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Synthesis and Electronic Properties of Alkynylated Phenothiazines
Author(s) -
Krämer Christa S.,
Müller Thomas J. J.
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300250
Subject(s) - chemistry , sonogashira coupling , intramolecular force , alkyne , cyclic voltammetry , delocalized electron , redox , photochemistry , aldehyde , electron delocalization , aryl , combinatorial chemistry , electronic effect , phenothiazine , coupling reaction , stereochemistry , organic chemistry , steric effects , electrochemistry , palladium , catalysis , medicine , alkyl , electrode , pharmacology
Alkynylated phenothiazines 1 , 2 , 5 , 7 , and 12 − 15 can be synthesized in moderate to excellent yields by sequences of aldehyde−alkyne transformations and/or Sonogashira cross‐coupling reactions from suitable phenothiazine aldehydes or bromides. The electronic properties of (hetero)aryl ethynyl‐substituted N ‐methyl‐phenothiazines (UV/Vis absorption, fluorescence, redox potentials) strongly correlate with Hammett σ P parameters and indicate that remote substituents transmit their electronic information through π‐electron delocalization and the σ‐framework. Phenothiazinyl dyads ( 7g , 12 , 13 ) and triads ( 14 ) reveal different degrees of intramolecular electronic coupling as demonstrated by cyclic voltammetry, qualifying them as good model candidates for redox‐active molecular wires. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)