Christian Reichardt, Prof. em., Dr.phil., Dr.h.c.

Philipps University Marburg, Fachbereich Chemie, Emeritus

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Papers by Christian Reichardt, Prof. em., Dr.phil., Dr.h.c.

Synthesen mit aliphatischen Dialdehyden, XXXII [1] Darstellung und Reaktionen N-substituierter 2-Aminomalondialdehyde / Syntheses with Aliphatic Dialdehydes, XXXII [1] Syntheses and Reactions of N-Substituted 2-Aminomalondialdehydes

Zeitschrift für Naturforschung B, Feb 1, 1982

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Chiral Tri- and Pentamethinium Cyanine Dyes with 1,2,3,4-Tetrahydro-6-methylquinolyl End Groups: UV/Vis and CD Spectroscopy and Structure Correlations

Liebigs Annalen, Nov 1, 1996

Cyanine dyes, chiral / Dyes / Chirality / Circular dichroism UV/Vis and CD spectra of the chiral ... more Cyanine dyes, chiral / Dyes / Chirality / Circular dichroism UV/Vis and CD spectra of the chiral trimethinium cyanine dyes T2 to T5 and the pentamethinium cyanine dyes P2 to P5 have been studied for possible correlations between chiroptical properties and molecular structure. With a non-planar conjugated rr-system as a consequence of steric interaction between the two end groups and the polymethine chain and with the methyl substituents in the 2-or 3-ring positions acting as chiral anchors, the inherent chirality of these dyes manifests itself in the CD spectra which follow the same pattern throughout: monosignate CD absorptions in the longwavelength cyanine band region and bisignate in the aromatic-end-group region. A correlation between the sense of twist of the polymethine chain and the observed and calculated sign of the cyanine band is established, which allows the assignment of the absolute configuration for the 2-, but not for the 3-methyl substituted dye derivatives. Neither in the trimethinium nor in the pentamethinium dyes do the calculated energies, geometries or chiroptical properties indicate any interaction between the two end groups.

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UV-visible spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in eight binary solvent mixtures

Journal of Physical Organic Chemistry, Sep 1, 2003

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY J. Phys. Org. Chem. 2003; 16: 626632 Published online in W... more

Comments on “Quantifying solvent effects through QSPR: A new look over different model equations”

Journal of Molecular Liquids, 2019

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UV-Vis spectroscopic study of the hydrophilic and solvatochromic 4-[2,6-diphenyl-4-(pyridin-4-yl)pyridinium-1-yl]-2,6-bis(pyridin-3-yl)phenolate betaine dye in aqueous tetra-n-butylammonium bromide

Journal of Physical Organic Chemistry, Oct 1, 2005

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY J. Phys. Org. Chem. 2005; 18: 10131017 Published online 8 ... more

Chiral dimers of a chiral pentamethine cyanine dye and of an achiral pentamethine cyanine dye in γ-cyclodextrin as chiral host

Journal of the Chemical Society, 1992

Introducing education for sustainable development in the undergraduate laboratory: quantitative analysis of bioethanol fuel and its blends with gasoline by using solvatochromic dyes

Chemistry Education. Research and Practice, 2012

The concept of Education for Sustainable Development, ESD, has been introduced in a period where ... more The concept of Education for Sustainable Development, ESD, has been introduced in a period where chemistry education is undergoing a major change, both in emphasis and methods of teaching. Studying an everyday problem, with an important socioeconomic impact in the laboratory is a part of this approach. Presently, the students in many countries go to school in vehicles that run, at least partially, on biofuels; it is high time to let them test these fuels. The use of renewable fuels is not new: since 1931 the gasoline sold in Brazil contains 20 to 25 vol-% of bioethanol; this composition is being continually monitored. With ESD in mind, we have employed a constructivist approach in an undergraduate course, where UV-vis spectroscopy has been employed for the determination of the composition of two fuel blends, namely, bioethanol/ water, and bioethanol/gasoline. The activities started by giving a three-part quiz. The first and second ones introduced the students to historical and practical aspects of the theme (biofuels). In the third part, we asked them to develop a UV-vis experiment for the determination of the composition of fuel blends. They have tested two approaches: (i) use of a solvatochromic dye, followed by determination of fuel composition from plots of the empirical fuel polarity versus its composition; (ii) use of an ethanol-soluble dye, followed by determination of the blend composition from a Beer's law plot; the former proved to be much more convenient. Their evaluation of the experiment was highly positive, because of the relevance of the problem; the (constructivist) approach employed, and the bright colors that the solvatochromic dye acquire in these fuel blends. Thus ESD can be fruitfully employed in order to motivate the students; make the laboratory ''fun'', and teach them theory (solvation). The experiments reported here can also be given to undergraduate students whose major is not chemistry (engineering, pharmacy, biology, etc.). They are low-cost and safe to be introduced at high-school level.

