Substituenteneinfluß auf die Strukturisomerie bei Metallchelaten unsymmetrischer o,o′‐Dihydroxyazoverbindungen
Abstract: Bei dünnschichtchromatographischen Untersuchungen wird beobachtet, daß die Azoverbindungen 1–3 mit Cu, Ni, Cr und Co jeweils nur ein bestimmtes Chelat bilden. Ursache für das Ausbleiben der erwarteten Nα/Nβ‐Isomerie vom Typ 5 = 6 ist eine starke Asymmetrie des Rotations‐potentials um die Nβ—C‐Einfachbindung. Sie resultiert aus der Besetzung der dritten o‐Position durch eine Methyl‐ oder Methylengruppe. Spektraldaten, die für Azobenzole 7 erhalten werden, bestätigen die Potentialasymmetrie. EHT‐ und [MINDO/3]‐R… Show more
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The article contains sections titled: 1. Introduction and History 2. Structure of Metal‐Complex Dyes 2.1. Chelates 2.2. Stereochemistry and Isomerism 3. Production 4. Ecology and Toxicology 5. Uses of Metal‐Complex Dyes 5.1. Textile Dyeing 5.1.1. Wool and Polyamides 5.1.2. Cotton 5.1.3. Polypropylene 5.1.4. Dust‐Free Preparations 5.2. Nontextile Uses 5.2.1. Leather 5.2.2. Paper 5.2.3. Dyes for Anodized Aluminum 5.2.4. Solvent and Ink‐Jet Dyes 5.2.5. Pigments 5.2.6. Redox Catalysts 5.2.7. Analysis 5.2.8. Photo Dyes 5.2.9. Charge Stabilizers 5.2.10. Optical Applications 6. Formazan Dyes 6.1. Physical Properties and Structure 6.1.1. Metal‐Free Formazans 6.1.2. Metal‐Containing Formazans 6.2. Production 6.2.1. Coupling of Diazonium Compounds with Hydrazones 6.2.2. Metallization 6.2.3. Double Coupling of Diazonium Compounds with Compounds Containing an Acidic CH Group 6.2.4. Oxidative Coupling of Azole Hydrazines with Hydrazones 6.3. Uses
The article contains sections titled: 1. Introduction and History 2. Structure of Metal‐Complex Dyes 2.1. Chelates 2.2. Stereochemistry and Isomerism 3. Production 4. Ecology and Toxicology 5. Uses of Metal‐Complex Dyes 5.1. Textile Dyeing 5.1.1. Wool and Polyamides 5.1.2. Cotton 5.1.3. Polypropylene 5.1.4. Dust‐Free Preparations 5.2. Nontextile Uses 5.2.1. Leather 5.2.2. Paper 5.2.3. Dyes for Anodized Aluminum 5.2.4. Solvent and Ink‐Jet Dyes 5.2.5. Pigments 5.2.6. Redox Catalysts 5.2.7. Analysis 5.2.8. Photo Dyes 5.2.9. Charge Stabilizers 5.2.10. Optical Applications 6. Formazan Dyes 6.1. Physical Properties and Structure 6.1.1. Metal‐Free Formazans 6.1.2. Metal‐Containing Formazans 6.2. Production 6.2.1. Coupling of Diazonium Compounds with Hydrazones 6.2.2. Metallization 6.2.3. Double Coupling of Diazonium Compounds with Compounds Containing an Acidic CH Group 6.2.4. Oxidative Coupling of Azole Hydrazines with Hydrazones 6.3. Uses
Bei diinnschichtchromatographischen Untersuchungen wird beobachtet, daI3 die Azoverbindungen 1 -3 mit Cu, Ni, Cr und Co jeweils nur ein bestimmtes Chelat bilden. Ursache fur das Ausbleiben der erwarteten N,/Ng-Isomerie vom Typ 5 + 6 ist eine starke Asymmetrie des Rotationspotentials um die Np -C-Einfachbindung. Sie resultiert aus der Besetzung der dritten o-Position durch eine Methyl-oder Methylengruppe. Spektraldaten, die fur Azobenzole 7 erhalten werden, bestatigen die Potentialasymmetrie. EHT-und [MIND0/3]-Rechnungen zeigen, da13 die selektive Bildung des Isomeren 5 energetisch begunstigt ist. Influence of Substituents upon the Formation of Isomeric Metal Chelates of Asymmetric o, 0'-Dihydroxyazo Compounds **)It could be shown by thin-layer chromatography that azo compounds 1 -3 form only one definite chelate with Cu, Ni, Cr, and Co. The non-occurrence of the expected N,/Np-isomerism of type 5 + 6 can be rationalized in terms of the strongly asymmetric rotational potential of the NB-C single bond, which is caused by the methyl or methylene groups in the 3rd o-position. The asymmetric shape of the potential can be confirmed by spectral data of 7. EHT and MIND0/3 calculations show that selective formation of isomer 5 is energetically favored.
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