Structural Principles of Unsaturated Organic Compounds: Evidence by Quantum Chemical Calculations

Dähne, S.; Moldenhauer, F.

doi:10.1002/9780470171943.ch1

Cited by 65 publications

(9 citation statements)

References 107 publications

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“…This finding could be confirmed about 60 years later by other authors using modern structural‐analytical methods [24] . More recently, extensive quantum‐chemical studies have been carried out on the structure‐property relationships of Polymethines which confirm the more intuitive concepts of König approximately one‐hundred years before [25] …”

Section: Figuresupporting

confidence: 58%

“…[24] More recently, extensive quantum-chemical studies have been carried out on the structureproperty relationships of Polymethines which confirm the more intuitive concepts of König approximately one-hundred years before. [25] In respect to the practical use, Polymethines dyes were found as not well-suited for dyeing of native fibers due to their poor colour fastness. However, they were well-suited for sensitization of photographic halogen silver halide materials, especially in the long-wavelength region.…”

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confidence: 99%

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The Historical Dyestuff Collection at the Technical University Dresden: A Cultural–Historical Treasure and a Rich Source of Light‐Absorbing Materials with Great Prospects for Current and Future Research

Hartmann

2021

ChemPhotoChem

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The Historical Dyestuff Collection at the Technical University Dresden houses a large collection of colorants, such as more than 20 000 synthetic organic dyes, more than 500 natural organic dyes and a comprehensive collection of inorganic natural and synthetic pigments, as well as more than 3 000 shade cards and a variety of other objects related to dyestuff chemistry. Moreover, all theses performed at the Institute of Color and Textile Chemistry, the home of the Dyestuff Collection, together with all substance probes prepared during [a]

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Section: Figuresupporting

confidence: 58%

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confidence: 99%

The Historical Dyestuff Collection at the Technical University Dresden: A Cultural–Historical Treasure and a Rich Source of Light‐Absorbing Materials with Great Prospects for Current and Future Research

Hartmann

2021

ChemPhotoChem

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“…This has been attributed to the noninvolvement of the donor group in the S 0 −S 1 excitation. , Law also points out that in accordance with the calculations of Bigelow and Freund, though these are primarily charge-transfer states, the bathochromic shift, induced by changing the substitutions, is very small when compared to other polar molecules it was suggested that the carbenium ion is the acceptor and, on the basis of the Konig and Ismailsky empirical model of D−π−A−π−D, − absorbs in the longer wavelength region because of the increased π conjugation. When this acceptor is replaced by squaric acid, which contains two formal positive charges, the absorption shifts to the red, and when the the squaric acid is replaced by the croconic acid, which is supposed to contain three positive charges, a larger red shift is seen.…”

Section: Introductionmentioning

confidence: 57%

Near-Infrared Absorption in Symmetric Squarylium and Croconate Dyes: A Comparative Study Using Symmetry-Adapted Cluster-Configuration Interaction Methods

et al. 2005

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Symmetric croconate (CR) and squarylium dyes (SQ) are well-known near-infrared (NIR) dyes and, in general, are considered to be donor-acceptor-donor type molecules. It is established in the literature that CR dyes absorb in a longer wavelength region than the corresponding SQ dyes. This has been attributed to the CR ring being a better acceptor than the SQ ring. Thus increasing the donor capacity should lead to a bathochromic shift in both SQ and CR. On the other hand, some experiments reported in the literature have revealed that increasing the conjugation in the donor part of the SQ molecule leads first to red shift, which upon a further increase of the conjugation changes to a blue shift. Hence, to understand the role of the central ring and the substitutions in the absorption of these dyes, we carried out high-level symmetry-adapted cluster-configuration interaction (SAC-CI) calculations of some substituted SQ and CR dyes and compare the absorption energy with the existing experimental data. We found that there is very good agreement. We also carried out SAC-CI calculations of some smaller model molecules, which contain the main oxyallyl substructure. We varied the geometry (angle) of the oxyallyl subgroup and the substitution in these model molecules to establish a correlation with the bathochromic shift. We found that the charge transfer is very small and does not play the key role in the red shift, but on the other hand, the perturbation of the HOMO-LUMO gap (HLG) from both the geometry and substitution seems to be responsible for this shift. We suggest as a design principle that increasing the donor capacity of the groups may not help in the red shift, but introducing groups which perturb the HLG and decrease it without changing the MO character should lead to a larger bathochromic shift.

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“…Langhals analyzed the reason for this drastic red shift . It was suggested that the carbenium ion is the acceptor, and on the basis of the empirical model of Konig and Ismailsky of D−π−A−π−D (D = donor and A = acceptor), − absorbance in the longer-wavelength region is due to the increased π-conjugation. When this acceptor is replaced by squaric acid, which contains two formal positive charges, the absorption shifts to the red.…”

Section: Introductionmentioning

confidence: 99%

Role of the Oxyallyl Substructure in the Near Infrared (NIR) Absorption in Symmetrical Dye Derivatives: A Computational Study

et al. 2005

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It is well-known from experimental studies that the oxyallyl-substructure-based squarylium and croconium dyes absorb in the NIR region of the spectrum. Recently, another dye has been reported (J. Am. Chem. Soc. 2003, 125, 348) which contains the same basic chromophore, but the absorption is red-shifted by at least 300 nm compared to the former dyes and is observed near 1100 nm. To analyze the reasons behind the large red shift, in this work we have carried out symmetry-adapted cluster-configuration interaction (SAC-CI) studies on some of these NIR dyes which contain the oxyallyl substructure. From this study, contrary to the earlier reports, it is seen that the donor groups do not seem to play a major role in the red-shift of the absorption. On the other hand, on the basis of the results of the high-level calculations carried out here and using qualitative molecular orbital theory, it is observed that the orbital interactions play a key role in the red shift. Finally, design principles for the oxyallyl-substructure-based NIR dyes are suggested.

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Structural Principles of Unsaturated Organic Compounds: Evidence by Quantum Chemical Calculations

Cited by 65 publications

References 107 publications

The Historical Dyestuff Collection at the Technical University Dresden: A Cultural–Historical Treasure and a Rich Source of Light‐Absorbing Materials with Great Prospects for Current and Future Research

The Historical Dyestuff Collection at the Technical University Dresden: A Cultural–Historical Treasure and a Rich Source of Light‐Absorbing Materials with Great Prospects for Current and Future Research

Near-Infrared Absorption in Symmetric Squarylium and Croconate Dyes: A Comparative Study Using Symmetry-Adapted Cluster-Configuration Interaction Methods

Role of the Oxyallyl Substructure in the Near Infrared (NIR) Absorption in Symmetrical Dye Derivatives: A Computational Study

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