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  • (Phenyl)methylium  (1)
  • Phenylmethylium  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Phenylvinylog erweiterte Triphenylmethylium-Systeme (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 2351-2359 
    Details
    ISSN: 0009-2940
    Keywords: Chromophores, combined ; Ethene, diphenyl- ; Ethyne, diphenyl- ; Phenylmethylium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phenylvinylogously Extended Triphenylmethylium SystemsAs isoconjugated models for (phenylazo)tritylium ions of type A the tritylium systems containing one to three styryl or phenylethynyl substituents have been investigated. In accordance with simple theoretical model considerations these ions have VIS absorptions at considerably longer wavelengths than tritylium ion itself. They also show the expected bathochromic band shifts in going from the singly branched (1, 4) to the doubly and triply branched systems 2, 3 and 5, 6 as well as the predicted bathochromic shifts for 4-methoxystyryl (1b-3b) and hypsochromic shifts for 4-(dimethylammoniostyryl)- and 4-(nitrostyryl)tritylium ions 1c-3c and 1d, respectively. For most of the newly prepared tritylium systems fully resolved NMR spectra were obtained, whose signal positions correlate very well with the charge distributions derived from the elementary conjugation model. For the 4,4′-(1,2-ethenediyl)bistritylium system 12, whose color resembles that of 4-styryltritylium ion 1a, only the resonance lines of the inner protons 3,β-H and carbons C-4,β show significant deviations from the corresponding signal positions of the reference systems 1a and tritylium (13).
    Notes: Als isokonjugierte Modelle für (Phenylazo)tritylium-Ionen des Typs A wurden die einfach bis dreifach Styryl- und Phenylethinyl-substituierten Trityliumsysteme 1-6 untersucht. Im Einklang mit einfachen theoretischen Modellbetrachtungen weisen diese Ionen wesentlich längerwellige VIS-Absorptionen als das Tritylium-Ion selbst auf und zeigen auch die erwarteten bathochromen Bandenverschiebungen von den einzweigigen (1, 4) zu den zwei- und dreizweigigen Systemen (2, 3 bzw. 5, 6) hin. Ebenso klar kommen auch die für die 4-Methoxystyryl- (1b-3b) und 4-(Dimethylammoniostyryl)tritylium-Ionen 1c-3c sowie das 4-(Nitrostyryl)tritylium-Ion 1d vorhergesagten bathochromen und hypsochromen VIS-Bandenverschiebungen zum Ausdruck. Von den meisten der neu hergestellten Trityliumsysteme konnten voll aufgelöste NMR-Spektren erhalten werden, deren Signallagen sehr gut mit den aus dem elementaren Konjugationsmodell folgenden Ladungsdichteverteilungen vereinbar sind. Beim farblich dem 4-Styryltritylium-Ion 1a entsprechenden 4,4′-(1,2-Ethendiyl)bistritylium-System 12 zeigen nur die Resonanzlinien der inneren Protonen 3,β-H und Kohlenstoffe C-4,β signifikante Abweichungen von den entsprechenden Signallagen der Referenzsysteme 1a und Tritylium (13).
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891221223
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  • 2
    Electronic Resource
    Electronic Resource
    Phenylazo-substituierte Triphenylmethylium-Systeme (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2207-2226 
    Details
    ISSN: 0009-2940
    Keywords: Chromophores, combined ; Azobenzene ; (Phenyl)methylium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenylazo-Substituted Triphenylmethylium SystemsTriphenylmethanols (or their ethers) bearing phenylazo groups react with trifluoroacetic acid to give deeply colored solutions of the tritylium ions 7+ - 9+, (RC6H4N = N-C6H4)n+ C(C6H5)3-n (R = H, Me, C1, NOz, MeO, H2N, Me2N), whose long wavelengths VIS absorptions and lowfield 1H- NMR signals are consistent with the existence of through- conjugated n-electron systems. After addition of trifluorometh- anesulfonic acid significant hypsochromic shifts of the VIS bands as well as additional proton deshieldings in the 1HNMR spectrum are observed, which are in accordance with the formation of proximally azo-protonated phenylazotrity- lium ions 7+·H+, 8+·2H+, and 9+·3H+, (RC6H4N=NH- C6H4)nC(C6H53 - n. Fully analogous acid-strength-dependent ionisation/protonation reactions result for the overall p-sub- stituted ions 17+, 18+, (RC6H4N= NC6H4)C(C6H4R)2 (R, R' = Me, MeO, Me2N), as well as for the azobistritylium system,102+ (C6H5)2CC6H4N=NC6H4(C6H52, and its azoxy deriv- ative 112+. The linearly extended bis- and trisazo systems 19+, 22+, MeC6H4N = N(C6H4N = N)1,2C6H4C(C6H5)2 and the (ph+e-ny1azo)styryl system 20+, MeC6 H4N = NC6H4CH = CHC6H4C- (C6H5), in trifluoroacetic acid do not show any significant color changes relativ to the corresponding monofunctional parent types. In trifluoromethanesulfonic acid, however, compounds 19+, 22+ exhibit the usual bathochromic shifts of the longest wavelength VIS absorptions accompanying the increasing protonation of the polyazo systems. In the case of the tritylium ions containing azomethine bridges, 24+, only for the methoxy derivative 24b+ indications for the existence of the conjuga- tively extended tritylium system (MeOC6H4N = CHC6H,)C- (C6H5)2 are found. The amide derivatives 26+ - 29+, on the other hand, present no clues for the existence of through-con- jugated systems of the kind ArC(OH)=NC6H4Ckz and ArN = C(OH)C6H4CAr2, respectively.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231120
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