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Synthesen mit aliphatischen Dialdehyden, XXVII [1] Eine „non-template“-Synthese zur Darstellung metallfreier 1.4.8.11-Tetraaza [14] annulen-Derivate / Syntheses with Aliphatic Dialdehydes, XXVII [1] A Non-Template Synthesis for the Preparation of Metal-Free 1,4,8,11-Tetraaza[14]annulene Derivatives

Zeitschrift für Naturforschung B, 1978

The reaction of 2-substituted malonaldehydes (7) with aromatic 1,2-diamines (5 or 6) in ethanol/a... more The reaction of 2-substituted malonaldehydes (7) with aromatic 1,2-diamines (5 or 6) in ethanol/acetic acid (10:1) leads to 6,13-disubstituted 1,4,8,11 -tetraaza[14]annulene derivatives (8 or 9) even in the absence of coordinating metal cations ("non-template" synthesis), and not to 3-substituted 1,5-benzodiazepines such as 4. Cobalt(II), nickel(II), and copper(II) complexes of the macrocyclic chelate ligands 8 and 9 have been observed by subsequent metallization with the corresponding acetates in N,N-dimethylformamide. The structures of 8-11 have been assigned mainly by their mass spectra.

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Solvent Properties of Water in Aqueous Solutions of Elastin-Like Polypeptide

International Journal of Molecular Sciences, 2015

The phase-transition temperatures of an elastin-like polypeptide (ELP) with the (GVGVP)40 sequenc... more The phase-transition temperatures of an elastin-like polypeptide (ELP) with the (GVGVP)40 sequence and solvent dipolarity/polarizability, hydrogen-bond donor acidity, and hydrogen-bond acceptor basicity in its aqueous solutions were quantified in the absence and presence of different salts (Na2SO4, NaCl, NaClO4, and NaSCN) and various osmolytes (sucrose, sorbitol, trehalose, and trimethylamine N-oxide (TMAO)). All osmolytes decreased

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Solute-Solvent Interactions

Solvents and Solvent Effects in Organic Chemistry

Appendix A. Properties, Purification, and Use of Organic Solvents

Solvents and Solvent Effects in Organic Chemistry

ChemInform Abstract: Chiral Polymethine Dyes: A Remarkable but Forgotten Conjugated π System

ChemInform

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ChemInform Abstract: Solvatochromic Dyes as Solvent Polarity Indicators

ChemInform

ChemInform Abstract: Chiral Polymethine Dyes. Part 5. Syntheses, Absolute Configuration, Spectroscopic, and Chiroptical Properties of Chiral Dinuclear Tri- and Pentamethinium as well as Trinuclear (2.2.2)Heptamethinediium Cyanine Dyes with 3-sec-Butyl-1,3

ChemInform

Starting from the commercially available chiral (I) the ketone (V) is prepared, which leads in a ... more Starting from the commercially available chiral (I) the ketone (V) is prepared, which leads in a zeolite-catalyzed Fischer indole synthesis as a key step to (VII). Alkylation and separation by fractional recrystallization yield the new quaternary iminium salt (VIII), which serves as starting material for the synthesis of new chiral title dyes such as (X) and (XI). The spectroscopic and chiroptical properties of the new cyanine dyes are determined.

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Solvation by Glycerol at Temperatures from 353 to 77 K: Its Solvatochromic Characterization and Use to Block the Molecular Structure of Conformationally Flexible Structures

The Journal of Physical Chemistry A

Glycerol is UV/vis spectroscopically characterized by using suitable solvatochromic polarity prob... more Glycerol is UV/vis spectroscopically characterized by using suitable solvatochromic polarity probes spanning a wide temperature range of 353 to 77 K. For the first time we find experimental evidence that, when the solvent preserves its internal structure in a broad range of temperatures, all solvatochromically derived solvent parameters (i.e., SP, SdP, SA, and SB) also maintain their values unchanged. On the basis of these solvatochromic measurements, it is shown that, below 180 K, glycerol efficiently blocks the molecular structure of conformationally flexible solutes.