| | 1 | Author
| Boron Chelates, BoronMetal Chelates, Eberhard Hohaus, Klaus Wessendorf | Requires cookie* | | | Title
| Borchelate und Bormetallchelate, VI [1] Zur Bildung von Borchelaten aromatischer Azoverbindungen  | | | | Abstract
| Bidentate chelate reagents incorporating a suitable group (e.g. OH, NH2) in ortho position to the azo-group react with diphenylboronic acid anhydride or boron trihalides (BF3, BCI3) resulting in the BR2-six membered ring-chelates of types 1 and 2. The products of the reaction of tridentate chelate reagents with phenylboronic acid or boron trifluoride at elevated temperature are BR-chelates with two six membered rings (types 3 and 4). The conditions of the formation of the bicyclic chelates 5 and 6 depend on the position of the substituents of the chelate reagents. The incorporation of only one BR2 group is possible if the order of the substituents in 2,2'-dihydroxyazobenzenes is not symmetrical (chelates of the type 7). Structural isomers of boron chelates of the types 5, 6 or 7 with Na/N/S isomerism have not yet been observed. The identification of the structures of the above-mentioned complexes was achieved by means of iH, n B and 19 F NMR and IR spectroscopy. For mass spectrometric analysis see ref. [2]. Einführung Azomethine des Salicylaldehyds sind mit Bor-verbindungen leicht zu Chelaten umzusetzen [3-5]. Die ähnlich strukturierten Azo-Chelate sind da-gegen kaum [6] beschrieben worden. Folgende Aspekte führten zu den Synthesen der Borchelate: In den Chelaten 1^1 ist das Bor an dasjenige N-Atom der Azogruppe gebunden, dessen Koordination zu einem (Typ I und 2) oder zwei Chelat-6-Ringen (3 und 4) führt. Im Gegensatz zu 1-4 sind bei 5-7 die Bindungsverhältnisse der ko-ordinativen B-N-Bindung unklar. Von besonderem Interesse waren die Umsetzungen mit unsym-metrisch substituierten 2.2'-Dihydroxyazobenzolen, da die Bildung strukturisomerer Chelate (Na/N^-Isomerie) erwartet werden konnte. Ein weiterer Aspekt war die Farbvertiefung bei der Chelatbildung, die quantitative Bestimmungen | | | |
Reference
| Z. Naturforsch. 35b, 319—325 (1980); eingegangen am 21. Dezember 1979 | | | |
Published
| 1980 | | | |
Keywords
| Boron Chelates, Azo Compounds, NMR, IR | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0319.pdf | | | | Identifier
| ZNB-1980-35b-0319 | | | | Volume
| 35 | |
| 2 | Author
| Rudolf Allmann, Eberhard Hohaus, Stanislaw 01ejnik | Requires cookie* | | | Title
| Boron Chelates and Boron-Metal Chelates, X [1] 3-(2-Hydroxyphenyl)-2,2-diphenyl-l-oxa-3-azonia-2-borata-naphthalene- methanol (1/1): Synthesis, Spectroscopic Investigations and Crystal Structure | | | | Abstract
| 2-Aminophenol, salicylaldehyde and diphenylboric anhydride react in methanol to form a fluorescent, chelate-like azomethineboron compound containing methanol. The title compound, C25H20BNO2 • CH3OH, was examined by UV, IR, HI, and NMR spectroscopy as well as by thermogravimetry and X-ray structure analysis (Pbnb, a= 8.815, b= 17.309, c = 28.992 Ä, R = 5.5%). These investigations show the six-membered chelate ring (chelate A) to exist as formulated in [2] and not as a five-membered chelate ring B. One methanol molecule connects two chelate molecules by hydrogen bonds, resulting in an overall ratio of chelate to methanol of 1 : 1. | | | |
Reference
| Z. Naturforsch. 37b, 1450—1455 (1982); received May 1 O/June 11 1982 | | | |
Published
| 1982 | | | |
Keywords
| Boron Chelate, Azomethine, Crystal Structure, UV Spectra, NMR Spectra | | | |
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| default:Reihe_B/37/ZNB-1982-37b-1450.pdf | | | | Identifier
| ZNB-1982-37b-1450 | | | | Volume
| 37 | |
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