depends on their type. In the unsymmetrical trimethine cyanine of the mixed type, negative deviations are observed in their absorption spectra.

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Section: Dye Hetmentioning

confidence: 55%

Section: Dye Hetmentioning

confidence: 98%

Section: Dye Hetmentioning

confidence: 99%

See 1 more Smart Citation

Studies of 2‐Azaazulenium Derivatives: Unsymmetrical Trimethine Cyanine Dyes Bearing a 2‐Azaazulenium Moiety as One of the Terminal Groups

Bricks

Ryabitskii

Kachkovskii

2010

Chemistry A European J

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“…It was shown previously [20] that terminal groups with their own highly localised orbitals can make determining contributions to the highly occupied MOs of cyanine dyes with comparatively short PCs. On the other hand, going from neutral molecules to ions of conjugated systems leads to fundamental shifts of the bands of both vacant and occupied levels.…”

Section: Generation Of the Frontier And Nearest Molecular Orbitalsmentioning

confidence: 97%

Studies of 2‐Azaazulenium Derivatives: The Natures of Electron Transitions in the 2‐Azaazulenium Cation and in Monomethine Cyanine Dyes Bearing 2‐Azaazulenium Moieties as Terminal Groups

2009

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A series of novel monomethine cyanine dyes derived from 2‐azaazulene have been synthesized. Combined spectral and quantum‐chemical investigations of their molecular geometries and of their electronic structures and the natures of their lowest electron transitions have been performed. The analysis results obtained by ab initio and semiempirical methods, together with experimental data obtained from absorption and 13C NMR spectra, have shown that there is practically no difference between the charge distributions over the π‐electron systems in the ground state in a reference 2‐azaazulenium salt and in monomethine cyanines bearing 2‐azaazulene as a terminal group, because these are not dependent on the relative locations of molecular orbitals. However, the spectral properties of – and correspondingly the natures of electron transitions in – the chromophores of the salt and of the monomethine cyanine are drastically different, due to the different mechanisms of frontier molecular orbital generation. Similar differences in properties in ground and excited states are observed for unsymmetrical monomethine cyanines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…In this work we analyze the excited state absorption spectra (ESA) and lifetime dynamics of cyanine structures, introduced in our previous manuscript Ref. [16], with specific terminal groups of dihydrobenzo[cd]furo [2,3-f]indolium, which have their own extended p conjugation system, which in turn can interact strongly with the main chromophore. This leads to an increase of the total conjugation without increasing the length of the chromophore and without decreasing its photochemical stability.…”

Section: Introductionmentioning

confidence: 99%